Microchip Technology MIC5249-2.6BMM-TR

Overview

MIC5249-2.6BMM-TR from Micrel is a 300mA, 2.6V fixed-output CMOS low-dropout (LDO) regulator with programmable power-on-reset (POR) delay and noise-reduction bypass capability. It delivers ±1.0% initial output accuracy, 340mV dropout at full load, 85µA quiescent current, and operates from 2.7V to 6V input. Used in cellular phones and fiber optic modules for stable, ultra-low-noise biasing of RF and analog circuitry.

For engineers reviewing the MIC5249-2.6BMM-TR datasheet, MIC5249-2.6BMM-TR pinout, MIC5249-2.6BMM-TR application, or MIC5249-2.6BMM-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 ceramic-capacitor stability without requiring high-ESR components.

Technical Context

The MIC5249-2.6BMM-TR integrates a precision bandgap reference, CMOS pass transistor, and active-clamp shutdown circuit enabling rapid output discharge. Its POR function is implemented by charging an external capacitor on the DELAY pin using a 0.55µA internal current source, with reset assertion triggered when VDELAY reaches 1.4V.

It features an open-drain RESET output that asserts low only when both undervoltage detection (VOUT < 89–91% nominal) and fault conditions (overcurrent/thermal) coincide-preventing false triggering. The CBYP pin accepts a 0.01µF capacitor to bypass the internal reference and improve PSRR to 65dB at 120Hz.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (MM), 3.0mm × 3.0mm × 1.0mm body, 0.65mm pitch, exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2602E/TT and TCS2102-2.6V, the MIC5249-2.6BMM-TR uniquely combines adjustable POR delay, open-drain RESET with intelligent fault AND-undervoltage logic, and reference-bypass noise filtering-making it optimal for compact, noise-critical, and sequenced-power applications where design flexibility and signal integrity are prioritized.

Availability

MIC5249-2.6BMM-TR is available at Aetrix Electronics and suitable for cellular phones, fiber optic modules, and handheld terminals requiring stable component supply across extended temperature ranges (–40°C to +125°C) and long production lifecycles.

Supply support for MIC5249-2.6BMM-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 ICs.

The MIC5249 family was designed for noise-sensitive, battery-powered portable electronics requiring precise, low-quiescent, and feature-rich LDO regulation with integrated power sequencing and fault signaling-targeting cellular, PDA, and optical module markets.

FAQ

What is the maximum input voltage for MIC5249-2.6BMM-TR in continuous operation?

The absolute maximum input voltage for MIC5249-2.6BMM-TR is +7V, but the recommended operating range is +2.7V to +6V. At 300mA load and 25°C ambient, thermal limits constrain practical VIN to ≤4.56V in the MSOP-8 package due to θJA = 160°C/W and TJ(max) = 125°C. Exceeding this risks thermal shutdown.

Does MIC5249-2.6BMM-TR require an external pull-up resistor on the RESET pin?

Yes, MIC5249-2.6BMM-TR has an open-drain RESET output and requires an external pull-up resistor-typically connected to VIN or VOUT-to establish a valid high logic level when no fault is present. The datasheet specifies no internal pull-up, and omission causes undefined RESET behavior during normal operation.

Can MIC5249-2.6BMM-TR operate stably with zero load current?

Yes, MIC5249-2.6BMM-TR maintains regulation and stability at zero load-a key differentiator from many LDOs. This capability is explicitly verified in the datasheet and enables use in CMOS RAM keep-alive circuits and microcontroller sleep modes where load current drops to near-zero between wake events.

What capacitor value is needed on the DELAY pin for a 500ms POR delay in MIC5249-2.6BMM-TR?

Using the formula TDELAY = CDELAY × 1.4V / 0.55µA, a 500ms delay requires CDELAY = (500ms × 0.55µA) / 1.4V ≈ 196nF. A standard 220nF capacitor yields ~560ms delay. Values must be low-ESR ceramic types; tolerance and temperature drift affect timing accuracy.

Is the NC pin (Pin 6) on MIC5249-2.6BMM-TR safe to connect to ground or leave floating?

Pin 6 (NC) on MIC5249-2.6BMM-TR is not internally bonded and must remain unconnected-neither grounded nor tied to any signal. Connecting it may cause unpredictable behavior or damage, as confirmed in the official Micrel datasheet Pin Description table.