Datasheet
Data Sheet ADM1171
Rev. A | Page 5 of 16
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
TIMER
1
GND
2
SS
3
ON
4
V
CC
8
SENSE
7
CSOUT
6
G
ATE
5
ADM
1171-1AUJ
T
O
P VIEW
(Not to Scale)
05125-006
Figure 2. Pin Configuration, 1AUJ Model
TIMER
1
GND
2
SS
3
ON-CLR
4
V
CC
8
SENSE
7
CSOUT
6
G
A
TE
5
ADM
1
171-2AUJ
TOP VIEW
(Not to Scale)
05125-007
Figure 3. Pin Configuration, 2AUJ Model
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 TIMER Timer Input Pin. The initial and circuit breaker timing cycles are set by this external capacitor. The initial timing
delay is 272.9 ms/μF, and 21.7 ms/µF for a circuit breaker delay. When the TIMER pin is pulled beyond the upper
threshold, the GATE turns off.
2 GND Chip Ground Pin.
3
SS
Soft Start Pin. An external capacitor between the SS pin and GND sets the ramp rate of the current limit
reference.
4 ON (ON-
CLR
) Input Pin. The ON (ON-
CLR
) pin is an input to a comparator that has a low-to-high threshold of 1.3 V with 80 mV
hysteresis and a glitch filter. The ADM1171 is reset when the ON (ON-
CLR
) pin is low. When the ON (ON-
CLR
) pin is
high, the
ADM1171 is enabled. A rising edge on this pin has the added function of clearing a fault and restarting
the device on the latched off model, the ADM1171-2.
5 GATE Gate Output Pin. An internal charge pump provides a 12 µA pull-up current to drive the gate of an N-channel
MOSFET. In an overcurrent condition, the ADM1171 controls the external FET to maintain a constant load
current.
6 CSOUT Current Sense Output. The voltage on this pin represents the differential voltage across the V
CC
and SENSE pins
gained up by a factor of 20.
7
SENSE
Current Limit Sense Input Pin. The current limit is set via a sense resistor between the V
CC
and SENSE pin. In an
overcurrent condition, the gate of
the FET is controlled to maintain the SENSE voltage at 50 mV. When this limit is
reached, the TIMER circuit breaker mode is activated. The circuit breaker limit can be disabled by connecting the
V
CC
pin and SENSE pin together.
8 V
CC
Positive Supply Input Pin. The ADM1171 operates between 2.7 V to 16.5 V. An undervoltage lockout (UVLO)
circuit with a glitch filter resets the ADM1171 when the supply voltage drops below the specified UVLO limit.