Microchip Technology MIC2571-2YMM-TR

Overview

MIC2571-2YMM-TR from Micrel is an adjustable-output micropower boost switching regulator designed for single-cell battery operation (0.9V–15V input), delivering up to 36V output with 1.1A current limiting and fixed 20kHz switching frequency. It integrates a gated-oscillator architecture with internal 0.22V reference, enabling high-efficiency operation in portable LCD bias, remote control, and detector power supplies.

For engineers reviewing the MIC2571-2YMM-TR datasheet, MIC2571-2YMM-TR pinout, MIC2571-2YMM-TR application, or MIC2571-2YMM-TR equivalent, key selection considerations include its adjustable feedback threshold (0.22V), SYNC input for noise reduction, MSOP-8 thermal performance (θ_JA = 240°C/W), and guaranteed startup down to 0.9V input.

Technical Context

The MIC2571-2YMM-TR implements a gated oscillator topology where the NPN switch (SW pin) is disabled when output voltage exceeds the comparator threshold-reducing quiescent current to 120µA typical. Its 0.22V internal reference feeds a comparator that monitors external resistor-divider feedback (FB pin), enabling precise output regulation across wide input ranges.

Switching behavior is controlled by duty cycle (67% nominal) and synchronized via the SYNC pin's falling-edge trigger. Current limiting operates by dynamically reducing on-time above 1.1A, preserving inductor and switch integrity without abrupt shutdown-critical for stable low-power, high-ratio boost applications.

Key Specifications

Pinout & Package

Package: 8-lead MSOP (MM), 3.0mm × 3.0mm × 0.85mm body, exposed pad not present, θ_JA = 240°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX756CPA+ and TPS61022RSAR, the MIC2571-2YMM-TR uniquely supports sub-1V startup, 36V adjustable output, and 20kHz synchronization - making it irreplaceable for low-input, high-ratio, noise-sensitive single-cell applications.

Availability

MIC2571-2YMM-TR is available at Aetrix Electronics and suitable for LCD bias generators, battery-powered detectors, remote controls, pagers, and portable instrumentation requiring stable component supply across extended temperature and long-life battery operation.

Supply support for MIC2571-2YMM-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; known for high-reliability power management and timing solutions.

The MIC2571 product line was engineered specifically for ultra-low-voltage, micropower boost conversion in space-constrained portable electronics - emphasizing minimal external components, sub-1V startup, and thermal robustness in MSOP packaging.

FAQ

What is the minimum input voltage required for MIC2571-2YMM-TR to start regulating?

The MIC2571-2YMM-TR guarantees startup at 0.9V input voltage, as confirmed in Absolute Maximum Ratings and Electrical Characteristics tables. This allows reliable operation even with deeply discharged alkaline or NiMH cells. The gated oscillator architecture ensures regulation initiates immediately upon reaching this threshold, and the 120µA quiescent current preserves battery life during standby. MIC2571-2YMM-TR maintains regulation across the full 0.9V–15V input range without external assist circuitry.

How does the FB pin on MIC2571-2YMM-TR set the output voltage?

The FB pin on MIC2571-2YMM-TR connects to the center tap of an external resistor divider between V_OUT and GND. The internal comparator holds the FB node at 0.22V, so V_OUT = 0.22V × (1 + R2/R1), where R2 is the upper resistor and R1 the lower. This configuration enables precise adjustment from input voltage up to 36V. MIC2571-2YMM-TR's 25nA FB input bias current minimizes divider error, supporting high-resistance networks for low quiescent loss.

Can MIC2571-2YMM-TR synchronize to an external clock, and what are the timing requirements?

Yes, MIC2571-2YMM-TR uses the SYNC pin to accept external falling-edge triggers that reset its 20kHz oscillator. The sync threshold voltage is 0.7V, with valid pulse width ≥100ns. When unused, SYNC must be grounded to prevent spurious operation. Synchronization reduces broadband EMI by correlating switching noise to a known system frequency - a key advantage in remote controls and detectors where RF integrity matters. MIC2571-2YMM-TR does not require continuous clocking; single pulses suffice for periodic alignment.

What thermal limitations apply to MIC2571-2YMM-TR in continuous operation?

MIC2571-2YMM-TR has a junction temperature limit of +125°C and MSOP package thermal resistance θ_JA = 240°C/W. At maximum ambient (+85°C), allowable power dissipation is ~146mW before reaching TJ_max. With 1.1A current limit and typical switch saturation voltage of 500mV at 800mA, power loss remains within safe margins for standard PCB layouts. Derating is required above 70°C ambient if delivering >500mA output current. MIC2571-2YMM-TR's thermal specs are validated per JEDEC JESD51-2.

Is MIC2571-2YMM-TR compatible with ceramic output capacitors, and what ESR considerations apply?

Yes, MIC2571-2YMM-TR is compatible with ceramic output capacitors, but low-ESR is mandatory: typical recommended ESR is ≤50mΩ to limit ripple voltage. High-ESR aluminum electrolytics cause excessive ripple - e.g., 200mΩ ESR with 500mA peak current yields 100mV ripple. Tantalum and multilayer ceramic capacitors (MLCCs) meet this requirement. MIC2571-2YMM-TR's stability is verified with 15µF–47µF output capacitance; values below 10µF may degrade transient response. Layout must minimize trace inductance to preserve capacitor effectiveness.