ISL3331IRZ - Intersil Corporation

FN6361.0

ISL3330, ISL3331

3.3V, ±15kV ESD Protected, Dual Protocol

(RS-232/RS-485) Transceivers

These devices are BiCMOS interface ICs that are user

configured as either a single RS-422/RS-485 differential

transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver.

In RS-232 mode, the on-board charge pump generates

RS-232 compliant ±5V Tx output levels, from a supply as low

as 3.15V. Four small 0.1µF capacitors are required for the

charge pump. The transceivers are RS-232 compliant, with

the Rx inputs handling up to ±25V.

In RS-485 mode, the transceivers support both the RS-485

and RS-422 differential communication standards. The

RS-485 receiver features "full failsafe" operation, so the Rx

output remains in a high state if the inputs are open or

shorted together. The RS-485 transmitter supports up to

three data rates, two of which are slew rate limited for

problem free communications. The charge pump disables in

RS-485 mode, thereby saving power, minimizing noise, and

eliminating the charge pump capacitors.

Both RS-232/RS-485 modes feature loopback and shutdown

functions. The loopback mode internally connects the Tx

outputs to the corresponding Rx input, which facilitates the

implementation of board level self test functions. The outputs

remain connected to the loads during lo opback, where

connection problems (e.g., shorted connectors or cables)

can be detected. The shutdown mode disables the Tx and

Rx outputs, disables the charge pump if in RS-232 mode,

and places the IC in a low current (30µA) mo de.

The ISL3331 is a QFN packaged device that offers

additional functionality, including a lower speed and edge

rate option (115kbps) for EMI sensitive design s, or to allow

longer bus lengths. It also features a logic supply voltage pin

(VL) that sets the VOH level of logic outputs, and the

switching points of logic inputs, to be compatible with

another supply voltage in mixed volt age systems. The QFN's

choice of active high or low Rx enable pins increases design

flexibility, allowing Tx/Rx direction control vi a a si ng l e si gn a l

by connecting DEN and RXEN together.

For a dual port version of these devices, please see the

ISL3332/ISL3333 data sheet.

Features

• User Selectable RS-232 or RS-485/RS-422 Interface Port

(Two RS-232 Transceivers or One RS-485/RS-42 2

Transceiver)

• Operates From a Single 3.3V Supply

• ±15kV (HBM) ESD Protected Bus Pins (RS-232 or

RS-485)

• 5V Tolerant Logic Inputs

• True Flow-Through Pinouts Simplify Board Layouts

• Pb-Free (RoHS Compliant)

• Full Failsafe (Open/Short) Rx in RS-485/RS-422 Mode

• Loopback Mode Facilitates Board Self Test Functions

• User Selectable RS-485 Data Rates . . . . . . . . . . 20Mbps

- Slew Rate Limited . . . . . . . . . . . . . . . . . . . . . . . 460kbps

- Slew Rate Limited (ISL3331 Only) . . . . . . . . . . 115kbps

• Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 400kbps

• Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . 30µA

• QFN Package Saves Board Space (ISL3331 Only)

• Logic Supply Pin (VL) Eases Operation in Mixed Supply

Systems (ISL3331 Only)

Applications

• Gaming Applications (e.g., Slot machines)

• Single Board Computers

• Factory Automation

• Security Networks

• Industrial/Process Control Networks

• Level Translators (e.g., RS-232 to RS-422)

• Point of Sale Equipment

Related Literature

• Application Note AN1401 “Implementing a Three Pin,

Half-Duplex, Dual Protocol Interface”

TABLE 1. SUMMARY OF FEATURES

PART

NUMBER NO. OF

PORTS PACKAGE OPTIONS RS-485 DATA

RATE (bps) RS-232 DATA

RATE (kbps) VL PIN? ACTIVE H or L

Rx ENABLE? LOW POWER

SHUTDOWN?

ISL3330 1 20 Ld SSOP 20M, 460k 400 No H Yes

ISL3331 1 40 Ld QFN (6mmx6mm) 20M, 460k, 115k 400 Yes Both Yes

Data Sheet May 20, 2008

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774 |Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

2FN6361.0

May 20, 2008

Pinouts ISL3330

(20 LD SSOP)

TOP VIEW

ISL3331

(40 LD QFN)

TOP VIEW

Ordering Information

PART NUMBER (NOTE) PART MARKING TEMP. RANGE (°C) PACKAGE (Pb-Free) PKG. DWG. #

ISL3330IAZ 3330 IAZ -40 to +85 20 Ld SSOP M20.209

ISL3330IAZ-T* 3330 IAZ -40 to +85 20 Ld SSOP (Tape and Reel) M20.209

ISL3331IRZ ISL3331IRZ -40 to +85 40 Ld 6x6 QFN L40.6x6

ISL3331IRZ-T* ISL3331IRZ -40 to +85 40 Ld 6x6 QFN (Tape and Reel) L40.6x6

*Please refer to TB347 for details on reel specifications.

NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die att ach materials, and 100%

matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations).

Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J

STD-020.

C1+

C1-

V+

485/232

DEN

C2+

VCC

V-

C2-

DZ/SLEW

RXEN

GND

39 38 37 36 35 34 33 32 31

11 12 13 14 15 16 17 18 19 20

C1-

C1+

C2+

C2-

VCC

DZ/SLEW

V+

DEN

485/232

GND

RXEN

V-

RXEN

SPB

ISL3330, ISL3331

3FN6361.0

May 20, 2008

TABLE 2. ISL3330 FUNCTION TABLE

INPUTS RECEIVER

OUTPUTS DRIVER OUTPUTS DRIVER

SPEED

(Mbps)

CHARGE

PUMPS

(Note 1) LOOPBACK

(Note 2) MODE485/232 ON RXEN DEN SLEW RARBYZ

0 1 0 0 N/A High-Z High-Z High-Z High-Z - ON OFF RS-232

0 1 0 1 N/A High-Z High-Z ON ON 0.46 ON OFF RS-232

0 1 1 0 N/A ON ON High-Z High-Z - ON OFF RS-232

0111N/AONONONON0.46 ON OFFRS-232

0 0 0 1 N/A High-Z High-Z ON High-Z 0.46 ON OFF RS-232

0 0 1 0 N/A High-Z ON ON High-Z 0.46 ON OFF RS-232

0011N/AONONONON0.46 ON ONRS-232

X 0 0 0 X High-Z High-Z High-Z High-Z - OFF OFF Shutdown

1 1 0 0 X High-Z High-Z High-Z High-Z - OFF OFF RS-485

1 X 0 1 1/0 High-Z High-Z ON ON 20/0.46 OFF OFF RS-485

1 X 1 0 X ON High-Z High-Z High-Z - OFF OFF RS-485

1 1 1 1 1/0 ON High-Z ON ON 20/0.46 OFF OFF RS-485

1 0 1 1 1/0 ON High-Z ON ON 20/0.46 OFF ON RS-485

NOTES:

1. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN are high.

2. Loopback is enabled when ON = 0, and DEN = RXEN = 1.

ISL3330 Truth Tables

RS-232 TRANSMITTING MODE

INPUTS (ON = 1) OUTPUTS

485/232 DEN DYDZYZ

010011

010110

011001

011100

0 0 X X High-Z High-Z

RS-232 RECEIVING MODE

INPUTS (ON = 1) OUTPUT

485/232 RXEN A B RARB

010011

010110

011001

011100

0 1 Open Open 1 1

0 0 X X High-Z High-Z

RS-485 TRANSMITTING MODE

INPUTS (ON = 1) OUTPUTS

485/232 DEN DYSLEW Y Z DATA RATE

(Mbps)

110110 20

111101 20

110010 0.46

111001 0.46

1 0 X X High-Z High-Z -

RS-485 RECEIVING MODE

INPUTS (ON = 1) OUTPUT

485/232 RXEN B-A RARB

11 ≥ -40mV 1 High-Z

11 ≤ -200mV 0 High-Z

1 1 Open or Shorted together 1 High-Z

1 0 X High-Z High-Z

ISL3330, ISL3331

4FN6361.0

May 20, 2008

TABLE 3. ISL3331 FUNCTION TABLE

INPUTS RECEIVER

OUTPUTS DRIVER

DATA

RATE

(Mbps)

CHARGE

PUMPS

(Note 3) MODE 485/232 ON

RXEN

AND/OR

RXEN DEN SLEW SPB RARBYZ

0 1 1 and 0 0 N/A N/A High-Z High-Z High-Z High-Z - ON RS-232

0 1 1 and 0 1 N/A N/A High-Z High-Z ON ON 0.46 ON RS-232

0 1 0 or 1 0 N/A N/A ON ON High-Z High-Z - ON RS-232

0 1 0 or 1 1 N/A N/A ON ON ON ON 0.46 ON RS-232

0 0 1 and 0 1 N/A N/A High-Z High-Z ON High-Z 0.46 ON RS-232

0 0 0 or 1 0 N/A N/A High-Z ON ON High -Z 0.46 ON RS-232

0 0 0 or 1 1 N/A N/A ON ON ON ON 0.46 ON RS-232 (Note 4)

X 0 1 and 0 0 X X High-Z High-Z High-Z High-Z - OFF Shutdown

1 1 1 and 0 0 X X High-Z High-Z High-Z High-Z - OFF RS-485

1 X 1 and 0 1 0 1/0 High-Z High-Z ON ON 0.46/0.115 OFF RS-485

1 X 1 and 0 1 1 X High-Z High-Z ON ON 20 OFF RS-485

1 X 0 or 1 0 X X ON High-Z High-Z High-Z - OFF RS-485

1 1 0 or 1 1 0 1/0 ON High-Z ON ON 0.46/0.115 OFF RS-485

1 1 0 or 1 1 1 X ON High-Z ON ON 20 OFF RS-485

1 0 0 or 1 1 0 1/0 ON High-Z ON ON 0.46/0.115 OFF RS-485 (Note 4)

1 0 0 or 1 1 1 X ON High-Z ON ON 20 OFF RS-485 (Note 4)

NOTES:

3. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN is high, or RXEN is low.

