High Voltage Input Protection Device
ADM1270
Data Sheet
FEATURES
SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM
VCC/SENSE+ SENSE–
Controls supply voltages from 4 V to 60 V
Gate drive for low voltage drop reverse supply protection
Gate drive for P-channel FETs
RPFG
ADM1270
Inrush current limiting control
VCAP
LDO
+
–
Adjustable current limit
Foldback current limiting
I
OUT
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
UV
OV
+
–
1V
1V
GATE DRIVE/
LOGIC
GATE
–
+
16-lead QSOP
APPLICATIONS
REF
SELECT
FLB
ISET
CURRENT
LIMIT
Industrial modules
Battery-powered/portable instrumentation
+
–
CURRENT-
FB_PG
LIMIT
TIMER
ON
CONTROL
GENERAL DESCRIPTION
TIMER_OFF
TIMER
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.
TIMER
TIMEOUT
FAULT
V
CB
ENABLE
PWRGD
GND
Figure 1.
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.
Rev. A
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