Microchip Technology MIC2267YML-TR

Overview

MIC2267YML-TR from Micrel is a USB Power Maximizer™ synchronous buck regulator with integrated 150mΩ MOSFETs, adjustable input current limiting (100mA–1.6A), and 400kHz–1.5MHz programmable switching frequency. It delivers up to 96% efficiency at 500mA output and supports adjustable output voltage down to 1.0V - designed specifically for USB-powered wireless router cards and portable devices requiring precise input current budgeting.

For engineers reviewing the MIC2267YML-TR datasheet, MIC2267YML-TR pinout, MIC2267YML-TR application, or MIC2267YML-TR equivalent, key selection criteria include its cycle-by-cycle input current limit architecture, 100% duty cycle capability via P-channel high-side switch, thermal shutdown (160°C), and MLF®-12 (3mm × 3mm) package with exposed thermal pad.

Technical Context

The MIC2267YML-TR implements a current-mode control architecture with external slope compensation (via SLOPEC pin) and user-adjustable loop compensation (COMP pin), enabling stable operation across wide duty cycles including 100%. Its input current limiting is charge-based and cycle-by-cycle, using dual integrators on LIMIT and FILTER pins to shape transient response during plug-in events and load steps.

It features an adaptive soft-start, open-drain PGOOD output referenced to VOUT or VIN, and independent AGND/PGND separation for noise isolation. The internal P-channel high-side switch enables dropout-free operation near VOUT = VIN, while the NMOS low-side switch provides efficient synchronous rectification.

Key Specifications

Pinout & Package

Package: 12-pin 3mm × 3mm MLF® (Micro Lead Frame) with exposed thermal pad (ePAD). RoHS-compliant, halogen-free mold compound, NiPdAu lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62231DRVR and LT3502AEDD#TRPBF, the MIC2267YML-TR uniquely integrates USB-specific input current profiling, 100% duty cycle support, and dual-ground layout for noise-sensitive analog loads - making it irreplaceable in USB-powered peripherals requiring strict bus compliance and thermal robustness.

Availability

MIC2267YML-TR is available at Aetrix Electronics and suitable for USB power management, wireless router cards, and industrial USB peripheral adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MIC2267YML-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 power management, timing, and interface ICs, acquired by Microchip Technology in 2015. Known for high-reliability analog solutions targeting industrial and communications infrastructure.

The MIC2267YML-TR belongs to Micrel's USB Power Maximizer™ product line - engineered specifically to maximize usable power from current-limited USB ports while maintaining strict electrical compliance and thermal safety in space-constrained portable designs.

FAQ

What is the purpose of the FILTER pin on the MIC2267YML-TR?

The FILTER pin on the MIC2267YML-TR implements a programmable delay for the input current limit function using an external capacitor. It prevents false triggering during brief inrush events (e.g., USB plug-in) by allowing controlled charge accumulation before activating current limiting. This ensures compliance with USB 2.0's 330mV port droop requirement while preserving available energy from upstream hub capacitance. The MIC2267YML-TR uses this feature to dynamically manage input current profile without sacrificing output stability.

Can the MIC2267YML-TR operate with 100% duty cycle, and how is this achieved?

Yes, the MIC2267YML-TR supports true 100% duty cycle operation via its integrated P-channel high-side MOSFET. When the output voltage approaches the input voltage (e.g., 4.2V → 3.3V), the controller sustains conduction without switching, eliminating dropout and maintaining regulation even under low VIN conditions. This capability is explicitly confirmed in the datasheet's "Maximum Duty Cycle" specification (100%) and functional description. The MIC2267YML-TR leverages this to deliver uninterrupted power during USB VBUS sag, unlike N-channel-only buck regulators that require minimum off-time.

How does the MIC2267YML-TR implement input current limiting, and is it cycle-by-cycle?

The MIC2267YML-TR implements true cycle-by-cycle input current limiting using a charge-based integrator architecture. It converts the programmed current limit (via LIMIT pin resistor) into a per-cycle charge quota (QTOT), then compares it against integrated input current (QIN) on each switching cycle. When QIN ≥ QTOT, the high-side switch terminates early. This method ensures precise average current control while permitting continued low-side conduction - a key distinction from conventional LDO-style current limiting. The MIC2267YML-TR's datasheet confirms this behavior in the Functional Description and Figure 2.

What is the recommended inductor value range for the MIC2267YML-TR, and why?

The MIC2267YML-TR is optimized for inductors between 3.3µH and 10µH, as specified in the Application Information section. Lower values (e.g., 3.3µH) reduce DCR losses and improve efficiency at high loads but increase output ripple; higher values (e.g., 10µH) suppress ripple and improve transient response but may raise DCR and reduce peak efficiency. The MIC2267YML-TR's current-mode control adapts well across this range, and inductor selection must also consider short-circuit thermal limits - the IC's internal thermal shutdown protects the inductor during faults, as verified in the Inductor section (page 14).

Does the MIC2267YML-TR require external compensation components, and what are the typical values?

Yes, the MIC2267YML-TR requires external compensation on the COMP pin for loop stability - it uses current-mode control with accessible error amplifier output. The datasheet recommends a series RC network: 11.5kΩ resistor and 15nF capacitor to AGND, plus an optional 680pF capacitor to suppress switching noise. These values optimize phase margin across load and input variations. The MIC2267YML-TR's COMP pin design enables fine-tuning for specific output capacitor ESR and inductor values, ensuring robust performance in custom USB peripheral layouts.