4. Loopback is enabled when ON = 0, and DEN = 1, and (RXEN = 1 or RXEN = 0).

ISL3331 Truth Tables

RS-232 TRANSMITTING MODE

INPUTS (ON = 1) OUTPUTS

485/232 DEN DYDZYZ

010011

010110

011001

011100

0 0 X X High-Z High-Z

RS-232 RECEIVING MODE

INPUTS (ON = 1) OUTPUT

485/232 RXEN and/or RXEN A B RARB

00 or 10011

00 or 10110

00 or 11001

00 or 11100

0 0 or 1 Open Open 1 1

0 1 and 0 X X High-Z High-Z

RS-485 TRANSMITTING MODE

INPUTS (ON = 1) OUTPUTS DATA

485/232 DEN SLEW SPB DYYZMbps

1 1 0 0 0/1 1/0 0/1 0.115

1 1 0 1 0/1 1/0 0/1 0.460

1 1 1 X 0/1 1/0 0/1 20

1 0 X X X High-Z High-Z -

RS-485 RECEIVING MODE

INPUTS (ON = 1) OUTPUT

485/232 RXEN and/or RXEN B-A RARB

10 or 1 ≥ -40mV 1 High-Z

10 or 1≤ -200mV 0 High-Z

1 0 or 1 Open or Shorted

together 1 High-Z

1 1 and 0 X High-Z High-Z

ISL3330, ISL3331

5FN6361.0

May 20, 2008

Pin Descriptions

PIN MODE FUNCTION

485/232 BOTH Interface Mode Select input. High for RS-485 Mode and low for RS-232 Mode.

DEN BOTH Driver output enable. The driver outputs, Y and Z, are enabled by bringing DEN high. They are high impedance when DEN

is low.

GND BOTH Ground connection.

NC BOTH No Connection.

ON BOTH In RS-232 mode only, ON high enables the charge pumps. ON low, with DEN and RXEN low (and RXEN high if QFN), turns

off the charge pump s (in RS-232 mode), and in either mode places the device in low power shutdown. In both modes, when

ON is low, and DEN is high, and RXEN is high or RXEN is low, loopback is enabled.

RXEN BOTH Receiver output enable. Rx is enabled when RXEN is high; Rx is high impedance when RXEN is low and, if using the QFN

package, RXEN is high. When using the QFN and the active high Rx enable function, RXEN should be high or floating.

RXEN BOTH Active low receiver output enable. Rx is enabled when RXEN is low; Rx is high impedance when RXEN is high and RXEN

is low . (i.e., to use active low Rx enable function, tie RXEN to GND). For single signal Tx/Rx direction control, connect RXEN

to DEN. Internally pulled high. (QFN only)

VCC BOTH System power supply input (3.3V).

VLBOTH Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. QFN logic input pins that are externally

tied high in an application, should use the VL supply for the high voltage level. (QFN only)

A RS-232 Receiver input with ±15kV ESD protection. A low on A forces RA high; A high on A forces RA low.

RS-485 Inverting receiver input with ±15kV ESD protection.

B RS-232 Receiver input with ±15kV ESD protection. A low on B forces RB high; A high on B forces RB low.

RS-485 Noninverting receiver input with ±15kV ESD protection.

DYRS-232 Driver input. A low on DY forces output Y high. Similarly, a high on DY forces output Y low.

RS- 485 Driver input. A low on DY forces output Y high and output Z low . Similarly , a high on DY forces output Y low and output Z high.

DZ/SLEW RS-232 Driver input. A low on DZ forces output Z high. Similarly, a high on DZ forces output Z low.

RS-4 85 Slew rate control. With the SLEW pin high, the drivers run at the maximum slew rate (20Mbps). With the SLEW pin low, the

drivers run at a reduced slew rate (460kbps). The QFN version works in conjunction with SPB to select one of three RS-485

data rates. Internally pulled high in RS-485 mode.

SPB RS-485 Speed control. Works in conjunction with the SLEW pin to select the 20Mbps, 460kbps or 115kbps RS-485 data rate.

Internally pulled high. (QFN only)

RARS-232 Receiver output.

RS-485 Receiver output: If B > A by at le ast -40 mV, RA is high; If B < A by -200 mV or mo re, R A is low; RA = High if A and B a re

unconnected (floating) or sh orted tog ethe r (i.e., full f ail-safe ).

RBRS-232 Receiver output.

RS-485 Not used. Output is high impedance, and unaffected by RXEN and RXEN.

Y RS-232 Driver output with ±15kV ESD protection.

RS-485 Inverting driver output with ±15kV ESD protection.

Z RS-232 Driver output with ±15kV ESD protection.

RS-485 Noninverting driver output with ±15kV ESD protection.

C1+ RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.

C1- RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.

C2+ RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.

C2- RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.

V+ RS-232 Internally generated positive RS-232 transmitter supply (+5.5V). C3 not needed in RS-485 Mode.

V- RS-232 Internally generated negative RS-232 transmitter supply (-5.5V). C4 not needed in RS-485 Mode.

ISL3330, ISL3331

6FN6361.0

May 20, 2008

Typical Operating Circuits

RS-232 MODE WITHOUT LOOPBACK RS-232 MODE WITH LOOPBACK

RS-485 MODE WITHOUT LOOPBACK RS-485 MODE WITH LOOPBACK

VCC

0.1µF

+0.1µF

0.1µF

V+

V-

C1+

C1-

C2+

C2-

0.1µF

5kΩ

B516

5kΩ

+C3

RXEN 12

GND

+3.3V +0.1µF

485/232 ON

813

VCC

DEN

VCC

NOTE: PINOUT FOR SSOP

VCC

0.1µF

+0.1µF

0.1µF

V+

V-

C1+

C1-

C2+

C2-

0.1µF

+C3

RXEN 12

GND

+3.3V +0.1µF

485/232 ON

813

VCC

DEN

VCC

NOTE: PINOUT FOR SSOP

5kΩ

A1 4

B1 5

VCC

ZDY

SLEW

0.1µF

+0.1µF

0.1µF

V+

V-

C1+

C1-

C2+

C2-

0.1µF

+C3

RXEN

GND

+3.3V +0.1µF

485/232 ON

813

VCC

DEN

VCC

NOTE: PINOUT FOR SSOP

VCC

ZDY

SLEW

0.1µF

+0.1µF

0.1µF

V+

V-

C1+

C1-

C2+

C2-

0.1µF

+C3

RXEN

GND

+3.3V +0.1µF

485/232 ON

813

VCC

DEN

VCC

NOTE: PINOUT FOR SSOP

VCC

ISL3330, ISL3331

7FN6361.0

May 20, 2008

Absolute Maximum Ratings (TA = +25°C) Thermal Information

VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V

VL (QFN Only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VCC + 0.5V

Input Voltages

All Except A,B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V

Input/Output Voltages

A, B (Any Mode). . . . . . . . . . . . . . . . . . . . . . . . . . . . -25V to +25V

Y, Z (Any Mode, Note 5). . . . . . . . . . . . . . . . . . . -12.5V to +12.5V

RA, RB (Non-QFN Package) . . . . . . . . . . . -0.5V to (VCC + 0.5V)

RA, RB (QFN Package) . . . . . . . . . . . . . . . . -0.5V to (VL + 0.5V)

Output Short Circuit Duration

Y, Z, RA, RB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite

ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table

Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W)

20 Ld SSOP Package (Note 6) . . . . . . 55 N/A

40 Ld QFN Package (Notes 7, 8). . . . . 31 2.5

Maximum Junction Temperature (Plastic Package) . . . . . . +150°C

Maximum Storage Temperature Range. . . . . . . . . -65°C to +150°C

Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . see link below

http://www.intersil.com/pbfree/Pb-FreeReflow.asp

Operating Conditions

Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C

CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and

result in failures not covered by warranty.

NOTES:

5. One output at a time, IOUT ≤ 100mA for ≤ 10 minutes.

6. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.

7. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See

Tech Brief TB379.

8. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside.

Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.

