Microchip Technology MIC2951-4.85BM-TR

Overview

MIC2951-4.85BM-TR from Micrel is a 150mA low-dropout linear voltage regulator with fixed 4.85V output, ±1% accuracy over –40°C to +125°C, 250mV dropout at 100mA load, and integrated error flag and shutdown control - used in automotive power rails, battery-backed avionics, and SMPS post-regulation where reverse-battery and load-dump robustness are required.

For engineers reviewing the MIC2951-4.85BM-TR datasheet, MIC2951-4.85BM-TR pinout, MIC2951-4.85BM-TR application, or MIC2951-4.85BM-TR equivalent, key selection criteria include guaranteed 150mA output under 4.85V regulation, open-collector ERR flag for low-VOUT detection, SOIC-8 package thermal performance (160°C/W), and survival of –20V reverse-battery and +60V transient inputs.

Technical Context

The MIC2951-4.85BM-TR integrates a precision 1.235V bandgap reference, error amplifier, and open-collector comparator for early-warning dropout detection. Its feedback loop uses internal resistor taps (TAP and FB pins) to fix output at 4.85V without external components.

It features dual protection architecture: reverse-battery tolerance down to –20V on IN and +60V positive transients (≤100ms, ≤1% duty cycle), plus current and thermal limiting. Shutdown input (SHDN) accepts TTL-compatible logic levels (low = enable, high = shutdown), and ground current remains below 6mA at 150mA load.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (M), body size 3.9mm × 4.9mm, 1.27mm pitch, JEDEC MS-012AC, thermal resistance θ_JA = 160°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2951CM-4.85/NOPB and TPS763485DBVR, the MIC2951-4.85BM-TR uniquely combines automotive-grade transient robustness, integrated ERR/SHDN functionality, and sub-250mV dropout in a single SOIC-8 package - reducing component count and validation effort in harsh-environment designs.

Availability

MIC2951-4.85BM-TR is available at Aetrix Electronics and suitable for automotive electronics, avionics keep-alive systems, and SMPS post-regulation requiring stable component supply across extended temperature and transient stress conditions.

Supply support for MIC2951-4.85BM-TR 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 family was designed specifically for automotive and industrial applications demanding high reliability under voltage transients, wide temperature operation, and integrated fault monitoring - distinguishing it from general-purpose LDOs.

FAQ

What is the maximum input voltage the MIC2951-4.85BM-TR can handle continuously?

The MIC2951-4.85BM-TR supports a continuous input voltage range of +2.0V to +30V. It also withstands non-repetitive transients: –20V reverse-battery events and +60V positive load-dump spikes (limited to ≤100ms duration and ≤1% duty cycle). These ratings are absolute maximums - sustained operation above +30V will damage the device.

Does the MIC2951-4.85BM-TR require external resistors to set its 4.85V output?

No, the MIC2951-4.85BM-TR delivers a factory-trimmed 4.85V output without external resistors. Its internal voltage divider connects pins TAP (6) and FB (7), and ties OUT (1) to SNS (2) - enabling fixed operation out-of-the-box. External resistors are only needed for adjustable configurations outside 4.85V.

How does the ERR pin on the MIC2951-4.85BM-TR behave during startup and dropout?

The ERR pin on the MIC2951-4.85BM-TR is an open-collector output that goes low when V_OUT drops ≈5% below nominal (i.e., <4.61V). During startup, ERR remains high until V_IN exceeds ~1.3V, then asserts low once regulation is lost - providing reliable power-good and brownout detection without external circuitry.

Can the MIC2951-4.85BM-TR be used in adjustable mode despite its fixed 4.85V designation?

Yes, the MIC2951-4.85BM-TR supports adjustable operation from 1.24V to 29V using external resistors on FB and GND. Its internal 1.235V reference and feedback architecture remain fully functional - the "-4.85" suffix denotes factory configuration, not functional limitation. Refer to Figure 2 in the datasheet for resistor calculation.

What is the thermal performance of the MIC2951-4.85BM-TR in its SOIC-8 package?

The MIC2951-4.85BM-TR in SOIC-8 (M) package has a junction-to-ambient thermal resistance (θ_JA) of 160°C/W under standard JEDEC test conditions. At 150mA load and 5.1V input (250mV dropout), power dissipation is ~38mW - resulting in <7°C junction rise above ambient, ensuring stable operation without heatsinking.