6-21
File Number
4458.3
1-800-999-9445 or 1-847-824-1188
|
Copyright
©
Littelfuse, Inc. 1999
SP724
SCR/Diode Array for ESD and Transient
Over-Voltage Protection
The SP724 is a quad array of transient voltage clamping
circuits designed to suppress ESD and other transient
over-voltage events. The SP724 is used to help protect
sensitive digital or analog input circuits on data, signal, or
control lines operating on power supplies up to 20VDC.
The SP724 is comprised of bipolar SCR/diode structures to
protect up to four independent lines by clamping transients
of either polarity to the power supply rails. The SP724 offers
very low leakage (1nA Typical) and low input capacitance
(3pF Typical). Additionally, the SP724 is rated to withstand
the IEC 1000-4-2 ESD specification for both contact and air
discharge methods to level 4.
The SP724 is connected to the sensitive input line and its
associated power supply lines. Clamping action occurs
during the transient pulse, turning on the diode and fast
triggering SCR structures when the voltage on the input line
exceeds one V
BE
threshold above the V+ supply (or one V
BE
threshold below the V- supply). Therefore, the SP724
operation is unaffected by poor power supply regulation or
voltage fluctuations within its operating range.
Pinout
SP724
(SOT-23)
TOP VIEW
Features
• An Array of 4 SCR/Diode Pairs in 6-Lead SOT-23
• ESD Capability per HBM Standards
- IEC 1000-4-2, Direct Discharge . . . . . . . . 8kV (Level 4)
- IEC 1000-4-2, Air Discharge. . . . . . . . . . 15kV (Level 4)
- MIL STD 3015.7 . . . . . . . . . . . . . . . . . . . . . . . . . . .>8kV
• Input Protection for Applications with Power Supplies Up
to +20V (Single-Ended Voltage), and
±
10V (Differential
Voltage)
• Rated for Peak Current Capability
• Low Input Leakage. . . . . . . . . . . . . . . . . . . . . .1nA Typical
• Low Input Capacitance. . . . . . . . . . . . . . . . . . . 3pF Typical
• Operating Temperature Range . . . . . . . . . -40
o
C to 105
o
C
Applications
• Microprocessor/Logic Input Protection
• Data Bus Protection
• Analog Device Input Protection
• Voltage Clamp
Functional Block Diagram
NOTES:
1. The design of the SP724 SCR/Diode ESD Protection Arrays is
covered by Littelfuse patent 4567500.
2. The full ESD capability of the SP724 is achieved when wired in a
circuit that includes connection to both the V+ and V- pins. When
handling individual devices, follow proper procedures for
electrostatic discharge.
Ordering Information
PART
NUMBER
TEMP. RANGE
(
o
C) PACKAGE PKG. NO.
SP724AH -40 to 105 6 Ld Plastic SOT-23 P6.064
SP724AHT -40 to 105 Tape and Reel
SP724W -40 to 105 Wafer on Film Frame
123
654
2
V+
V-
IN
3, 4 AND 6
IN
1
5
Data Sheet April 1999
[ /Title
(SP724
)
/Sub-
ject
(SCR/
Diode
Array
for
ESD
and
Tran-
sient
Over-
Volt-
age
Protec-
tion)
/Autho
r ()
/Key-
words
(TVS,
Tran-
sient
Sup-
pres-
sion,
Protec-
tion,
Auto-
motive,
Load
Dump,
Alter-
nator
Field
Decay,
6-22
ESD Rating
ESD rating is dependent on the defined test standard. The
evaluation results for various test standards and methods
based on Figure 1 are shown in Table 1.
The SP724 has a Level 4 rating when tested to the IEC
1000-4-2 Human Body Model (HBM) standard and connected
in a circuit in which the V+ and V- pins have a return path to
ground. Level 4 specifies a required capability greater than 8kV
for direct discharge and greater than 15kV for air discharge.
The “Modified” MIL-STD-3015.7 condition is defined as an “in-
circuit” method of ESD testing, the V+ and V- pins have a return
path to ground. The SP724 ESD capability is greater than 8kV
with 100pF discharged through 1.5k
Ω
. By strict definition of the
standard MIL-STD-3015.7 method using “pin-to-pin” device
testing, the ESD voltage capability is greater than 2kV.
For the SP724 EIAJ IC121 Machine Model (MM) standard,
the ESD capability is typically greater than 1.8kV with 200pF
discharged through 0k
Ω
.
The Charged Device model is based upon the self-
capacitance of the SOT-23 package through 0k
Ω
.