Typicals are at VCC = 3.3V, TA = +25°C (Note 9)

PARAMETER SYMBOL TEST CONDITIONS TEMP

(°C) MIN

(Note 15) TYP MAX

(Note 15) UNITS

DC CHARACTERISTICS - RS-485 DRIVER (485/232 = VCC)

Driver Differential VOUT (no load) VOD1 Full - - VCC V

Driver Differential VOUT (with load) VOD2 R = 50Ω (RS-422) (Figure 1) Full 2 2.3 - V

R = 27Ω (RS-485) (Figure 1) Full 1.5 2 5 V

VOD3 RD = 60Ω, R = 375Ω, VCM = -7V to 12V

(Figure 1) Full 1.5 - 5 V

Change in Magnitude of Driver

Differential VOUT for

Complementary Output States

ΔVOD R = 27Ω or 50Ω (Figure 1) Full - 0.01 0.2 V

Driver Common-Mode VOUT VOC R = 27Ω or 50Ω (Figure 1) Full - - 3.0 V

Change in Magnitude of Driver

Common-Mode VOUT for

Complementary Output States

ΔVOC R = 27Ω or 50Ω (Figure 1) Full - 0.01 0.2 V

Driver Short-Circuit Current,

VOUT = High or Low IOS -7V ≤ (VY or VZ) ≤ 12V (Note 11) Full 35 - 250 mA

Driver Three-State Output Leakage

Current (Y, Z) IOZ Outputs Disabled,

VCC = 0V or 3.45V VOUT = 12V Full - - 150 µA

VOUT = -7V Full -150 - - µA

DC CHARACTERISTICS - RS-232 DRIVER (485/232 = 0V)

Driver Output Voltage Swing VOAll TOUTS Loaded with 3kΩ to Ground Full ±5.0 - - V

Driver Output Short-Circuit Current IOS VOUT = 0V Full -60 - 60 mA

DC CHARACTERISTICS - LOGIC PINS (i.e., DRIVER AND CONTROL INPUT PINS)

Input High Voltage VIH1 VL = VCC if QFN Full 2.2 - V

VIH2 2.7V ≤ VL < 3.0V (QFN Only) Full 2 - V

VIH3 2.3V ≤ VL < 2.7V (QFN Only) Full 1.6 - V

VIH4 1.6V ≤ VL < 2.3V (QFN Only) Full 0.7*VL-V

VIH5 1.2V ≤ VL < 1.6V (QFN Only) 25 - 0.7*VL-V

ISL3330, ISL3331

8FN6361.0

May 20, 2008

Input Low Voltage VIL1 VL = VCC if QFN Full - - 0.8 V

VIL2 VL ≥ 2.7V (QFN Only) Full - - 0.8 V

VIL3 2.3V ≤ VL < 2.7V (QFN Only) Full - - 0.7 V

VIL4 1.6V ≤ VL < 2.3V (QFN Only) Full - - 0.35*VLV

VIL5 1.3V ≤ VL < 1.6V (QFN Only) 25 0.35*VL-V

VIL6 1.2V ≤ VL < 1.3V (QFN Only) 25 0.25*VL-V

Input Current IIN1 Except SLEW, RXEN (QFN), and SPB (QFN) Full -2 - 2 µA

IIN2 SLEW (Note 13), RXEN (QFN), and SPB (QFN) Full -25 - 25 µA

DC CHARACTERISTICS - RS-485 RECEIVER INPUTS (485/232 = VCC)

Receiver Differential Threshold

Voltage VTH -7V ≤ VCM ≤ 12V, Full Failsafe Full -0.2 - -0.04 V

Receiver Input Hysteresis ΔVTH VCM = 0V 25 - 35 - mV

Receiver Input Current (A, B) IIN VCC = 0V or 3.15V to 3.45V VIN = 12V Full - - 0.8 mA

VIN = -7V Full -0.64 - - mA

Receiver Input Resistance RIN -7V ≤ VCM ≤ 12V, VCC = 0 (Note 12), or

3.15V ≤ VCC ≤ 3.45V Full 15 - - kΩ

DC CHARACTERISTICS - RS-232 RECEIVER INPUTS (485/232 = GND)

Receiver Input Voltage Range VIN Full -25 - 25 V

Receiver Input Threshold VIL Full - 1.1 0.8 V

VIH Full 2.4 1.6 - V

Receiver Input Hysteresis ΔVTH 25 - 0.5 - V

Receiver Input Resistance RIN VIN = ±15V, VCC Powered-Up (Note 12) Full 3 5 7 kΩ

DC CHARACTERISTICS - RECE IVER OUTPUTS (485 OR 232 MODE)

Receiver Output High Voltage VOH1 IO = -1.5mA (VL = VCC if QFN) Full VCC - 0.4 - V

VOH2 IO = -100µA, VL ≥ 1.2V (QFN Only) Full VL - 0.1 - V

VOH3 IO = -500µA, VL = 1.5V (QFN Only) Full 1.2 - V

VOH4 IO = -150µA, VL = 1.2V (QFN Only) Full 1.0 - V

Receiver Output Low Voltage VOL IO = 5mA Full - 0.2 0.4 V

Receiver Short-Circuit Current IOSR 0V ≤ VO ≤ VCC Full 7 - 85 mA

Receiver Three-State Output

Current IOZR Output Disabled, 0V ≤ VO ≤ VCC (or VL for QFN) Full - - ±10 µA

POWER SUPPLY CHARACTERISTICS

No-Load Supply Current (Note 10) ICC232 485/232 = 0V, ON = VCC Full - 3.7 7 mA

ICC485 485/232 = VCC, ON = VCC Full - 1.3 5 mA

Shutdown Supply Current ISHDN232 ON = DEN = RXEN = 0V

(RXEN = SPB = VL if QFN) Full - 10 30 µA

ISHDN485 ON = DEN = RXEN = SLEW = 0V

(RXEN = VL, SPB = 0V if QFN) Full - 30 60 µA

ESD CHARACTERISTICS

Bus Pins (A, B, Y, Z) Any Mode Human Body Model 25 - ±15 - kV

All Other Pins Human Body Model 25 - ±2.5 - kV

Machine Model 25 - ±200 - V

Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.

Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)

PARAMETER SYMBOL TEST CONDITIONS TEMP

(°C) MIN

(Note 15) TYP MAX

(Note 15) UNITS

ISL3330, ISL3331

9FN6361.0

May 20, 2008

RS-232 DRIVER and RECEIVER SWITCHING CHARACTERISTICS (485/232 = 0V, ALL VERSIONS AND SPEEDS)

Driver Output Transition Region

Slew Rate SR RL=3kΩ, Measured From 3V

to -3V or -3V to 3V CL ≥ 15pF Full - 20 30 V/µs

CL ≤ 2500pF Full 4 12 - V/µs

Driver Output Transition Time tr, tfRL=3kΩ, CL = 2500pF, 10% to 90% Full 0.22 1.2 3.1 µs

Driver Propagation Delay tDPHL RL=3kΩ, CL= 1000pF (Figure 6)Full - 1 2 µs

tDPLH Full - 1.2 2 µs

Driver Propagation Delay Skew tDSKEW tDPHL - tDPLH (Figure 6)Full - 300 450 ns

Driver Enable Time tDEN 25 - 1200 - ns

Driver Disable Time tDDIS RL=5kΩ, Measured at VOUT = ±3V 25 - 500 - ns

Driver Enable Time from Shutdown tDENSD VOUT = ±3.0V (Note 14)25 - 25 - µs

Driver Maximum Data Rate DRDRL=3kΩ, CL= 1000pF, One Transmitter

Switching Full 250 400 - kbps

Receiver Propagation Delay tRPHL CL= 15pF (Figure 7) Full - 40 120 ns

tRPLH Full - 60 120 ns

Receiver Propagation Delay Skew tRSKEW tRPHL - tRPLH (Figure 7) Full - 20 40 ns

Receiver Maximum Data Rate DRRCL= 15pF Full 0.46 2 - Mbps

Receiver Enable to Output Low tZL CL = 15pF, SW = VCC (Figure 5) Full - 18 - ns

Receiver Enable to Output High tZH CL = 15pF, SW = GND (Figure 5) Full - 18 - ns

Receiver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 5) Full - 22 - ns

Receiver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 5) Full - 22 - ns

Receiver Enable from Shutdown to

Output Low tZLSHDN CL = 15pF, SW = VCC (Figure 5, Note 14)25-60-ns

Receiver Enable from Shutdown to

Output High tZHSHDN CL = 15pF, SW = GND (Figure 5, Note 14)25-20-ns

RS-485 DRIVER SWITCHING CHARACTERISTICS (FAST DATA RATE (20Mb ps), 485/232 = VCC, SLEW = VCC, ALL VERSIONS)

Driver Differential Input to Output

Delay tDLH, tDHL RDIFF = 54Ω, CL = 100pF (Figure 2) Full 10 20 35 ns

Driver Output Skew tSKEW RDIFF = 54Ω, CL = 100pF (Figure 2) Full - 2 10 ns

Driver Differential Rise or Fall Time tR, tFRDIFF = 54Ω, CL = 100pF (Figure 2) Full 3 20 30 ns

Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 28 60 ns

Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 39 60 ns

Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 30 60 ns

Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3 ) Full - 25 60 ns

Driver Enable from Shutdown to

Output Low tZL(SHDN) RL = 500Ω, CL = 100pF, SW = VCC

(Figure 3, Note 14)Full - 100 250 ns

Driver Enable from Shutdown to

Output High tZH(SHDN) RL = 500Ω, CL = 100pF, SW = GND

(Figure 3, Note 14)Full - 290 375 ns

Driver Maximum Data Rate fMAX RDIFF = 54Ω, CL = 100pF (Figure 2) Full 20 35 - Mbps

RS-485 DRIVER SWITCHING CHARACTERISTICS (MEDIUM DA T A RA TE (460kbps), 485/232 = VCC, SLEW = 0V , SPB (QFN Only) = VCC, ALL

VERSIONS)

Driver Differential Input to Output

Delay tDLH, tDHL RDIFF = 54Ω, CL = 100pF (Figure 2) Full 200 500 1000 ns

Driver Output Skew tSKEW RDIFF = 54Ω, CL = 100pF (Figure 2) Full - 10 150 ns

Driver Differential Rise or Fall Time tR, tFRDIFF = 54Ω, CL = 100pF (Figure 2) Full 300 660 1100 ns

Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.

Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)

PARAMETER SYMBOL TEST CONDITIONS TEMP

(°C) MIN

(Note 15) TYP MAX

(Note 15) UNITS

ISL3330, ISL3331

10 FN6361.0

May 20, 2008

Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 42 100 ns

Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 350 450 ns

Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 30 60 ns

Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3 ) Full - 25 60 ns

Driver Enable from Shutdown to

Output Low tZL(SHDN) RL = 500Ω, CL = 100pF, SW = VCC

(Figure 3, Note 14)Full - - 500 ns

Driver Enable from Shutdown to

Output High tZH(SHDN) RL = 500Ω, CL = 100pF, SW = GND

(Figure 3, Note 14)Full - - 750 ns

Driver Maximum Data Rate fMAX RDIFF = 54Ω, CL = 100pF (Figure 2) Full 460 2000 - kbps

RS-485 DRIVER SWITCHING CHARACTERISTICS (SLOW DATA RATE (115kbps, QFN ONLY), 485/232 = VCC, SLEW = SPB = GND)

Driver Differential Input to Output

Delay tDLH, tDHL RDIFF = 54Ω, CL = 100pF (Figure 2) Full 800 1600 2500 ns

Driver Output Skew tSKEW RDIFF = 54Ω, CL = 100pF (Figure 2) Full - 250 500 ns

Driver Differential Rise or Fall Time tR, tFRDIFF = 54Ω, CL = 100pF (Figure 2) Full 1000 1700 3100 ns

Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 45 100 ns

Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 910 1200 ns

Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 35 60 ns

Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3 ) Full - 29 60 ns

Driver Enable from Shutdown to

Output Low tZL(SHDN) RL = 500Ω, CL = 100pF, SW = VCC

(Figure 3, Note 14) Full - - 800 ns

Driver Enable from Shutdown to

Output High tZH(SHDN) RL = 500Ω, CL = 100pF, SW = GND

(Figure 3, Note 14) Full - - 1500 ns

Driver Maximum Data Rate fMAX RDIFF = 54Ω, CL = 100pF (Figure 2) Full 115 800 - kbps

RS-485 RECEIVER SWITCHING CHARACTERISTICS (485/232 = VCC, ALL VERSIONS AND SPEEDS)

Receiver Input to Output Delay tPLH, tPHL (Figure 4) Full 20 45 70 ns

Receiver Skew | tPLH - tPHL |t

SKEW (Figure 4) Full - 3 10 ns

Receiver Maximum Data Rate fMAX Full 20 40 - Mbps

Receiver Enable to Output Low tZL CL = 15pF, SW = VCC (Figure 5) Full - 15 60 ns

Receiver Enable to Output High tZH CL = 15pF, SW = GND (Figure 5) Full - 15 60 ns

Receiver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 5) Full - 20 60 ns

Receiver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 5) Full - 20 60 ns

Receiver Enable from Shutdown to

Output Low tZLSHDN CL = 15pF, SW = VCC (Figure 5, Note 14) Full - 500 900 ns

Receiver Enable from Shutdown to

Output High tZHSHDN CL = 15pF, SW = GND (Figure 5, Note 14) Full - 500 900 ns

NOTES:

9. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise

specified.

10. Supply current specification is valid for loaded drivers when DEN = 0V.

11. Applies to peak current. See “Typical Performance Curves” beginning on page 19 for more information.

12. RIN defaults to RS-485 mode (>15kΩ) when the device is unpowered (VCC = 0V), or in SHDN, regardless of the state of the 485/232 pin.

13. The Slew pin has a pull-up resistor that enables only when in RS-485 mode (485/232 = VCC).

14. ON, RXEN, and DEN all simultaneously switched Low-to-High.

15. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. T emperature limits established by characterization

and are not production tested.

Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.

Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)

PARAMETER SYMBOL TEST CONDITIONS TEMP

(°C) MIN

(Note 15) TYP MAX

(Note 15) UNITS

ISL3330, ISL3331

11 FN6361.0

May 20, 2008

Test Circuits and Waveforms

FIGURE 1. RS-485 DRIVER VOD AND VOC TEST CIRCUIT

FIGURE 2A. TEST CIRCUIT FIGURE 2B. MEASUREMENT POINTS

FIGURE 2. RS-485 DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES

FIGURE 3A. TEST CIRCUIT FIGURE 3B. MEASUREMENT POINTS

FIGURE 3. RS-485 DRIVER ENABLE AND DISABLE TIMES

DEN

VCC

VOD

VOC

VCM

DEN

VCC

SIGNAL

GENERATOR

CL = 100pF

RDIFF

ZCL = 100pF

OUT (Z)

tPLH

1.5V1.5V

VOH

VOL

50% 50%

tPHL

OUT (Y)

tPHL

VOH

VOL

50% 50%

tPLH

DIFF OUT (Z - Y)

+VOD

-VOD

90% 90%

10% 10%

SKEW = |tPLH (Y OR Z) - tPHL (Z OR Y)|

0V 0V

tDHL

tDLH

DEN

500Ω

VCC

GND

SIGNAL

GENERATOR

FOR SHDN TESTS, SWITCH ON AND DEN L- H SIMULTANEOUSLY

PARAMETER OUTPUT RXEN DY SW CL (pF)

tHZ Y/Z X 0/1 GND 15

tLZ Y/Z X 1/0 VCC 15

tZH Y/Z X 0/1 GND 100

tZL Y/Z X 1/0 VCC 100

tZH(SHDN) Y/Z 0 0/1 GND 100

tZL(SHDN) Y/Z 0 1/0 VCC 100

OUT (Y, Z)

1.5V1.5V

VOH

2.3V

VOH - 0.5V

tHZ

OUT (Y, Z)

VCC

VOL

2.3V VOL + 0.5V

tLZ

DEN

OUTPUT HIGH

OUTPUT LOW

tZL

tZH

tZH(SHDN)

tZL(SHDN)

ENABLED

ISL3330, ISL3331

12 FN6361.0

May 20, 2008

FIGURE 4A. TEST CIRCUIT FIGURE 4B. MEASUREMENT POINTS

FIGURE 4. RS-485 RECEIVER PROPAGATION DELAY

FIGURE 5A. TEST CIRCUIT FIGURE 5B. MEASUREMENT POINTS

FIGURE 5. RS-485 RECEIVER ENABLE AND DISABLE TIMES

FIGURE 6A. TEST CIRCUIT FIGURE 6B. MEASUREMENT POINTS

FIGURE 6. RS-232 DRIVER PROPAGATION DELAY

FIGURE 7A. TEST CIRCUIT FIGURE 7B. MEASUREMENT POINTS

FIGURE 7. RS-232 RECEIVER PROPAGATION DELAY

Test Circuits and Waveforms (Continued)

SIGNAL

GENERATOR

RRA

RXEN

15pF

VCC

+1.5V

-1.5V

tPLH

0V0V

VCC

1.5V 1.5V

tPHL

1kΩVCC

GND

FOR SHDN TESTS, SWITCH ON AND RXEN L- H SIMULTANEOUSLY

PARAMETER DEN B (V) SW

tHZ X+1.5GND

tLZ X-1.5V

tZH X+1.5GND

tZL X-1.5V

tZH(SHDN) 0+1.5GND

tZL(SHDN) 0-1.5V

SIGNAL

GENERATOR

RRA

RXEN

15pF

1.5V1.5V

VOH

1.5V

VOH - 0.5V

tHZ

VCC

VOL

1.5V VOL + 0.5V

tLZ

RXEN

OUTPUT HIGH

OUTPUT LOW

tZL

tZH

tZL(SHDN)

tZH(SHDN)

ENABLED

DEN

DY,Z

VCC

SIGNAL

GENERATOR

Y, Z CL

OUT (Y,Z)

tDPHL

1.5V1.5V

VO+

VO-

0V 0V

tDPLH

DY,Z

SKEW = |tDPHL - tDPLH|

RXEN

A, B

VCC

SIGNAL

GENERATOR

RA, RBCL = 15pF

RA, RB

tRPHL

50%50%

VOH

VOL

50% 50%

tRPLH

A, B

SKEW = |tRPHL - tRPLH|

ISL3330, ISL3331

13 FN6361.0

May 20, 2008

Detailed Description

The ISL333x port supports dual protocols: RS-485/RS-422,

and RS-23 2. RS-485 and RS-422 are differential (balanced)

data transmission standards for use in high speed (up to

20Mbps) networks, or long haul and noisy environments.

The differential signalling, coupled with RS-485’s

requirement for an extended common mode range (CMR) of

+12V to -7V make these transceivers extremely tolerant of

ground potential differences, as well as voltages induced in

the cable by external fields. Both of these effects are real

concerns when communicating over the RS-485/RS-422

maximum distance of 4000’ (1220m). It is import ant to note

that the ISL333x don’t follow the RS-485 convention

whereby the inverting I/O is labeled “B/Z”, and the non

inverting I/O is “A/Y”. Thus, in the application diagrams,

see Figures 8 and 9, the 333x A/Y (B/Z) pins connect to

the B/Z (A/Y) pins of the generic RS-485/RS-422 ICs.

