Monolithic Power Systems Inc. MP1720DQ-3-LF-P

Overview

MP1720DQ-3-LF-P from Monolithic Power Systems is a mono Class-D audio amplifier delivering 2.7W into 4Ω at 10% THD+N with 5V supply, featuring pin-selectable 1MHz/1.3MHz switching frequency, 90% efficiency, and integrated 250mΩ MOSFETs. It operates in fully differential mode, supports unfiltered speaker drive up to 24-inch cable, and targets compact portable audio systems requiring low EMI and pop-free startup.

For engineers reviewing the MP1720DQ-3-LF-P datasheet, MP1720DQ-3-LF-P pinout, MP1720DQ-3-LF-P application, or MP1720DQ-3-LF-P equivalent, key selection criteria include its fixed 3dB gain setting, QFN10 thermal-pad package, shutdown current of 0.1μA, and FCC-compliant radiated emissions performance without external LC filtering.

Technical Context

The MP1720DQ-3-LF-P implements a BTL (bridge-tied load) Class-D architecture with fully differential inputs and outputs, using internal sawtooth-based PWM modulation. Its oscillator supports three modes: internal 1.0MHz (CLK=GND), internal 1.3MHz (CLK=FLOAT), or synchronization to external TTL clock (0.5–1.4MHz).

It integrates protection circuitry including thermal shutdown (trip at +125°C, resume at +112°C), short-circuit detection on both high- and low-side MOSFETs, and 15ms controlled startup to eliminate pop noise. Input bias voltage is fixed at 950–1035mV for the -3 variant, enabling DC-coupled differential input operation within 0.2–1.9V common-mode range.

Key Specifications

Pinout & Package

MP1720DQ-3-LF-P is housed in a thermally enhanced 3mm × 3mm 10-pin QFN package with exposed thermal pad (Pin 10) that must be soldered to PCB ground for thermal management and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TAS5086RTJR and MAX9718AETA+, MP1720DQ-3-LF-P uniquely combines filterless FCC compliance, differential input noise immunity, and ultra-low shutdown current - making it optimal for space-constrained, battery-sensitive portable audio where EMI and power budget are primary constraints.

Availability

MP1720DQ-3-LF-P is available at Aetrix Electronics and suitable for smartphone audio subsystems, wireless headset driver circuits, and portable media player designs requiring stable component supply, consistent parametric performance across production lots, and long-term lifecycle support.

Supply support for MP1720DQ-3-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP1720 series belongs to MPS's Class-D audio amplifier product line, engineered specifically for portable consumer electronics demanding high efficiency, low EMI, and minimal external component count in ultra-thin form factors.

FAQ

What is the exact gain value of MP1720DQ-3-LF-P, and how is it implemented?

The MP1720DQ-3-LF-P has a fixed voltage gain of 1.3–1.5 V/V (3dB), set by internal resistor ratios and verified per Electrical Characteristics table. This gain is factory-trimmed and non-adjustable; no external resistors or configuration pins modify it. The gain applies to differential input signals and remains stable over temperature (±10% variation from −40°C to +85°C).

Can MP1720DQ-3-LF-P drive an 8Ω speaker, and what output power is achievable?

Yes - at 10% THD+N and 5V supply, MP1720DQ-3-LF-P delivers 1.56W into 8Ω (typical). At 1% THD+N, output drops to 1.19W. Lower impedance loading increases current demand and thermal stress; derating is required above 4Ω for sustained full-power operation due to thermal resistance limits (θJA = 50°C/W in QFN10).

Is the thermal pad (Pin 10) electrically connected, and how must it be handled on the PCB?

Yes - Pin 10 (PVIN/thermal pad) is internally connected to the power MOSFET sources and must be soldered to a solid PCB ground plane. It serves dual roles: electrical return for switching current and primary thermal conduction path. Minimum recommended solder mask opening is 2.5mm × 2.5mm with ≥6 thermal vias (0.3mm diameter) to inner ground layers.

Does MP1720DQ-3-LF-P support single-ended input, and what are the trade-offs?

Yes - single-ended input is supported using INP with INN AC-grounded via 15kΩ resistor. However, CMRR degrades from −66dB to ≈−40dB, increasing susceptibility to noise. Input coupling capacitors become mandatory, and maximum input swing is reduced (2.99VPP vs. 5.98VPP differential), limiting output power to 0.52W into 4Ω.

What is the minimum recommended input coupling capacitor value for single-ended operation?

For 20Hz low-frequency cutoff, use C_IN = 1/(2π × 15kΩ × 20Hz) ≈ 0.53μF. A 1μF X7R ceramic capacitor is recommended to ensure ±10% tolerance, low voltage coefficient, and stable corner frequency across temperature and bias - preventing bass attenuation and channel imbalance.

How does the CLK pin affect EMI performance in different configurations?

Setting CLK=GND (1.0MHz) places fundamental switching energy below cellular LTE bands; CLK=FLOAT (1.3MHz) shifts harmonics away from Wi-Fi 2.4GHz band. External clock synchronization allows precise placement of spectral peaks outside sensitive RF receivers - validated in MPS application note AN-107 for FCC testing with 24-inch cable.

What happens during thermal shutdown, and how does recovery work?

When junction temperature exceeds +125°C, internal circuitry disables all MOSFETs and holds outputs in high-impedance state. Operation resumes automatically only after die temperature falls below +112°C, with a minimum 50μs lockout period to prevent cycling. No external reset or power cycle is needed.