Monolithic Power Systems Inc. MPQ8636GV-20-Z

Overview

MPQ8636GV-20-Z from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC converter delivering up to 20A output current from a 4.5V–18V input, featuring Constant-On-Time (COT) control, programmable 200kHz–1MHz switching frequency, and integrated 9.9mΩ/2.4mΩ MOSFETs. It targets high-density power rails in telecom base stations and server VRMs where fast transient response and thermal robustness are critical.

For engineers reviewing the MPQ8636GV-20-Z datasheet, MPQ8636GV-20-Z pinout, MPQ8636GV-20-Z application, or MPQ8636GV-20-Z equivalent, key selection considerations include its non-latch OCP/OVP protection scheme, pre-bias startup capability, 0.611V–13V adjustable output, soft-start programmability via external capacitor, and QFN-25 (5mm×4mm) thermal-pad package with 21 PGND pins for low-impedance grounding.

Technical Context

The MPQ8636GV-20-Z implements adaptive COT control without an external oscillator, using the FREQ pin's resistor-to-IN connection for line feed-forward compensation-ensuring stable switching frequency across input voltage variation. Its internal architecture integrates high-side and low-side MOSFETs with dead-time control to prevent shoot-through.

It operates exclusively in continuous conduction mode (CCM), supporting negative inductor current during light load. Protection logic includes valley-current-based non-latch over-current detection, 120% non-latch over-voltage response with hiccup recovery, and thermal shutdown at 150°C with 25°C hysteresis-enabling reliable operation in thermally constrained environments.

Key Specifications

Pinout & Package

MPQ8636GV-20-Z is housed in a thermally enhanced 25-pin QFN package (5mm × 4mm, 0.5mm pitch) with an exposed thermal pad (Pin 21–24 PGND and Pin 14–20 PGND) requiring solder paste stencil optimization and ≥6 thermal vias to inner ground planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ8636HGV-20-Z, the MPQ8636GV-20-Z offers stricter OVP shutdown behavior ideal for unattended infrastructure; versus TPS546B24RVFT, it trades digital control for minimal BOM count and smaller footprint-making it optimal for cost- and space-sensitive fixed-output applications.

Availability

MPQ8636GV-20-Z is available at Aetrix Electronics and suitable for telecom base stations, server VRMs, and flat-panel display power supplies requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MPQ8636GV-20-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 MPQ8636 series belongs to MPS's high-current integrated buck converter product line, engineered specifically for space-constrained, high-efficiency point-of-load applications in networking, computing, and consumer electronics.

FAQ

What is the recommended minimum output capacitance for stable operation?

The MPQ8636GV-20-Z requires ≥330μF total output capacitance for stable CCM operation with ceramic or POSCAP outputs. For ceramic-only designs, use ≥470μF with low-ESR (≤5mΩ) X7R/X5R types and add external ramp compensation (R4/C4) per Equation 4 in the datasheet to ensure slope stability.

Can the MPQ8636GV-20-Z operate with an input voltage below 4.5V?

No. The absolute minimum input voltage is 4.5V per the Recommended Operating Conditions table. Operation below this level risks UVLO activation and unregulated output. The internal VCC LDO requires ≥4.0V to maintain regulation, and EN pin logic thresholds assume valid 4.5V–18V rail operation.

How does the FREQ pin resistor value affect switching frequency accuracy?

The FREQ resistor sets ON-time per τ_ON = 0.4 × (V_IN – 6.1)/R_FREQ. At fixed V_IN, a 1% resistor tolerance yields ~1% frequency variation. Input voltage feed-forward compensates for V_IN drift, keeping frequency stable within ±3% across 4.5V–18V when R_FREQ is selected for nominal 500kHz at mid-range V_IN.

Is the thermal pad (EPAD) electrically connected to any internal node?

Yes-the exposed thermal pad is internally tied to PGND. It must be soldered to a solid PCB ground plane with ≥6 thermal vias (0.3mm diameter, spaced ≤1mm apart) to achieve the specified θ_JA = 38°C/W and prevent thermal shutdown at full 20A load.

Does the MPQ8636GV-20-Z support forced PWM mode or DCM operation?

No. The MPQ8636GV-20-Z operates exclusively in continuous conduction mode (CCM) with adaptive COT control. It does not support discontinuous conduction mode (DCM), pulse-skipping, or forced PWM-inductor current is permitted to go negative during light load, but the controller maintains fixed-frequency-like behavior via COT timing.

What is the maximum allowable voltage on the PG pin?

The PG pin is an open-drain MOSFET output rated for ≤5.5V pull-up voltage. Exceeding 5.5V risks damage to the internal drain structure. Standard practice uses a 100kΩ pull-up to VCC (4.8V) or system 3.3V rail-ensuring safe sink current (<12mA) and compatible logic levels.

How does pre-bias startup behave when output voltage exceeds 0.611V before enable?

During pre-bias startup, the IC disables both HS- and LS-FETs until the SS capacitor voltage exceeds the FB pin voltage. This prevents reverse current flow and ensures monotonic rise-even if the output is pre-charged to 3.3V or 5V-by holding the output in high-impedance state until soft-start initiates forward regulation.