The RS-422 is typically a point-to-point (one driver talking to

one receiver on a bus), or a point-to-multipoint (multidrop)

standard that allows only one driver and up to 10 receivers

on each bus. Because of the one driver per bus limitation,

RS-422 networks use a two bus, full duplex structure for

bidirectional communication, and the Rx inputs and Tx

outputs (no tri-state required) connect to different busses, as

shown in Figure 9. The Tx and Rx enables aren’t required,

so connect RXEN and DEN to VCC through a 1kΩ resistor.

Conversely, RS-485 is a true multipoint standard, which

allows up to 32 devices (any combina tion of drivers that must

be tri-stat able an d receivers) on ea ch bus. No w bidire ctio nal

communication takes place on a single bus, so the Rx input s

and Tx output s of a port connect to the same bu s lines, a s

shown in Figure 8. A port set to RS-485/RS-422 mode

includes one Rx and one Tx. See Application Note AN140 1

for details about implementi ng a three pin, select abl e

RS-232/half-duplex RS-485 port.

RS-232 is a point-to-point, singled end ed (signal voltages

referenced to GND) communication protocol targeting fairly

short (< 150’, 46m) and low data rate (<1Mbps) applications.

A port contains two transceivers (2 Tx and 2 Rx) in RS-23 2

mode.

Protocol selection is handled via the 485/232 logic pin.

FIGURE 8. TYPICAL HALF DUPLEX RS-485 NETWORK

FIGURE 9. TYPICAL RS-422 NETWORK

0.1µF

VCC

GND

RXEN*

DEN

+3.3V

0.1µF+

VCC

GND

A/Y

B/Z

+5V

0.1µF

VCC GND

RO RE DE DI

A/Y

B/Z

+5V

ISL333x

GENERIC 1/2 DUPLEX 485 XCVR

Tx/Rx

*QFN ONLY,

CONNECT RXEN TO GND

0.1µF

VCC

GND

DEN

+3.3V

0.1µF

VCC

GND

+5V

0.1µF

VCC GND

RO RE

+5V

ISL3330 (MASTER)

GENERIC 422 Rx (SLAVE)

GENERIC FULL DUPLEX 422 XCVR (SLAVE)

1kΩ

RXEN

ISL3330, ISL3331

14 FN6361.0

May 20, 2008

ISL333x Advan ta g es

These dual protocol ICs offer many parametric

improvements vs those offered on competing dual protocol

devices. Some of the major improvements are:

•3.3V Supply Voltage - Eliminates the 5V supply that

powers just the interface IC

•15kV Bus Pin ESD - Eases board level requirements

•Full Failsafe RS-485 Rx - Eliminates bus biasing

•Selectable RS-485 Data Rate - Up to 20Mbps, or slew

rate limited for low EMI and fewer termination issues

•High RS-232 Data Rate - >250kbps

•Lower Tx and Rx Skews - Wider, consistent bit widths

•Lower ICC - Max ICC is 2x to -4x lower than competi tio n

•Flow-Thru Pinouts - Tx, Rx bus pins on one side/logic

pins on the other, for easy routing to connector/UART

•Packaging - Smaller (QFN) and Pb-free.

RS-232 Mode

RX FEATURES

RS-2 32 rec eive rs invert and convert RS-232 input levels

(±3V to ±25V) to the standard TTL/CMOS levels required by

a UART, ASIC, or µcontroller serial port. Receivers are

designed to operate at faster data rates than the drivers, and

they feature very low skews (20ns) so the receivers

contribute negligibly to bit width distortion. Inputs include the

standards required 3kΩ to 7kΩ pull-down resistor , so unused

inputs may be left unconnected. Rx inputs also have built-in

hysteresis to increase noise immunity and to decrease

erroneous triggering due to slowly transitioning input signals.

Rx outputs are short circuit protected , and are tri-st at able via

the active high RXEN pin, when the IC is shutdown (SHDN;

see Tables 2 and 3, and the “Low Power Shutdown (SH DN)

Mode” on page 16), or via the active lo w RXEN pin avail able

on the QFN package opti on (see “ISL3331 (QFN Package )

Special Features” on page 17).

TX FEATURES

RS-232 drivers invert and convert the standard TTL/CMOS

leve ls from a UART, or µcontrol ler serial p ort to RS-232

compliant levels (±5V minimum). The Tx delivers these

compliant output levels even at data rates of 400kbps, and

with loads of 1000pF. The drivers are designed for low skew

(typically 12% of the 400kbps bit width), and are compliant to

the RS-232 slew rate specification (4V to 30 V/µs) for a wide

range of load capacitances. Tx inputs float if left

unconnected and may cause ICC increases. For the best

results, connect unused inputs to GND.

Tx outputs are short circuit protected, and incorporate a

thermal SHDN feature to protect the IC in situations of

severe power dissipation. See the “RS-485 Mode” on

page 14 for more details. Drivers disable via the active high

DEN pin, in SHDN (see Tables 2 and 3, and the “Low Power

Shutdown (SHDN) Mode” on page 16), or when th e 3.3V

power supply is off. Because RS-232 is a point-to-point (only

one Tx allowed on the bus) standard, the main use for this

DEN disable function is to reduce power by eliminating the

load current (approximately 1mA per T x output) through the

5kΩ resistor in the Rx at the cable’s far end.

CHARGE PUMPS

The on-chip charge pumps create the RS-232 tran smitter

power supplies (typically +5.7/-5.3V) from a single supply as

low as 3.15V, and are enabled only if the port is configured

for RS-2 32 operation, and not in SHDN. The efficient design

requires only four small 0.1µF ca pacitors for the voltage

doubler and inverter functions. By operating discontinuously

(i.e., turning off as soon as V+ and V- pump up to the

nominal values), the charge pump contribution to RS-232

mode ICC is reduced significantly. Unlike competing devices

that require the charge pump in RS-485 mode, disabling the

charge pump saves power, and minimizes noise. If the

application is a dedicated RS-485 port, then the charge

pump capacitors aren’t even required.

DATA RATES AND CABLING

Drivers operate at data rates up to 400kbps, and are

guaranteed for data rates up to 250kbps. The charge pumps

and drivers are designed such that one driver can be

operated at the rated load, and at 250kbps (see Figure 33).

Figure 33 also shows that drivers can easily drive several

thousands of picofarads at data rates up to 250kbps, while

still delivering compliant ±5V output levels.

Receivers operate at data rates up to 2Mbps. They are

designed for a higher data rate to facilitate faster factory

downloading of software into the final product, thereby

improving the user’s manufacturing throughput.

Figures 36 and 37 illustrate driver and receiver waveforms at

250kbps, and 400kbps, respectively. For these graphs, one

driver drives the specified capaciti ve load, and a receiver.

RS-232 doesn’t require anything special for cabling; just a

single bus wire per transmitter and receiver, and another

wire for GND. So an ISL333x RS-232 port uses a five

conductor cable for interconnection. Bus terminations are

not required, nor allowed, by the RS-232 standard.

RS-485 Mode

RX FEATURES

RS-485 receivers convert differential input signals as small

as 200mV, as required by the RS -485 and RS-422

standards, to TTL/CMOS output levels. The differential Rx

provides maximum sensitivity, noise immunity, and common

mode rejection. Per the RS-485 st a ndard, receiver inputs

function with common mode voltages as great as +12V and

-7V, regardless of supply voltage, making them ideal for long

networks where induced voltages are a realistic concern.

ISL3330, ISL3331

15 FN6361.0

May 20, 2008

Each RS-485/422 port includes a singl e receiver (RA), and

the unused Rx output (RB) is disabled.

Worst case receiver input currents are 20% lower than the

1 “unit load” (1mA) RS-485 limit, which translates to a 15kΩ

minimum input resistance.

These receivers include a “full fail-safe” function that

guarantees a high level receiver output if the receiver inputs

are unconnected (floating), shorted together, or if the bus is

terminated but undriven (i.e., differential voltage collapses to

near zero due to termination). Failsafe with shorted or

terminated and undriven inp uts is accomplished by setting

the Rx upper switching point at -40mV, thereby ensuring that

the Rx recognizes a 0V differential as a high level.

All the Rx outputs are short circuit protected, and are

tri-statable via the active high RXEN pin, or when the IC is

shutdown (see Tables 2 and 3, and the “Low Power

Shutdown (SHDN) Mode” on page 16). ISL3331 (QFN)

receiver outputs are also tri-statable via an active low RXEN

input (see “ISL3331 (QFN Package) S pecial Features” on

page 17).

For the ISL3331 (QFN), when using the active high RXEN

function, the RXEN pin may be left floating (internal ly pulled

high), or should be connected to VCC through a 1kΩ resistor .

If using the active low RXEN, then the RXEN pin must be

connected to GND.

TX FEATURES

The RS-485/RS-422 driver is a differential output device that

delivers at least 1.5V across a 54Ω load (RS-485), and at

least 2V across a 100Ω load (RS-422). The drivers feature

low propagation delay skew to maximize bit widths, and to

minimize EMI.

To allow multiple drivers on a bus, the RS-485 specification

requires that drivers survive worst case bus contentions

undamaged. The ISL333x drivers meet this require ment via

driver output short circuit current limits, and on-chip thermal

shutdown circuitry. The output stages incorporate current

limiting circuitry that ensures that the output current never

exceeds the RS-485 specification, even at the common

mode voltage range extremes of 12V and -7V. In th e e vent of

a major short circuit condition, device s also in clude a thermal

shutdown feature that disab les the drivers when ever the die

temperature becomes excessive. This eliminates the power

dissipation, all owing the die to cool . The drivers automatically

re-enable after the die temperature drops about +15°C. If the

contention persists, the ther ma l sh ut down /re-ena ble cycle

repeats unti l the fault is clear ed. Receivers st ay operation al

during thermal sh ut down .

