±1°C Fail-Safe Remote/Local Temperature

Sensors with SMBus Interface

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5

Pin Description

PIN

MAX6680

MAX6681

NAME

FUNCTION

12

A 200

Ω series resistor is recommended, but not required for additional noise

filtering. See the Typical Operating Circuit.

2, 5

1, 5

CRIT1,

CRIT0

Hardware-Programmable Default Alarm Threshold for

OVERT Limits. Use Table

4 to set default temperatures.

3

3

DXP

Combined Remote-Diode Current Source and A/D Positive Input for Remote-

Diode Channel. DO NOT LEAVE DXP FLOATING; connect DXP to DXN if no

remote diode is used. Place a 2200pF capacitor between DXP and DXN for

noise filtering.

44

DXN

Combined Remote-Diode Current Sink and A/D Negative Input. DXN is

internally biased to one diode drop above ground.

6

6

ADD1

SMBus Address Select Pin (Table 9). ADD0 and ADD1 are sampled upon

power-up. Excess capacitance (>50pF) at the address pins when floating may

cause address-recognition problems.

7

7

RESET

Reset Input. Drive RESET high to set all registers to their default values (POR

state). Drive RESET low or leave floating for normal operation.

8

8

GND

Ground

99

OVERT

Overtemperature Active-Low Output. Open drain.

10

10

ADD0

SMBus Slave Address Select Pin (see ADD1).

11

11

ALERT

SMBus Alert (Interrupt) Active-Low Output. Open drain.

12

12

SMBDATA

SMBus Serial-Data Input/Output, Open Drain

13

13

INT_SEL

Input. Connect high or leave floating to conform to the standard SMBus

ALERT

protocol. See the

ALERT Interrupts section. Connect to GND to invoke

comparator mode, where

ALERT is asserted whenever any of the temperature

conditions is violated by the remote sensor. In this mode,

ALERT can only be

deasserted by the condition returning within the temperature limits by enabling

the mask bit in the Configuration register.

14

14

SMBCLK

SMBus Serial-Clock Input

15

15

STBY

Input. Hardware Standby. Connect to ground to place in device in standby.

Supply current drops below 10µA and all registers’ data are maintained.

Input. Selects which temperature sensor (local, remote, or both) activates

OVERT.

16

16

SENS_SEL

High = Local, Low = Remote, Open = Local and Remote