Datasheet

ADT7470 Data Sheet
Rev. E | Page 6 of 40
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
04684-0-003
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GND
V
CC
TACH3
TACH2
TACH1
PWM2
SCL
PWM1
SMBALERT
FULL_SPEED/TMP_START
PWM4
PWM3 TACH4
ADDR
TMP_IN
SDA
ADT7470
TOP VIEW
(Not to Scale)
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Description
1 SCL Digital Input (Open Drain). SMBus serial clock input. Requires SMBus pull-up, typically 2k2Ω.
2 GND Ground Pin.
3 V
CC
Power Supply Pin.
4 TACH3 Digital Input (Open Drain). Fan tachometer input to measure the speed of Fan 3.
5 PWM2 Digital I/O (Open Drain). Requires 10 kΩ typical pull-up. Pulse-width modulated output to control
the speed of Fan 2. Can be configured as GPIO by setting Bit 0x7F[2] = 1.
6
TACH1
Digital Input (Open Drain). Fan tachometer input to measure the speed of Fan 1.
7 TACH2 Digital Input (Open Drain). Fan tachometer input to measure the speed of Fan 2.
8 PWM3 Digital I/O (Open Drain). Pulse-width modulated output to control the speed of Fan 3.
Requires 10 kΩ typical pull-up. Can be configured as GPIO by setting Bit 0x7F[1] = 1.
9 TACH4 Digital Input (Open Drain). Fan tachometer input to measure the speed of Fan 4.
10 PWM4 Digital I/O (Open Drain). Pulse-width modulated output to control the speed of Fan 4.
Requires 10 kΩ typical pull-up. Can be configured as GPIO by setting Bit 0x7F[0] = 1.
11 ADDR Three-state Input. Used to set the SMBus device address.
12 TMP_IN Digital Input (Open Drain). PWM input to PWM processing engine that interprets daisy-chained output
from multiple TMP05 temperature sensors. Readings from individual TMP05 temperature sensors are
available by reading the temperature reading registers over the SMBus.
13
FULL_SPEED
Digital Input Active Low (Open Drain). This input blasts the fans to maximum speed when the pin is pulled low
externally. Do not leave pin 13 open when not I use, tie to V
CC.
13 TMP_START Digital Output (Open Drain). This pin can be used as an output to start daisy-chained temperature
measurements from TMP05 or TMP06 temperature sensors. Requires 10 kΩ typical pull-up.
14
SMBALERT
Digital Output Active Low (Open Drain). This pin can be reconfigured as an
SMBALERT
interrupt output
to signal out-of-limit conditions such as fan failures.
15 PWM1 Digital I/O (Open Drain). Pulse-width modulated output to control the speed of Fan 1.
Requires 10 kΩ typical pull-up. Can be configured as GPIO by setting Bit 0x7F[3] = 1.
16 SDA Digital I/O (Open Drain). SMBus bidirectional serial data. Requires SMBus pull-up, typically 2k2Ω.