Monolithic Power Systems Inc. MPQ4321CGDE-5-AEC1-Z

Overview

MPQ4321CGDE-5-AEC1-Z from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified, synchronous step-down DC/DC converter with integrated 70mΩ/50mΩ MOSFETs, 3.3V–36V input range, 42V load dump tolerance, and fixed 5V output delivering up to 1A. It operates from –40°C to +150°C junction temperature and supports automotive cold-crank (3.1V min VIN) in QFN-12 (2mm×3mm) wettable flank package.

For engineers reviewing the MPQ4321CGDE-5-AEC1-Z datasheet, MPQ4321CGDE-5-AEC1-Z pinout, MPQ4321CGDE-5-AEC1-Z application, or MPQ4321CGDE-5-AEC1-Z equivalent, key selection criteria include 42V transient robustness, 1μA shutdown current for battery-sensitive systems, CISPR25 Class 5 EMI compliance, configurable switching frequency (350kHz–2.5MHz), and integrated power-good signaling with ±1.5% threshold hysteresis.

Technical Context

The MPQ4321CGDE-5-AEC1-Z uses peak-current-mode control with frequency foldback during startup to prevent inductor current runaway. Its MeshConnect™ flip-chip QFN package enables symmetric VIN pinout and low-inductance layout for EMI reduction.

It integrates forced continuous conduction mode (FCCM), low-dropout (LDO) mode for cold-crank, over-current protection with hiccup recovery, and thermal shutdown at 160°C–185°C with 20°C hysteresis - all optimized for automotive infotainment, clusters, and ADAS power rails requiring high reliability under wide temperature and voltage transients.

Key Specifications

Pinout & Package

MPQ4321CGDE-5-AEC1-Z is housed in a wettable flank QFN-12 (2mm × 3mm) package with exposed thermal pad. The package supports automated optical inspection (AOI) and improves solder joint reliability in automotive reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4321CGDE-5-AEC1-Z, the adjustable MPQ4321CGDE-AEC1-Z offers voltage flexibility at the cost of two extra resistors, while the TPS543320RTWR delivers higher current but lacks automotive-grade transient protection and qualification - making the MPQ4321CGDE-5-AEC1-Z optimal for safety-critical 5V rails in harsh environments.

Availability

MPQ4321CGDE-5-AEC1-Z is available at Aetrix Electronics and suitable for automotive infotainment systems, instrument clusters, and ADAS ECUs requiring stable component supply with guaranteed AEC-Q100 Grade 1 compliance and long-term production continuity.

Supply support for MPQ4321CGDE-5-AEC1-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, and global manufacturing partnerships.

The MPQ4321C product line targets automotive power conversion with emphasis on AEC-Q100 qualification, load dump resilience, and EMI robustness - specifically engineered for infotainment, cluster, and ADAS subsystems demanding high reliability under extreme thermal and electrical stress.

FAQ

What is the exact output voltage tolerance of MPQ4321CGDE-5-AEC1-Z over temperature?

The fixed 5V output maintains ±1.13% accuracy (4.887V to 5.113V) across the full –40°C to +150°C junction temperature range, as specified in the Electrical Characteristics table (VOUT, TJ = –40°C to +150°C). This is tighter than typical 5% industrial buck converters and enables direct powering of 5V-tolerant microcontrollers without post-regulation.

Does MPQ4321CGDE-5-AEC1-Z require an external bootstrap capacitor?

Yes - a 0.1µF X7R ceramic capacitor must be placed directly between the BOOT and SW pins. This capacitor supplies gate drive energy for the high-side MOSFET and is critical for proper operation; omission causes immediate failure to regulate or erratic switching behavior.

How is the 42V load dump tolerance implemented without external components?

The 42V rating is achieved through internal process hardening and integrated clamp circuitry on the VIN pin, validated per ISO 16750-2 pulse 5a test conditions. No external TVS diode is required, though layout best practices (short traces, local decoupling) remain essential to maintain this rating in end equipment.

Can MPQ4321CGDE-5-AEC1-Z operate in forced continuous conduction mode (FCCM) at light loads?

Yes - FCCM is enabled by default and remains active across the entire load range, eliminating audible switching frequency variation and ensuring consistent EMI profile even at 1mA output. This differs from skip-mode converters that modulate frequency under light load, which can complicate EMI filtering.

What is the thermal resistance (θJA) of the QFN-12 (2mm×3mm) package in standard JEDEC layout?

For the QFN-12 (2mm×3mm) package on a 4-layer JEDEC JESD51-7 board (2oz copper), θJA is 60°C/W. On the recommended evaluation board EVQ4321C-D-00A (8.3cm×8.3cm, 4-layer), measured θJA drops to 35.5°C/W - confirming effective thermal design is achievable with proper PCB copper area and vias under the exposed pad.

Is the PG pin actively driven or open-drain, and what pull-up value is recommended?

The PG pin is strictly open-drain. A 10kΩ pull-up to the output voltage rail (5V) is recommended per the datasheet, providing sufficient rise time (<1µs) while limiting current to <0.5mA during fault conditions. Floating PG is not allowed and may cause undefined system behavior.

Does the FREQ pin support dynamic frequency adjustment during operation?

No - the FREQ pin sets switching frequency at startup only via a fixed resistor to AGND. Dynamic reconfiguration is not supported; changing frequency mid-operation requires cycling EN or performing a full reset. The resistor value determines fSW per the lookup table in the datasheet (e.g., 86.6kΩ = 415kHz).