Applications Information

Thermal Considerations

The key to accurate temperature monitoring is good

thermal contact between the MAX6629–MAX6632 pack-

age and the object being monitored. In some applica-

tions, the 6-pin SOT23 package is small enough to fit

underneath a socketed µP, allowing the device to moni-

tor the µP’s temperature directly. Accurate temperature

monitoring depends on the thermal resistance between

the object being monitored and the MAX6629–MAX6632

die. Heat flows in and out of plastic packages primarily

through the leads. If the sensor is intended to measure

the temperature of a heat-generating component on the

circuit board, it should be mounted as close as possible

to that component and should share supply and ground

traces (if they are not noisy) with that component where

possible. This maximizes the heat transfer from the com-

ponent to the sensor.

The MAX6629/MAX6630 supply current is typically

200µA, and the MAX6631/MAX6632 supply current is

typically 32µA. When used to drive high-impedance

loads, the device dissipates negligible power.

Therefore, the die temperature is essentially the same

as the package temperature.

The rise in die temperature due to self-heating is given

by the following formula:

MAX6629–MAX6632, and

resistance.

The typical thermal resistance is +110°C/W for the

6-pin SOT23 package. To limit the effects of self-heat-

ing, minimize the output currents. For example, if the

MAX6629–MAX6632 sink 1mA, the output voltage is

guaranteed to be less than 0.4V. Therefore, an addi-

tional 0.4mW of power is dissipated within the IC. This

corresponds to a 0.044°C shift in the die temperature in

the 6-pin SOT23.

Chip Information

PROCESS: BiCMOS

Package Information

For the latest package outline information and land patterns,

“-” in the package code indicates RoHS status only. Package

drawings may show a different suffix character, but the drawing

pertains to the package regardless of RoHS status.

12-Bit + Sign Digital Temperature Sensors

with Serial Interface

_______________________________________________________________________________________

7

VOLTAGE

REFERENCE

SPI-COMPATIBLE

INTERFACE

TEMPERATURE

SENSOR

12-BIT + SIGN

∑ΔADC

MAX6629

MAX6630

MAX6631

MAX6632

SO

SCK

CS

Functional Diagram

PACKAGE TYPE

PACKAGE CODE

DOCUMENT NO.

6 SOT23

U6FH-6

21-0058

6 TDFN-EP

T633+2

21-0137