Monolithic Power Systems Inc. MPQ8643GLE-P

Overview

MPQ8643GLE-P from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC converter delivering up to 20A output current with input voltage range of 4V–16V, selectable 600/800/1000kHz switching frequency, and ±0.5% reference voltage accuracy (0°C–70°C). It integrates high- and low-side MOSFETs (R_DS(ON) = 12.2mΩ / 3.5mΩ), supports differential remote sensing, and enables voltage tracking via TRK/REF for coordinated power sequencing in multi-rail systems such as server VRMs.

For engineers reviewing the MPQ8643GLE-P datasheet, MPQ8643GLE-P pinout, MPQ8643GLE-P application, or MPQ8643GLE-P equivalent, key selection criteria include configurable current limit (via CS resistor), pre-biased start-up capability, output discharge function, adaptive COT control for sub-100ns transient response, and thermal shutdown at 160°C with 30°C hysteresis.

Technical Context

The MPQ8643GLE-P employs adaptive constant-on-time (COT) control with internal ramp compensation, enabling stable regulation with zero-ESR ceramic output capacitors across full VIN (4–16V) and VOUT (0.6–5.5V) ranges. Its valley-current sensing architecture provides cycle-by-cycle over-current protection with non-latch hiccup recovery after 31 consecutive fault cycles.

Switching frequency is set by external R_MODE (30.1kΩ/60.4kΩ/pull-to-AGND) and remains fixed regardless of load or input variation. The device supports dual operating modes-forced continuous conduction mode (FCCM) for ripple-sensitive applications and pulse-skip mode (PSM) for light-load efficiency-both selectable via the same MODE pin configuration.

Key Specifications

Pinout & Package

MPQ8643GLE-P is housed in a thermally enhanced QFN-21 (3mm × 4mm) package with exposed thermal pad (PGND-connected) and 0.4mm pitch. Pin 1 is marked with a dot; top view orientation follows standard MPS QFN convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RTQ2132BGQW, MPQ8643GLE-P offers superior transient response and sequencing control; compared with TPS546D24RSAR, it provides lower solution cost and smaller footprint at the expense of digital configurability and current rating headroom.

Availability

MPQ8643GLE-P is available at Aetrix Electronics and suitable for server VRMs, telecom base station power supplies, cloud storage controllers, and high-end graphics card designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MPQ8643GLE-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 power management ICs, with over two decades of expertise in DC/DC conversion, motor drivers, and LED lighting solutions.

The MPQ8643 belongs to MPS's high-current monolithic buck converter product line, designed specifically for demanding point-of-load applications in datacenter, networking, and computing infrastructure where efficiency, thermal performance, and reliability are critical.

FAQ

What is the minimum recommended input capacitance for MPQ8643GLE-P?

At least three 10µF X5R or X7R ceramic capacitors (total ≥30µF) placed directly at VIN pins 10 and 21 are required. These must be low-ESR types with rated voltage ≥25V and mounted with short, wide traces to minimize high-frequency loop inductance and prevent input voltage sag during heavy load transients.

How does the MPQ8643GLE-P handle pre-biased outputs during start-up?

The device detects pre-bias on the FB pin and holds both HS- and LS-FETs off until TRK/REF exceeds the sensed FB voltage. If BST voltage drops below 2.3V during this period, the LS-FET pulses briefly to recharge BST via VCC - ensuring monotonic rise without reverse current or output droop.

Can the MPQ8643GLE-P operate with only ceramic output capacitors?

Yes. Its adaptive COT control with internal ramp compensation is explicitly designed for zero-ESR MLCC-only output filters. Stability is guaranteed across full VIN (4–16V), VOUT (0.6–5.5V), and temperature (-40°C to +125°C) ranges when using ≥220µF total ceramic capacitance with appropriate layout practices.

What is the purpose of the RGND pin, and how should it be connected?

RGND serves as the dedicated low-side reference for differential remote sensing. It must be connected directly to the negative side of the output voltage sense point - not to PGND - to cancel trace IR drop. If remote sensing is unused, RGND must be shorted to PGND at the IC pad, not elsewhere on the board.

How is over-current protection configured and what happens during a fault?

OCP is set by the resistor between CS and AGND, targeting ILIMIT = 1.2V / RCS. Upon detection, the device enters hiccup mode after 3ms delay: it disables switching for ~11ms, then attempts soft-start. Recovery occurs only after 31 consecutive fault-free cycles or removal of the over-current condition.

Is the MPQ8643GLE-P pin-compatible with earlier MPQ8643 variants?

Yes. MPQ8643GLE-P shares identical pinout, package (QFN-21), and electrical specifications with MPQ8643GLE. The "-P" suffix denotes tape-and-reel packaging with enhanced moisture sensitivity level (MSL) handling per J-STD-020, but functional behavior and PCB layout are fully interchangeable.

What thermal derating applies above 85°C ambient temperature?

No explicit derating curve is published, but junction temperature must remain ≤160°C. With θ_JB = 9°C/W and typical board thermal resistance, output current must be reduced linearly above 85°C ambient - e.g., ~16A at 100°C ambient assuming 200LFM airflow and standard 4-layer board construction.