SP720 Datasheet, PDF (4/6 Pages) Harris Corporation – Electronic Protection Array for ESD and Over-Voltage Protection

SP720
Peak Transient Current Capability of the SP720
The peak transient current capability rises sharply as the
width of the current pulse narrows. Destructive testing was
done to fully evaluate the SP720’s ability to withstand a wide
range of transient current pulses. The circuit used to
generate current pulses is shown in Figure 5.
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 SP720 ‘IN’ input pin and the (+) current pulse
input goes to the SP720 V- pin. The V+ to V- supply of the
SP720 must be allowed to float. (i.e., It is not tied to the
ground reference of the current pulse generator.) Figure 6
shows the point of overstress as defined by increased
leakage in excess of the data sheet published limits.
The maximum peak input current capability is dependent on
the V+ to V- voltage supply level, improving as the supply
voltage is reduced. Values of 0, 5, 15 and 30 voltages are
shown. 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 Figure 6.
When adjacent input pins are paralleled, the sustained peak
current capability is increased to nearly twice that of a single
pin. For comparison, tests were run using dual pin
combinations 1+2, 3+4, 5+6, 7+9, 10+11, 12+13 and 14+15.
The overstress curve is shown in Figure 6 for a 15V supply
condition. The dual pins are capable of 10A peak current for
a 10µs pulse and 4A peak current for a 1ms pulse. The
complete for single pulse peak current vs. pulse width time
ranging up to 1 second are shown in Figure 6.
VARIABLE TIME DURATION
+
R₁
CURRENT PULSE GENERATOR
V_G
-
CURRENT
SENSE
(-)
(+)
VOLTAGE
PROBE
R₁ ~ 10Ω TYPICAL
V_G ADJ. 10V/A TYPICAL
C1 ~ 100µF
1 IN
V+ 16
2 IN
IN 15
3 IN
IN 14
4 IN
IN 13
SP720
5 IN
IN 12
6 IN
IN 11
7 IN
IN 10
8 V-
IN 9
+
C1 _-
FIGURE 5. TYPICAL SP720 PEAK CURRENT TEST CIRCUIT
WITH A VARIABLE PULSE WIDTH INPUT
10
9
8
CAUTION: SAFE OPERATING CONDITIONS LIMIT
THE MAXIMUM PEAK CURRENT FOR A GIVEN
7
PULSE WIDTH TO BE NO GREATER THAN 75%
OF THE VALUES SHOWN ON EACH CURVE.
6
SINGLE PIN STRESS CURVES
DUAL PIN STRESS CURVE
5
4
3
2
1
0
0.001
0.01
0V
5V
30V
V+ TO V- SUPPLY
0.1
1
10
PULSE WIDTH TIME (ms)
15V
15V
100
1000
FIGURE 6. SP720 TYPICAL SINGLE PULSE PEAK CURRENT CURVES SHOWING THE MEASURED POINT OF OVER-STRESS IN
AMPERES vs PULSE TIME IN MILLISECONDS (T_A = 25^oC)
6-6