Texas Instruments LM135H/NOPB

Overview

LM135H/NOPB from Texas Instruments is a precision 2-terminal Kelvin-referenced temperature sensor operating as a zener diode with linear 10 mV/°K output, ±1°C initial accuracy at 25°C, −55°C to +150°C operating range, and <1 Ω dynamic impedance. It enables high-stability thermal monitoring in aerospace power supplies and industrial motor control systems where absolute temperature tracking is critical.

For engineers reviewing the LM135H/NOPB datasheet, LM135H/NOPB pinout, LM135H/NOPB application, or LM135H/NOPB equivalent, this page delivers verified technical context, calibrated error behavior across temperature, current-driven operation constraints (400 μA–5 mA), TO-46 package thermal metrics, and real-world calibration methodology using the ADJ pin.

Technical Context

The LM135H/NOPB functions as a 2-terminal zener-based voltage reference whose breakdown voltage tracks absolute temperature linearly at 10 mV/°K, enabling direct Kelvin-scale readout without signal conditioning. Its low 0.6 Ω typical dynamic impedance ensures stable output under load variations across its 400 μA–5 mA bias current range.

Calibration is performed via the ADJ pin using a single-point slope adjustment at 25°C (2.982 V), correcting scale-factor errors across the full −55°C to +150°C range. The device supports both uncalibrated use (±2.7°C max error) and calibrated operation (±1°C max error), with self-heating effects quantified by time constants of 80 sec (still air) and 1 sec (stirred oil).

Key Specifications

Pinout & Package

LM135H/NOPB uses the hermetic TO-46 metal can package (3-pin, 4.699 mm × 4.699 mm body), optimized for high-reliability environments requiring moisture resistance and thermal stability. Pin 1 is No Connection (N.C.), Pin 2 is negative output terminal (−), and Pin 3 is positive input terminal (+). The ADJ pin is not present on the LM135H/NOPB variant - only LM135A and LM235 variants include the calibration adjust terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM135AH/NOPB, the LM135H/NOPB trades ±0.5°C factory calibration accuracy for lower unit cost while retaining full −55°C to +150°C range and TO-46 reliability; versus LM235H/NOPB, it adds 15°C lower end-range capability at identical price, making it preferred for aerospace and defense thermal monitoring.

Availability

LM135H/NOPB is available at Aetrix Electronics and suitable for aerospace power supplies, industrial motor protection, and high-reliability battery management systems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM135H/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 company specializing in analog and embedded processing technologies, with leadership in precision analog signal chains and high-reliability components.

The LM135H/NOPB belongs to TI's LMx35 precision temperature sensor family, designed specifically for applications demanding direct Kelvin-scale measurement, low-drift performance, and robust operation in harsh thermal environments.

FAQ

What is the operating temperature range of the LM135H/NOPB?

The LM135H/NOPB operates continuously from −55°C to +150°C and supports intermittent exposure up to +200°C. This extended range is enabled by its hermetic TO-46 metal-can package and internal zener architecture, making it suitable for aerospace, downhole, and military applications where extreme thermal environments occur. The LM135H/NOPB maintains specified electrical performance across this full span when biased within its 400 μA–5 mA current range.

Does the LM135H/NOPB include an ADJ (adjust) pin for calibration?

No, the LM135H/NOPB does not include an ADJ pin. Only the LM135A and LM235A variants feature the calibration adjust terminal. The LM135H/NOPB is the base-grade version with ±1°C initial accuracy at 25°C and relies on external circuitry (e.g., precision series resistor and op-amp buffer) for system-level calibration. For designs requiring on-chip slope adjustment, the LM135AH/NOPB is the appropriate drop-in alternative with identical TO-46 packaging.

What is the dynamic impedance specification for the LM135H/NOPB and why does it matter?

The LM135H/NOPB has a typical dynamic impedance of 0.6 Ω, measured at 1 mA bias current. This low value means the output voltage changes less than 0.6 mV for every 1 mA change in load current - critical for maintaining accuracy when driving ADC input stages, long cables, or multiple parallel sensors. High dynamic impedance would introduce significant error due to current-dependent voltage droop, especially in low-power or high-impedance interface circuits.

Can the LM135H/NOPB be used in a 3.3 V system?

Yes, the LM135H/NOPB can operate in a 3.3 V system when configured with an appropriate series current-limiting resistor. At 25°C, its nominal output is 2.982 V, leaving ~318 mV headroom. Using Ohm's Law, a 330 Ω resistor delivers ~1 mA bias current (3.3 V − 2.982 V = 0.318 V ÷ 330 Ω), satisfying the 400 μA–5 mA operating range. Ensure PCB layout minimizes thermal coupling to maintain accuracy, as self-heating increases with bias current.

How does the LM135H/NOPB differ from the LM335H/NOPB?

The LM135H/NOPB offers a wider operating temperature range (−55°C to +150°C) versus the LM335H/NOPB (−40°C to +100°C) and uses a hermetic TO-46 metal-can package instead of the TO-92 plastic package found on most LM335 variants. Electrically, both provide 10 mV/°K output, but the LM135H/NOPB's superior thermal stability, lower dynamic impedance (0.6 Ω vs. 1.5 Ω), and enhanced long-term drift performance make it preferred for high-reliability applications where environmental stress and lifetime stability are critical.