Monolithic Power Systems Inc. MP8771GQ-Z

Overview

MP8771GQ-Z from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC converter delivering 10A continuous output current with 3V–18V input range, fixed 700kHz switching frequency, and internal 17mΩ/8mΩ MOSFETs. It employs constant-on-time (COT) control for fast transient response and tight regulation in security cameras, set-top boxes, and flat-panel displays.

For engineers reviewing the MP8771GQ-Z datasheet, MP8771GQ-Z pinout, MP8771GQ-Z application, or MP8771GQ-Z equivalent, key selection criteria include its QFN-16 (3mm×3mm) package, pre-biased start-up capability, power-good (PG) open-drain output, thermal shutdown at 150°C, and support for external soft-start timing via capacitor.

Technical Context

The MP8771GQ-Z uses constant-on-time (COT) control architecture to maintain stable switching frequency across input voltage variations while enabling rapid load transient response without external compensation. Its valley-current-limit OCP and hiccup-mode recovery ensure robust short-circuit protection.

Internal bootstrap charging supports high-side N-channel MOSFET drive, with BST UVLO (1.7V rising threshold) and recommended R4 ≤ 4.7Ω. The 3.4V VCC LDO powers internal circuitry across full VIN range, decoupled by a 1µF ceramic capacitor placed near VCC and PGND.

Key Specifications

Pinout & Package

MP8771GQ-Z is housed in a thermally enhanced QFN-16 package (3mm × 3mm, 0.5mm pitch) with exposed thermal pad (PGND-connected) for efficient heat dissipation in high-power density layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RTQ2132BGQW and TPS546B24RVFT, MP8771GQ-Z delivers identical 10A/700kHz performance in a smaller 3mm×3mm footprint, includes PG and pre-biased start-up as standard, and operates down to 3V input-making it optimal for cost-sensitive, space-constrained, and multi-rail consumer electronics.

Availability

MP8771GQ-Z is available at Aetrix Electronics and suitable for security cameras, digital set-top boxes, and flat-panel television designs requiring stable component supply, long-term production continuity, and RoHS-compliant packaging.

Supply support for MP8771GQ-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 mixed-signal ICs for power management, motor drive, and automotive applications.

The MP8771 belongs to MPS's high-current monolithic buck converter product line, designed specifically for compact, high-efficiency power delivery in consumer, surveillance, and computing equipment where thermal performance and layout simplicity are critical.

FAQ

What is the minimum recommended soft-start capacitor value for MP8771GQ-Z?

The datasheet specifies that soft-start capacitors below 4.7nF should be avoided. A 10nF capacitor yields ~1.4ms soft-start time (T_SS = 0.83 × C_SS × V_REF / I_SS). Larger values (e.g., 47nF → ~6.5ms) improve inrush control but extend startup latency; selection must balance load capacitance and current-limit margin.

Does MP8771GQ-Z support forced PWM mode to eliminate light-load frequency variation?

No - MP8771GQ-Z automatically transitions between CCM (PWM) and PFM (skip) modes based on load. It lacks a MODE pin or register to force continuous switching. For fixed-frequency operation under all loads, consider MPS's MPQ8633 series or TI's TPS546D24.

How is thermal performance affected by the QFN-16 exposed pad connection?

The exposed thermal pad (pins 9–13) must be soldered to a dedicated PGND copper pour with ≥4 thermal vias (0.3mm diameter) to an internal GND plane. Without this, θ_JA degrades from 38°C/W to >50°C/W, risking thermal shutdown above 6A at 12V_IN/1V_OUT.

Can MP8771GQ-Z operate with an input voltage below 3V?

No - the absolute minimum operating input is 3V per Recommended Operating Conditions. At 2.9V, VCC LDO drops out and internal bias fails, causing erratic behavior or shutdown. For sub-3V inputs, consider MPS's MP2166 (2.5V–6V) or Analog Devices' LT8609S (2.8V–42V).

What is the maximum allowable BST capacitor ESR for reliable high-side gate drive?

The BST capacitor must have ESR < 50mΩ to sustain sufficient charge during 700kHz switching. A 0.1µF X7R ceramic capacitor (e.g., GRM188R71C104KA01D) meets this requirement and fits within the 0603 footprint recommended in the EV8771-Q-00A reference design.

Is the PG pin compatible with 5V logic systems?

Yes - PG is an open-drain output rated for 5V pull-up. When pulled to 5V via 100kΩ, PG sinks up to 4mA at 0.4V saturation, meeting standard TTL/CMOS input thresholds. No level-shifter is needed for interfacing with 3.3V or 5V microcontrollers.

How does the valley-current OCP respond during short-circuit events?

Under short-circuit, valley-current sensing triggers immediate LS-FET turn-off and disables HS-FET re-triggering until current falls below limit. After ~50ms, VFB drops below 50% VREF, initiating hiccup mode: soft-start capacitor discharges, then full restart cycle begins every ~100ms until fault clears.