onsemi LM2931CTV

Overview

LM2931CTV from ON Semiconductor (formerly Motorola) is an adjustable low-dropout linear voltage regulator in a 5-pin TO-220 vertical leadform package, delivering ≥100 mA output current with dropout voltage as low as 0.16 V at 100 mA and bias current of 0.4 mA at 10 mA load. It features reverse polarity protection (–50 V), 60 V load dump survival, internal current limiting, thermal shutdown, and output inhibit functionality - designed for automotive and battery-powered industrial systems requiring robust regulation under harsh transients.

For engineers reviewing the LM2931CTV datasheet, pinout, applications, or equivalent options, this page provides verified pin assignments, thermal performance data for vertical-mount TO-220 (Case 314B), real-world dropout behavior across temperature and load, output inhibit threshold specs (2.15–3.25 V), and validated alternatives for adjustable LDO replacement in safety-critical 12 V/24 V subsystems.

Technical Context

The LM2931CTV uses a PNP pass transistor architecture enabling ultra-low dropout operation while maintaining stability with external output capacitance (≥100 µF, ESR ≤0.3 Ω). Its reference voltage is internally trimmed to 1.20 V (±6%) and set between Output and Adjust pins, allowing programmable output from 3.0 V to 24 V via resistive divider.

It integrates fault protection including mirror-image insertion tolerance, overvoltage shutdown (26–40 V), and reverse transient immunity - all without external components. The Output Inhibit pin enables microprocessor-controlled power gating with defined turn-on/turn-off thresholds dependent on junction temperature.

Key Specifications

Pinout & Package

LM2931CTV is housed in Case 314B: 5-pin TO-220 vertical leadform with heatsink surface electrically connected to Pin 3 (Ground). Mounting orientation is vertical; thermal performance assumes heatsink contact to Pin 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-ADJ and MCP1826T-ADJ, the LM2931CTV uniquely combines automotive-grade transient protection, output inhibit, and sub-0.2 V dropout in a thermally efficient TO-220 package - making it irreplaceable in cost-constrained, safety-critical 12 V/24 V embedded designs where reliability under fault conditions is mandatory.

Availability

LM2931CTV is available at Aetrix Electronics and suitable for automotive body electronics, industrial data loggers, and portable medical devices requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LM2931CTV 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

ON Semiconductor is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, communications, and computing markets.

The LM2931 series was developed specifically for automotive power management, emphasizing survivability against reverse battery, load dump, and thermal stress - targeting engine control, lighting, and infotainment subsystems.

FAQ

What is the maximum input voltage rating for the LM2931CTV?

The LM2931CTV supports 40 V continuous input voltage and can withstand 60 V transient input (≤100 ms, 1.0% duty cycle) per ISO 7637-2 Pulse 5a. This makes it suitable for 24 V commercial vehicle systems and 12 V automotive applications with alternator load dump events. Exceeding 60 V transient may cause permanent damage.

Does the LM2931CTV require an external output capacitor, and what are the stability requirements?

Yes, the LM2931CTV is not internally compensated and requires an external output capacitor for stability. Minimum recommended value is 100 µF with ESR ≤0.3 Ω (electrolytic or tantalum). Solid tantalum is preferred for compact designs, but ESR must remain within 0.15–0.3 Ω across –40°C to +125°C to avoid oscillation in the "Unstable" region shown in Figure 22 of the datasheet.

How does the Output Inhibit function work on the LM2931CTV?

The Output Inhibit pin (Pin 2) enables digital control of regulation: output is active when voltage ≥2.15 V (at –40°C) to ≥3.25 V (at +125°C); output is disabled (pulled low) when voltage drops below 1.20 V. This allows direct interfacing with 3.3 V or 5 V MCU GPIOs without level-shifting, supporting low-power sleep states in battery-operated LM2931CTV applications.

What is the thermal performance of the LM2931CTV in its Case 314B package?

In the Case 314B (5-pin TO-220 vertical leadform), the LM2931CTV has RθJC = 5.0 °C/W and RθJA = 65 °C/W (free-air, 25°C ambient). With a properly mounted heatsink contacting Pin 3 (case), it can dissipate >3 W continuously. Derating is required above 25°C ambient - e.g., at 50°C TA, max power drops to ~2.3 W before reaching 125°C TJ limit.

Can the LM2931CTV be used as a fixed-output regulator, or is it strictly adjustable?

The LM2931CTV is exclusively an adjustable-output regulator. Its internal reference is 1.20 V between Output and Adjust pins, requiring an external resistor divider to set VOUT = 1.20 × (1 + R1/R2). Fixed-output variants (e.g., LM2931T–5.0) exist in the same family but use different die and pinouts - the LM2931CTV cannot be configured as fixed-output without external feedback components.