Detailed Description

The MAX6511/MAX6512/MAX6513 fully integrated tem-

perature switches incorporate a precision bandgap ref-

erence, a conversion block, a current source, and a

comparator (Figure 1). These devices use an external

P-N junction as the temperature-sensing element. They

steer bias currents through the external diode, measure

the forward voltages, and compute the temperature

using a precision chopper stabilized amplifier.

Resistance values of less than 100

Ω in series with the

external sense junction will result in trip-point errors

<1°C. The MAX6511/MAX6512/MAX6513 provide noise

immunity by integration and oversampling of the diode

voltage, but good design practice includes routing the

DXP and DXN lines away from noise sources, such as

high-speed digital lines, switching regulators, induc-

tors, and transformers. The DXP and DXN traces

should be paired together and surrounded by ground

plane whenever possible.

In applications where the temperature changes rapidly,

the measured temperature will be approximately equal

to the average value of the temperature during the

measurement period.

The MAX6512 has an active-low, open-drain output struc-

ture that can only sink current. The MAX6511 has an active-

low CMOS output structure, and the MAX6513 has an

active-high CMOS output.

The MAX6511/MAX6512/MAX6513 are available with

preset temperature thresholds from +45°C to +125°C in

10°C increments.

Low-Cost, Remote SOT Temperature Switches

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Pin Description

PIN

MAX6511

MAX6512

MAX6513

NAME

FUNCTION

11

capacitor.

22

GND

Ground

33

HYST

°C for HYST = GND.

4—

TOVER

CMOS Active-Low Output (MAX6511) or Open-Drain Active-Low Output

(MAX6512). TOVER goes low when the temperature exceeds the factory-

programmed temperature threshold. This pin can only sink current in the

MAX6512.

—4

TOVER

CMOS Active-High Output (MAX6513). TOVER goes high when the temperature

exceeds the factory-programmed temperature threshold.

55

DXN

This pin connects to the negative (cathode) terminal of the external P-N sense

junction. DXN must be connected to GND.

66

DXP

This pin connects to the positive (anode) terminal of the external P-N sense

junction.

DXP

DXN

TEMPERATURE

CONVERSION

BANDGAP

VOLTAGE

REFERENCE

COMPAR-

ATOR

LATCH

TOVER

Figure 1. Functional Block Diagram