Littelfuse SP725 Series - Manual (Page 4)

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 04/24/13
TVS Diode Arrays
(SPA ® Diodes)
General Purpose ESD Protection - SP725 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 SP725 ’s ability to withstand
a wide range of peak current pulses vs time. 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 SP725 ‘IN’ input pin and the (+) current pulse
input goes to the SP725 V- pin. The V+ to V- supply of the
SP725 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 ambient temperature, improving as the temperature
is reduced. Peak current curves are shown for ambient
temperatures of 25 º C and 105 º C and a 15V power supply
condition. 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 curves of Figure 5.
Note that adjacent input pins of the SP725 may be
paralleled to improve current (and ESD) capability. The
sustained peak current capability is increased to nearly
twice that of a single pin.
+
-
CURRENT
SENSE
VOLTAGE
PROBE
6
7
8
5
1
2
3
4
IN
IN
IN
V-
V+
V+
V- +
-
R 1 ~ 10 Ω TYPICAL
SP725
V X
V X ADJ. 10V/A TYPICAL
R 1
( - )
(+)
C1 ~ 100 μF
VARIABLE TIME DURATION
CURRENT PULSE GENERATOR
IN
C1
Figure 5: SP725 Typical Nonrepetitive Peak Current
Pulse Capability
14
12
10
8
6
4
2
0
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
V+ TO V-SUPPLY = 15V
0.0001 0.01 0.1 1 10 100 1000
PULSE WIDTH TIME (ms)
T
A
= 25ºC
T
A
= 105ºC
PEAK CURRENT (A)
Showing the Measured Point of Overstress in Amperes vs
pulse width time in milliseconds
Figure 4: Typical SP725 Peak Current Test Circuit
with a Variable Pulse Width Input