©2011 Littelfuse, Inc.

Specifications are subject to change without notice.

Please refer to

58

Revision: April 14, 2011

SP720 Lead-Free/Green Series

General Purpose ESD Protection - SP720 Series

Peak Transient Current Capability for Long Duration Surges

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 4.

The test circuit of Figure 4 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

5 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 5.

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 5 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 5.

+

-

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

C1

VARIABLE TIME DURATION

CURRENT PULSE GENERA TOR

0.001

0.01

0.1

1

10

7

6

5

4

3

2

1

0

0V

5V

15V

100

1000

10

9

30V

15V

8

CAUTION: SAFE OPERATING CONDITIONS LIMIT

THE MAXIMUM PEAK CURRENT FOR A GIVEN

PULSE WIDTH TO BE NO GREATER THAN 75%

OF THE VALUES SHOWN ON EACH CURVE.

SINGLE PIN STRESS CURVES

DUAL PIN STRESS CURVE

V+ TOV-SUPPLY

PULSE WIDTH TIME (ms)

Showing the Measured Point of Overstress in Amperes vs

pulse width time in milliseconds (T

Figure 5: SP720 Typical Nonrepetitive Peak Current

Pulse Capability

Figure 4: Typical SP720 Peak Current Test Circuit

with a Variable Pulse Width Input