ADT7470

Data Sheet

Rev. E | Page 6 of 40

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

GND

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

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

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.