Microchip Technology MIC5249-3.0BMM-TR

Overview

MIC5249-3.0BMM-TR from Micrel is a 300mA, 3.0V fixed-output CMOS low-dropout (LDO) regulator with programmable power-on-reset (POR) delay, ±1.0% initial output accuracy, 340mV dropout at full load, and ultra-low 85µA quiescent current-designed for noise-sensitive battery-powered systems such as cellular handsets and fiber optic modules.

For engineers reviewing the MIC5249-3.0BMM-TR datasheet, MIC5249-3.0BMM-TR pinout, MIC5249-3.0BMM-TR application, or MIC5249-3.0BMM-TR equivalent, key selection criteria include its MSOP-8 package compatibility, adjustable POR delay via external capacitor, open-drain RESET output with 89–91% VOUT undervoltage threshold, and stable operation with 2.2µF ceramic output capacitance.

Technical Context

The MIC5249-3.0BMM-TR integrates a precision bandgap reference, CMOS pass element, and dedicated POR timing circuitry driven by a 0.55µA current source into the DELAY pin. Its active-clamp shutdown discharges the output during disable, while the CBYP pin accepts a 0.01µF capacitor to reduce reference noise and improve PSRR.

It operates across VIN = 2.7V to 6V, delivers regulated 3.0V ±1.0% over temperature, maintains stability with low-ESR ceramic capacitors (≤300mΩ), and features thermal shutdown, current limiting, and logic-compatible ENABLE with <0.4V logic-low threshold and <0.01µA input current.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (MM), 3.0mm × 3.0mm × 1.0mm body, exposed pad optional, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A2030PDBVR and AP2112K-3.0TRG1, the MIC5249-3.0BMM-TR uniquely combines 300mA capability with integrated POR delay, open-drain RESET, and reference bypass-reducing BOM count and PCB area in space-constrained, noise-critical applications where sequencing and reliability are prioritized over minimal IQ.

Availability

MIC5249-3.0BMM-TR is available at Aetrix Electronics and suitable for cellular handsets, fiber optic transceivers, and portable medical devices requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MIC5249-3.0BMM-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 analog and mixed-signal semiconductor company founded in 1978 and acquired by Microchip Technology in 2015; it specialized in high-performance power management, timing, and interface solutions.

The MIC5249-3.0BMM-TR belongs to Micrel's µCap LDO family-engineered specifically for handheld and battery-powered systems demanding ultra-low noise, low dropout, and integrated power sequencing functions without external components.

FAQ

What is the maximum input voltage for MIC5249-3.0BMM-TR when delivering 300mA at 3.0V output?

The maximum input voltage is determined by thermal limits. With θJA = 160°C/W and TJ(max) = 125°C, ambient temperature of 50°C yields PD(max) = 468mW. Using PD ≈ (VIN – 3.0V) × 300mA, VIN(max) calculates to 4.56V. Exceeding this risks thermal shutdown under continuous load. The MIC5249-3.0BMM-TR must operate within this constraint to maintain regulation and reliability.

How is the power-on-reset delay time set for MIC5249-3.0BMM-TR?

The delay time is set by an external capacitor connected from the DELAY pin to GND. The MIC5249-3.0BMM-TR sources a precise 0.55µA current into this capacitor, and the delay TDELAY equals (CDELAY × 1.4V) / 0.55µA. For example, a 100nF capacitor yields ~255ms delay. No capacitor results in immediate RESET assertion-functioning as a basic undervoltage flag.

Does MIC5249-3.0BMM-TR require a minimum load to maintain regulation?

No. The MIC5249-3.0BMM-TR remains stable and in regulation with zero output load-a key differentiator from many older LDO architectures. This feature enables direct use in CMOS RAM keep-alive circuits, real-time clock backup supplies, and other ultra-low-power applications where load current may drop to near-zero during sleep modes.

What is the purpose of the CBYP pin on MIC5249-3.0BMM-TR?

The CBYP pin connects to the internal voltage reference node and accepts a 0.01µF capacitor to ground. This bypass capacitor filters reference noise, directly lowering output voltage noise and improving PSRR-especially critical in RF and high-resolution analog applications. Increasing CBYP capacitance further reduces noise but slightly increases turn-on time due to charging dynamics.

Can MIC5249-3.0BMM-TR drive a 2.2µF ceramic output capacitor reliably?

Yes. The MIC5249-3.0BMM-TR is explicitly optimized for stability with 2.2µF ceramic output capacitors having ESR ≤300mΩ. X7R or X5R dielectrics are recommended for temperature stability. Larger values are acceptable but yield diminishing returns in transient response improvement-the design achieves optimal phase margin and settling behavior at 2.2µF.