Microchip Technology MIC5259-1.5BML TR

Overview

MIC5259-1.5BML TR from Micrel is a 1.5V, 300mA CMOS low-dropout linear regulator optimized for ultra-low-noise RF power supply applications. It delivers 1.5% initial output accuracy, 300mV dropout at full load, and 30µV(rms) output noise with ceramic capacitor support - enabling clean biasing of sensitive analog/RF circuitry in space-constrained portable devices.

For engineers reviewing the MIC5259-1.5BML TR datasheet, MIC5259-1.5BML TR pinout, MIC5259-1.5BML TR application, or MIC5259-1.5BML TR equivalent, key selection criteria include PSRR performance at low VIN (70dB @ 1kHz), TTL-compatible enable input behavior, thermal shutdown threshold (150°C), and MLF® package thermal resistance (θJA = 90°C/W).

Technical Context

The MIC5259-1.5BML TR integrates a precision bandgap reference, error amplifier, and active-clamp shutdown circuit in a CMOS architecture. Its noise-bypass pin (BYP) connects to an external 0.01µF capacitor to shunt reference noise, directly reducing output voltage ripple without compromising transient response.

It operates across 2.7V–6.0V input range with internal current limiting (350–475mA) and thermal protection (150°C trip, 10°C hysteresis). The device maintains regulation down to zero load and supports fast turn-on via a dedicated quick-start circuit that drives the BYP capacitor without significant delay.

Key Specifications

Pinout & Package

Package: 6-pin 2mm × 2mm MLF® (MicroLeadFrame), exposed thermal pad, RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MIC5259-1.5BML TR, the XC6219B152MR-G trades noise performance and PSRR for smaller footprint and cost, while the ADP160ACBZ-1.5-R7 offers superior noise but halves maximum output current and adds soft-start latency - making MIC5259-1.5BML TR optimal for 300mA, BYP-tunable, RF-grade 1.5V regulation.

Availability

MIC5259-1.5BML TR is available at Aetrix Electronics and suitable for cellular front-end power, wearable biometric signal chains, and portable medical sensor bias requiring stable component supply with guaranteed long-term sourcing.

Supply support for MIC5259-1.5BML 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 MIC5259 family was designed specifically for battery-powered RF and portable electronics requiring ultra-low-noise, high-PSRR, ceramic-capacitor-compatible LDO regulation at sub-3V output voltages.

FAQ

What is the minimum input voltage required for MIC5259-1.5BML TR to regulate at full 300mA load?

The MIC5259-1.5BML TR requires a minimum input voltage of 1.8V to maintain regulation at 300mA, calculated as VOUT + VDROPOUT = 1.5V + 0.3V. However, per Absolute Maximum Ratings, the device is only specified to operate down to 2.7V input - below which performance (e.g., PSRR, noise) is not guaranteed. Always maintain VIN ≥ 2.7V for full specification compliance.

Can MIC5259-1.5BML TR operate without the BYP capacitor, and what is the impact?

Yes, MIC5259-1.5BML TR functions without the BYP capacitor, but output noise increases from 30µV(rms) to approximately 90µV(rms), and PSRR degrades by ~15dB at 1kHz. The BYP pin may be left open if noise performance is non-critical; however, for RF or precision analog applications, the 0.01µF capacitor is mandatory to achieve datasheet noise and PSRR specs.

Is the NC pin on MIC5259-1.5BML TR required to be grounded or left floating?

The NC (No Connect) pin on MIC5259-1.5BML TR is internally unconnected and must remain unconnected on the PCB - neither grounded nor tied to any voltage. Connecting it risks unintended current paths or latch-up. The MLF® package thermal pad underneath should be soldered to a large GND copper area for thermal performance, but this is electrically separate from the NC pin.

Does MIC5259-1.5BML TR support reverse polarity protection or input overvoltage protection?

No, MIC5259-1.5BML TR does not integrate reverse polarity or input overvoltage protection. Its Absolute Maximum Rating for VIN is +7V, and operation above +6V violates the recommended operating range. External protection (e.g., series Schottky diode for reverse polarity, TVS diode for overvoltage) must be added if system-level hazards exist - the IC itself provides only thermal shutdown and current limit.

How does the active shutdown clamp in MIC5259-1.5BML TR affect system-level power sequencing?

The active shutdown clamp in MIC5259-1.5BML TR rapidly discharges the output capacitor and downstream load when EN is pulled low, ensuring the 1.5V rail collapses within microseconds. This eliminates hold-up time and prevents back-powering of upstream logic or leakage-induced wake-up - critical for deterministic power-down in multi-rail portable systems using MIC5259-1.5BML TR as a controlled domain supply.