The RS-485 multi-driver operation also requires drivers to

include tri-state functionality, where the port has a DEN pin

to control this function. If the driver is used in an RS-422

network, such that driver tri-state isn’t required, then the

DEN pin should connect to VCC through a 1kΩ resistor.

Drivers are also tri-stated when the IC is in SHDN, or when

the 3.3V power supply is off.

SPEED OPTIONS

The ISL3330 (SSOP) features two speed options that are

user selectable via the SLEW pin: a high slew rate setting

optimized for 20Mbps data rates (Fast), and a slew rate

limited option for operation up to 460kbps (Med). The

ISL3331 (QFN) offers an additional, more slew rate limited,

option for data rates up to 115kb ps (Slow). See the “Data

Rate“ and “RS-485 Slew Rate Limited Data Rates” on

page 17 for more information.

Receiver performance is the same for all three speed

options.

DATA RATE, CABLES, AND TERMINATIONS

RS-485/RS-422 are intended for network lengths up to 4000’

(1220m), but the maximum system data rate decreases as

the transmission length increases. Devices operating at the

maximum data rate of 20Mbps are limited to lengths of 20’ to

30’ (6m to 9m), while devices operating at or below 115kbps

can operate at the maximum length of 4000’ (1220m).

Higher data rates require faster edges, so both the ISL333x

versions offer an edge rate capable of 20Mbps data rates.

They both have a second option for 460kbps, but the

ISL3331 also offers another , very slew rate limited, edge rate

to minimize problems at slow data rates. Nevertheless, for

the best jitter performance when driving long cables, the

faster speed settings may be preferable, even at low data

rates. See the “RS-485 Slew Rate Limited Data Rates” on

page 17 for details.

Twisted pair is the cable of choice for RS-485/RS-422

networks. Twisted pair cables tend to pick-up noise and

other electromagnetically induced voltages as common

mode signals, which are effectively rejected by the

dif fe ren tial receivers in these ICs.

The preferred cable connection technique is

“daisy-chaining”, where the cable runs from the connector of

one device directly to the connector of the next device, such

that cable stub lengths are negligible. A “backbone”

structure, where stubs run from the main backbone cable to

each device’s connector, is the next best choice, but care

must be taken to ensure that each stub is electrically “short”.

See Table 4 for recommended maximum stub lengths for

each speed option.

TABLE 4. RECOMMENDED STUB LENGTHS

SPEED OPTION MAXIMUM STUB LENGTH

ft. (m)

SLOW 350 to 500 (107 to 152)

MED 100 to 150 (30.5 to 46)

FAST 1 to 3 (0.3 to 0.9)

ISL3330, ISL3331

16 FN6361.0

May 20, 2008

Proper termination is imperative to minimize reflections

when using the 20Mbps speed option. Short networks using

the medium and slow speed options need not be terminated,

but terminations are recommended unless power dissipation

is an overriding concern. Note that the RS-485 specification

allows a maximum of two terminations on a network,

otherwise the Tx output voltage may not meet the required

VOD.

In point-to-point, or point-to-multipoint (RS-422) networks,

the main cable should be terminated in its characteristic

impedance (typically 120Ω) at the end farthest from the

driver. In multi-receiver applications, stubs connecting

receivers to the main cable should be kept as short as

possible, but definitely shorter than the limits shown in

Table 4. Multipoint (RS-485) systems require that the main

cable be terminated in its characteristic impedance at both

ends. Again, keep stubs connecting a transceiver to the

main cable as short as possible (refer to Table 4). Avoid

“star”, and other configurations, where there are many

“ends” which would require more than the two allowed

terminations to prevent reflections.

High ESD

All pins on the ISL333x include ESD protection structures

rated at ±2.5kV (HBM), which is good enough to survive

ESD events commonly seen during manufacturing. But the

bus pins (Tx outputs and Rx inputs) are particularly

vulnerable to ESD events because they connect to an

exposed port on the exterior of the finished product. Simply

touching the port pins, or connecting a cable, can destroy an

unprotected port. ISL333 x bus pins are fitted with advanced

structures that deliver ESD protection in excess of ±15kV

(HBM), without interfering with any signal in th e RS-485 or

the RS-232 range. This high level of protection may

eliminate the need for board level protection, or at the very

least will increase the robustness of any board level scheme.

Small Packages

Competing 3.3V dual protocol ICs are available only in a

20 Ld or 24 Ld SSOP. The ISL3331’s tiny 6mmx6mm QFN

footprint is 36% to 44% smaller than the competing SSOPs.

Flow-Through Pinouts

Even the ISL333x pinouts are features, in that the

“flow-through” design simplifies board layout. Having the bus

pins all on one side of the package for easy routing to a

cable connector, and the Rx outputs and Tx inputs on the

other side for easy connection to a UART, avoids costly and

problematic crossovers. Figure 10 illustrates the

flow-through nature of the pinout.

Low Power Shutd o wn (SHDN) Mode

The ISL333x enter the SHDN mode when ON = 0, and the

Tx and Rx are disabled (DEN = 0, RXEN = 0, and

RXEN = 1) and the already low supply current drops to as

low as 10µA. SHDN disables the Tx and Rx outputs, and

disables the charge pumps if the port is in RS-232 mode, so

V+ collapses to VCC, and V- collapses to GND.

All but 10µA of SHDN ICC current is due to control input

(SPB, SLEW) pull-up resistors (~10µA/resistor), so SHDN

ICC varies depending on the ISL333x configuration. The

specification tables indicate the worst case values, but

careful selection of the configuration yi elds lower currents.

For example, in RS-232 mode the SPB pin isn’t used, so

floating it or tying it high minimizes SHDN ICC.

When enabling from SHDN in RS-232 mode, allow at least

25µs for the charge pumps to stabilize before transmitting

data. If fast enables are required, and ICC isn’t the greatest

concern, disable the drivers with the DEN pin to keep the

charge pumps active. The charge pumps aren’t used in

RS-485 mode, thus the transceiver is ready to send or

receive data in less than 2µs, which is much faster than

competing devices that require the charge pump for all

modes of operation.

Internal Loopback Mode

Setting ON = 0, DEN = 1, and RXEN = 1 or RXEN = 0 (QFN

only), places the port in the loopback mode, a mode that

facilitates implementing board level self test functions. In

loopback, internal switches disconnect the Rx inputs from

the Rx outputs, and feed back the Tx outputs to the

appropriate Rx output. This way the data driven at the Tx

input appears at the corresponding Rx output (refer to

“Typical Operating Circuits” on page 6). The Tx outputs

remain connected to their terminals, so the external loads

are reflected in the loopback performance. This allows the

loopback function to potentially detect some common bus

faults such as one or both driver outputs shorted to GND, or

outputs shorted together.

Note that the loopback mode uses an additional set of

receivers, as shown in the “Typical Operating Circuits” on

page 6. These loopback receivers are not standards

compliant, so the loopback mode can’t be used to implement

a half-duplex RS-485 transceiver. See Application Note

AN1401 for specific details on implementing a 3-pin, half

duplex, dual protocol port.

UART

ASIC

µCONTROLLER

CONNECTOR

ISL3330

FIGURE 10. ILLUSTRATION OF FLOW-THROUGH PINOUT

ISL3330, ISL3331

17 FN6361.0

May 20, 2008

ISL3331 (QFN Package) Special Features

Logic Supply (VL Pin)

The ISL3331 (QFN) includes a VL pin that powers th e logic

inputs (Tx inputs and control pins) and Rx outputs. These

pins interface with “logic” devices such as UARTs, ASICs,

and µcontrollers, and today many of these devices use

power supplies significantly lower than 3.3V. Thus, a 3.3V

output level from a 3.3V powered dual protocol IC might

seriously overdrive and damage the logic device input.

Similarly, the logic device’s low VOH might not exceed the

VIH of a 3.3V powered dual protocol input. Con necting the

VL pin to the power supply of the logic device (as shown in

Figure 11) limi ts the ISL3331’s Rx output VOH to VL (see

Figure 14) and reduces the Tx and control input switching

points to values compatible with the logic device output

levels. Tailoring the logic pin input switching points and

output levels to the supply voltage of the UART, ASIC, or

µcontroller eliminates the need for a level shifter/translator

between the two ICs.

VL can be anywhere from VCC down to 1.2V, but the input

switching points may not provide enough noise margin when

VL< 1.5V. Table 5 indicates typical VIH and VIL values for

various VL voltages so the user can ascertain whether or not

a particular VL voltage meets his needs.

Note: With VL ≤ 1.6V, the ISL3331 may not operate at the full

data rate unless the logic signal VIL is at least 0.2V below

the typical value listed in Tab le 5.

The VL supply current (IL) is typically less than 35µA, as

shown in Figures 19 and 20. All of the DC VL current is due

to inputs with internal pull-up resistors (SPB, SLEW, RXEN)

being driven to the low input state. The worst case IL current

occurs when all three of the inputs are low (see Figure 19),

due to the IL through the pull-up resistors. IIL through an

input pull-up resistor is ~10µA, so the IL in Figure 19 drops

by about 18µA (at VL= 3.3V) when the SPB is high and 232

mode disables the SLEW pin pull-up (middle vs top curve).

When all three inputs are driven high, IL drops to ~10nA.

