STMicroelectronics LM150K

Overview

LM150K from STMicroelectronics is a three-terminal adjustable positive voltage regulator delivering guaranteed 3 A output current with adjustable output down to 1.2 V, ±1% reference voltage (1.19–1.29 V), line regulation of 0.005%/V typical, and thermal regulation of 0.002%/W - used in industrial power supplies requiring stable low-drift biasing and wide-temperature operation.

For engineers reviewing the LM150K datasheet, LM150K pinout, LM150K application, or LM150K equivalent, key selection considerations include guaranteed -55°C to +150°C operating junction temperature, TO-3 package thermal resistance (1.5°C/W junction-to-case), minimum load current (3.5 mA), ripple rejection (65 dB at 120 Hz), and adjustment pin current stability (50–100 µA).

Technical Context

The LM150K implements a bandgap-referenced feedback control loop with internal current limiting and thermal shutdown. Its 1.25 V nominal reference voltage is developed between output and adjustment terminals, enabling precise external resistor-based output programming via VO = Vref(1 + R2/R1) + Iadj·R2.

It features constant-current limit over temperature, internally limited power dissipation, and pulse-tested thermal regulation (20 ms). The device requires no external compensation and remains stable with ≥1 µF solid tantalum output capacitance, avoiding ringing in the 500 pF–5 nF range.

Key Specifications

Pinout & Package

LM150K is housed in a metal-can TO-3 package with case-connected collector (heat sink tab), suitable for high-power dissipation and direct mounting to chassis or heatsinks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM350K and LM250K, the LM150K uniquely supports full military-grade temperature operation (-55°C to +150°C) while retaining identical regulation accuracy, noise, and thermal performance - making it the sole option for extreme-environment linear regulation.

Availability

LM150K is available at Aetrix Electronics and suitable for industrial programmable power supplies, aerospace avionics modules, test equipment bias rails, and high-temperature motor control boards requiring stable component supply across extended temperature ranges.

Supply support for LM150K 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LM150K belongs to ST's legacy linear regulator product line, engineered specifically for high-reliability, wide-temperature-range analog power conditioning in mission-critical systems.

FAQ

What is the minimum load current required for stable regulation with LM150K?

The LM150K requires a minimum load current of 3.5 mA (typ. 5 mA) to maintain regulation. This is due to internal quiescent current returning to the output terminal. If load falls below this threshold, output voltage may rise uncontrollably. A bleeder resistor or light auxiliary load ensures compliance across all operating conditions.

Can LM150K be used without an output capacitor?

Yes - the LM150K is unconditionally stable without an output capacitor. However, adding ≥1 µF solid tantalum capacitance improves transient response and suppresses high-frequency ringing that can occur with parasitic capacitances between 500 pF and 5 nF. Aluminum electrolytic (≥25 µF) is acceptable but less effective at high frequencies.

How does the adjustment pin current affect output accuracy?

The adjustment pin draws 50–100 µA (typ. 75 µA), introducing error in the R2 term of VO = Vref(1 + R2/R1) + Iadj·R2. For R2 = 2.4 kΩ, this adds up to ~0.18 mV error. Using lower R2 values or compensating Iadj in design calculations mitigates impact - especially critical in precision 0.1% output tolerance applications.

Is the TO-3 case electrically connected, and how should it be mounted?

Yes - the TO-3 metal case is internally connected to the input (Pin 1) terminal. It must be electrically isolated from chassis ground unless the input is referenced to system ground. Use insulating shoulder washers and mica pads with thermal grease when mounting to heatsinks to prevent short circuits while maintaining optimal thermal transfer (1.5°C/W junction-to-case).