Monolithic Power Systems Inc. MPQ9842GL-Z

Overview

MPQ9842GL-Z from Monolithic Power Systems is a 36V, 2A, AEC-Q100 Grade-1 qualified synchronous step-down converter with integrated 125mΩ high-side and 55mΩ low-side MOSFETs, 14μA no-load quiescent current, and programmable 350kHz–2.5MHz switching frequency. It delivers stable 3.3V or 5V fixed/adjustable output in automotive infotainment power rails and ADAS camera modules.

For engineers reviewing the MPQ9842GL-Z datasheet, MPQ9842GL-Z pinout, MPQ9842GL-Z application, or MPQ9842GL-Z equivalent, key selection criteria include its AEC-Q100 qualification, ultra-low IQ for battery-backed systems, hiccup-mode OCP, PG signal accuracy (±10%), and QFN-16 wettable flank package compatibility with automated optical inspection.

Technical Context

The MPQ9842GL-Z employs peak-current-mode control with internal error amplifier and 0.8V reference for precise output regulation. Its dual-mode operation-selectable forced CCM or Advanced Asynchronous Mode (AAM)-enables deterministic EMI behavior under load or ultra-high light-load efficiency via power-save mode.

Bootstrap refresh logic maintains >2.5V BST–SW differential to sustain >95% duty cycle operation during dropout conditions. The integrated 5V VCC regulator supports full 3.3V–36V input range, while BIAS pin enables external 5–18V supply for reduced thermal dissipation in high-power-density layouts.

Key Specifications

Pinout & Package

MPQ9842GL-Z is housed in a thermally enhanced, wettable flank QFN-16 (3mm × 4mm, 0.5mm pitch) package optimized for automotive reflow and AOI inspection. Exposed thermal pad requires solder connection to PCB ground plane for θJA = 43°C/W performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4420AGL-AEC1-Z and TPS543B20RTWR, the MPQ9842GL-Z uniquely combines AEC-Q100 Grade-1, PG output, 14μA no-load IQ, and wettable flank packaging-making it the only option qualified for safety-critical, space-constrained automotive domains requiring both functional safety and manufacturability assurance.

Availability

MPQ9842GL-Z is available at Aetrix Electronics and suitable for automotive ADAS camera modules, telematics control units, and electric power steering sensor interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MPQ9842GL-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 MPQ9842 belongs to MPS's automotive-grade DC/DC converter product line, engineered specifically for AEC-Q100-compliant power delivery in infotainment, ADAS, and body electronics where low IQ, high efficiency, and robust thermal performance are mandatory.

FAQ

What is the maximum allowable input voltage for MPQ9842GL-Z, and what happens beyond that?

The absolute maximum VIN is 40V. Operation above 36V violates recommended conditions and risks permanent damage due to overstress on internal MOSFETs and gate drivers. The device includes under-voltage lockout (2.4V–3.2V threshold) but no over-voltage protection-external TVS or crowbar circuitry is required for load-dump transients exceeding 36V.

Can MPQ9842GL-Z operate with a 24V input and 3.3V output at 2MHz switching frequency?

Yes. With RFREQ = 27kΩ, fSW is set to ~2.5MHz. At VIN = 24V and VOUT = 3.3V, the duty cycle is ~14%, well above the 80ns minimum on-time limit (achievable up to ~2.8MHz). Efficiency remains >88% at 1A load with proper layout and 4.7μH inductor.

How does the BIAS pin improve thermal performance, and what voltage should be applied?

BIAS supplies the internal gate drivers directly, bypassing the VIN-to-5V linear regulator. Applying 5–18V to BIAS reduces power dissipation by up to 300mW at VIN = 24V, lowering junction temperature. For optimal benefit, use a clean 5V rail derived from a separate LDO or buck converter.

Is the MPQ9842GL-Z pin-compatible with other MPQ9842 variants like MPQ9842GLE-5-AEC1-Z?

Yes-mechanically and electrically identical. All MPQ9842 variants share the same QFN-16 footprint, pinout, and electrical characteristics. Differences are limited to factory-programmed feedback configuration (adjustable vs. fixed 3.3V/5V) and marking; no board redesign is needed when migrating between versions.

What layout practices are critical for achieving CISPR 25 Class 5 EMI compliance?

Key practices include: (1) minimizing high di/dt loop area (VIN → SW → PGND → VIN), (2) placing input capacitor ≤3mm from VIN/PGND pins, (3) using solid PGND plane under IC and connecting thermal pad with ≥4 vias, (4) routing FB and SS traces away from noisy nodes, and (5) adding common-mode chokes and π-filters as shown in Figure 14 of the datasheet.

Does MPQ9842GL-Z support output capacitor discharge during shutdown?

No. The device lacks an active discharge FET. During shutdown, output voltage decays passively through the load and feedback divider. For applications requiring rapid VOUT discharge, an external NMOS switch controlled by EN or PG signal must be added across the output capacitor.

What is the purpose of the PHASE pin, and is it required for basic operation?

The PHASE pin selects synchronization phase (0° or 180°) when multiple MPQ9842GL-Z devices are used in parallel to reduce input ripple. It is optional-tie to GND for default in-phase operation or leave floating only if unused. No function is lost if omitted in single-regulator designs.