© 2013 Littelfuse, Inc.

Specifications are subject to change without notice.

Revised: 04/24/13

General Purpose ESD Protection - SP724 Series

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 4. Figure

5 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 5.

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 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

+

-

SP724

(-)

(+)

C1 ~ 100 µF

VARIABLE TIME DURATION

CURRENT PULSE GENERATOR

0.001

0.01

0.1

1

10

7

6

5

4

3

2

1

0

100

1000

8

SQUARE WAVE PULSE WIDTH (ms)

NOTE:TO ENSURE SAFE OPERATION LIMIT

THE MAXIMUM PEAK CURRENT FOR A GIVEN

PULSE WIDTH TO BE NO GREATER THAN 75%

OF THE VALUES SHOWN.

T

V+ TO V-SUPPLY = 15V

Showing the Measured Point of Overstress in Amperes vs

pulse width time in milliseconds

Figure 5: SP724 Typical Nonrepetitive Peak Current

Pulse Capability

Figure 4: Typical SP724 Peak CurrentTest Circuit

with a Variable Pulse Width Input