Microchip Technology MIC2937A-3.3BU

Overview

MIC2937A-3.3BU from Microchip Technology is a 3.3 V fixed-output, 3 A low-dropout linear regulator with thermal shutdown, current limiting, and reverse-battery protection. It operates over an input voltage range of 4.5 V to 26 V, maintains ±1% output voltage accuracy over load/line/temperature, and delivers up to 3 A continuous output current in the TO-263-5 package. It is used in industrial power supplies and embedded control systems requiring stable, noise-sensitive 3.3 V rail generation.

For engineers reviewing the MIC2937A-3.3BU datasheet, MIC2937A-3.3BU pinout, MIC2937A-3.3BU application, or MIC2937A-3.3BU equivalent, key selection criteria include dropout voltage at full load, guaranteed output accuracy across temperature, integrated reverse-battery protection, and thermal performance in high-ambient industrial environments.

Technical Context

The MIC2937A-3.3BU employs a PNP pass transistor architecture enabling ultra-low dropout (typically 350 mV at 3 A), unlike NPN-based regulators requiring higher headroom. Its internal bandgap reference and error amplifier ensure tight regulation without external components.

It integrates foldback current limiting that reduces output current during short-circuit events, and thermal shutdown activates at 160°C junction temperature with automatic recovery upon cooling. Reverse-battery protection blocks conduction when VIN is reversed relative to GND, preventing damage in automotive or field-service scenarios.

Key Specifications

Pinout & Package

Package: TO-263-5 (D2PAK), surface-mount, thermally enhanced with exposed tab tied to GND for optimal heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2937ET-3.3/NOPB and NCP1117ST33T3G, the MIC2937A-3.3BU uniquely combines 3 A output, reverse-battery protection, and ±1% accuracy in a single TO-263-5 package-enabling simplified, robust power design for mission-critical industrial and automotive systems.

Availability

MIC2937A-3.3BU is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MIC2937A-3.3BU 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

Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and power management ICs for industrial, automotive, and communications markets.

The MIC2937A-3.3BU belongs to Microchip's high-current LDO family designed specifically for ruggedized 3.3 V power delivery in harsh environments where reliability, fault protection, and thermal resilience are critical.

FAQ

What is the minimum input voltage required for MIC2937A-3.3BU to maintain regulation?

The MIC2937A-3.3BU requires a minimum input voltage of 3.65 V to sustain 3.3 V output at 3 A load, based on its typical 350 mV dropout voltage. At lighter loads, dropout decreases-e.g., 250 mV at 1 A-allowing operation from as low as 3.55 V. Input must remain ≥4.5 V per absolute maximum ratings to avoid stress.

Does MIC2937A-3.3BU require external capacitors, and what values are recommended?

Yes, MIC2937A-3.3BU requires both input and output capacitors. A minimum 10 µF ceramic capacitor (X5R/X7R, ≥6.3 V rating) is recommended at the output; 10 µF–47 µF improves transient response. An input capacitor ≥10 µF (same dielectric) is mandatory for stability and EMI suppression. The SENSE pin may be bypassed with 0.1 µF if remote sensing is unused.

How does the SENSE pin function on MIC2937A-3.3BU, and when should it be used?

The SENSE pin on MIC2937A-3.3BU provides remote voltage feedback to compensate for IR drop in PCB traces between the regulator and load. When connected directly to the load's 3.3 V node, it ensures ±1% accuracy at point-of-load. If not used, SENSE must be tied to OUT. Using SENSE avoids output voltage sag under dynamic load changes in high-current routing paths.

Can MIC2937A-3.3BU be used in automotive applications with battery reverse-connection risk?

Yes, MIC2937A-3.3BU includes integrated reverse-battery protection that blocks current flow when VIN is negative relative to GND-up to –26 V-without external components. This makes it suitable for automotive body control modules, telematics units, and service-accessible systems where accidental reverse-jump-starting may occur.

What thermal considerations apply when operating MIC2937A-3.3BU at 3 A continuous current?

At 3 A and 26 V input, MIC2937A-3.3BU dissipates up to 6.8 W. With its TO-263-5 package and exposed GND tab, thermal resistance θ_JA is ~40°C/W on a 1-in² 2-oz copper pad. To maintain T_J ≤125°C in 70°C ambient, a minimum 25 cm² copper area and optional airflow or heatsink is recommended. Thermal shutdown triggers at 160°C junction temperature.