6-6

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 10

µs 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.

+

-

CURRENT

SENSE

VOLTAGE

PROBE

14

15

16

9

13

12

11

10

1

2

3

4

5

7

6

8

IN

IN

IN

IN

IN

IN

V-

IN

V+

IN

IN

IN

IN

IN

IN

IN

+

-

SP720

(-)

(+)

C1

µF

C1

VARIABLE TIME DURATION

CURRENT PULSE GENERATOR

FIGURE 5. TYPICAL SP720 PEAK CURRENT TEST CIRCUIT

WITH A VARIABLE PULSE WIDTH INPUT

0.001

0.01

0.1

1

PULSE WIDTH TIME (ms)

10

7

6

5

4

3

2

1

0

0V

5V

15V

V+ TO V- SUPPLY

100

1000

10

9

30V

15V

CAUTION: SAFE OPERATING CONDITIONS LIMIT

OF THE VALUES SHOWN ON EACH CURVE.

PULSE WIDTH TO BE NO GREATER THAN 75%

THE MAXIMUM PEAK CURRENT FOR A GIVEN

SINGLE PIN STRESS CURVES

DUAL PIN STRESS CURVE

8

FIGURE 6. SP720 TYPICAL SINGLE PULSE PEAK CURRENT CURVES SHOWING THE MEASURED POINT OF OVER-STRESS IN

SP720