Monolithic Power Systems Inc. MP4423HGQ-P

Overview

MP4423HGQ-P from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 85mΩ/55mΩ MOSFETs, delivering 3A continuous output current across a 4V–36V input range. It operates at a default 410kHz switching frequency, supports external clock synchronization (200kHz–2.2MHz), and features power-good indication, thermal shutdown, and hiccup-mode over-current protection - deployed in automotive cold-crank and industrial distributed power systems.

For engineers reviewing the MP4423HGQ-P datasheet, MP4423HGQ-P pinout, MP4423HGQ-P application, or MP4423HGQ-P equivalent, key selection criteria include its wide VIN range, internal bootstrap driver architecture, adjustable soft-start, high-duty-cycle capability (>92%), and QFN-8 (3mm×3mm) thermal performance (θJA = 55°C/W).

Technical Context

The MP4423HGQ-P uses peak-current-mode control with an internal 0.8V reference and optimized compensation to achieve fast transient response and stable regulation without external loop components. Its integrated high-side and low-side MOSFETs enable synchronous rectification across the full load range, minimizing conduction losses.

It implements adaptive bootstrap charging via an internal regulator that maintains ~5V BST voltage during LS-FET conduction, with UVLO (2.2V rising) on the floating driver. The EN/SYNC pin serves dual function: digital enable control and external clock synchronization with 2ms delay for phase alignment.

Key Specifications

Pinout & Package

MP4423HGQ-P is housed in a thermally enhanced QFN-8 package (3mm × 3mm, 0.5mm pitch) with exposed thermal pad. The package supports ≤2.27W continuous power dissipation at +25°C ambient and requires soldering the thermal pad to a dedicated PCB ground plane for optimal θJC (13°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with MP4423HGQ-P, MPQ4423HGQ-P adds automotive qualification without sacrificing performance, while LM61480RQR trades BST flexibility and cold-crank headroom for higher-frequency operation and simplified layout - making MP4423HGQ-P optimal for thermally demanding, transient-resilient industrial and automotive body applications.

Availability

MP4423HGQ-P is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLCs, distributed telecom power supplies, and medical diagnostic equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP4423HGQ-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 MP4423H product line delivers compact, high-efficiency synchronous buck converters for automotive, industrial, and telecom applications where wide input range, thermal resilience, and functional safety readiness are essential.

FAQ

What is the minimum input voltage required for reliable startup?

The MP4423HGQ-P requires VIN ≥ 3.5V (rising UVLO threshold) to initiate startup. Below this, the internal VCC regulator cannot establish bias, and the device remains in shutdown. For cold-crank scenarios, ensure the input does not dip below 3.5V for more than 100ms to avoid unintended restarts.

Can the switching frequency be adjusted without an external clock source?

No - the MP4423HGQ-P has a fixed internal oscillator at 410kHz (±20%). Frequency adjustment requires applying a clean external clock signal (200kHz–2.2MHz) to the EN/SYNC pin; no resistor or capacitor tuning is supported.

How is the power-good (PG) signal used in system-level sequencing?

The open-drain PG pin pulls low during startup until VOUT reaches 90% of target, then asserts high after a 90μs delay. It goes low again if VOUT drops to 84% of target, or if EN is deasserted or thermal shutdown occurs - enabling precise reset timing and fault detection in MCU-based systems.

What is the purpose of the 20Ω resistor between BST and SW?

The 20Ω resistor dampens ringing and reduces voltage spikes at the SW node during high dv/dt transitions. It limits peak BST capacitor charging current and improves EMI performance without significantly impacting efficiency - omission may cause gate driver instability or false OCP triggering.

Does the MP4423HGQ-P support adjustable soft-start time?

No - soft-start duration is internally fixed at 1.5ms typical (0.45–2.55ms). It cannot be modified externally. However, the ramp is monotonic and ensures controlled output voltage rise from 10% to 90% of final value without overshoot.

Is an external bootstrap diode necessary for normal operation?

No - the internal bootstrap charging circuit suffices for most applications. An external diode (e.g., 1N4148) is optional and only beneficial at very high duty cycles (>65%) to improve efficiency by reducing BST capacitor discharge losses; it adds cost and board space.

What is the maximum achievable output voltage accuracy over temperature and line?

Output voltage accuracy is dominated by the 792mV feedback reference (±1.5% over −40°C to +125°C) and resistor divider tolerance. With 1% resistors, total VOUT error remains within ±2.2% across full operating conditions - sufficient for most digital and analog rail requirements.