Microchip Technology MIC24085AYML-TX

Overview

MIC24085AYML-TX from Micrel is an adjustable-output, 18V input, 3A synchronous buck regulator with integrated high- and low-side MOSFETs, fixed 1MHz switching frequency, 0.9V reference (±1.5%), and operation from –40°C to +125°C. It delivers regulated DC power in space-constrained networking and embedded systems such as gateways and set-top boxes.

For engineers reviewing the MIC24085AYML-TX datasheet, MIC24085AYML-TX pinout, MIC24085AYML-TX application, or MIC24085AYML-TX equivalent, key selection criteria include its 3mm × 3mm QFN-16 package, internal compensation, PFM light-load mode, 4ms soft-start, and integrated overcurrent/thermal protection - all critical for compact, thermally demanding DC/DC designs.

Technical Context

The MIC24085AYML-TX implements peak current-mode PWM control with internal slope compensation and fully integrated loop compensation, enabling stable operation with low-ESR ceramic output capacitors without external compensation components. Its current-sense architecture supports cycle-by-cycle current limiting and frequency foldback during overload.

It operates in forced PWM mode under heavy load and transitions to asynchronous PFM mode at light load to maintain high efficiency across the full 0–3A range. The device integrates a 0.9V precision reference, enable with hysteresis, open-drain power-good output, and bootstrapped high-side gate drive requiring only a 0.1µF BST-to-SW capacitor.

Key Specifications

Pinout & Package

Package: 16-pin 3mm × 3mm QFN (ML) with exposed thermal pad (ePAD), RoHS-compliant Pb-free finish. Junction temperature range: –40°C to +125°C. θ_JA = 68°C/W, θ_JC = 7.5°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2451DT-LF-Z and TPS54331DR, the MIC24085AYML-TX offers superior integration (internal compensation, PG, PFM), smaller 3mm × 3mm QFN footprint, and tighter reference accuracy - making it optimal for space- and efficiency-critical embedded power rails.

Availability

MIC24085AYML-TX is available at Aetrix Electronics and suitable for networking gateways, set-top box power supplies, and industrial camera modules requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MIC24085AYML-TX 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 power IC manufacturer, acquired by Microchip Technology in 2015. Known for high-performance, thermally robust power management solutions.

The MIC24085AYML-TX belongs to Micrel's high-density synchronous buck regulator product line, designed specifically for cost-sensitive yet thermally demanding applications in networking, consumer, and industrial equipment where small size and integrated protection are essential.

FAQ

What is the feedback reference voltage of the MIC24085AYML-TX and how does it affect output adjustment?

The MIC24085AYML-TX features a precision 0.9V feedback reference voltage with ±1.5% accuracy over –40°C to +125°C. This reference sets the regulation point for the adjustable output: V_OUT = 0.9V × (1 + R1/R2), where R1 and R2 form the external resistor divider. Its tight tolerance ensures minimal output drift across temperature and load, critical for powering sensitive logic rails in the MIC24085AYML-TX-based design.

Does the MIC24085AYML-TX require external compensation components?

No, the MIC24085AYML-TX includes fully internal loop compensation optimized for stability with low-ESR ceramic output capacitors. This eliminates the need for external RC networks typically required in voltage-mode or uncompensated current-mode controllers. Engineers can implement robust, high-frequency buck regulation using only the MIC24085AYML-TX, an inductor, input/output capacitors, and the FB divider - significantly reducing design complexity and bill-of-materials count.

How does the MIC24085AYML-TX handle overload conditions?

The MIC24085AYML-TX employs cycle-by-cycle current limiting with frequency foldback: when inductor current exceeds 3.4–4.4A, switching frequency drops from 1MHz to 250kHz to reduce average power dissipation. Unlike latch-off protection, this allows continued operation under moderate overload while preventing thermal runaway. Once the overload clears, the MIC24085AYML-TX automatically resumes normal operation after internal soft-start, ensuring system resilience without manual reset.

What is the role of the BST pin on the MIC24085AYML-TX and what capacitor value is required?

The BST (bootstrap) pin on the MIC24085AYML-TX supplies gate drive voltage to the internal high-side N-channel MOSFET. It requires a 0.1µF ceramic capacitor connected between BST and SW pins to generate the boosted voltage above V_IN. This capacitor must be placed close to the MIC24085AYML-TX with short, low-inductance traces; failure to meet this requirement risks high-side FET turn-on failure and erratic regulation in the MIC24085AYML-TX circuit.

Can the MIC24085AYML-TX be used in automotive applications?

The MIC24085AYML-TX is rated for –40°C to +125°C junction temperature and meets industrial reliability standards, but it is not AEC-Q200 qualified or specified for automotive use. Its datasheet does not guarantee performance under automotive transients (e.g., load dump, cold crank), nor does it provide automotive-grade qualification documentation. For automotive applications, designers should select AEC-Q100-qualified alternatives; the MIC24085AYML-TX remains appropriate for industrial, networking, and consumer equipment meeting its specified operating envelope.