EVAL-ADM1275EBZ Datasheet, PDF (10/48 Pages) Analog Devices – Hot-Swap Controller and Digital Power

ADM1275
Data Sheet
Pin No.
QSOP LFCSP
12
10
13
11
14
12
Mnemonic
SDA
SCL
PWRGD
15
13
FLB
16
14
VOUT
17
15
GND
18
16
GATE
19
17
SENSE−
20
18
SENSE+
N/A
EP
EPAD
Description
Serial Data Input/Output Pin. Open-drain input/output. Requires an external resistive pull-up.
Serial Clock Pin. Open-drain input. Requires an external resistive pull-up.
Power-Good Signal. Used to indicate that the supply is within tolerance. This signal is based on the
voltage present on the FLB pin.
Foldback Pin. A foldback resistor divider is placed from the source of the FET to this pin. Foldback is
used to reduce the current limit when the source voltage drops. The foldback feature ensures that
the power through the FET is not increased beyond the SOA limits.
This pin is used to read back the output voltage using the internal ADC. A 1 kΩ resistor should be
inserted in series between the source of a FET and the VOUT pin.
Chip Ground Pin.
Gate Output Pin. This pin is the high-side gate drive of an external N-channel FET. This pin is driven
by the FET drive controller, which uses a charge pump to provide a pull-up current to charge the FET
gate pin. The FET drive controller regulates to a maximum load current by regulating the GATE pin.
GATE is held low when the supply is below UVLO.
Negative Current Sense Input Pin. A sense resistor between the SENSE+ pin and the SENSE− pin sets
the analog current limit. The hot-swap operation of the ADM1275 controls the external FET gate to
maintain the sense voltage (VSENSE+ − VSENSE−). This pin also connects to the FET drain pin.
Positive Current Sense Input Pin. This pin connects to the main supply input. A sense resistor
between the SENSE+ pin and the SENSE− pin sets the analog current limit. The hot-swap operation
of the ADM1275 controls the external FET gate to maintain the sense voltage (VSENSE+ − VSENSE−). This
pin is also used to measure the supply input voltage using the ADC.
Exposed Paddle on Underside of LFCSP. Solder the exposed paddle to the board to improve thermal
dissipation. The exposed paddle can be connected to ground.
Rev. D | Page 10 of 48