Texas Instruments LM317HVH

Overview

LM317HVH from Texas Instruments is a high-voltage, three-terminal adjustable positive linear voltage regulator delivering up to 1.5 A output current with 1.25 V to 57 V programmable output range and 60 V maximum input-to-output differential. It uses two external resistors for voltage setting, integrates internal short-circuit and thermal overload protection, and operates from 0°C to 125°C - commonly deployed in industrial power supplies and PLC systems requiring stable, wide-range DC regulation.

For engineers reviewing the LM317HVH datasheet, LM317HVH pinout, LM317HVH application, or LM317HVH equivalent, key selection considerations include its 60 V differential rating, 1.25 V reference accuracy, TO-220 package thermal performance (R_θJA = 23.0°C/W), and use as a precision current regulator via ADJ–VOUT resistor connection.

Technical Context

The LM317HVH regulates by maintaining a precise 1.25 V reference between its output (VOUT) and adjustment (ADJ) terminals, enabling output voltage calculation via V_OUT = 1.25 V × (1 + R₂/R₁) + I_ADJ × R₂. Its internal bandgap reference, error amplifier, and pass transistor operate in series-regulator topology with fixed 1.25 V feedback threshold.

Overload protection includes current limiting (1.5 A typical), thermal shutdown, and safe-area protection - all functional even if the ADJ pin is disconnected. Ripple rejection reaches 80 dB at 120 Hz with 10 μF ADJ-to-ground bypass capacitor, and line/load regulation are specified at 0.01%/V and 0.1% respectively under full operating conditions.

Key Specifications

Pinout & Package

LM317HVH is supplied in a TO-220 package (14.986 mm × 10.16 mm) with metal tab acting as the output terminal and integral heat sink interface. The package supports >20 W power dissipation with appropriate heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM317H, LM317HVH enables 50% higher differential voltage headroom for high-input applications; versus LT1083CP, it offers lower cost and TI's long-term supply assurance while trading off ultimate line regulation and maximum voltage rating.

Availability

LM317HVH is available at Aetrix Electronics and suitable for industrial power supplies, PLC systems, and factory automation systems requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for LM317HVH 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs with broad industrial and automotive qualification.

The LM317HVH belongs to TI's high-voltage linear regulator product line, designed specifically for industrial applications demanding extended input–output differential capability, robust thermal performance, and integrated protection in standard through-hole packages.

FAQ

What is the maximum input–output voltage differential supported by the LM317HVH?

The LM317HVH supports a maximum input–output voltage differential of 60 V, as specified in its Absolute Maximum Ratings. This allows it to regulate outputs from high-voltage sources such as rectified 48 VAC or multi-cell battery packs. Exceeding this limit risks permanent device damage, especially during fault conditions like output short-circuit. Always verify (VIN – VOUT) ≤ 60 V in worst-case operating scenarios for the LM317HVH.

Can the LM317HVH be used as a constant-current source?

Yes, the LM317HVH can function as a precision constant-current source by connecting a single resistor between its VOUT and ADJ terminals. Because the device maintains a stable 1.25 V reference across those pins, output current equals 1.25 V divided by the resistor value (e.g., 1.25 Ω yields 1 A). This configuration is widely used in LED drivers and battery chargers, and the LM317HVH's low adjustment current drift ensures stable current over temperature and line variations.

Does the LM317HVH require external capacitors for stability?

The LM317HVH is internally compensated and stable without external capacitors. However, an input bypass capacitor (≥0.1 μF ceramic) is recommended if the device is located more than 6 inches from the main filter capacitor. An optional 1–1000 μF output capacitor improves transient response, and a 10 μF capacitor from ADJ to ground enhances ripple rejection to 80 dB. These capacitors do not affect basic stability but optimize performance in real-world layouts for the LM317HVH.

What is the thermal resistance of the LM317HVH in its TO-220 package?

The LM317HVH in TO-220 package has a junction-to-ambient thermal resistance (R_θJA) of 23.0°C/W with standard PCB mounting and no heatsink. With an appropriately sized heatsink, effective R_θJA drops significantly - enabling continuous 1.5 A operation at elevated ambient temperatures. Thermal performance must be validated using actual board layout, copper area, and airflow, as R_θJA is highly dependent on PCB design for the LM317HVH.

How does the LM317HVH handle overload conditions?

The LM317HVH incorporates three independent protection mechanisms: internal current limiting (activates near 1.5 A), thermal shutdown (triggers above safe junction temperature), and safe-area protection (prevents simultaneous high voltage/current stress). All remain fully operational even if the ADJ pin is disconnected. These features make the LM317HVH "blowout proof" in industrial environments - eliminating need for external foldback or shutdown circuitry in most designs using the LM317HVH.