_______________________SCR Latchup
Like all junction-isolated CMOS circuits, the ICL7665 has
an inherent four-layer or SCR structure that can be
triggered into destructive latchup under certain con-
ditions. Avoid destructive latchup by following these
precautions:
1) If either V
SET
terminal can be driven to a voltage
greater than V+ or less than ground, limit the input
current to 500µA maximum. Usually, an input volt-
age divider resistance can be chosen to ensure
the input current remains below 500µA, even
when the input voltage is applied before the
ICL7665 V+ supply is connected.
2) Limit the rate-of-rise of V+ by using a bypass
capacitor near the ICL7665. Rate-of-rise SCRs
rarely occur unless: a) the battery has a low
impedance—as is the case with NiCd and lead
acid batteries; b) the battery is connected directly
to the ICL7665 or is switched on via a mechanical
switch with low resistance; or c) there is little or no
input filter capacitance near the ICL7665. In line-
powered systems, the rate-of-rise is usually limited
by other factors and will not cause a rate-of-rise
SCR action under normal circumstances.
3) Limit the maximum supply voltage (including tran-
sient spikes) to 18V. Likewise, limit the maximum volt-
age on OUT1 and OUT2 to +18V and the maxi-
mum voltage on HYST1 and HYST2 to 18V below V+.
ICL7665
Microprocessor Voltage Monitor with
Dual Over/Undervoltage Detection
PART TEMP. RANGE PIN-PACKAGE
ICL7665AC/D 0°C to +70°C Dice*
ICL7665EPA -40°C to +85°C 8 Plastic DIP
ICL7665AEPA -40°C to +85°C 8 Plastic DIP
ICL7665ESA -40°C to +85°C 8 SO
ICL7665AESA -40°C to +85°C 8 SO
___________________Chip Topography
_Ordering Information (continued)
ICL7665IPA -20°C to +85°C 8 Plastic DIP
ICL7665IJA -20°C to +85°C 8 CERDIP
*Contact factory for dice specifications.
ICL7665CTV 0°C to +70°C 8 TO-99
ICL7665ACTV 0°C to +70°C 8 TO-99
ICL7665BCTV 0°C to +70°C 8 TO-99
TRANSISTOR COUNT: 38
SUBSTRATE CONNECTED TO V+.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12
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