Monolithic Power Systems Inc. MP4420HGJ-Z

Overview

MP4420HGJ-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 90mΩ/55mΩ MOSFETs, delivering 2A 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 signaling, thermal shutdown, and hiccup-mode over-current protection-used in automotive cold-crank and industrial distributed power systems.

For engineers reviewing the MP4420HGJ-Z datasheet, MP4420HGJ-Z pinout, MP4420HGJ-Z application, or MP4420HGJ-Z equivalent, key selection criteria include its wide VIN range, internal bootstrap driver architecture, adjustable soft-start, feedback voltage accuracy (±1.5%), and TSOT23-8 package constraints for high-density PCB layouts.

Technical Context

The MP4420HGJ-Z employs peak-current-mode control with an internal 0.8V reference and optimized compensation to simplify loop stability. Its current-mode architecture enables fast transient response and eliminates need for external compensation components in most designs.

It integrates a floating high-side gate driver powered by a dedicated bootstrap regulator (BST pin), with built-in UVLO (2.2V rising) for the driver and system-level UVLO (3.5V rising) on VIN. The EN/SYNC pin serves dual function: digital enable control and external clock synchronization input with 2ms delay alignment.

Key Specifications

Pinout & Package

MP4420HGJ-Z is housed in an 8-pin TSOT23-8 package with exposed thermal pad (not electrically connected), optimized for compact high-voltage DC/DC designs requiring minimal board area and thermal resistance (θ_JA = 100°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM61480RQWR and TPS54240DGQR, MP4420HGJ-Z offers the smallest footprint (TSOT23-8), lowest quiescent current (0.7mA), and tightest FB tolerance (±1.5%)-making it optimal for space- and efficiency-critical 2A automotive and industrial applications where 36V max input suffices.

Availability

MP4420HGJ-Z is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power rails, and distributed telecom power systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP4420HGJ-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, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP4420H product line delivers compact, high-efficiency synchronous buck converters for automotive, industrial, and telecom applications where wide input range, thermal resilience, and minimal external components are critical.

FAQ

What is the minimum input voltage required for reliable startup?

The MP4420HGJ-Z requires VIN ≥ 3.5V (UVLO rising threshold) to initiate startup. Below this, the internal regulator remains disabled. Once running, it sustains operation down to 4V due to hysteresis-enabling functionality during automotive cold-crank events where battery voltage dips to ~4.5V.

Can the MP4420HGJ-Z operate without an external BST resistor?

Yes, it can operate without the 20Ω BST resistor, but MPS strongly recommends it. Omitting the resistor increases SW node voltage spikes and EMI, potentially causing false triggering of over-voltage protection or degrading long-term reliability of the internal high-side driver.

How does the frequency fold-back feature protect the device during short-circuit?

When FB voltage drops below 660mV (indicating severe overload or short), the oscillator frequency folds back from 410kHz to ~100kHz. This reduces peak inductor current per cycle, limiting thermal stress and average power dissipation-allowing hiccup-mode recovery instead of immediate thermal shutdown.

Is the PG pin compatible with 5V logic systems?

Yes-the PG pin is open-drain and rated for 6V maximum. When pulled up to 5V via a 100kΩ resistor, it asserts low (<0.3V) during fault conditions and high (>4V) when VOUT is within 90–93.5% of target, providing direct compatibility with standard CMOS logic inputs.

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

Over –40°C to +125°C junction temperature, ±15% line regulation, and 0–2A load range, the output voltage error remains within ±3%-dominated by FB reference tolerance (±1.5%), resistor divider drift, and layout-induced noise coupling to the FB node.

Does the MP4420HGJ-Z support forced PWM mode at light loads?

No-it operates in automatic power-save mode (PFM at light loads, PWM at heavier loads) only. There is no pin or register to force continuous PWM; this trade-off prioritizes light-load efficiency over output ripple consistency.

How is thermal performance affected by PCB copper area in TSOT23-8?

With the recommended 4-layer PCB (2oz copper, thermal vias under exposed pad), θ_JA is 100°C/W. Reducing copper area or omitting vias increases θ_JA to >150°C/W-raising junction temperature by >25°C at 2A, risking thermal shutdown. MPS specifies minimum 25mm² copper pour connected to GND pin via ≥4 vias.