High Voltage Input Protection Device
Data Sheet
Rev. A Document Feedback
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FEATURES
Controls supply voltages from 4 V to 60 V
Gate drive for low voltage drop reverse supply protection
Gate drive for P-channel FETs
Inrush current limiting control
Adjustable current limit
Foldback current limiting
Automatic retry or latch-off on current fault
Programmable current-limit timer for safe operating area (SOA)
Power-good and fault outputs
Analog undervoltage (UV) and overvoltage (OV) protection
16-lead, 3 mm × 3 mm LFCSP
16-lead QSOP
APPLICATIONS
Industrial modules
Battery-powered/portable instrumentation
GENERAL DESCRIPTION
The ADM1270 is a current-limiting controller that provides
inrush current limiting and overcurrent protection for modular
or battery-powered systems. When circuit boards are inserted
into a live backplane, discharged supply bypass capacitors draw
large transient currents from the backplane power bus as they
charge. These transient currents can cause permanent damage
to connector pins, as well as dips on the backplane supply that
can reset other boards in the system.
The ADM1270 is designed to control the inrush current, when
powering on the system, via an external P-channel field effect
transistor (FET).
To protect the system from a reverse polarity input supply, there
is a provision made to control an additional external P-channel
FET. This feature prevents reverse current flow in case of a reverse
polarity connection, which can damage the load or the ADM1270.
The ADM1270 is available in a 3 mm × 3 mm, 16-lead LFCSP and
a 16-lead QSOP.
SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM
1V
1V
GATE DRIVE/
LOGIC
V
CB
TIMER
ON
TIMEOUT
I
OUT
CURRENT
LIMIT
TIMER
VCC/SENSE+ SENSE–
GATE
TIMER
GND
UV
OV
RPFG
FLB
LDO
VCAP
REF
SELECT
ISET
FAULT
FB_PG
ENABLE
TIMER_OFF
PWRGD
+
+
+
–
–
+
–
–
CURRENT-
LIMIT
CONTROL
ADM1270
12259-001
Figure 1.
