Texas Instruments LM34CAH/NOPB

Overview

LM34CAH/NOPB from Texas Instruments is a precision analog Fahrenheit temperature sensor in a hermetic TO-46 metal can package, delivering 10.0 mV/°F linear output, ±1.0°F accuracy at 77°F, and operation across −40°F to +230°F. It requires no external calibration and draws only 75 µA, enabling low-power remote sensing in HVAC and appliance control systems.

For engineers reviewing the LM34CAH/NOPB datasheet, LM34CAH/NOPB pinout, LM34CAH/NOPB application, or LM34CAH/NOPB equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, application-specific implementation insights, and two confirmed alternative options with documented functional and thermal trade-offs.

Technical Context

The LM34CAH/NOPB implements a delta-V_BE temperature-sensing element buffered by a Class-A amplifier with 0.4 Ω typical output impedance, enabling direct drive of 1-mA loads without external buffering. Its output voltage strictly follows V_OUT = 10 mV/°F × T(°F), with no offset subtraction required for Fahrenheit scaling.

It operates from 4 V to 30 V supply, exhibits ±0.5°F typical nonlinearity over its full −40°F to +230°F range, and achieves <0.18°F self-heating in still air due to sub-100 µA quiescent current. The TO-46 package provides robust thermal coupling to metal surfaces and supports clamping or soldering directly to heat sinks or pipes.

Key Specifications

Pinout & Package

LM34CAH/NOPB uses a 3-pin hermetic TO-46 (NDV) metal can package with case connected to GND. Pinout is defined from bottom view per TI SNIS161D Rev D: Pin 1 = +VS, Pin 2 = V_OUT, Pin 3 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM34CAZ/NOPB, LM34CAH/NOPB offers superior thermal coupling and hermetic reliability at the cost of larger footprint; compared with LM35DZ/NOPB, it eliminates firmware conversion overhead and maintains native Fahrenheit resolution without interpolation loss.

Availability

LM34CAH/NOPB is available at Aetrix Electronics and suitable for industrial oven monitoring, refrigeration system control, and automotive under-hood sensing requiring stable component supply, long-term calibration retention, and hermetic packaging integrity.

Supply support for LM34CAH/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 and embedded processing technologies, with decades of heritage in precision sensor design and high-reliability industrial ICs.

The LM34 series was developed specifically for direct Fahrenheit temperature measurement in industrial, HVAC, and appliance systems-eliminating offset math and enabling plug-and-play analog integration without software compensation.

FAQ

What is the guaranteed accuracy of LM34CAH/NOPB at 77°F?

The LM34CAH/NOPB has a tested accuracy limit of ±1.0°F at 77°F, as specified in TI's SNIS161D datasheet Section 6.5. This value is 100% production-tested and applies across the full −40°F to +230°F operating range. The device achieves this without external calibration due to wafer-level trimming, making LM34CAH/NOPB suitable for factory-calibration-free deployments.

Can LM34CAH/NOPB be mounted directly to a metal surface?

Yes-LM34CAH/NOPB's TO-46 metal can package has the case internally connected to the GND pin, allowing direct soldering or mechanical clamping to metal surfaces such as engine blocks or oven walls. This establishes a low-thermal-resistance path (<43°F/W with infinite heatsink) and ensures die temperature closely tracks the surface, as confirmed in TI's Layout Guidelines (Section 10.1).

What is the maximum cable length LM34CAH/NOPB can drive without signal degradation?

LM34CAH/NOPB's 0.4 Ω output impedance allows driving up to 100 ft of standard 24 AWG twisted-pair cable (≈50 Ω total loop resistance) while maintaining <0.1% gain error at 230°F output (2.3 V). For longer runs or noisy environments, TI recommends adding a 75 Ω series resistor + 0.2 µF capacitor damper at the receiving end, per Figure 13 in SNIS161D.

Does LM34CAH/NOPB require a bypass capacitor on its supply pin?

A 0.01 µF ceramic bypass capacitor between +VS and GND is recommended for noisy environments (e.g., motor drives or switching supplies), as shown in TI's Layout Example (Figure 28). In clean lab or battery-powered applications, LM34CAH/NOPB operates reliably without it due to its 75 µA quiescent current and internal regulation tolerance.

How does LM34CAH/NOPB differ from LM34C in terms of specification and packaging?

LM34CAH/NOPB is the hermetic TO-46 packaged version of the LM34C grade, sharing identical electrical specs (−40°F to +230°F range, ±1.0°F accuracy at 77°F) but differing in thermal performance and environmental robustness. The TO-46 package provides lower thermal resistance and hermetic sealing versus the plastic TO-92 used for LM34C variants like LM34CAZ/NOPB, making LM34CAH/NOPB preferred for harsh or high-reliability applications.