Texas Instruments LM57CISD-10/NOPB

Overview

LM57CISD-10/NOPB from Texas Instruments is a resistor-programmable precision temperature switch with dual digital outputs (active-high push-pull TOVER and active-low open-drain TOVER) and an analog VTEMP voltage output proportional to die temperature. It operates from −50°C to +150°C, features ±2.3°C trip-point accuracy and ±1.3°C VTEMP sensor accuracy, and uses two external 1% resistors to set trip temperature across 256 values in the −40°C to +150°C range - deployed in industrial overtemperature protection circuits.

For engineers reviewing the LM57CISD-10/NOPB datasheet, LM57CISD-10/NOPB pinout, LM57CISD-10/NOPB application, or LM57CISD-10/NOPB equivalent, key selection criteria include its 10°C factory-set hysteresis, programmable NTC-slope VTEMP gain (J2–J5), TRIP-TEST in-system verification capability, and WSON-8 package compatibility with high-density thermal monitoring layouts.

Technical Context

The LM57CISD-10/NOPB integrates an internal DAC-driven comparator architecture where SENSE1/SENSE2 resistor ratios select one of 16 logic levels, mapping to 256 discrete trip points and simultaneously configuring VTEMP's negative temperature coefficient slope (−5.166 mV/°C to −12.924 mV/°C). Its dual-output topology enables both latched fault signaling (via TOVER tied to TRIP-TEST) and real-time analog temperature feedback without external ADC.

Thermal hysteresis is fixed at 10°C (THYST = 9.6–10.6°C), preventing output oscillation during slow thermal transitions. The VTEMP output remains valid across the full −50°C to +150°C range regardless of selected J-gain segment, and TRIP-TEST assertion forces both digital outputs active while presenting VTRIP at VTEMP for system-level calibration validation.

Key Specifications

Pinout & Package

LM57CISD-10/NOPB is housed in an 8-pin WSON (2.50 mm × 2.50 mm) package with exposed thermal pad connected to GND. This leadless, space-efficient封装 supports automated reflow and provides low thermal resistance (RθJA = 71.3°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar temperature switch applications.

Compared with LM57CISD-10/NOPB, LM57BISD-10/NOPB delivers higher trip accuracy without changing layout, while LM57FPW/NOPB offers identical functionality in a larger, more manufacturable package - enabling trade-offs between precision, density, and assembly method.

Availability

LM57CISD-10/NOPB is available at Aetrix Electronics and suitable for industrial automation, down-hole instrumentation, and avionics thermal management requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM57CISD-10/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with decades of precision sensor and thermal management IC expertise.

The LM57 product line delivers resistor-programmable overtemperature protection with integrated analog sensing - designed specifically for industrial, automotive, and harsh-environment systems demanding configurability without digital overhead.

FAQ

What is the hysteresis value for LM57CISD-10/NOPB, and how is it implemented?

The LM57CISD-10/NOPB has a factory-set hysteresis of 10°C (specified as 9.6–10.6°C). It is implemented internally via analog circuitry that shifts the comparator's reference threshold downward by THYST after trip activation, ensuring TOVER and TOVER remain asserted until temperature falls below (TTRIP − 10°C). No external components are needed - this hysteresis is fixed and cannot be adjusted.

How do I calculate the trip temperature for LM57CISD-10/NOPB using external resistors?

The trip temperature for LM57CISD-10/NOPB is determined by the ratio of RSENSE1 and RSENSE2, which selects one of 16 logic levels decoded into a DAC code. Use TI's LM57 Resistor Calculator tool or Table 1 in SNIS152E to map resistor pairs to exact TTRIP values (−40°C to +150°C in 256 steps). The LM57CISD-10/NOPB datasheet provides lookup tables correlating resistance ratios to trip points and corresponding VTEMP gain (J2–J5).

Can LM57CISD-10/NOPB operate at −50°C, and what is its accuracy at that temperature?

Yes, LM57CISD-10/NOPB is fully specified from −50°C to +150°C. At −50°C, its VTEMP analog sensor accuracy is ±1.3°C (per J2–J5 specifications in Section 7.6), and trip-point accuracy remains ±2.3°C across the full range including extremes. The device uses a bandgap-referenced architecture validated for operation at −50°C ambient and die temperature.

What is the purpose of the TRIP-TEST pin on LM57CISD-10/NOPB, and how should it be used?

The TRIP-TEST pin (Pin 5) is an active-high digital input that forces both TOVER and TOVER outputs active and presents the trip-reference voltage VTRIP at the VTEMP pin. It enables in-system functional verification - for example, a microcontroller can drive TRIP-TEST high, read VTEMP to confirm VTRIP level, and monitor TOVER/TOVER state change - all without thermal stimulus. Leave TRIP-TEST unconnected or tie to GND if unused.

Does LM57CISD-10/NOPB require external pull-up resistors on its digital outputs?

Only TOVER (Pin 6, active-low open-drain) requires an external pull-up resistor (typically 4.7 kΩ to VDD) to establish a valid logic-high state when inactive. TOVER (Pin 7, active-high push-pull) drives both high and low actively and needs no external components. Both outputs are short-circuit protected per datasheet Section 7.7.