Dual-Channel Temperature Monitors and

Fan-Speed Controllers with Thermistor Inputs

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5

PIN

MAX6616

MAX6615

NAME

FUNCTION

1, 2, 5, 20,

23, 24

—

GPIO0–

GPIO5

3

1

PWM1

Fan Driver Output 1. The pullup resistor can be connected to a supply voltage as high as

12V, regardless of the supply voltage. See the PWM Output section for configuration.

4

2

TACH1

Fan Tachometer Input. Accepts logic-level signal from fan’s tachometer output. Can be

connected to a supply voltage as high as 12V, regardless of the supply voltage.

6

3

ADD0

SMBus Slave Address Selection

7

4

ADD1

SMBus Slave Address Selection

8

5, 10

GND

Ground. Must be connected together for MAX6615.

9

6

TH1

External Thermistor Input 1. Connect a thermistor in series with a fixed resistor between

REF and ground.

10, 15

—

N.C.

No Connection

11

7

REF

Reference Voltage Output. Provides 1V during measurements. High impedance when not

measuring.

12

8

TH2

External Thermistor Input 2. Connect a thermistor in series with a fixed resistor between

REF and ground.

13

9

FAN_FAIL

Fan-Failure Output. Asserts low when either fan fails. Can be pulled up as high as 5.5V

14

—

PRESET

16

11

OT

Overtemperature Output. Active low, open drain. Typically used for system shutdown or

17

12

Power Supply. 3.3V nominal. Bypass with a 0.1µF capacitor to GND.

18

13

SDA

SMBus Serial-Data Input/Output. Pull up with a 10k

Ω resistor. Can be pulled up as high

19

14

SCL

SMBus Serial-Clock Input. Pull up with a 10k

Ω resistor. Can be pulled up as high as 5.5V

21

15

TACH2

Fan Tachometer Input. Accepts logic-level signal from fan’s tachometer output. Can be

connected to a supply voltage as high as 12V, regardless of the supply voltage.

22

16

PWM2

Fan Driver Output 2. The pullup resistor can be connected to a supply voltage as high as

12V, regardless of the supply voltage. See the PWM Output section for configuration.

Pin Description