DS229
Triple RS–232 Transmitter/Receiver
DS229
021998 1/9
FEATURES
•Compatible with DS1229
•5V operation
•20–pin DIP or SOIC package
•20–pin TSSOP package for height restricted applica-
tions
•Operate from single +5V power
•Meets all EIA–232E and V.28 specifications
•Uses small capacitors: 0.1 µF
•Optional industrial temperature range available
(–40°C to +85°C)
ORDERING INFORMATION
DS229 20–pin DIP
DS229N 20–pin DIP (Industrial)
DS229S 20–pin SOIC
DS229SN 20–pin SOIC (Industrial)
DS229E 20–pin TSSOP
DS229EN 20–pin TSSOP (Industrial)
PIN ASSIGNMENT
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
T3IN
R3OUT
1
2
3
4
5
6
7
8
9
10
C1+
V+
C1–
C2+
C2–
V–
T2OUT
R2IN
T3OUT
R3IN
20
19
18
17
16
15
14
13
12
11
20–PIN DIP, SOIC AND TSSOP
PIN DESCRIPTION
VCC – +5 V olt Supply
GND – Ground
V+ – Positive Supply Output
V– – Negative Supply Output
T1IN, T2IN, T3IN – RS–232 Driver Inputs
T1OUT, T2OUT, T 3OUT – RS–232 Driver Outputs
R1IN, R2IN, R3IN – Receiver Inputs
R1OUT, R2OUT, R3OUT – Receiver Outputs
C1+, C1– – Capacitor 1 Connections
C2+, C2– – Capacitor 2 Connections
DESCRIPTION
The DS229 is a triple RS–232 driver/receiver pair that
generates RS–232 voltage levels from a single +5 volt
power supply. Additional ±12 volt supplies are not
needed since the DS229 uses on–board charge pumps
to convert the +5 volt supply to ±10 volts. The DS229 is
fully compliant with EIA RS–232E and V.28/V.24 stan-
dards. The DS229 contains three drivers and three
receivers. Driver slew rates and data rates are guaran-
teed up to 1 16 kbits/sec. The DS229 operates with only
0.1 µF charge pump capacitors.
OPERATION
The diagram in Figure 1 shows the main elements of the
DS229. The following paragraphs describe the function
of each pin.
DS229
021998 2/9
FUNCTIONAL DIAGRAM OF DS229 Figure 1
+5V TO +10V
VOLTAGE DOUBLER
+10V TO –10V
VOLTAGE INVERTER
+5V INPUT C3
+
2 +10V
20
+
C5
VCC V+C1+
C1–
C2+
C2– V– –10V
6
+C4
RS–232
OUTPUTS
RS–232
INPUTS
7
9
17
8
1
3
4
5
14
12
16
13
400k
+5V
400k
+5V
GND
5k
5k
TTL/CMOS
TTL/CMOS
INPUTS
OUTPUTS
T2IN
T3IN
R1OUT
R2OUT
T2OUT
T3OUT
R1IN
R2IN
+
+
19
1011 R3OUT R3IN
1815
400k
+5V
T1IN T1OUT
5k
NOTE: C5 is a recommended decoupling capacitor
which is the same value as C1, C2, C3, and C4.
DS229
021998 3/9
PIN DESCRIPTIONS
VCC, GND: DC power is provided to the device on these
pins. VCC is the +5 volt input.
V+: Positive supply output (RS–232). V+ requires an
external storage charge capacitor of at least 0.1 µF. A
larger capacitor (up to 10 µF) can be used to reduce
supply ripple.
V–: Negative supply output (RS–232). V– requires an
external storage capacitor of at least 0.1 µF. A larger
capacitor (up to 10 µF) can be used to reduce supply rip-
ple.
T1IN, T2IN, T3IN: Standard TTL/CMOS inputs for the
RS–232 drivers. The inputs of unused drivers can be
left unconnected since each input has a 400 kΩ pull–up
resistor.
T1OUT, T2OUT, T3OUT: Driver outputs at RS–232 levels.
Driver output swing meets RS–232 levels for loads up to
3 kΩ. These driver outputs provide current necessary to
meet RS–232 levels for loads up to 2500 pF.
R1IN, R2IN, R3IN: Receiver inputs. These inputs accept
RS–232 level signals (±25 volts) into a protected 5 kΩ
terminating resistor. Each receiver provides 0.5V hys-
teresis (typical) for noise immunity.
