Monolithic Power Systems Inc. MP7782DF-LF-Z

Overview

MP7782DF-LF-Z from Monolithic Power Systems is a mono, 50W Class D audio amplifier in TSSOP20F package with exposed thermal pad, integrating four 180mΩ MOSFETs for bridged-tied-load (BTL) operation into 6Ω loads at 24V supply, featuring ADAM™ variable-frequency modulation, 90% efficiency, and 0.06% THD+N at 1W.

For engineers reviewing the MP7782DF-LF-Z datasheet, MP7782DF-LF-Z pinout, MP7782DF-LF-Z application, or MP7782DF-LF-Z equivalent, this device supports high-fidelity audio amplification in space-constrained consumer electronics where thermal management, PSRR >60dB, and click/pop suppression are critical design requirements.

Technical Context

The MP7782 implements a full-bridge BTL output stage with dual independent switching channels (SW1/SW2), each driven by integrated 180mΩ MOSFETs and bootstrap gate drivers (BS1/BS2). It operates on a single 9.5–24V supply and uses ADAM™ topology - a proprietary variable-frequency PWM scheme enabling fast transient response and high PSRR without external clock synchronization.

Feedback is implemented via dual differential inputs (FB1/FB2) tied to internal comparators, supporting closed-loop stability across audio bandwidth (20Hz–20kHz). Thermal shutdown activates at 150°C with 30°C hysteresis, and enable control (EN) provides mute/standby mode with <10µA standby current.

Key Specifications

Pinout & Package

MP7782DF-LF-Z uses a thermally enhanced 20-pin TSSOP20F package with exposed copper pad (pin 0) for junction-to-board heat transfer. Package dimensions: 4.5mm × 6.6mm × 1.0mm (max height), 0.65mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP7748S and TAS5706APHP, MP7782DF-LF-Z offers lowest component count and smallest footprint for fixed-function 50W mono BTL, though it lacks digital control and has narrower supply range - optimal for cost-sensitive, volume-manufactured consumer audio.

Availability

MP7782DF-LF-Z is available at Aetrix Electronics and suitable for home theater soundbars, smart TV audio modules, multimedia gaming consoles, and portable DVD/Blu-ray players requiring stable component supply and legacy design support.

Supply support for MP7782DF-LF-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, headquartered in Kirkland, WA, with global design and support centers.

The MP7782 belongs to MPS' second-generation Class D audio amplifier product line, engineered specifically for high-efficiency, low-THD mono BTL applications in space-constrained consumer electronics.

FAQ

Is MP7782DF-LF-Z still recommended for new designs?

No - the datasheet explicitly states "NOT RECOMMENDED FOR NEW DESIGNS" and directs users to MP7748S as the functional successor. MP7782DF-LF-Z remains available for legacy production and repair, but lacks updated features like lower THD+N, wider VDD range, and improved thermal performance found in MP7748S.

What is the minimum recommended LC filter configuration for MP7782DF-LF-Z?

The datasheet specifies 15µH inductors (L1/L2) and 0.22µF film capacitors (C7/C12) for 6Ω loads. Inductor Q must be 0.7–2.0 to avoid peaking; gapped ferrite or MPP cores are recommended. C4 (2.2nF) sets idle switching frequency near 500kHz - critical for balancing EMI and efficiency.

How should the exposed thermal pad be connected on the MP7782DF-LF-Z PCB?

The exposed pad (pin 0) must be soldered to a large copper pour connected to PGND1/PGND2 with ≥4 thermal vias (0.3mm diameter, spaced ≤1.2mm apart) to an inner-layer ground plane. This achieves the specified θJC = 6°C/W and prevents junction temperature exceedance above 30W continuous output.

Does MP7782DF-LF-Z support differential input signals?

No - it accepts single-ended audio input referenced to VDD/2. The FB1/FB2 pins implement differential feedback sensing from SW1/SW2 nodes, not input signal reception. Input coupling capacitors (C6/C9) block DC offset, and gain is set by external resistors R3/R4 per the datasheet equation.

Can MP7782DF-LF-Z drive 4Ω speakers?

Yes, but with derated output power and increased thermal stress. At 24V, maximum safe output into 4Ω is ~35W (per SOA limits), requiring enhanced heatsinking. The 50W rating is validated only for 6Ω loads at 10% THD+N; lower impedance increases current demand and conduction loss.

What is the purpose of the NC pins (1, 5, 11, 16) on MP7782DF-LF-Z?

These pins are not internally connected and serve no electrical function. Per the datasheet, they must be grounded in PCB layout to reduce EMI susceptibility and provide mechanical stability - floating NC pins can act as antennas and degrade EMC performance.

How does the ADAM™ modulation differ from standard fixed-frequency Class D topologies?

ADAM™ uses variable-frequency PWM that adapts switching rate based on input signal amplitude and load conditions. This eliminates beat frequencies with external clocks, improves PSRR across audio band, and reduces EMI peak energy - unlike fixed-frequency schemes that require careful LC filter tuning to avoid resonance.