Monolithic Power Systems Inc. MPQ8634AGLE-Z

Overview

MPQ8634AGLE-Z from Monolithic Power Systems is a fully integrated, high-frequency synchronous buck converter delivering up to 12A output current with 0.9V–6V adjustable output voltage, 600–1000kHz programmable switching frequency, and differential remote sensing. It employs adaptive constant-on-time (COT) control for ultrafast transient response and operates across 4V–16V input range with internal 3V LDO biasing. Used in server point-of-load regulation where tight load regulation and fast step-load recovery are critical.

For engineers reviewing the MPQ8634AGLE-Z datasheet, MPQ8634AGLE-Z pinout, MPQ8634AGLE-Z application, or MPQ8634AGLE-Z equivalent, key selection criteria include its programmable current limit (1.2V threshold), PGOOD open-drain timing (0.9ms assertion delay), soft-start configurability (1.5ms minimum), negative current limiting (–9A), and latch-off OVP/OCP protection behavior under fault conditions.

Technical Context

The MPQ8634AGLE-Z implements an internally compensated adaptive COT control architecture that maintains stable regulation without external loop compensation while supporting zero-ESR MLCC output capacitors. Its dual-mode operation-pin-selectable forced CCM or pulse-skip-enables efficiency optimization across 0–12A load range.

It integrates high-side (13.3mΩ) and low-side (3.8mΩ) MOSFETs, supports pre-bias start-up, and features TRK/REF-based voltage tracking with 0.3V–1.4V analog reference input. Protection includes latch-off OVP (116% VREF), UVP (80% VREF), OTP (160°C), and cycle-by-cycle valley-current OCP with programmable trip via CS resistor.

Key Specifications

Pinout & Package

MPQ8634AGLE-Z is housed in a thermally enhanced QFN-21 package (3mm × 4mm, 0.5mm pitch) with exposed thermal pad (Pin 19 VCC on top surface, Pin 11–18 PGND on bottom perimeter).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ8634AGLE-Z, MPQ8633AGLE-Z reduces feature set and current capability for lower-cost PoL, while TPS546D24ARVFT adds digital control at the expense of analog simplicity and higher component count.

Availability

MPQ8634AGLE-Z is available at Aetrix Electronics and suitable for telecom base stations, cloud server point-of-load regulation, and high-end GPU power delivery requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MPQ8634AGLE-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MPQ8634A belongs to MPS's high-current monolithic buck converter product line, engineered for compact, high-efficiency DC/DC conversion in space-constrained infrastructure equipment where thermal performance and transient response are critical.

FAQ

What is the minimum recommended input voltage for reliable startup?

The MPQ8634AGLE-Z requires VIN ≥2.4V (rising UVLO threshold) with internal VCC bias, but stable operation begins at 4V per recommended conditions. Below 4V, VCC regulation degrades and may cause erratic switching or failure to sustain 12A output. External 3.3V VCC bias enables operation down to 2.85V input, though this configuration is less common in production designs.

How does the TRK/REF pin affect soft-start behavior?

When TRK/REF is used for voltage tracking, the internal 1.5ms soft-start timer is disabled. The output voltage ramps only as fast as the tracked source, eliminating inrush risk during coordinated multi-rail power-up. If TRK/REF is unused, soft-start is controlled solely by the capacitor on TRK/REF–VSNS-, with CSS = 1nF yielding 1.5ms as specified.

Can the MPQ8634AGLE-Z operate without remote sensing?

Yes - shorting VSNS- to AGND disables differential remote sensing, reverting to single-point FB sensing. However, output regulation accuracy degrades by up to ±15mV under full load due to PCB trace IR drop. For applications demanding <±5mV load regulation, remote sensing is mandatory and requires matched-length, low-impedance VSNS+/VSNS– traces.

What happens during a PGOOD fault condition when VIN drops below UVLO?

When VIN falls below 1.85V (UVLO falling threshold), the internal VCC regulator collapses, causing PGOOD to actively clamp at ~0.7V regardless of FB status. This low-level state persists until VIN recovers above 2.4V and the internal circuits reinitialize - providing unambiguous system-level power-fail signaling without external supervision.

Is the MODE pin compatible with standard logic voltage levels?

No - MODE is a resistor-programmed analog input, not a digital logic pin. It must be pulled to AGND, VCC, or GND via precision resistors (e.g., 30.1kΩ ±20%) to select frequency and light-load mode. Direct connection to 3.3V or 5V logic violates absolute maximum ratings and will damage the pin.

Does the device support output capacitor ESR cancellation?

No - the MPQ8634AGLE-Z is optimized for zero-ESR ceramic capacitors and does not require or support ESR-based compensation. Its adaptive COT architecture uses internal ramp generation to ensure stability with MLCC-only output filters, eliminating the need for tantalum or polymer capacitors traditionally used for ESR damping.

What is the purpose of the discharge MOSFET during EN deassertion?

When EN is pulled low, the discharge MOSFET (RON ≈80Ω) connects SW to PGND, actively discharging the output capacitor through the inductor and low-side FET path. This ensures VOUT falls monotonically within milliseconds, preventing hold-up voltage issues that could disrupt downstream logic sequencing or cause latch-up in powered-off subsystems.