Microchip Technology MIC2951-03BM

Overview

MIC2951-03BM from Micrel is a 5.0V, ±1% accuracy, 150mA low-dropout linear voltage regulator in 8-pin SOIC package, featuring 250mV dropout at 100mA, reverse-battery protection (–20V), and load-dump tolerance (+60V). It serves as a robust power supply for automotive control modules requiring stable 5V rail under harsh transients.

For engineers reviewing the MIC2951-03BM datasheet, MIC2951-03BM pinout, MIC2951-03BM application, or MIC2951-03BM equivalent, key selection criteria include guaranteed 150mA output across –40°C to +125°C, open-collector error flag for battery health monitoring, logic-controlled shutdown, and programmable output capability via external resistors.

Technical Context

The MIC2951-03BM integrates a precision 1.235V bandgap reference with <50 ppm/°C temperature coefficient, enabling use as both regulator and voltage reference. Its error comparator monitors FB pin voltage relative to VREF, asserting active-low ERR when output drops >5% below nominal-e.g., below 4.75V for 5V operation.

It employs internal current and thermal limiting, supports adjustable output from 1.24V to 29V using R1/R2 feedback network, and maintains stability with ≥1.5µF output capacitance. Shutdown input accepts TTL-compatible logic levels (VIL ≤ 0.7V, VIH ≥ 2.0V) and draws ≤100µA in shutdown mode.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (M), body size 3.9mm × 4.9mm, standard lead finish, RoHS-compliant option available (MIC2951-03YM).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with MIC2951-02BM, the MIC2951-03BM trades minor accuracy for cost efficiency while retaining identical pinout, protection features, and thermal rating. Against LP2951ACN, it delivers superior transient immunity and 30% lower dropout-enabling operation in wider input ranges without redesign.

Availability

MIC2951-03BM is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor nodes, avionics cabin units, and cellular IoT trackers requiring stable component supply across extended temperature ranges and harsh electrical environments.

Supply support for MIC2951-03BM 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

Micrel Inc. was a U.S.-based semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015.

The MIC2951 product line was designed for automotive and industrial applications demanding high reliability, wide-input-voltage operation, and integrated fault protection-targeting ECU, telematics, and safety-critical subsystems.

FAQ

What is the maximum input voltage the MIC2951-03BM can handle continuously?

The MIC2951-03BM supports continuous input voltages from +2.0V to +30V. While it survives +60V transients for ≤100ms (per ISO 7637-2), sustained operation above +30V risks permanent damage. For automotive cold-crank scenarios, VIN as low as 6V remains within specification due to its 250mV dropout at 100mA load.

Does the MIC2951-03BM require an external capacitor for stability, and what value is recommended?

Yes, the MIC2951-03BM requires a minimum 1.5µF output capacitor between OUT and GND for stability. Aluminum or tantalum electrolytics with ESR ≤5Ω are recommended. For loads ≥100mA or adjustable configurations, increasing to 3.3µF or adding a 0.01µF capacitor across R1 further reduces noise to 100µV_RMS.

How does the ERR pin on the MIC2951-03BM function, and what external components are needed?

The ERR pin is an open-collector output that pulls low when VOUT drops >5% below nominal (e.g., <4.75V for 5V output). It requires an external pull-up resistor-typically 100kΩ to 1MΩ-to VOUT or another supply. This resistor sets leakage current during fault conditions; values ≥470kΩ minimize battery drain in low-power systems using MIC2951-03BM.

Can the MIC2951-03BM be used as a programmable voltage regulator, and what is the output range?

Yes, the MIC2951-03BM supports programmable output from 1.24V to 29V using two external resistors connected to FB and TAP pins. The internal 1.235V reference and <60nA feedback bias current enable precise setting; for best accuracy, R2 ≤100kΩ is recommended to limit error from bias current to <0.17%.

What thermal derating applies to the MIC2951-03BM in SOIC package at elevated ambient temperatures?

In its 8-pin SOIC (M) package with θ_JA = 160°C/W, the MIC2951-03BM's maximum power dissipation decreases linearly above +25°C ambient. At +85°C ambient, usable power drops to ~0.7W (vs. 1.25W at +25°C); at +125°C junction limit, output current must be reduced to maintain safe operation-e.g., ≤100mA with VIN = 12V and VOUT = 5V.