Monolithic Power Systems Inc. MP28127DQ-LF-P

Overview

MP28127DQ-LF-P from Monolithic Power Systems is a 1.5MHz fixed-frequency synchronous step-down DC/DC regulator delivering up to 1.25A output current from 2.7V–5.5V input, with adjustable output down to 0.8V, integrated high- and low-side MOSFETs, and power-good (POK) monitoring - deployed in FPGA core supplies and point-of-load regulation for telecom equipment.

For engineers reviewing the MP28127DQ-LF-P datasheet, MP28127DQ-LF-P pinout, MP28127DQ-LF-P application, or MP28127DQ-LF-P equivalent, key selection criteria include its internal compensation, 10-lead QFN package thermal performance (θJA = 50°C/W), hiccup-mode short-circuit protection, and EN/SYNC dual-function pin for enable control or external clock synchronization.

Technical Context

The MP28127DQ-LF-P uses peak-current-mode PWM control with transconductance gain of 11.25A/V from COMP voltage to output current, enabling stable single-pole loop modeling and Type II compensation integration. Its internal soft-start time is fixed at 120µs, and startup behavior includes pre-bias detection that halts switching until the FB voltage falls below the rising soft-start reference.

Power sequencing is supported via open-drain POK output with ±10% output window detection and 30µs deglitch timing; the EN/SYNC pin accepts 1–2MHz external clocks for frequency synchronization or logic-level enable/disable with 0.4V/1.6V thresholds and 4µs minimum pulse width.

Key Specifications

Pinout & Package

The MP28127DQ-LF-P is housed in a thermally enhanced 3mm × 3mm, 10-lead QFN package with exposed thermal pad on the underside, rated for –40°C to +85°C operation and θJA = 50°C/W on 1"² 1oz copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62864DRLR and RTQ2132BGQW, the MP28127DQ-LF-P uniquely combines POK monitoring, frequency synchronization, hiccup protection, and internal compensation in a 3mm×3mm QFN - making it optimal for space-constrained, reliability-critical industrial and telecom point-of-load designs.

Availability

MP28127DQ-LF-P is available at Aetrix Electronics and suitable for FPGA core supplies, telecom point-of-load regulation, and LCD TV logic board power delivery requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MP28127DQ-LF-P 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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP28127 belongs to MPS's high-efficiency synchronous buck regulator product line, engineered for compact, thermally robust point-of-load conversion in networking, computing, and industrial embedded systems.

FAQ

What is the maximum allowable input voltage for MP28127DQ-LF-P?

The absolute maximum input voltage (IN to GND) is +6V, but the recommended operating range is strictly 2.7V to 5.5V. Exceeding 5.5V may trigger internal undervoltage lockout hysteresis or cause permanent damage due to overstress on the high-side MOSFET oxide layer.

Can MP28127DQ-LF-P operate with pre-biased outputs?

Yes - during startup, if the output is pre-biased above the target voltage, the IC disables both high- and low-side switches until the internal soft-start capacitor voltage exceeds the sensed FB voltage, preventing reverse current flow and ensuring controlled ramp-up.

How does the EN/SYNC pin behave when used for synchronization?

When an external 1–2MHz clock is applied, the internal oscillator locks to that frequency after detecting several cycles. If any ON or OFF period exceeds 4µs, the signal is interpreted as an enable command instead, disabling synchronization and reverting to free-running 1.5MHz operation.

What is the purpose of the BS pin and required external component?

The BS pin connects to a bootstrap capacitor (typically 0.1µF X7R ceramic) between BS and SW. This capacitor supplies the floating gate drive voltage for the high-side N-channel MOSFET during its on-time, enabling efficient synchronous rectification without external high-side driver circuitry.

Does MP28127DQ-LF-P require external compensation components?

No - the device integrates full Type II compensation, eliminating external RC networks. Loop bandwidth is adjusted solely by the upper feedback resistor (R1); typical values range from 127kΩ to 806kΩ depending on output voltage and output capacitance.

What thermal derating applies above 85°C ambient?

The device is rated for operation up to +85°C ambient. Above this, derating follows θJA = 50°C/W: for every 1°C rise beyond 85°C, maximum continuous output current must be reduced by approximately 25mA to maintain junction temperature ≤150°C under standard PCB layout conditions.

Is the exposed thermal pad electrically connected internally?

Yes - the exposed pad is internally connected to GND and must be soldered to a solid ground plane. It serves both thermal conduction and electrical grounding functions; omitting this connection degrades thermal performance by >30% and risks instability due to ground bounce.