Pi N Configuration And Function Descriptions - Analog Devices dBCool ADT7473 Manual

PIN CONFIGURATION AND FUNCTION DESCRI
Table 4. 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 modulate
Can be configured as a high or low frequenc
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 I put (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 Bidirectional THERM pin. 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 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
5 (Not to Scale)
TACH1
6
TACH2
7
PWM3 8
Figure 3. Pin Configuration
n
Rev. A | Page 7 of 76
PTIONS
SDA
16
PWM1/XTO
15
V
14
CCP
13 D1+
D1–
12
D2+
11
D2–
10
9 TACH4/GPIO/THERM/SMBALERT
y drive.
oltage (0 V to 3 V).
ADT7473
d output to c ontrol Fan 2 speed.