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LM57

ACTIVE

±0.7°C Temperature Sensor with Resistor-Programmable Temperature Switch

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Data sheet

LM57

ACTIVE
Data sheet Order now

Product details

Setpoint type Resistor Programmable Setpoint value (°C) -40 to 150 Operating temperature range (°C) -50 to 150 Accuracy over temp range (max) (°C) 1.5 Sensor gain (mV/°C) -12.924, -10.339, -7.752, -5.166 Output type Open drain, Push Pull Supply voltage (min) (V) 2.4 Supply voltage (max) (V) 5.5 Supply current (typ) (µA) 24 Number of comparator channels 1 Features Built-in hysteresis, Trip-Test Pin Rating Catalog Interface type Analog output, Switch
Setpoint type Resistor Programmable Setpoint value (°C) -40 to 150 Operating temperature range (°C) -50 to 150 Accuracy over temp range (max) (°C) 1.5 Sensor gain (mV/°C) -12.924, -10.339, -7.752, -5.166 Output type Open drain, Push Pull Supply voltage (min) (V) 2.4 Supply voltage (max) (V) 5.5 Supply current (typ) (µA) 24 Number of comparator channels 1 Features Built-in hysteresis, Trip-Test Pin Rating Catalog Interface type Analog output, Switch
TSSOP (PW) 8 19.2 mm² 3 x 6.4 WSON (NGR) 8 6.25 mm² 2.5 x 2.5
  • See LM57-Q1 datasheet for AEC-Q100 Grade 1/Grade 0/Grade 0 Extended (Qualified and Manufactured on an Automotive Grade Flow)
  • Trip Temperature Set by External Resistors with
    Accuracy of ±1.7°C or ±2.3°C from -40°C to +150°C
  • Resistor Tolerance Contributes Zero Error
  • Push-Pull and Open-Drain Switch Outputs
  • Wide Operating Temperature and Trip-Temperature Range of −50°C to 150°C,
  • Very Linear Analog VTEMP Temp Sensor Output
    with ±0.8°C or ±1.3°C Accuracy from -40°C to +150°C
  • Short-Circuit Protected Analog and Digital Outputs
  • Latching Function for Digital Outputs
  • TRIP-TEST Pin Allows In-System Testing
  • Low Power Minimizes Self-Heating to Under 0.02°C
  • See LM57-Q1 datasheet for AEC-Q100 Grade 1/Grade 0/Grade 0 Extended (Qualified and Manufactured on an Automotive Grade Flow)
  • Trip Temperature Set by External Resistors with
    Accuracy of ±1.7°C or ±2.3°C from -40°C to +150°C
  • Resistor Tolerance Contributes Zero Error
  • Push-Pull and Open-Drain Switch Outputs
  • Wide Operating Temperature and Trip-Temperature Range of −50°C to 150°C,
  • Very Linear Analog VTEMP Temp Sensor Output
    with ±0.8°C or ±1.3°C Accuracy from -40°C to +150°C
  • Short-Circuit Protected Analog and Digital Outputs
  • Latching Function for Digital Outputs
  • TRIP-TEST Pin Allows In-System Testing
  • Low Power Minimizes Self-Heating to Under 0.02°C

The LM57 device is a precision, dual-output, temperature switch with analog temperature sensor output for wide temperature industrial applications. The trip temperature (TTRIP) is selected from 256 possible values in the range of –40°C to +150°C. The VTEMP is a class AB analog voltage output that is proportional to temperature with a programmable negative temperature coefficient (NTC). Two external 1% resistors set the TTRIP and VTEMP slope. The digital and analog outputs enable protection and monitoring of system thermal events.

Built-in thermal hysteresis (THYST) prevents the digital outputs from oscillating. The TOVER and TOVER digital outputs will assert when the die temperature exceeds TTRIP and will de-assert when the temperature falls below a temperature equal to TTRIP minus THYST.

TOVER is active-high with a push-pull structure. TOVER is active-low with an open-drain structure. Tying TOVER to TRIP-TEST will latch the output after it trips. The output can be cleared by forcing TRIP-TEST low. Driving the TRIP-TEST high will assert the digital outputs. A processor can check the state of TOVER or TOVER, confirming they changed to an active state. This allows for in-situ verification that the comparator and output circuitry are functional after system assembly. When TRIP-TEST is high, the trip-level reference voltage appears at the VTEMP pin. The system could then use this voltage to calculate the threshold of the LM57.

The LM57 device is a precision, dual-output, temperature switch with analog temperature sensor output for wide temperature industrial applications. The trip temperature (TTRIP) is selected from 256 possible values in the range of –40°C to +150°C. The VTEMP is a class AB analog voltage output that is proportional to temperature with a programmable negative temperature coefficient (NTC). Two external 1% resistors set the TTRIP and VTEMP slope. The digital and analog outputs enable protection and monitoring of system thermal events.

Built-in thermal hysteresis (THYST) prevents the digital outputs from oscillating. The TOVER and TOVER digital outputs will assert when the die temperature exceeds TTRIP and will de-assert when the temperature falls below a temperature equal to TTRIP minus THYST.

TOVER is active-high with a push-pull structure. TOVER is active-low with an open-drain structure. Tying TOVER to TRIP-TEST will latch the output after it trips. The output can be cleared by forcing TRIP-TEST low. Driving the TRIP-TEST high will assert the digital outputs. A processor can check the state of TOVER or TOVER, confirming they changed to an active state. This allows for in-situ verification that the comparator and output circuitry are functional after system assembly. When TRIP-TEST is high, the trip-level reference voltage appears at the VTEMP pin. The system could then use this voltage to calculate the threshold of the LM57.
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Technical documentation

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* Data sheet LM57 Resistor-Programmable Temperature Switch and Analog Temperature Sensor datasheet (Rev. E) PDF | HTML 15 Jul 2015
EVM User's guide LM57EVM Evaluation Module (EVM) User's Guide 11 Sep 2013
Application note AN-1984 LM57 Temperature Switch vs Thermistors (Rev. C) 01 May 2013

Design & development

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Evaluation board

LM57EVM — LM57 evaluation module

The Texas Instruments LM57EVM evaluation module helps designers evaluate the operation and performance of the LM57 Resistor-Programmable Temperature Switch and Analog Temperature Sensor.

User guide: PDF
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TSSOP (PW) 8 Ultra Librarian
WSON (NGR) 8 Ultra Librarian
TI's Standard Terms and Conditions for Evaluation Items apply.

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