Datasheet

Thermal Considerations
The key to accurate temperature monitoring is good ther-
mal contact between the MAX6629–MAX6632 package
and the object being monitored. In some applications, the
6-pin SOT23 package is small enough to fit underneath
a socketed μP, allowing the device to monitor 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 tem-
perature 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 component 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 pack-
age temperature.
The rise in die temperature due to self-heating is given by
the following formula:
ΔT
J
= P
DISSIPATION
x θ
JA
where P
DISSIPATION
is the power dissipated by the
MAX6629–MAX6632, and θ
JA
is the package’s thermal
resistance.
The typical thermal resistance is +110°C/W for the 6-pin
SOT23 package. To limit the effects of self-heating, mini-
mize the output currents. For example, if the MAX6629–
MAX6632 sink 1mA, the output voltage is guaranteed
to be less than 0.4V. Therefore, an additional 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.
PACKAGE
TYPE
PACKAGE
CODE
DOCUMENT
NO.
LAND
PATTERN
NO.
6 SOT23 U6FH-6 21-0058 90-0175
6 TDFN-EP T633+2 21-0137 90-0058
VOLTAGE
REFERENCE
SPI-COMPATIBLE
INTERFACE
TEMPERATURE
SENSOR
12-BIT + SIGN
∑∆ ADC
MAX6629
MAX6630
MAX6631
MAX6632
SO
SCK
CS
MAX6629–MAX6632 12-Bit + Sign Digital Temperature Sensors
with Serial Interface
www.maximintegrated.com
Maxim Integrated │ 7
Functional Diagram
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” 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.