Monolithic Power Systems Inc. MP7758GF-Z

Overview

MP7758GF-Z from Monolithic Power Systems is a 18V, stereo bridge-tied load (BTL) Class-D audio amplifier with inductorless topology, delivering 15W per channel into 8Ω at 16V supply, featuring integrated 240mΩ MOSFETs, adjustable power limit (PLIMIT), and automatic shutdown on input signal absence. It targets compact, EMI-sensitive audio systems requiring high efficiency (90%) and pop-free startup/shutdown.

For engineers reviewing the MP7758GF-Z datasheet, MP7758GF-Z pinout, MP7758GF-Z application, or MP7758GF-Z equivalent, key selection criteria include BTL output configuration, PLIMIT voltage programmability, /FAULT open-drain fault reporting, and TSSOP-28 EP thermal performance under 125°C junction operation.

Technical Context

The MP7758GF-Z implements a fixed-frequency (260–360 kHz) PWM-based Class-D modulation with differential analog inputs and fully integrated half-bridge drivers per channel. Its internal bootstrap circuitry enables high-side N-MOSFET gate drive without external charge pumps, while the PLIMIT function dynamically caps peak output voltage by clamping duty cycle to establish a virtual rail (VP = 9 × V_PLIMIT).

It integrates dual-channel independent protection: over-current detection per switch leg with auto-retry, thermal shutdown at 150°C (20°C hysteresis), and under-voltage lockout at 4.6V rising threshold. The INABSENCE open-drain flag and CAP_D timing capacitor support configurable idle-time shutdown for battery-powered devices.

Key Specifications

Pinout & Package

TSSOP-28 EP package with exposed thermal pad on bottom; 0.65mm pitch, 9.7mm × 4.4mm body; θ_JA = 32°C/W on 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPA3110D2PWP and MAX9744ETJ+, the MP7758GF-Z uniquely combines inductorless operation, integrated PLIMIT, and INABSENCE-driven auto-sleep - making it optimal for space-constrained, battery-aware, and EMI-sensitive stereo audio systems where component count and thermal management are critical.

Availability

MP7758GF-Z is available at Aetrix Electronics and suitable for wireless speakers, smart TVs, and active studio monitors requiring stable component supply, consistent thermal performance, and long-term production continuity.

Supply support for MP7758GF-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 power management ICs, including DC/DC converters, LED drivers, and Class-D audio amplifiers.

The MP7758 product line delivers integrated, inductorless stereo audio amplification targeting portable, consumer, and professional audio equipment where efficiency, EMI compliance, and small form factor are essential.

FAQ

What is the maximum continuous output power per channel for MP7758GF-Z?

The MP7758GF-Z delivers 15W per channel into an 8Ω load at 16V supply with 10% THD+N, and 20W total (10W per channel) at 18V. Output power scales with supply voltage and load impedance per the formula P_OUT = V_PP² / (8 × R_L), where V_PP is limited by PLIMIT or PVCC.

How does the PLIMIT function prevent speaker damage?

The PLIMIT pin sets a virtual voltage rail (V_PP = 9 × V_PLIMIT) that caps peak-to-peak output voltage independently of PVCC. For example, setting V_PLIMIT = 1.44V limits V_PP to 23.6V, restricting max power to 10W into 8Ω - avoiding mechanical over-excursion and thermal overload during bass transients.

Can MP7758GF-Z operate with single-ended audio inputs?

Yes. Though optimized for differential inputs (INxA/INxB), the MP7758GF-Z accepts single-ended signals by AC-coupling the source to INxA and tying INxB to 2.5V bias. Gain remains programmable via GAIN0/GAIN1, but common-mode noise rejection is reduced compared to true differential operation.

What thermal derating applies above 25°C ambient?

With θ_JA = 32°C/W on a 4-layer PCB, the MP7758GF-Z's max continuous power drops linearly: at 60°C ambient, max dissipation is (150°C − 60°C)/32°C/W = 2.8W, limiting usable output to ~5W/channel. Use the exposed pad and thermal vias to maintain T_J ≤ 125°C in sustained operation.

Is the /FAULT pin compatible with 3.3V logic microcontrollers?

Yes. The /FAULT pin is open-drain with 20mA sink capability and no internal pull-up. A 3.3V microcontroller GPIO can directly read its state using an external 10kΩ pull-up to 3.3V; the pin pulls low (<0.4V) during over-temperature or over-current events, meeting standard logic-low thresholds.

How is EMI performance achieved without output inductors?

EMI suppression relies on magnetic-bead + capacitor filters at each SW node, exploiting the MP7758GF-Z's fixed 260–360 kHz switching frequency. High-impedance beads (e.g., Murata NFZ2M series) attenuate harmonics, while the capacitor forms a low-pass filter - enabling CISPR22 Class B compliance without bulky inductors or shielding.

What is the minimum delay time for INABSENCE assertion?

The shortest configurable delay is set by the minimum practical CAP_D value (≈100pF), yielding t_DELAY ≈ 16ms per Equation (4). This allows brief audio pauses (e.g., between tracks) without false shutdown; larger capacitors (e.g., 10nF → 1.6s) support longer idle timeouts in portable devices.