Texas Instruments LM337H/NOPB

Overview

LM337H/NOPB from Texas Instruments is a 3-terminal adjustable negative linear voltage regulator delivering up to −1.5 A output current, with output voltage programmable from −1.25 V to −37 V using two external resistors. It features 77 dB ripple rejection, 0.01%/V typical line regulation, and thermal overload protection. It serves as the negative complement to LM317 in dual-rail industrial power supplies.

For engineers reviewing the LM337H/NOPB datasheet, LM337H/NOPB pinout, LM337H/NOPB application, or LM337H/NOPB equivalent, key selection criteria include its TO-3 metal-can package thermal performance, −55°C to +150°C operating junction temperature range, internal short-circuit current limiting, and compatibility with standard negative-bias applications requiring high reliability and low thermal drift.

Technical Context

The LM337H/NOPB operates by maintaining a precise −1.25 V reference between its output (VOUT) and adjustment (ADJ) terminals, enabling programmable output via an external resistor divider. Its architecture integrates internal current limiting, thermal shutdown, and safe-area compensation to prevent damage under overload or fault conditions.

Designed for high-stability negative bias generation, it supports stable operation with only one output capacitor (1 μF solid tantalum or 10 μF aluminum electrolytic) and exhibits 50 ppm/°C temperature coefficient and 0.3% typical load regulation - critical for instrumentation-grade analog circuits and IGBT gate drive supplies.

Key Specifications

Pinout & Package

LM337H/NOPB uses the TO-3 metal-can package (NDT), 8.255 mm × 8.255 mm body size, with case-connected collector (VIN) for direct heatsink mounting and superior thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable negative regulator applications.

Compared with LM337T/NOPB and LM337IMP/NOPB, the LM337H/NOPB offers the widest temperature range (−55°C to +150°C) and highest ruggedness in a metal-can TO-3 package - making it the sole choice for military, aerospace, and high-reliability industrial deployments where thermal margin and long-term stability are non-negotiable.

Availability

LM337H/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, PLC systems, and factory automation requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LM337H/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 power management technologies with over 50 years of innovation in high-reliability linear regulators.

The LM337 family was designed specifically for demanding negative-voltage regulation in industrial control, instrumentation, and power conversion - emphasizing thermal robustness, precision reference stability, and intrinsic fault protection without external components.

FAQ

What is the maximum input-output voltage differential for LM337H/NOPB?

The absolute maximum input-output voltage differential for LM337H/NOPB is −40 V, meaning |VIN − VOUT| must not exceed 40 V. Exceeding this risks permanent damage. At high differentials, output current must be derated per Figure 7-2 in the datasheet to maintain junction temperature ≤150°C - for example, full −1.5 A is only achievable at |VIN − VOUT| ≤15 V in the TO-3 package.

Does LM337H/NOPB require an input capacitor?

LM337H/NOPB does not strictly require an input capacitor for stability, but TI recommends a ≥10 μF aluminum electrolytic capacitor at the VIN pin if the device is located more than 4 inches from the main power supply filter capacitor. This prevents oscillation and improves transient response during input line disturbances - especially critical in factory automation systems with long cable runs.

Can LM337H/NOPB be used as a constant current source?

Yes, LM337H/NOPB can be configured as a constant current source by connecting a single resistor R1 between VOUT and ADJ pins. Since the regulator maintains −1.25 V across R1, output current equals −1.25 V / R1. For example, a 12.5 Ω resistor sets −100 mA. The LM337H/NOPB's internal current limiting and thermal protection ensure safe operation even under open-load or short-circuit conditions.

What is the purpose of the ADJ pin bypass capacitor in LM337H/NOPB circuits?

A bypass capacitor (typically 1–10 μF tantalum) at the ADJ pin of LM337H/NOPB significantly improves ripple rejection - boosting it from 66 dB to 77 dB at 120 Hz - by shunting AC noise away from the sensitive reference node. Placing it within 5 mm of the ADJ pin is essential; longer traces degrade high-frequency PSRR. This is critical in networking and instrumentation applications where clean negative bias directly impacts signal integrity.

Is LM337H/NOPB RoHS compliant?

Yes, LM337H/NOPB is RoHS compliant, as confirmed by Texas Instruments' official packaging addendum: "RoHS: Yes" and "Lead finish: AU (gold)" with MSL Level-1 rating. The "NOPB" suffix explicitly denotes lead-free (Pb-free) construction, meeting EU Directive 2011/65/EU and JEDEC J-STD-020 requirements for halogen-free, lead-free assembly processes.