Monolithic Power Systems Inc. MP9840GL-P

Overview

MP9840GL-P from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 125mΩ high-side and 55mΩ low-side MOSFETs, delivering 3.5A continuous output current across a 3.3V–36V input range. It features 14μA no-load quiescent current, programmable 350kHz–2.5MHz switching frequency, and power-good (PG) monitoring - enabling use in automotive infotainment power rails and battery-powered industrial sensors.

For engineers reviewing the MP9840GL-P datasheet, MP9840GL-P pinout, MP9840GL-P application, or MP9840GL-P equivalent, key selection criteria include its 80ns minimum on-time for high-duty-cycle operation, selectable forced CCM/AAM mode for light-load efficiency optimization, hiccup-mode over-current protection, and QFN-16 (3mm×4mm) thermal performance with θJA = 48°C/W.

Technical Context

The MP9840GL-P employs peak-current-mode control with internal error amplifier and 0.8V reference for precise output regulation. Its PLL-based oscillator supports external synchronization and phase alignment (in-phase or 180° out-of-phase) across multiple units to reduce input ripple.

It integrates BST refresh logic for low-dropout operation up to ~100% duty cycle, bootstrap charging via dedicated regulator, and pre-bias start-up handling. The device uses internal current-sense FETs for cycle-by-cycle hiccup OCP and reverse-current limiting at 3A.

Key Specifications

Pinout & Package

MP9840GL-P is housed in a thermally enhanced QFN-16 package (3mm × 4mm, 0.5mm pitch) with exposed thermal pad. The package supports ≤2.6W continuous power dissipation at +25°C ambient and requires PCB copper pour + multiple vias under the pad for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4420AGL-A-Z, MP9840GL-P delivers 75% more output current and 44% lower quiescent current, making it superior for automotive body-control modules. Against LM61480RQR, MP9840GL-P offers identical IQ and input range in a smaller footprint but trades 4.5A current headroom for tighter board area utilization.

Availability

MP9840GL-P is available at Aetrix Electronics and suitable for automotive infotainment power, industrial sensor node supply, and ADAS camera module supply requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MP9840GL-P 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 MP9840 product line targets high-efficiency, wide-input DC/DC conversion for automotive and industrial environments - emphasizing low IQ, robust protection, and thermal resilience in compact packages.

FAQ

What is the recommended input capacitor configuration for MP9840GL-P?

A 4.7µF–10µF X5R/X7R ceramic capacitor placed close to VIN and PGND is required for bulk filtering, supplemented by a 0.1µF 0603 ceramic capacitor directly at the VIN pin to suppress high-frequency switching noise. Total RMS input ripple current must be rated ≥1.5× the maximum output current.

How does the MP9840GL-P handle pre-biased outputs during start-up?

When FB voltage exceeds SS − 150mV at startup, the MP9840GL-P inhibits both HS- and LS-FET turn-on until SS rises above FB, preventing reverse current flow into a pre-charged output. This ensures safe hot-plug and power-sequencing compliance without external diodes or controllers.

Can MP9840GL-P operate without an external BIAS supply?

Yes - the MP9840GL-P operates fully from VIN alone, using its internal 2.6V regulator. BIAS is optional: connecting 5V–18V to BIAS reduces power dissipation in high-VIN conditions (e.g., 24V+ inputs), improving efficiency by ~2–3% and lowering junction temperature.

What is the function of the PHASE pin beyond synchronization?

The PHASE pin controls relative switching timing between paralleled MP9840GL-P units: pulling high selects in-phase operation; pulling low selects 180° out-of-phase. This enables interleaved operation to halve input ripple current and reduce required input capacitance by up to 50% in multi-rail systems.

Does MP9840GL-P support output voltages below 0.8V?

No - the internal reference is fixed at 0.8V ±2%, and the FB pin expects this voltage as the regulation point. Output voltages below 0.8V require external amplification or a different regulator architecture; the lowest achievable output is 0.8V with a direct FB connection.

How is thermal performance affected by PCB layout for the QFN-16 package?

Thermal resistance θJA drops from 48°C/W (4-layer JEDEC standard) to ≤35°C/W with ≥6 thermal vias under the exposed pad, 2oz copper, and ≥2cm² copper pour. Poor layout (e.g., no thermal vias or small pad) can raise junction temperature by >40°C at full load, triggering thermal shutdown prematurely.