Monolithic Power Systems Inc. MP4323CGRHE-Z

Overview

MP4323CGRHE-Z from Monolithic Power Systems is a 42V load-dump-tolerant, 3A synchronous step-down converter with integrated 70mΩ high-side and 50mΩ low-side MOSFETs, configurable switching frequency (350kHz–2.5MHz), and operation across 3.3V–36V input. It delivers regulated output in automotive aftermarket USB chargers and cold-crank battery-powered systems, featuring 1μA shutdown current and power-good monitoring.

For engineers reviewing the MP4323CGRHE-Z datasheet, MP4323CGRHE-Z pinout, MP4323CGRHE-Z application, or MP4323CGRHE-Z equivalent, key selection criteria include 42V transient survival, -40°C to +150°C junction temperature rating, QFN-14 (2.5mm×3.5mm) wettable flank package, CISPR25 Class 5 EMI compliance, and low-dropout mode for 3.1V cold-crank support.

Technical Context

The MP4323CGRHE-Z implements peak current mode control with frequency foldback during start-up to prevent inductor current runaway. Its integrated power stage includes matched high- and low-side MOSFETs with 65ns minimum on-time and 50ns minimum off-time, enabling high-frequency operation up to 2.5MHz while maintaining stability under wide VIN and load transients.

It supports forced continuous conduction mode (FCCM), hiccup over-current protection, thermal shutdown at 160°C–185°C, and a precision 0.8V feedback reference with ±10mV tolerance over temperature. The open-drain PG signal asserts when VOUT is within 94.5%–105.5% of nominal, with 70µs rising and 60µs falling deglitch timing.

Key Specifications

Pinout & Package

MP4323CGRHE-Z is housed in a QFN-14 (2.5mm × 3.5mm) package with wettable flanks for automated optical inspection (AOI). The thermally enhanced flip-chip construction improves power dissipation, with θJA = 48.6°C/W on JEDEC 4-layer board and θJC = 7.4°C/W (bottom).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4323GDR-AEC1-Z, the MP4323CGRHE-Z offers identical performance at lower cost for non-OEM applications; compared with LM61480RQRJR, it provides superior automotive transient resilience and wider VIN range but requires external frequency-setting resistor.

Availability

MP4323CGRHE-Z is available at Aetrix Electronics and suitable for USB chargers, aftermarket automotive electronics, and battery-powered systems requiring stable component supply, automotive-grade reliability, and compact QFN packaging.

Supply support for MP4323CGRHE-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 design centers in the US, China, and Taiwan.

The MP4323C product line targets automotive aftermarket and industrial DC-DC conversion, emphasizing load dump survivability, cold-crank operation, and EMI-compliant integration in ultra-compact packages.

FAQ

What is the maximum allowable input voltage for continuous operation?

The MP4323CGRHE-Z supports continuous operation up to 36V input. It withstands 42V transients per ISO16750 for ≤100ms, but sustained voltage above 36V risks permanent damage. The VIN over-voltage protection triggers at 35.5V–40V rising threshold, latching off until reset via EN pin cycling.

How is the switching frequency configured, and what resistor values are recommended?

Switching frequency is set by connecting a resistor from FREQ pin to GND. Recommended values: 86.6kΩ for 415kHz, 34.8kΩ for 1MHz, and 15kΩ for 2.2MHz. Frequency varies ±10% with temperature and supply; actual measured fSW at 25°C is 415kHz, 1000kHz, and 2200kHz respectively.

Does the MP4323CGRHE-Z support adjustable output voltage, and what is the feedback reference accuracy?

Yes, it supports adjustable output via external resistor divider on FB pin. The internal reference is 0.8V with ±10mV (±1.25%) initial accuracy at 25°C, and ±20mV (±2.5%) over -40°C to +150°C. This enables precise 3.3V, 5V, or custom outputs with <±1% total regulation error including resistor tolerance.

What thermal derating applies at elevated ambient temperatures?

Using θJA = 48.6°C/W, maximum continuous output current derates linearly above 25°C ambient. At 85°C ambient, max output drops to ~2.2A (assuming 150°C max junction); at 105°C ambient, it falls to ~1.7A. PCB copper area and airflow significantly impact real-world thermal performance.

Is the PG (power good) signal compatible with microcontroller GPIO inputs?

Yes - PG is an open-drain output requiring an external pull-up (typically 10kΩ to 3.3V or 5V). It drives low (<0.3V at 1mA sink) when VOUT is outside 94.5%–105.5% window, and floats high otherwise. Microcontroller GPIO can monitor this with internal or external pull-up; no level-shifting is needed for 3.3V/5V logic.

Can the MP4323CGRHE-Z operate in forced continuous conduction mode (FCCM)?

Yes - FCCM is enabled by pulling the MODE pin (not present on MP4323CGRHE-Z) high. However, the MP4323CGRHE-Z does not expose a MODE pin; FCCM is not user-configurable on this variant. It operates in auto-mode (DCM at light loads, CCM at heavy loads) by default.

What is the minimum output voltage achievable with the MP4323CGRHE-Z?

The minimum regulated output is constrained by the 0.8V feedback reference and practical resistor divider limits. With standard 1% resistors, outputs down to 0.8V are supported. Lower voltages (e.g., 0.6V) are not possible without external reference scaling circuitry, as the FB pin is designed for 0.8V nominal regulation.