Pin Configuration And Function Descriptions - Analog Devices ADT7473 Manual

ADT7473

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Table 3. Pin Function Descriptions
Pin
No. Mnemonic Description
1 SCL Digital Input (Open Drain). SMBus serial clock input. Requires SMBus pull-up.
2 GND Ground Pin for the ADT7473.
3 V Power Supply. Powered by 3.3 V.
CC
4 TACH3 Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 3.
5 PWM2 Digital Output (Open Drain). Requires 10 kΩ typical pull-up. Pulse width modulated output to control Fan 2 speed.
Can be configured as a high or low frequency drive.
SMBALERT Digital Output (Open Drain). Can be reconfigured as an SMBALERT interrupt output to signal out-of-limit conditions.
6 TACH1 Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 1.
7 TACH2 Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 2.
8 PWM3 Digital I/O (Open Drain). Pulse width modulated output to control the speed of Fan 3 and Fan 4. Requires 10 kΩ
typical pull-up. Can be configured as a high or low frequency drive.
9 TACH4 Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 4.
GPIO General-Purpose Open Drain Digital I/O.
THERM Can be configured as a bidirectional THERM pin, which can be used to time and monitor assertions on the THERM
input as well as to assert when an ADT7473 THERM overtemperature limit is exceeded. For example, the pin can be
connected to the PROCHOT output of an Intel Pentium 4 processor or to the output of a trip point temperature
sensor. Can be used as an output to signal overtemperature conditions.
SMBALERT Digital Output (Open Drain). This pin can be reconfigured as an SMBALERT interrupt output to signal out-of-limit
conditions.
10 D2− Cathode Connection to Second Thermal Diode.
11 D2+ Anode Connection to Second Thermal Diode.
12 D1− Cathode Connection to First Thermal Diode.
13 D1+ Anode Connection to First Thermal Diode.
14 V Analog Input. Monitors processor core voltage (0 V − 3 V).
CCP
15 PWM1 Digital Output (Open Drain). Pulse-width modulated output to control Fan 1 speed. Requires 10 kΩ typical pull-up.
XTO Also functions as the output from the XNOR tree in XNOR test mode.
16 SDA Digital I/O (Open Drain). SMBus bidirectional serial data. Requires 10 kΩ typical pull-up.
SCL
1
GND
2
V
3
CC
ADT7473
TACH3
4
TOP VIEW
PWM2/SMBALERT
(Not to Scale)
5
TACH1
6
TACH2
7
PWM3 8
Figure 3. Pin Configuration
Rev. 0 | Page 6 of 76
SDA
16
PWM1/XTO
15
V
14
CCP
D1+
13
D1–
12
D2+
11
D2–
10
9 TACH4/GPIO/THERM/SMBALERT