Monolithic Power Systems Inc. MP28127DQ-LF-Z

Overview

MP28127DQ-LF-Z from Monolithic Power Systems is a 1.25A, 1.5MHz fixed-frequency synchronous step-down DC/DC regulator in a 3mm × 3mm QFN-10 package. It operates from 2.7V–5.5V input, delivers adjustable output down to 0.8V, integrates high-side and synchronous rectifier MOSFETs, and features power-good (POK), frequency synchronization, and hiccup-mode short-circuit protection - used for powering µP/FPGA core rails in space-constrained embedded systems.

For engineers reviewing the MP28127DQ-LF-Z datasheet, MP28127DQ-LF-Z pinout, MP28127DQ-LF-Z application, or MP28127DQ-LF-Z equivalent, key selection criteria include its internal compensation, 120µs soft-start, ±10% POK window, 1.25A continuous output with 2.0A high-side current limit, and compatibility with all-ceramic capacitor designs in point-of-load applications.

Technical Context

The MP28127DQ-LF-Z uses peak-current-mode PWM control with integrated Type II compensation, eliminating external compensation components while enabling stable loop response across 50–150kHz bandwidths. Its transconductance gain of 11.25A/V links COMP voltage directly to inductor current, simplifying transient design for fast load steps.

It supports dual-function EN/SYNC pin operation: logic-level enable/disable (1.6V/0.4V thresholds) and external clock synchronization (1–2MHz), with automatic fallback to internal oscillator if sync signal violates 4µs timing. The bootstrap circuit enables efficient high-side N-MOSFET drive without external charge pumps.

Key Specifications

Pinout & Package

MP28127DQ-LF-Z is housed in a thermally enhanced 3mm × 3mm QFN-10 package with exposed thermal pad (JEDEC MO-229 VEED-5). Pin 1 is marked by a circular indentation; pins 4/7 are IN, pins 3/8 are SW, pins 2/9 are GND + exposed pad, pin 5 is BS, pin 1 is FB, pin 10 is EN/SYNC, and pin 6 is open-drain POK.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down regulator applications.

Compared with TPS62130ARGTR and ADP2302ARDZ-R7, MP28127DQ-LF-Z uniquely balances 5.5V max input, integrated POK, 1.5MHz operation, and sync capability in a 3mm × 3mm footprint - making it optimal for compact, multi-rail, USB- or Li-ion-powered digital systems requiring precise power sequencing.

Availability

MP28127DQ-LF-Z is available at Aetrix Electronics and suitable for FPGA core supplies, ASIC power management units, and USB-powered embedded systems requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability.

Supply support for MP28127DQ-LF-Z 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with expertise in DC/DC conversion, LED drivers, and motor control solutions.

The MP28127 belongs to MPS's high-efficiency synchronous buck regulator product line, designed specifically for space-constrained, high-transient digital loads such as microprocessors, FPGAs, and ASICs in consumer, industrial, and networking equipment.

FAQ

What is the minimum output voltage supported by MP28127DQ-LF-Z?

The MP28127DQ-LF-Z supports a minimum regulated output voltage of 0.8V, set by its internal 0.800V ±3% feedback reference. This is achieved using an external resistor divider from VOUT to GND, with the FB pin connected to the divider midpoint. The 0.8V reference enables common low-voltage rails like 1.2V and 1.5V with appropriate resistor ratios.

Does MP28127DQ-LF-Z require external compensation components?

No, MP28127DQ-LF-Z integrates full Type II compensation, eliminating the need for external capacitors or resistors in the feedback loop. Loop bandwidth is adjusted solely by selecting the upper feedback resistor (R1), with recommended values between 400kΩ and 1MΩ depending on output capacitance and desired transient response.

How does the EN/SYNC pin function in synchronization mode?

In sync mode, the EN/SYNC pin accepts a 1–2MHz external clock signal. The internal oscillator locks to this frequency within one cycle. If the external clock's ON or OFF period exceeds 4µs, the device interprets it as an enable command instead, disabling synchronization and reverting to internal 1.5MHz operation.

What is the purpose of the BS (Bootstrap) pin, and what capacitor value is recommended?

The BS pin supplies the floating gate drive voltage for the internal high-side N-MOSFET via a bootstrap capacitor tied between BS and SW. A 0.1µF X7R ceramic capacitor is recommended - placed as close as possible to the BS and SW pins - to ensure reliable high-side turn-on and minimize shoot-through risk during switching transitions.

Can MP28127DQ-LF-Z operate with a pre-biased output?

Yes, MP28127DQ-LF-Z supports pre-biased startup: if the output voltage is already present at startup, the IC disables both switches until the internal soft-start capacitor voltage exceeds the sensed FB voltage. This prevents reverse current flow and ensures controlled ramp-up without damaging downstream circuitry.

What thermal performance can be expected with the exposed pad soldered to PCB ground?

With the exposed thermal pad fully soldered to a solid 1-inch² copper ground plane, MP28127DQ-LF-Z achieves a junction-to-ambient thermal resistance (θJA) of 50°C/W. This allows 1.25A continuous operation at up to +85°C ambient when properly laid out - verified per JEDEC JESD51-7 standards with 1 oz copper.