Absolute Maximum Ratings Thermal Information
Continuous Supply Voltage, (V+) - (V-) . . . . . . . . . . . . . . . . . . +20V
Forward Peak Current, I
IN
to V
CC
, GND
(Refer to Figure 6)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±
2.2A, 100
µ
s
ESD Ratings and Capability - See Figure 1, Table 1
Thermal Resistance (Typical, Note 3)
θ
JA
(
o
C/W)
SOT Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Maximum Storage Temperature Range . . . . . . . . . . -65
o
C to 150
o
C
Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .150
o
C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300
o
C
(SOT - Lead Tips Only)
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
3.
θ
JA
is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications
T
A
= -40
o
C to 105
o
C, V
IN
= 0.5V
CC
, Unless Otherwise Specified
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range,
V
SUPPLY
= [(V+) - (V-)] (Notes 4, 5)
V
SUPPLY
1-20V
Forward Voltage Drop
IN to V- V
FWDL
I
IN
= 2A (Peak Pulse) - 2 - V
IN to V+ V
FWDH
-2- V
Input Leakage Current I
IN
-10 1 10 nA
Quiescent Supply Current I
QUIESCENT
V+ = 20V, V- = GND - - 100 nA
Equivalent SCR ON Threshold (Note 6) - 1.1 - V
Equivalent SCR ON Resistance V
FWD
/I
FWD
(Note 6) - 1.0 -
Ω
Input Capacitance C
IN
-3-pF
NOTES:
4. In automotive and other battery charging systems, the SP724 power supply lines should be externally protected for load dump and reverse battery. When
the V+ and V- Pins are connected to the same supply voltage source as the device or control line under protection, a current limiting resistor should be
connected in series between the external supply and the SP724 supply pins to limit reverse battery current to within the rated maximum limits.
5. Bypass capacitors of typically 0.01
µ
F or larger should be connected closely between the V+ and V- Pins for all applications.
6. Refer to the Figure 3 graph for definitions of equivalent “SCR ON Threshold” and “SCR ON Resistance”. These characteristics are given here
for information to determine peak current and dissipation under EOS conditions.
TABLE 1. ESD TEST CONDITIONS
STANDARD TYPE/MODE R
D
C
D
±
V
D
IEC 1000-4-2
(Level 4)
HBM, Air Discharge 330
Ω
150pF 15kV
HBM, Direct Discharge 330
Ω
150pF 8kV
MIL-STD-3015.7 Modified HBM 1.5k
Ω
100pF 8kV
†
Standard HBM 1.5k
Ω
100pF 2kV
EIAJ IC121 Machine Model 0k
Ω
200pF 400V
US ESD DS 5.3 Charged Device Model 0k
Ω
NA 3kV
†
Upper limit of laboratory test set.
H.V.
SUPPLY
±VD
IN
DUT
CD
R1
IEC 1000-4-2: R150 to 100MΩ
RD
CHARGE
SWITCH
DISCHARGE
SWITCH
MIL STD 3015.7: R11 to 10MΩ
FIGURE 1. ELECTROSTATIC DISCHARGE TEST
SP724
6-23
Typical Performance Curves
FIGURE 2. LOW CURRENT SCR FORWARD VOLTAGE DROP
CURVE
FIGURE 3. HIGH CURRENT SCR FORWARD VOLTAGE DROP
CURVE
600 800 1000 1200
FORWARD SCR VOLTAGE DROP (mV)
200
160
120
80
40
0
FORWARD SCR CURRENT (mA)
TA = 25oC
SINGLE PULSE
5
4
3
2
1
0
FORWARD SCR CURRENT (A)
TA = 25oC
SINGLE PULSE
VFWD
IFWD
01 23
FORWARD SCR VOLTAGE DROP (V)
EQUIV. SAT. ON
THRESHOLD ~ 1.1V
+VCC
INPUT
DRIVERS
SP724 INPUT PROTECTION CIRCUIT (1 OF 4 SHOWN)
OR
SIGNAL
SOURCES
IN 1, 3, 4 AND 6
SP724
V-
TO +VCC
LINEAR OR
DIGITAL IC
INTERFACE
V+
+VCC
0.01µF
FIGURE 4. TYPICAL APPLICATION OF THE SP724 AS AN INPUT CLAMP FOR OVER-VOLTAGE, GREATER THAN 1VBE ABOVE V+ OR
LESS THAN -1VBE BELOW V-
SP724
6-24
Peak Transient Current Capability for Long Duration Surges
The peak transient current capability is inversely
proportional to the width of the current pulse. Testing was
done to fully evaluate the SP724’s ability to withstand long
duration current pulses using the circuit of Figure 5. Figure 6
shows the point of overstress as defined by increased
leakage in excess of the data sheet published limits. The
safe operating range of the transient peak current should be
limited to no more than 75% of the measured overstress
level for any given pulse width as shown in the curve of
Figure 6.
