Monolithic Power Systems Inc. MP4571GQB-Z

Overview

MP4571GQB-Z from Monolithic Power Systems is a fully integrated, synchronous buck converter delivering 1A continuous output current with 4.5V–60V input range, 2μA shutdown quiescent current, and internal 250mΩ/45mΩ MOSFETs - designed for automotive infotainment power rails requiring cold-crank operation and EMI-compliant 5V/3.3V conversion.

For engineers reviewing the MP4571GQB-Z datasheet, MP4571GQB-Z pinout, MP4571GQB-Z application, or MP4571GQB-Z equivalent, key selection criteria include its AAM/CCM light-load mode selection, 180° out-of-phase SYNCO clock capability, hiccup-mode short-circuit protection, and QFN-12 (2.5mm×3mm) wettable flank package compatibility with automotive AEC-Q200-adjacent layout requirements.

Technical Context

The MP4571GQB-Z employs peak-current-mode control with valley-current overcurrent detection and zero-crossing detection (ZCD) to prevent reverse inductor current. Its adaptive asynchronous modulation (AAM) dynamically scales switching frequency below 400kHz at light loads, reducing gate driver and switching losses while maintaining regulation accuracy.

It integrates internal compensation, soft-start (0.45ms), power-good (PG) with ±6% window, and low-dropout mode enabling stable 5V output down to 4.5V VIN - critical for automotive cold-crank (4V–5V) transients. Thermal shutdown activates at 170°C with 25°C hysteresis.

Key Specifications

Pinout & Package

MP4571GQB-Z is housed in a QFN-12 (2.5mm × 3mm) wettable flank package with exposed thermal pad, optimized for automotive PCB assembly and thermal performance on 2oz copper layers.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with MPQ4571GQB-A, the MP4571GQB-Z offers identical electrical performance but omits AEC-Q100 qualification and has lower ESD rating; versus LM61480RGER, it delivers superior cold-crank operation and automotive transient tolerance at 1A, but trades off output current scalability.

Availability

MP4571GQB-Z is available at Aetrix Electronics and suitable for automotive infotainment, LED lighting, and industrial PLC power systems requiring stable component supply, automotive-grade thermal reliability, and wettable flank package compatibility.

Supply support for MP4571GQB-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, with core expertise in DC-DC conversion, motor drivers, and LED controllers.

The MP4571 product line targets automotive and industrial applications demanding wide-input-voltage resilience, low quiescent power, and compact integration - specifically engineered for harsh environments where cold crank, load dump, and EMI compliance are mandatory.

FAQ

What is the minimum input voltage required for MP4571GQB-Z to regulate 5V output?

The MP4571GQB-Z maintains regulation down to 4.5V input in low-dropout mode, enabling stable 5V output during automotive cold-crank events where battery voltage dips to ~4.5V. Below this threshold, UVLO disables the device to protect internal circuitry.

Does MP4571GQB-Z require an external bootstrap capacitor?

Yes - a 0.1µF ceramic capacitor must be placed between BST and SW pins to provide gate-drive voltage for the internal high-side MOSFET. This capacitor charges through an internal diode during the low-side conduction phase.

How does the CCM/SYNCO pin function in AAM vs. forced CCM modes?

When CCM/SYNCO is floated, the device operates in AAM mode at light loads, reducing frequency to minimize losses. When pulled to GND via 10kΩ–300kΩ, it forces continuous conduction mode regardless of load - essential for noise-sensitive applications requiring fixed-frequency operation.

Can MP4571GQB-Z drive a 10µH inductor at 2.2MHz?

Yes - the datasheet confirms stable operation with 10µH inductors at 1MHz and 4.7µH at 2.2MHz. Using 10µH at 2.2MHz increases peak inductor current and may reduce efficiency, but remains within safe operating limits per Figure 13's switching frequency vs. RFREQ curve.

Is the PG pin actively driven or open-drain?

The PG pin is open-drain with internal pull-down. It requires an external pull-up resistor (typically 10kΩ to VOUT or VCC) to indicate valid regulation. PG goes high when VOUT is within 90–108% of nominal, and low when outside that window or during fault conditions.

What thermal performance can be expected on a 2-layer PCB?

On a standard 2-layer board with 1oz copper, θJA is ~75°C/W. With 1A load and 24V input, power dissipation is ~0.3W - resulting in ~22°C junction rise above ambient. For automotive use, 4-layer boards with thermal vias to inner ground planes are recommended to meet 125°C TJ limit.

Does MP4571GQB-Z support output voltages below 1V?

No - the datasheet specifies a minimum regulated output of 1V due to FB reference architecture and internal error amplifier constraints. For sub-1V rails, external resistive scaling or a different converter with adjustable reference is required.