Monolithic Power Systems Inc. MP8761GL-Z

Overview

MP8761GL-Z from Monolithic Power Systems is a fully-integrated, synchronous step-down DC/DC converter delivering 8A output current from a 4.5V–18V input with internal bias or 2.5V–18V with external 5V bias. It uses adaptive Constant-On-Time (COT) control, features 1% reference voltage accuracy over −40°C to +125°C, and integrates low-R_DS(ON) MOSFETs (28 mΩ HS / 16 mΩ LS) for high efficiency in compact power rails for set-top boxes and small-cell base stations.

For engineers reviewing the MP8761GL-Z datasheet, MP8761GL-Z pinout, MP8761GL-Z application, or MP8761GL-Z equivalent, key selection criteria include its programmable 200kHz–1MHz switching frequency, non-latch OCP/OVP/thermal shutdown, pre-bias startup capability, and QFN-13 (3mm×4mm) package with validated 13-pin terminal mapping.

Technical Context

The MP8761GL-Z implements adaptive COT control without an external oscillator, using the FREQ pin's resistor-to-IN connection for feed-forward-stabilized frequency setting and fixed on-time generation. Its internal 4.8V VCC LDO powers control logic, while BST-SW bootstrap circuitry enables high-side gate drive.

It supports both continuous-conduction-mode (CCM) PWM operation at heavy loads and discontinuous-conduction-mode (DCM) skip mode at light loads-using a current modulator to limit negative inductor current to −1mA and improve no-load efficiency. Protection includes valley-current-based non-latch OCP, 120% V_FB non-latch OVP, and thermal shutdown at 150°C with 25°C hysteresis.

Key Specifications

Pinout & Package

The MP8761GL-Z is housed in a thermally enhanced 3mm × 4mm QFN-13 package with exposed thermal pad (PGND-connected), optimized for high-power density and PCB heat spreading.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP8761GL-Z, MP8770GQ-Z delivers higher efficiency and lower thermal resistance in a pin-compatible 3×4mm footprint, while TPS54821RHLR trades integration for loop design flexibility at the cost of board area and component count - making MP8761GL-Z suitable only for legacy refreshes where QFN-13 compatibility is mandatory.

Availability

MP8761GL-Z is available at Aetrix Electronics and suitable for set-top box power supplies, DSLAM intermediate rails, small-cell RF power stages, and distributed power systems requiring stable component supply with known lifecycle status.

Supply support for MP8761GL-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.

The MP8761 belongs to MPS's high-current synchronous buck converter product line, engineered for space-constrained, thermally demanding applications in broadband, telecom infrastructure, and consumer electronics where integration, efficiency, and fast transient response are critical.

FAQ

What is the maximum allowable input voltage for MP8761GL-Z?

The absolute maximum input voltage is 21V, but the recommended operating range is 4.5V to 18V with internal bias or 2.5V to 18V when using an external 5V VCC bias. Exceeding 21V risks permanent damage to the IN, SW, and BST pins per Absolute Maximum Ratings.

Can MP8761GL-Z start up into a pre-biased output?

Yes - MP8761GL-Z supports monotonic pre-bias startup. When the FB voltage exceeds the soft-start capacitor voltage at power-on, both HS and LS switches remain off until the SS voltage rises above the sensed output, preventing reverse current flow and ensuring controlled ramp-up.

How is the switching frequency set and stabilized?

Frequency is set by connecting a resistor between FREQ and IN; the input voltage feeds forward into the one-shot ON-timer, keeping frequency nearly constant across VIN variation. Typical values range from 453kΩ (≈500kHz) to 1.18MΩ (≈200kHz), with 100kΩ yielding ~1MHz.

What thermal derating applies above +25°C ambient?

With θ_JA = 46°C/W, maximum continuous power dissipation drops linearly: PD_MAX = (150°C − T_A) / 46. At 85°C ambient, max dissipation falls to 1.41W - requiring careful layout, thermal vias, and copper area to sustain 8A output without thermal shutdown.

Is MP8761GL-Z RoHS and halogen-free compliant?

Yes - MP8761GL-Z is lead-free, halogen-free, and fully compliant with the EU RoHS directive. All MPS products meet these environmental standards, and green status verification is available on the MPS Quality Assurance webpage.

Why does the datasheet state "Not Recommended for New Designs"?

MPS explicitly designates MP8761GL-Z as obsolete for new designs in favor of MP8770GQ-Z, which offers lower R_DS(ON), improved thermal performance, and extended lifetime assurance - though MP8761GL-Z remains available for legacy repair and continuity builds.