Thus, to minimize power dissipation, drive these inputs high

when unneeded (e.g., SPB isn’t used in RS-232 mode, so

drive it high).

QFN logic input pins that are externally tied high in an

applicat ion, should use the VL supply for the high voltage

level.

Active Low Rx Enable (RXEN)

In many RS-485 applicatio ns, especially half duplex

configurations, users like to accomplish “echo cancellation”

by disabling the corresponding receiver while its driver is

transmitting data. This function is available on the QFN

package via an active low RXEN pin. The active low function

also simplifies direction co ntrol by allowing a single Tx/Rx

direction control line. If the active high RXEN were used,

either two valuable I/O pins would be used for direction

control, or an external inverter is required between DEN and

RXEN. Figure 12 details the advantage of using the RXEN

pin. When using RXEN, ensure th at RXEN is tied to GND.

RS-485 Slew Rate Limited Data Rates

The ISL333x FAST speed option (SLE W = High) utilizes Tx

output transitions optimized for a 20Mbps data rate. These

fast edges may increase EMI and reflecti on issues, even

though fast transitions aren’t required at the lower data rates

used by many applications. With the SLEW pin low, both

product types switch to a moderately slew rate limited output

transition targeted for 460kbps (MED) data rates. The

ISL3331 (QFN version), offers an additional slew rate limited

data rate that is optimized fo r 115kbps (SLOW), and is

selected when SLEW = 0 and SPB = 0 (see Table 3). The

FIGURE 11. USING VL PIN TO ADJUST LOGIC LEVELS

GND

RXD

TXD

VCC = +2V

UART/PROCESSOR

GND

VCC = +3.3V

ISL3330

VOH ≤ 2

VOH = 3.3V

VIH ≥ 2

ESD

DIODE

GND

RXD

TXD

VCC = +2V

UART/PROCESSOR

GND

VCC = +3.3V

ISL3331

VOH ≤ 2

VOH = 2V

VIH = 1.4V

ESD

DIODE

TABLE 5. VIH AND VIL vs VL FOR VCC = 3.3V

VL (V) VIH (V) VIL (V)

1.2 0.85 0.26

1.5 0.9 0.5

1.8 0.9 0.73

2.3 1.2 1.0

2.7 1.4 1.3

3.3 1.8 1.7

ISL3330, ISL3331

18 FN6361.0

May 20, 2008

slew limited edges permit longer unterminated networks, or

longer stubs off terminated busses, and help minimize EMI

and reflections. Nevertheless, for the best jitter performance

when driving long cables, the faster speed options may be

preferable, even at lower data rates. The faster output

transitions deliver less variability (jitter) when loaded with the

large capacitance associated with long cables. Of course,

faster transitions require more attention to ensuring short

stub lengths and quality terminations, so there are trade-offs

to be made. Assumi ng a jit te r budget of 10%, it is preferable

to go with the slow speed option for data rates of 115kbps or

less to minimize fast edge effects. Likewise, the medium

speed option is a good choice for data rates between

115kbps and 460kbps. For higher data rates, or when the

absolute best jitter is required, use the high speed option.

Evaluation Board

An evaluation board, part number ISL3331EVAL1Z, is

available to assist in assessing the dual protocol IC’s

performance. The evaluation board contains a QFN

packaged device, but because the same die is used in all

packages, the board is also useful for evaluating the

functionality of the other versions. The board’s design allows

for evaluation of all standard features, plus the QFN specific

features. Refer to the evaluation board application note for

details, and contact your sales representative for ordering

information.

FIGURE 12. USING ACTIVE LOW vs ACTIVE HIGH RX

ENABLE

0.1µF

VCC

GND

RXEN

DEN

+3.3V

ISL3331

Tx/Rx

ACTIVE HIGH RX ENABLE

0.1µF

VCC

GND

RXEN *

DEN

+3.3V

ISL3331

Tx/Rx

* QFN ONLY

ACTIVE LOW RX ENABLE

RXEN

1kΩ

OR NC

RXEN *

ISL3330, ISL3331

19 FN6361.0

May 20, 2008

Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified

FIGURE 13. RECEIVER OUTPUT CURRENT vs RECEIVER

OUTPUT VOLTAGE FIGURE 14. RECEIVE R HIGH OU TPUT VOLT AGE vs LOGIC

SUPPLY VOLTAGE (VL) (QFN ONLY)

FIGURE 15. RS-485, DRIVER OUTPUT CURRENT vs

DIFFERENTIAL OUTPUT VOLTAGE FIGURE 16. RS-485, DRIVER DIFFERENTIAL OUTPUT

VOLTAGE vs TEMPERATURE

FIGURE 17. RS-485, DRIVER OUTPUT CURRENT vs SHORT

CIRCUIT VOLTAGE FIGURE 18. SUPPLY CURRENT vs TEMPERATURE

RECEIVER OUTPUT VOLTAGE (V)

RECEIVER OUTPUT CURRENT (mA)

0.0

VOH, +25°C

VOH, +85°C

VOL, +25°C

VOL, +85°C

1.0 2.0 3.0 3.3 VL (V)

HIGH OUTPUT VOL TAGE (V)

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1.0 1.5 2.0 2.5 3.0

IOH = -1mA

IOH = -2mA

IOH = -6mA

IOH = -0.5mA

3.3

DIFFERENTIAL OUTPUT VOLTAGE (V)

DRIVER OUTPUT CURRENT (mA)

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 -40 0 50 85

TEMPERATURE (°C)

DIFFERENTIAL OUTPUT VOLTAGE (V)

-25 25 75

1.90

1.95

2.00

2.05

2.10

2.15

2.20

2.25

2.30

RDIFF = 54Ω

RDIFF = 100Ω

OUTPUT VOLTAGE (V)

-7 -6 -4 -2 0 2 4 6 8 10 12

OUTPUT CURRENT (mA)

-150

-100

-50

100

150

200

250

Y OR Z = HIGH

Y OR Z = LOW

+25°C

+85°C

-40°C

+25°C

+85°C

-40°C

-40 0 50 85

TEMPERATURE (°C)

ICC (mA)

-25 25 75

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

RS-232, RXEN, RXEN, ON = X, DEN = VCC

RS-485, DEN = GND, RXEN, RXEN = X, ON = VCC

RS-485, HALF DUPLEX, DEN = VCC, RXEN, RXEN, ON = X

RS-485, FULL DUPLEX, DEN = VCC, RXEN , RXEN, ON = X

RS-232, RXEN, RXEN = X, ON = VCC, DEN = GND

ISL3330, ISL3331

20 FN6361.0

May 20, 2008

FIGURE 19. RS-232, VL SUPPLY CURRENT vs VL VOLTAGE

(QFN ONLY) FIGURE 20. VCC and VL SHDN SUPPLY CURRENTS vs VL

VOLTAGE (QFN ONLY)

FIGURE 21. RS-485, DRIVER PROPAGATION DELAY vs

TEMPERATURE (SLOW DATA RATE, QFN ONLY) FIGURE 22. RS-485, DRIVER SKEW vs TEMPERATURE

(SLOW DATA RATE, QFN ONLY)

FIGURE 23. RS-485, DRIVER PROPAGATION DELAY vs

TEMPERATURE (MEDIUM DATA RATE) FIGURE 24. RS-485, DRIVER SKEW vs TEMPERATURE

(MEDIUM DATA RATE)

Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)

1.01.5 2.02.5 3.03.5 4.0

IL(µA)

VL (V)

VL ≤ VCC VL > VCC

RS-485, SLEW, SPB, RXEN = VL

NO LOAD

VIN = VL or GND

RS-232, SPB, RXEN = VL OR

RS-485, SLEW, SPB, RXEN = GND

RS-232, RXEN = GND, SPB = VL

DEN, RXEN, ON = GND

1.0 1.5 2.0 2.5 3.0 3.5 4.0

ICC AND IL (µA)

VL (V)

NO LOAD

VIN = VL OR GND

RXEN = VL

RS-232/RS-485 ICC

SPB = GND

SPB = VL

RS-485 IL

DEN, RXEN, DY, DZ/SLEW, ON = GND

SPB = VL

RS-232 IL

1550

1560

1570

1580

1590

1600

1610

1620

1630

1640

-40 0 50 85

TEMPERATURE (°C)

-25 25 75

PROPAGATION DELAY (ns)

tDLH

tDHL

RDIFF = 54Ω, CL = 100pF

tDHL

100

150

200

250

300

-40 0 50 85

TEMPERATURE (°C)

SKEW (ns)

-25 25 75

|tPLHZ - tPHLY|

|tPHLZ - tPLHY|

|tDLH - tDHL|

RDIFF = 54Ω, CL = 100pF

-40 0 50 85

TEMPERATURE (°C)

-25 25 75

PROPAGATION DELAY (ns)

tDLH

tDHL

RDIFF = 54Ω, CL = 100pF

515

520

525

530

535

540

545

550

-40 0 50 85

TEMPERATURE (°C)

SKEW (ns)

-25 25 75

16 RDIFF = 54Ω, CL = 100pF

|tPHLZ - tPLHY|

|tPLHZ - tPHLY|

|tDLH - tDHL|

ISL3330, ISL3331

21 FN6361.0

May 20, 2008

FIGURE 25. RS-485, DRIVER PROPAGATION DELAY vs

TEMPERATURE (FAST DATA RATE) FIGURE 26. RS-485, DRIVER SKEW vs TEMPERA TURE

(FAST DATA RATE)

