REV. 0
ADM1022
–5–
PIN FUNCTION DESCRIPTION
Pin
No. Mnemonic Description
1 FAN_OFF Digital Output (Open-Drain) Fan Off Request. When asserted low this indicates a request to shut
off the fan independent of the FAN_SPD output. When negated (output FET off) it indicates that
the fan may be turned on.
2 MR Digital Input, Manual Reset. A logic low on this input causes RST2 to be asserted. Once this input
is negated that output will remain asserted for t
RP
. This input has an internal 20 kΩ pull-up resistor.
Leave unconnected if not used.
3 RST1 Digital I/O (Open-Drain). This pin is asserted low while V
CC
remains below the reset threshold. It
remains asserted for t
RP
after the reset condition is terminated. It is bidirectional so the ADM1022 can
be optionally reset; external logic must be used to prevent system auxiliary reset from occurring
when used as an input.
4 GND GROUND. Power and Signal Ground.
5V
CC
POWER 3.3 V. Power source and voltage monitor input for first reset generator.
6V
MON
Analog Input. Voltage monitor input for second reset generator.
7 RST2 Digital Output (Open-Drain). This pin is asserted low under any of the following conditions:
– V
MON
or V
CC
remains below the reset threshold
– while MR is held low
– while RST1 is asserted.
It remains asserted for t
RP
after the reset conditions are terminated.
8 FAN_SPD/NTEST_IN Analog Output/Test Input. An active-high input that enables NAND board-level connectivity testing.
Refer to section on NAND testing. Used as an analog output for fan speed control when NAND
test is not selected.
9 D1– Remote Thermal Diode Negative Input. This is the negative input (current sink) from the remote
thermal diode. This also serves as the negative input into the A/D.
10 D1+ Remote Thermal Diode Positive Input. This is the positive input (current source) from the remote
thermal diode. This serves as the positive input into the A/D.
11 D2–/THERM Analog Input/Digital I/O (Open-Drain). Can be programmed as negative input for a second diode
temperature sensor, or as a digital I/O pin. In this case it is an active low thermal overload output
that indicates a violation of a temperature set point (over-temperature). Also acts as an input to
provide external fan control. When this pin is pulled low by an external signal, a status bit is set and
the fan speed is set to full on.
12 D2+/GPI Analog/Digital Input. Can be programmed as the positive input for a second diode sensor, or as a
general-purpose logic input. In this case it can be programmed as an active high or active low input
that sets Bit 4 of the Status Registers. This bit can only be reset by reading the status registers, pro-
vided GPI is in the inactive state.
13 ADD/NTEST_OUT Digital I/O. The lowest order programmable bit of the SMBus Address. ADD is sampled at power-
up and changing it while powered on will have no immediate effect. This pin also functions as an
output when doing a NAND test.
14 INT Digital Output (Open Drain), System Interrupt Output. This signal indicates a violation of a set
trip point. The output is enabled when Bit 1 of the Configuration Register is set to 1. The default
state is disabled.
15 SCL Digital Input SMBus Clock.
16 SDA Digital I/O (Open-Drain) SMBus Bidirectional Data.