The test circuit of Figure 5 is shown with a positive pulse
input. For a negative pulse input, the (-) current pulse input
goes to an SP724 ‘IN’ input pin and the (+) current pulse
input goes to the SP724 V- pin. The V+ to V- supply of the
SP724 must be allowed to float. (i.e., It is not tied to the
ground reference of the current pulse generator.)
Note that two input pins of the SP724 may be paralleled to
improve current (and ESD) capability. The sustained peak
current capability is increased to nearly twice that of a single
pin.
FIGURE 5. TYPICAL SP724 PEAK CURRENT TEST CIRCUIT
WITH A VARIABLE PULSE WIDTH INPUT
+
-CURRENT
SENSE
VOLTAGE
PROBE
+
-
R1 ~ 10Ω TYPICAL
SP724
VX
VX ADJ. 10V/A TYPICAL
R1
(-)
(+)
C1 ~ 100µF
C1
VARIABLE TIME DURATION
CURRENT PULSE GENERATOR
123
654
FIGURE 6. SP724 TYPICAL NONREPETITIVE PEAK CURRENT PULSE CAPABILITY
0.001 0.01 0.1 1
SQUARE WAVE PULSE WIDTH (ms)
PEAK CURRENT (A)
10
7
6
5
4
3
2
1
0
100 1000
NOTE:
OF THE VALUES SHOWN.
PULSE WIDTH TO BE NO GREATER THAN 75%
MAXIMUM PEAK CURRENT FOR A GIVEN
V+ TO V- SUPPLY = 15V
TA = 25oC
8
TO ENSURE SAFE OPERATION LIMIT THE
SP724
6-25
Ordering Information
Small Outline Transistor Plastic Packages (SOT23-6)
NOTES:
1. Dimensioning and tolerances per ANSI 14.5M-1982.
2. Package conforms to EIAJ SC-74 (1992).
3. Dimensions D and E1 are exclusive of mold flash, protrusions, or
gate burrs.
4. Footlength L measured at reference to seating plane.
5. “L” is the length of flat foot surface for soldering to substrate.
6. “N” is the number of terminal positions.
7. Controlling dimension: MILLIMETER. Converted inch
dimensions are not necessarily exact.
SP 724 AH
PREFIX
SP: Silicon Protection Series
PART NUMBER
AMBIENT TEMPERATURE
RANGE DESIGNATOR
A: -40oC to 105oC
PACKAGE DESIGNATOR
H: SOT-23, 6 Lead
W: Wafer
T
SUFFIX
T: Tape and Reel
D
e1
E E1
L
C
L
C
α
C
L
e
b
C
L
A2
AA1
C
L
0.20 (0.008) M
0.10 (0.004) C
C
-C-
SEATING
PLANE
12 3
456
P6.064
6 LEAD SMALL OUTLINE TRANSISTOR PLASTIC PACKAGE
SYMBOL
INCHES MILLIMETERS
NOTESMIN MAX MIN MAX
A 0.036 0.057 0.90 1.45 -
A1 0.000 0.0059 0.00 0.15 -
A2 0.036 0.051 0.90 1.30 -
b 0.0138 0.0196 0.35 0.50 -
C 0.0036 0.0078 0.09 0.20 -
D 0.111 0.118 2.80 3.00 3
E 0.103 0.118 2.60 3.00 -
E1 0.060 0.068 1.50 1.75 3
e 0.0374 Ref 0.95 Ref -
e1 0.0748 Ref 1.90 Ref -
L 0.004 0.023 0.10 0.60 4, 5
N6 66
α
0
o
10
o
0
o
10
o
-
Rev. 1 2/98
SP724
6-26
SP724
SOT23
8mm TAPE AND REEL
GENERAL INFORMATION
1. 3000 PIECES PER REEL.
2. ORDER IN MULTIPLES OF FULL REELS ONLY.
3. MEETS EIA-481 REVISION "A" SPECIFICATIONS.
2.0mm
4.0mm
C
L
1.75mm
1.5mm
DIA. HOLE
8mm
4.0mm
8.4mm
180mm
14.4mm
13mm
60mm
ACCESS HOLE
COVER TAPE
Rev. 0 2/99
USER DIRECTION OF FEED PIN 1
SOT-23 (8mm POCKET PITCH)
