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5

TVS Diode Arrays

SP724

SCR Diode Array for ESD and Transient Overvoltage Protection

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

+

-

SP724

(-)

(+)

VARIABLETIME DURATION

CURRENT PULSE GENERATOR

FIGURE 6. SP724 TYPICAL NONREPETITIVE PEAK CURRENT PULSE CAPABILITY

0.001

0.01

0.1

1

SQUARE WAVE PULSE WIDTH (ms)

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

8

TO ENSURE SAFE OPERATION LIMIT THE