Monolithic Power Systems Inc. MPQ4321CGRHE-AEC1-Z

Overview

MPQ4321CGRHE-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 1A continuous output current. It operates from –40°C to +150°C junction temperature and supports automotive cold-crank (3.1V min VIN) and low-noise applications via spread-spectrum modulation and CISPR25 Class 5 compliance.

For engineers reviewing the MPQ4321CGRHE-AEC1-Z datasheet, MPQ4321CGRHE-AEC1-Z pinout, MPQ4321CGRHE-AEC1-Z application, or MPQ4321CGRHE-AEC1-Z equivalent, key selection criteria include 42V transient survivability, wettable flank QFN-14 package for automated optical inspection, configurable 350kHz–2.5MHz switching frequency, and power-good monitoring with ±1.5% threshold hysteresis.

Technical Context

The MPQ4321CGRHE-AEC1-Z uses peak-current-mode control with frequency foldback during start-up to prevent inductor current runaway. Its dual-VIN pin architecture minimizes switching noise, while symmetric VIN pinout and MeshConnect™ flip-chip packaging reduce EMI.

It integrates forced continuous conduction mode (FCCM), low-dropout (LDO) mode for cold-crank operation, and hiccup-mode over-current protection. The device supports both adjustable (0.8V reference) and fixed-output variants, with PG output indicating regulation within ±5.5% of nominal VOUT.

Key Specifications

Pinout & Package

MPQ4321CGRHE-AEC1-Z is housed in a wettable flank QFN-14 (2.5mm × 3.5mm) package with exposed thermal pad, optimized for automated optical inspection and high thermal performance (θJA = 48.6°C/W on JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4321CGDE-AEC1-Z, the MPQ4321CGRHE-AEC1-Z offers lower thermal resistance (48.6°C/W vs. 60°C/W) and AOI-compatible wettable flanks; compared with TPS543320RHLT, it provides validated CISPR25 Class 5 compliance and tighter PG threshold hysteresis (1.5% vs. unspecified).

Availability

MPQ4321CGRHE-AEC1-Z is available at Aetrix Electronics and suitable for automotive infotainment, ADAS, instrument clusters, and industrial 24V power systems requiring stable component supply, AEC-Q100 qualification, and long-term lifecycle support.

Supply support for MPQ4321CGRHE-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 distribution through authorized partners.

The MPQ4321C product line delivers ultra-compact, AEC-Q100-qualified buck converters targeting automotive subsystems where space, thermal performance, and transient robustness are critical-especially infotainment, ADAS, and body electronics.

FAQ

What is the minimum input voltage required to start up the MPQ4321CGRHE-AEC1-Z?

The MPQ4321CGRHE-AEC1-Z has a VIN UVLO rising threshold of 3.4V to 3.9V (typical 3.65V). Startup is guaranteed above 3.9V, and the device sustains regulation down to 3.1V after startup-enabling operation during automotive cold-crank conditions per ISO 16750-2.

Does the MPQ4321CGRHE-AEC1-Z support fixed-output voltage configurations?

Yes-MPQ4321C offers factory-trimmed fixed-output versions (e.g., 5.0V ±2.25%) alongside adjustable variants. The MPQ4321CGRHE-AEC1-Z itself is the adjustable version; fixed-output equivalents like MPQ4321CGRHE-5-AEC1-Z use internal feedback dividers and require no external resistors.

How does the frequency spread spectrum (FSS) function impact EMI performance?

FSS modulates switching frequency by ±10% at 15kHz, spreading energy across a bandwidth instead of concentrating it at harmonics. This reduces peak conducted and radiated emissions by up to 10dB, enabling compliance with CISPR25 Class 5 without additional EMI filters in most layouts.

What thermal derating applies when operating at 150°C junction temperature?

At TJ = 150°C, the maximum continuous output current drops to ~750mA due to RDS(ON) increase and thermal limiting. Derating curves in Figure 14 (page 14) show 1A is sustainable up to 125°C ambient with 4-layer PCB and 2oz copper; above that, output current must be reduced linearly per θJA = 48.6°C/W.

Can the PG pin be left floating if not used in the system?

No-PG is an open-drain output and must be either pulled up to a valid logic voltage (e.g., 3.3V or 5V) via a 10kΩ resistor or actively driven. Floating PG may cause undefined logic states, false system resets, or increased leakage current. If unused, tie PG to AGND through a 100kΩ resistor to disable reporting.

Is the QFN-14 package of MPQ4321CGRHE-AEC1-Z compatible with standard reflow profiles?

Yes-the wettable flank QFN-14 is qualified for IPC/JEDEC J-STD-020D moisture sensitivity level 1 (MSL-1), allowing unlimited floor life and compatibility with standard lead-free reflow profiles (peak 260°C, 20–40 sec above 217°C). Visual solder joint inspection is supported via side-wall solder fillet imaging.

What is the typical efficiency at 12V input, 5V/1A output, and 2.2MHz switching frequency?

At VIN = 12V, VOUT = 5V, IOUT = 1A, fSW = 2.2MHz, L = 5.6µH, and COUT = 22µF × 2, typical efficiency is 92.5% (Figure 11, page 11). Efficiency remains >88% at 100mA load and improves to 94% at 500mA under identical conditions.