FIGURE 27. RS-485, DRIVER AND RECEIVER WAVEFORMS,

LOW TO HIGH (SLOW DATA RATE, QFN ONLY) FIGURE 28. RS-485, DRIVER AND RECEIVER WAVEFORMS,

HIGH TO LOW (SLOW DATA RATE, QFN ONLY)

FIGURE 29. RS-485, DRIVER AND RECEIVER WAVEFORMS,

LOW TO HIGH (MEDIUM DATA RATE) FIGURE 30. RS-485, DRIVER AND RECEIVER WAVEFORMS,

HIGH TO LOW (MEDIUM DATA RATE)

Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)

-40 0 50 85

TEMPERATURE (°C)

-25 25 75

PROPAGATION DELAY (ns)

tDLH

RDIFF = 54Ω, CL = 100pF

tDHL

0.5

1.0

1.5

2.0

2.5

3.0

-40 0 50 85

TEMPERATURE (°C)

SKEW (ns)

-25 25 75

RDIFF = 54Ω, CL = 100pF

|tPLHZ - tPHLY|

|tPHLZ - tPLHY|

|tDLH - tDHL|

TIME (400ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

TIME (400ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

TIME (200ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

TIME (200ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

ISL3330, ISL3331

22 FN6361.0

May 20, 2008

FIGURE 31. RS-485, DRIVER AND RECEIVER WAVEFORMS,

LOW TO HIGH (FAST DATA RATE) FIGURE 32. RS-485, DRIVER AND RECEIVER WAVEFORMS,

HIGH TO LOW (FAST DATA RATE)

FIGURE 33. RS-232, TRANSMITTER OUTPUT VOL TAGE vs

LOAD CAPACITANCE FIGURE 34. RS-232, TRANSMITTER OUTPUT VOL TAGE vs

TEMPERATURE

FIGURE 35. RS-232, TRANSMITTER SHORT CIRCUIT

CURRENT vs TEMPERATURE FIGURE 36. RS-232, TRANSMITTER AND RECEIVER

WAVEFORMS AT 250kbps

Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)

TIME (10ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

TIME (10ns/DIV)

RECEIVER OUTPUT (V)

DRIVER OUTPUT (V)

DRIVER INPUT (V)

RDIFF = 54Ω, CL = 100pF

-7.5

-5.0

-2.5

2.5

7.5

1000 2000 3000 4000 50000

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

RS-232 REGION OF NONCOMPLIANCE

5.0

1 TRANSMITTER AT 250kbps or 400kbps,

VOUT+

VOUT -

OTHER TRANSMITTER AT 30kbps

400kbps

250kbps

ALL TOUTS LOADED WITH 3kΩ TO GND

-40 0 50 85

TEMPERATURE (°C)

TRANSMITTER OUTPUT VOLTAGE (V)

-25 25 75

-7.5

-5.0

5.0

7.5

2.5

-2.5

VOUT+

VOUT -

OUTPUTS STATIC

ALL TOUTS LOADED WITH 3kΩ TO GND

AND AT V+ OR V-

-40 0 50 85

TEMPERATURE (°C)

TRANSMITTER OUTPUT CURRENT (mA)

-25 25 75

-30

-20

-10

Y OR Z = HIGH

Y OR Z = LOW

VOUT SHORTED TO GND

2µs/DIV

CL = 4000pF, 1 CHANNEL SWITCHING

Y/A

-5

ISL3330, ISL3331

23 FN6361.0

May 20, 2008

FIGURE 37. RS-232, TRANSMITTER AND RECEIVER

WAVEFORMS AT 400kbps FIGURE 38. RS-232, RECEIVER OUTPUT + DUTY CYCLE vs

DATA RATE

FIGURE 39. RS-232, TRANSMITTER MAXIMUM DA T A RA TE vs

LOAD CAPACITANCE FIGURE 40. RS-232, TRANSMITTER OUTPUT VOL TAGE vs

DATA RATE

FIGURE 41. RS-232, TRANSMITTER SKEW vs DATA RATE

Die Characteristics

SUBSTRATE AND QFN PAD POTENTIAL

(POWERED UP):

GND

TRANSISTOR COUNT:

2490

PROCESS:

BiCMOS

Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)

2µs/DIV

CL = 1000pF, 1 CHANNEL SWITCHING

Y/A

-5

0 500 1000 1500 2000

DATA RATE (kbps)

RECEIVER + DUTY CYCLE (%)

FULL TEMP RANGE

SR IN = 15V/µs

SR IN = 100V/µs

VIN = ±5

0 1000 2000 3000 4000 5000

100

150

200

250

300

350

400

450

500

550

LOAD CAPACITANCE (pF)

DATA RATE (kbps)

2 TRANSMITTERS AT +85°C

1 TRANSMITTER AT +25°C

VOUT ≥ ±4V AND DUTY CYCLE BETWEEN 40% AND 60%

ALL TOUTS LOADED WITH 5kΩ TO GND

1 TRANSMITTER AT +85°C

2 TRANSMITTERS AT +25°C

0 100 200 300 400 500 600

-7.5

-5.0

5.0

7.5

2.5

-2.5

DATA RATE (kbps)

TRANSMITTER OUTPUT VOLTAGE (V)

+25°C

+85°C

+25°C

+85°C

VOUT -

1 TRANSMITTER SWITCHING

ALL TOUTS LOADED WITH 5kΩ TO GND, CL = 1000pF

RS-232 REGION OF NONCOMPLIANCE

VOUT+

250

300

350

400

450

500

550

600

650

DATA RATE (kbps)

SKEW (ns)

0 200 400 600 650

+25°C

+85°C

-40°C

ALL TOUTS LOADED WITH 3kΩ TO GND, CL = 1000pF

2 TRANSMITTERS SWITCHING

ISL3330, ISL3331

24 FN6361.0

May 20, 2008

ISL3330, ISL3331

Package Outline Drawing

L40.6x6

40 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE

Rev 3, 10/06

located within the zone indicated. Th e pin #1 indentifier may be

Unless otherwise specified, tol erance : Decim al ± 0.05

Tiebar shown (if present) is a non-functional feature.

The configuration of the pin #1 identifier is optio nal, but must be

between 0.15mm an d 0.3 0m m from the te rminal tip.

Dimension b applies to the metallized terminal and is measured

Dimensions in ( ) for Reference Only.

Dimensioning and tolerancing conform to AMSE Y14.5m-1994 .

either a mold or mark feature.

Dimensions are in millimeters.1.

NOTES:

(4X) 0.15

INDEX AREA

PIN 1

6.00

36X 0.50

4.5

40 PIN #1 INDEX AREA

BOTTOM VIEW

40X 0 . 4 ± 0 . 1

20 B0.10

11 MAC

4 . 10 ± 0 . 15

0 . 90 ± 0 . 1 C

SEATING PLANE

BASE PLANE

0.08

0.10

SEE DETAIL "X"

0 . 00 MIN.

DETAIL "X"

0 . 05 MAX.

0 . 2 REF

SIDE VIEW

TYPICAL RECOMMENDED LAND PATTERN

( 5 . 8 TYP )

( 4 . 10 )

( 36X 0 . 5 )

( 40X 0 . 23 )

( 40X 0 . 6 )

TOP VIEW 0 . 23 +0 . 07 / -0 . 05

All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.

Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without

notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and

reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result

from its use. No lice nse is gran t ed by i mpli catio n or other wise u nder an y p a tent or patent rights of I nter sil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

FN6361.0

May 20, 2008

ISL3330, ISL3331

Shrink Small Outline Plastic Packages (SSOP)

NOTES:

1. Symbols are defined in the “MO Series Symbol List” in Section

2.2 of Publication Number 95.

2. Dimensioning and tolerancing per ANSI Y14.5M-1982.

3. Dimension “D” does not include mold flash, protrusions or gate

burrs. Mold flash, protrusion and gate burrs shall not exceed

0.20mm (0.0078 inch) per side.

4. Dimension “E” does not include interlead flash or protrusions. In-

terlead flash and protrusions shall no t exceed 0.20mm (0.0078

inch) per side.

5. The chamfer on the body is optional. If it is not present, a visual

index feature must be located within the crosshatched area.

6. “L” is the length of terminal for soldering to a substrate.

7. “N” is the number of terminal positions.

8. Terminal numbers are shown for reference only.

9. Dimension “B” does not include dambar protrusion. Allowable

dambar protrusion shall be 0.13mm (0.005 inch) total in excess

of “B” dimension at maximum material condition.

10. Controlling dimension: MILLIMETER. Conver ted inch dimen-

sions are not necessarily exact.

INDEX

AREA E

123

-B-

0.25(0.010) C A

MBS

-A-

-C-

SEATING PLANE

0.10(0.004) C

H0.25(0.010) B

0.25

0.010

GAUGE

PLANE

M20.209 (JEDEC MO-150-AE ISSUE B)

20 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE

SYMBOL

INCHES MILLIMETERS

NOTESMIN MAX MIN MAX

A0.068 0.078 1.73 1.99

A1 0.002 0.008’ 0.05 0.21

A2 0.066 0.070’ 1.68 1.78

B0.010’ 0.015 0.25 0.38 9

C0.004 0.008 0.09 0.20’

D0.278 0.289 7.07 7.33 3

E0.205 0.212 5.20’ 5.38 4

e 0.026 BSC 0.65 BSC

H0.301 0.311 7.65 7.90’

L0.025 0.037 0.63 0.95 6

N20 207

α0 deg. 8 deg. 0 deg. 8 deg.

Rev. 3 11/02