R1OUT, R2OUT, R3OUT: Receiver outputs at TTL/CMOS
levels.
C1+, C1–, C2+, C2–: Charge pump capacitor inputs.
These pins require two external capacitors (0.1 µF mini-
mum, 10 µF maximum and should be the same size as
C3 and C4). Capacitor 1 is connected between C1+ and
C1–. Capacitor 2 is connected between C2+ and C2–.
Capacitor C1 can be omitted if +12 volts is connected
directly to V+. Likewise, C2 can be omitted if –12V is
connected directly to V–.
DUAL CHARGE PUMP CONVERTERS
The DS229 has a two stage on–board charge pump cir-
cuit that is used to generate ±10 volts from a single +5
volt supply. In the first stage, capacitor C1 doubles the
+5V supply to +10 volts which is then stored on capaci-
tor C3. The second stage uses capacitor C2 to invert
the +10V potential to –10V. This charge is then stored
on capacitor C4. The ±10 volt supplies allow the DS229
to provide the necessary output levels for RS–232 com-
munication. The DS229 will operate with charge pump
capacitors as low as 0.1 µF. Larger capacitors (up to 10
µF) can be used to reduce supply ripple.
RS–232 DRIVERS
The three RS–232 drivers are powered by the internal
±10 volt supplies generated by the on–board charge
pump. The driver inputs are both TTL and CMOS com-
patible. Each input has an internal 400 kΩ pull–up resis-
tor so that unused transmitter inputs can be left uncon-
nected. The open circuit output voltage swing is from
(V+ – 0.6) to V– volts. Worst case conditions for
EIA–232E/V.28 of ±5 volt driving a 3 kΩ load and 2500
pF are met at maximum operating temperature and VCC
equal to 4.5 volts. Typical voltage swings of ±8 volts
occur when loaded with a nominal 5 kΩ RS–232
receiver. As required by EIA–232E and V.28 specifica-
tions, the slew rate at the output is limited to less than 30
volts/µs. Typical slew rates are 20 volts/µs unloaded
and 12 volts/µs with 3 kΩ and 2500 pF load. These slew
rates allow for bit rates of over 116 kbits/s. Driver out-
puts maintain high impedance when power is off.
RS–232 RECEIVERS
The three receivers conform fully to the RS–232E speci-
fications. The input impedance is typically 5 kΩ and can
withstand up to ±30 volts with or without VCC applied.
The input switching thresholds are within the ±3 volt limit
of RS–232E specification with an input threshold low of
0.8 volts and an input threshold high of 2.4 volts. The
receivers have 0.5 volts of hysteresis (typical) to
improve noise rejection. The TTL/CMOS compatible
outputs of the receivers will be low whenever the
RS–232 input is greater than 2.4 volts. The receiver out-
put will be high when the input is floating or driven
between +0.8 volts and –25 volts.
DS229
021998 4/9
ABSOLUTE MAXIMUM RATINGS*
Absolute Maximum Ratings
VCC –0.3V to +7.0V
V+ (VCC–0.3V) to +14V
V– +0.3V to –14V
Input Voltages
TIN –0.3V to (VCC+0.3V)
RIN ±30V
Output Voltages
TOUT (V+ + 0.3V) to (V– – 0.3V)
ROUT –0.3V to (VCC + 0.3V)
Short Circuit Duration, TOUT Continuous
* This is a stress rating only and functional operation of the device at these or any other conditions above those
indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS (0°C to 70°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Operating Supply Votlage VCC 4.5 5.5 V 1
DC ELECTRICAL CHARACTERISTICS (0°C to 70°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Power Supply Current (No Load) ICC1 615 mA
Power Supply Current (3 kΩ Load
All Outputs) ICC2 22.5 mA
RS–232 Transmitters
Output Voltage Swing VORS ±5±8 V 2
Input Logic Threshold Low VTTL 0.8 1.4 V
Input Logic Threshold High VTTH 1.4 2.0 V
Data Rate fD200 116 kbits/s
Logic Pull–up/Input Current IPU 540 µA
T ransmitter Output Resistance ROUT 300 10M Ω3
Output Short–Circuit Current ITSC ±15 ±30 ±100 mA 4
DS229
021998 5/9
DC ELECTRICAL CHARACTERISTICS (continued) (0°C to 70°C)
RS–232 Receivers
RS–232 Input Voltage Operating
Range VIR ±25 ±30 V
RS–232 Input Threshold Low VRTL 0.8 1.3 V
RS–232 Input Threshold High VRTH 1.8 2.4 V
RS–232 Input Hysteresis VHY 0.2 0.5 1 V
RS–232 Input Resistance RIN 3 5 7 kΩ
TTL/CMOS Output Voltage Low VROL 0.2 0.4 V 5
TTL/CMOS Output Voltage High VROH 3.5 VCC–0.2 V 6
TTL/CMOS Output Short Circuit
Current (VOUT=GND) IRSC –2 –10 mA
TTL/CMOS Output Short Circuit
Current (VOUT=VCC)IRSC 10 30 mA
AC ELECTRICAL CHARACTERISTICS (0°C to 70°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
T ransition Slew Rate tSR 612 30 V/µs 7
T ransmitter Propagation
Delay TTL to RS–232 tPHLT
tPLHT 1.3
1.5 3.5
3.5 µs
µs
Receiver Propagation
Delay RS–232 to TTL tPHLR
tPLHR 0.5
0.6 1
1µs
µs
T ransmitter + to – Propagation
Delay Difference tPHLT
–tPLHT 300 ns
Receiver + to – Propagation
Delay Difference tPHLR
–tPLHR 100 ns
NOTES:
1. All voltages are referenced to ground.
2. All transmitter outputs loaded with 3 kΩ to ground.
3. VCC = V+ = V– = 0V; VOUT = ±2V .
4. VOUT = 0V.
5. IOUT = 3.2 mA.
6. IOUT = –1.0 mA.
7. CL = 50 pF – 2500 pF; RL = 3 kΩ – 7 kΩ; VCC = 5V; TA = 25°C.
DS229
021998 6/9
TRANSMITTER PROPAGATION DELAY TIMING Figure 2
tPLHT tPHLT
INPUT
OUTPUT
+3V
0V
V+
0V
V–
RECEIVER PROPAGATION DELAY TIMING Figure 3
tPHLR tPLHR
50% 50%
0V
INPUT
OUTPUT VCC
GND
+3V
–3V
DS229
021998 7/9
20–PIN DIP (300 MIL)
A
B
C
E
F
GH
J
K
D
1
PKG 20-PIN
DIM MIN MAX
A IN.
MM 0.970
24.63 1.040
26.42
B IN.
MM 0.240
6.09 0.270
6.86
C IN.
MM 0.120
3.05 0.140
3.56
D IN.
MM 0.295
7.49 0.325
8.26
E IN.
MM 0.015
0.38 0.040
1.02
F IN.
MM 0.120
3.04 0.140
3.56
G IN.
MM 0.090
2.23 0.110
2.79
H IN
MM 0.310
7.87 0.390
9.91
J IN
MM 0.008
0.20 0.012
0.30
K IN.
MM 0.015
0.38 0.021
0.53
DS229
021998 8/9
20–PIN SOIC (300 MIL)
E1 H
L
A
A1
A2
D
1
N
b
e
C
Θ
PKG 20–PIN
DIM MIN MAX
A IN.
MM 0.094
2.39 0.105
2.67
A1 IN.
MM 0.004
0.102 0.012
0.30
A2 IN.
MM 0.089
2.26 0.095
2.41
b IN.
MM 0.013
0.33 0.020
0.51
C IN.
MM 0.009
0.229 0.013
0.33
D IN.
MM 0.498
12.65 0.511
12.99
e IN.
MM 0.050 BSC
1.27 BSC
E1 IN
MM 0.290
7.37 0.300
7.62
H IN
MM 0.398
10.11 0.416
10.57
L IN.
MM 0.016
0.40 0.040
1.02
Θ0°8°
DS229
021998 9/9
20–PIN TSSOP
D
H
E
SEE DETAIL A
DETAIL A
A1
A
B
L
G
e1
c
phi
n
A2
DIM MIN MAX
A MM –1.10
A1 MM 0.05 –
A2 MM 0.75 1.05
C MM 0.09 0.18
L MM 0.50 0.70
e1 MM 0.65 BSC
B MM 0.18 0.30
D MM 6.40 6.90
E MM 4.40 NOM
G MM 0.25 REF
H MM 6.25 6.55
phi 0°8°
