Microchip Technology MIC4721YMM

Overview

MIC4721YMM from Micrel Inc. is a 1.5A, 2MHz PWM synchronous-capable (non-synchronous) buck regulator with integrated p-channel MOSFET, adjustable output down to 1V, 94% peak efficiency, and 100% duty cycle capability for low-dropout operation in FPGA/DSP point-of-load applications.

For engineers reviewing the MIC4721YMM datasheet, MIC4721YMM pinout, MIC4721YMM application, or MIC4721YMM equivalent, key selection criteria include input voltage range (2.7–5.5V), feedback reference voltage (1.0V ±2%), thermal shutdown threshold (160°C), PGOOD accuracy (±10%), and MSOP-10 package compatibility with 1µH/4.7µF minimal external components.

Technical Context

The MIC4721YMM implements voltage-mode PWM control with proprietary internal type-III compensation, enabling >200kHz closed-loop bandwidth and stable operation with only a 1µH inductor and 4.7µF ceramic output capacitor. Its p-channel high-side switch supports 100% duty cycle for ultra-low dropout conditions.

It features micropower shutdown (<10µA), open-drain PGOOD with ±10% regulation window, and integrated protection including current limit (3.5–5A), thermal shutdown (160°C), and UVLO (2.55V turn-on with 100mV hysteresis).

Key Specifications

Pinout & Package

The MIC4721YMM is housed in a Pb-free 10-pin MSOP (MM) package with exposed thermal pad, rated for –40°C to +125°C junction temperature and θ_JA = 130°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MIC2207YMT and TPS561201DDFR, the MIC4721YMM uniquely integrates a p-channel high-side switch enabling true 100% duty cycle operation without external components - a critical advantage in battery-powered or low-V_IN/V_OUT delta applications where dropout margin is constrained.

Availability

MIC4721YMM is available at Aetrix Electronics and suitable for FPGA/DSP point-of-load, set-top box SoC power, and video card memory rail applications requiring stable component supply, long-term industrial lifecycle support, and Pb-free compliance.

Supply support for MIC4721YMM 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-performance power management and timing solutions.

The MIC4721YMM belongs to Micrel's high-frequency buck regulator product line, designed specifically for space-constrained, efficiency-critical point-of-load applications in computing, communications, and consumer electronics.

FAQ

What is the minimum output voltage supported by the MIC4721YMM?

The MIC4721YMM supports an adjustable output voltage down to 1.0V, set by an external resistor divider referenced to its internal 1.0V ±2% feedback voltage. This makes it suitable for powering modern low-voltage FPGA cores, DSP I/O, and SoC domains requiring 1.0V–3.3V rails. The MIC4721YMM achieves this using a precision error amplifier and stable internal compensation that does not require external loop compensation components.

Does the MIC4721YMM require an external freewheeling diode?

Yes, the MIC4721YMM is a non-synchronous buck regulator and requires an external Schottky diode connected from the SW pin to PGND. A low forward-voltage, fast-recovery Schottky diode rated for ≥1.5A average current and reverse voltage exceeding the maximum input voltage (e.g., 6V) is recommended. The MIC4721YMM's internal p-channel MOSFET handles only the high-side switching; the diode provides the return path during the off-time, and its VF directly impacts light-load efficiency.

What is the purpose of the BIAS pin on the MIC4721YMM?

The BIAS pin on the MIC4721YMM supplies power to the internal reference and control circuitry, decoupling sensitive analog blocks from noisy power-switching paths. It must be connected through a 10Ω resistor from VIN and bypassed with a 0.1µF ceramic capacitor to SGND. This filtering prevents high-frequency switching noise from degrading reference accuracy and loop stability - a critical design requirement confirmed in the MIC4721YMM's functional diagram and layout recommendations.

Can the MIC4721YMM operate with a 100% duty cycle, and under what conditions?

Yes, the MIC4721YMM supports 100% duty cycle operation when the feedback voltage (FB) ≤ 0.4V, enabling regulation even when input voltage drops close to the output voltage - essential for battery-powered systems nearing end-of-discharge. During 100% duty cycle, the internal p-channel MOSFET remains continuously on, eliminating switching losses and maintaining output regulation without requiring external components. This behavior is explicitly specified in the MIC4721YMM's Electrical Characteristics table and Application Information section.

What are the thermal characteristics of the MIC4721YMM in its MSOP-10 package?

The MIC4721YMM in the Pb-free 10-pin MSOP package has a junction-to-ambient thermal resistance (θ_JA) of 130°C/W and junction-to-case (θ_JC) of 43°C/W. Its thermal shutdown activates at 160°C with 20°C hysteresis. To maintain reliability, PCB layout must include adequate copper pour connected to the exposed thermal pad (Pin 8 PGND) and minimize thermal resistance to ambient - especially under 1.5A continuous load where power dissipation can exceed 0.5W depending on V_IN/V_OUT delta.