Monolithic Power Systems Inc. MP7751GF-P

Overview

MP7751GF-P from Monolithic Power Systems is a 26V, stereo bridge-tied-load (BTL) Class D audio amplifier IC delivering 20W per channel into 8Ω at 18V supply, featuring integrated 240mΩ MOSFETs, adjustable power limiting, automatic zero-signal shutdown, and open-drain fault reporting - deployed in TV audio stages, active speaker amplifiers, and home theater front-channel drivers.

For engineers reviewing the MP7751GF-P datasheet, MP7751GF-P pinout, MP7751GF-P application, or MP7751GF-P equivalent, key selection criteria include BTL output architecture, 260–360kHz fixed switching frequency, thermal/overcurrent fault flag behavior, gain configuration via GAIN0/GAIN1 pins, and TSSOP-28 EP package thermal performance under 9.5–36W total output power.

Technical Context

The MP7751GF-P implements a fixed-frequency (260–360kHz), fully differential stereo BTL topology with internal N-channel half-bridge drivers per channel, bootstrap gate drive for high-side MOSFETs (BST1A/BST1B/BST2A/BST2B), and analog input biasing at 2.5V on all INx pins. It uses duty-cycle limiting - not PWM modulation depth adjustment - to enforce the PLIMIT-derived "virtual rail" voltage.

Its signal absence detection relies on AC-coupled input monitoring with user-adjustable delay via external capacitor on Cap_D (Pin 14), while fault reporting combines overtemperature (>150°C trip, 130°C hysteresis) and short-circuit current sensing across both channels, asserting /FAULT low in either condition.

Key Specifications

Pinout & Package

TSSOP-28 EP package with exposed thermal pad (EP) - requires solder paste stencil aperture and thermal via array to PCB ground plane for θJA = 32°C/W operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stereo Class D audio amplifier applications.

Compared with TAS5756M and TPA3116D2, MP7751GF-P uniquely delivers analog-input stereo BTL amplification with integrated power limiting, zero-signal auto-shutdown, and fault flag - reducing external component count and firmware complexity in analog-source consumer audio systems.

Availability

MP7751GF-P is available at Aetrix Electronics and suitable for TV audio subsystems, active speaker production, and home theater soundbar manufacturing requiring stable component supply, RoHS-compliant packaging, and long-term industrial lifecycle support.

Supply support for MP7751GF-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MP7751 belongs to MPS' Class D Audio Amplifier product line, engineered specifically for high-efficiency, low-EMI stereo amplification in space-constrained consumer electronics - emphasizing integration, thermal resilience, and analog interface simplicity.

FAQ

What is the maximum continuous output power per channel at 24V supply?

At VCC = 24V, the MP7751GF-P delivers 36W total (18W per channel) into 8Ω with 10% THD+N, as specified in Operating Specifications. This assumes proper thermal management using the TSSOP-28 EP's exposed pad and adherence to recommended PCB copper area and via count per MPS AN-108 layout guidelines.

How does the PLIMIT pin function, and what voltage range should be applied?

The PLIMIT pin sets a "virtual rail" equal to 8× its voltage, capping peak-to-peak output swing. Apply 0.8V–1.8V for 6.4V–14.4V virtual rails; connect directly to AVCC (5.5V) for no limiting. A resistor divider from AVCC to AGND with 1µF bypass to ground is required - values must ensure stable DC bias under load.

Can the MP7751GF-P drive 4Ω speakers, and what derating applies?

Yes - it supports 4Ω loads, but output power must be reduced to maintain safe junction temperature. At 12V supply, max power drops to ~12W/ch (vs. 9.5W/ch at 8Ω); thermal derating follows PD(MAX) = (150°C – TA)/32°C/W. Use θJC = 6°C/W with thermal vias if ambient exceeds 60°C.

What is the purpose of the Cap_D pin (Pin 14), and how is delay time calculated?

Cap_D sets the hold time before InAbsence (Pin 13) asserts low after input signal loss. Delay ≈ 1.6×10⁸ × R × C seconds, where R = 100kΩ internal pull-up and C = external capacitor to AGND. For 30s delay, use 0.18µF; grounding Cap_D disables auto-shutdown entirely.

Does the MP7751GF-P require external bootstrap diodes?

No - the MP7751GF-P integrates internal bootstrap charging circuitry. External components needed per BST pin are only a 0.1–10µF ceramic capacitor between BSTx and SWx; no diode or additional charge pump IC is required, simplifying layout and reducing part count.

How does the /FAULT pin behave during thermal shutdown versus overcurrent events?

/FAULT pulls low identically for both conditions - it is not distinguishable by logic level alone. The pin remains low until the fault clears (TJ < 130°C or short removed), then releases open-drain after internal recovery timing (~10ms). System-level diagnostics require correlating /FAULT assertion with thermal sensor data or current sense readings.

What is the minimum input signal amplitude required to prevent false InAbsence triggering?

The input signal absence detector triggers below 2–8mV RMS (typical 5mV) at the INx pins. To avoid false shutdown, ensure analog source output ≥20mV RMS at full volume, and maintain signal path integrity - avoid unterminated cables or high-impedance dividers that attenuate below threshold.