Monolithic Power Systems Inc. MP7748DF-LF-P

Overview

MP7748DF-LF-P from Monolithic Power Systems is a stereo Class D audio amplifier IC delivering 20W per channel into 4Ω in single-ended mode or 50W into 6Ω in bridge-tied-load (BTL) mode at 24V VDD, featuring integrated 250mΩ MOSFETs, programmable undervoltage protection (UVP), and startup/shutdown pop elimination circuitry for consumer audio systems including flat-panel TVs and multimedia computers.

For engineers reviewing the MP7748DF-LF-P datasheet, MP7748DF-LF-P pinout, MP7748DF-LF-P application, or MP7748DF-LF-P equivalent, key selection considerations include output configuration flexibility (SE/BTL), thermal performance in TSSOP28-EP package, THD+N ≤0.02% at 1W/8Ω, 9.5–36V single-supply operation, and integrated protection features including thermal shutdown and short-circuit current limiting.

Technical Context

The MP7748DF-LF-P implements MPS' proprietary Analog Adaptive Modulation™ (AAM™) topology operating up to 1MHz, enabling high linearity and fast transient response without external clocking. Its dual-channel architecture supports independent enable (EN1/EN2) and UVP (UVP1/UVP2) control per channel, with internal VDD/2 reference (REF1/REF2) and bootstrap-driven high-side MOSFETs (BST1/BST2).

It integrates two complete Class D power stages-each with matched 250mΩ N-channel MOSFETs-and embeds timer-based pop suppression via external TIMER1/TIMER2 capacitors (e.g., 2.2µF), while maintaining analog input compatibility through AC-coupled differential inputs (IN1/IN2) referenced to internal mid-rail.

Key Specifications

Pinout & Package

MP7748DF-LF-P uses a thermally enhanced TSSOP28-Exposed Pad package (28-pin, 4.4mm × 9.7mm body, 0.65mm pitch), where the exposed pad must be soldered to a PCB ground plane for optimal thermal dissipation (θJC = 6°C/W).

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, MP7748DF-LF-P uniquely combines per-channel UVP/EN control, 20W+ output into 4Ω with <0.02% THD+N, and TSSOP28-EP thermal performance - making it optimal for space-constrained, high-fidelity analog audio subsystems requiring robust fault management.

Availability

MP7748DF-LF-P is available at Aetrix Electronics and suitable for flat panel televisions, portable docking stations, and home stereo systems requiring stable component supply, RoHS-compliant packaging, and long-term industrial availability.

Supply support for MP7748DF-LF-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 core expertise in DC/DC conversion, LED drivers, and Class D audio amplifiers.

The MP7748 product line targets high-efficiency, high-fidelity audio subsystems for consumer electronics, emphasizing integration, thermal resilience, and analog signal integrity without digital overhead.

FAQ

What is the minimum recommended input coupling capacitor value for MP7748DF-LF-P?

The input coupling capacitor (CIN1/CIN2) must set a corner frequency (f_IN) below the lowest audio frequency of interest. For 20Hz cutoff with typical 10kΩ input impedance, C_IN ≥ 0.8µF. A 1µF X7R ceramic capacitor is recommended to ensure stability and low phase shift across the audio band.

Can MP7748DF-LF-P operate from a 12V supply in stereo SE mode?

Yes - at 12V VDD, MP7748DF-LF-P delivers 10.6W per channel into 8Ω (10% THD+N) and maintains 96% efficiency. Output power scales with V², so 12V yields ~44% of 24V output. Ensure thermal design accounts for higher current draw at lower voltage.

How is the switching frequency adjusted for each channel in SE configuration?

Each channel's idle switching frequency is set independently using external timing capacitors on TIMER1 and TIMER2 pins. For example, 5.6nF on TIMER1 and 4.7nF on TIMER2 yield ~620kHz and ~700kHz respectively at 24V - a 50kHz offset that reduces intermodulation distortion in stereo layouts.

What LC filter component values are recommended for 24V/4Ω SE operation?

For 24V/4Ω SE, use 4.7µH inductors (soft-saturation ferrite core) and 220µF low-ESR electrolytic output coupling capacitors. The LC corner frequency should be ~30kHz (Q ≈ 0.8) to pass 20kHz audio while attenuating 600kHz+ switching noise by >40dB.

Does MP7748DF-LF-P require external bootstrap diodes?

No - the IC integrates internal bootstrap charging circuitry. A 0.1µF ceramic capacitor between BST1 and SW1 (and BST2/SW2) is sufficient; no external diode is needed, simplifying layout and improving reliability over discrete bootstrap solutions.

What is the maximum allowable voltage on the UVP pin?

The UVP pin accepts voltages from –1V to VDD + 1V per absolute maximum ratings. However, for functional UVP operation, the applied voltage must remain within 0–4V to avoid disabling the internal comparator; exceeding 4V forces permanent disable regardless of VDD level.

How does thermal derating work above 25°C ambient temperature?

With θ_JA = 32°C/W, maximum continuous power drops linearly: P_D(MAX) = (125°C – T_A) / 32. At 65°C ambient, max dissipation falls to 1.875W - requiring either reduced output power, forced airflow, or PCB copper pour expansion to maintain 20W/channel operation.