0.1 F

m

10 kW

(typ)

10 kW

(typ)

10 kW

(typ)

10 kW

(typ)

TMP401

D+

D-

V+

1

8

7

6

4

5

3

2

R

S

(2)

R

S

(2)

C

DIFF

(3)

C

DIFF

(3)

R

S

(2)

R

S

(2)

GND

SCL

SDA

ALERT/THERM2

THERM

+5 V

SMBus

Controller

Fan Controller

Diode-connected configuration :

(1)

Series Resistance

Transistor-connected configuration :

(1)

TMP401

SBOS371B – AUGUST 2006 – REVISED OCTOBER 2014

www.ti.com

7 Detailed Description

7.1 Overview

The TMP401 is a dual-channel digital temperature sensor that combines a local die temperature measurement

channel and a remote junction temperature measurement channel in a single VSSOP-8 package. The TMP401 is

two-wire- and SMBus interface-compatible and is specified over a temperature range of –40°C to +125°C. The

TMP401 contains multiple registers for holding configuration information, temperature measurement results,

temperature comparator limits, and status information.

User-programmed high and low temperature limits stored in the TMP401 can be used to monitor local and

remote temperatures to trigger an over- and undertemperature alarm (ALERT). Additional thermal limits can be

programmed into the TMP401 and used to trigger another flag (THERM) that can be used to initiate a system

response to rising temperatures.

The TMP401 requires only a transistor connected between D+ and D– for proper remote temperature sensing

operation. The SCL and SDA interface pins require pull-up resistors as part of the communication bus, while

ALERT and THERM are open-drain outputs that also need pull-up resistors. ALERT and THERM may be shared

with other devices if desired for a wired-OR implementation. A 0.1-

μF power-supply bypass capacitor is

recommended for good local bypassing. Figure 11 shows a typical configuration for the TMP401.

(1) The diode-connected configuration provides better settling time. The transistor-connected configuration provides better series resistance

cancellation. A 2N3906 PNP is used in this configuration.

(2) In most applications, RS is < 1.5 kΩ.

(3) In most applications, CDIFF is < 1000 pF.

Figure 11. Basic Connections

10

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