Monolithic Power Systems Inc. MPM3840GQV-Z

Overview

MPM3840GQV-Z from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC power module with built-in inductor and MOSFETs, delivering 4A continuous output current from a 2.8V–5.5V input. It features constant-on-time (COT) control, 1.2MHz switching frequency, 0.6V reference voltage, and 40μA quiescent current-enabling high-efficiency operation in space-constrained portable Li+-battery-powered systems such as handheld instrumentation and low-voltage I/O rails.

For engineers reviewing the MPM3840GQV-Z datasheet, MPM3840GQV-Z pinout, MPM3840GQV-Z application, or MPM3840GQV-Z equivalent, key selection criteria include its QFN-20 (3mm×5mm×1.6mm) package with integrated inductor, 1.5ms soft-start with pre-bias support, EN/PG sequencing capability, and dual-mode PWM/PFM operation with analog voltage dynamic regulation via the MODE pin.

Technical Context

The MPM3840GQV-Z implements a constant-on-time (COT) control architecture with input voltage feed-forward, ensuring stable 1.2MHz switching across its 2.8V–5.5V input range and down to 0.6V output. Its internal 25mΩ high-side and 12mΩ low-side MOSFETs enable high efficiency at full load while supporting 100% duty-cycle operation in dropout.

It integrates a 0.47μH inductor and supports external mode control for seamless transition between PWM (low-noise, fixed-frequency) and PFM (high light-load efficiency) modes. The MODE pin also enables analog dynamic output voltage adjustment (0.35V–0.6V reference) without changing feedback resistors, and the RAMP pin accepts a 10–47pF capacitor to optimize transient response.

Key Specifications

Pinout & Package

MPM3840GQV-Z is housed in an ultra-compact, thermally enhanced QFN-20 package (3mm × 5mm × 1.6mm) with exposed thermal pad. The package supports high-current routing via five GND pins (1,2,3,17,18) and four SW pins (4,5,6,16) for low-inductance inductor connection and minimized switching loop area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPSM84203 and LTM4622, the MPM3840GQV-Z uniquely balances ultra-compact size, Li+-optimized input range, analog dynamic regulation, and sub-50μA quiescent current-making it optimal for battery-powered, space-limited, single-output applications where design simplicity and runtime are critical.

Availability

MPM3840GQV-Z is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial IoT edge nodes, networking SFP+ modules, and automotive infotainment core rails requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MPM3840GQV-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 expertise in DC/DC conversion, motor drivers, and LED lighting controllers since 1997.

The MPM3840 belongs to MPS's integrated power module product line, designed specifically to reduce design time and board area in battery-powered and space-constrained applications by combining controller, MOSFETs, and inductor in a thermally optimized QFN package.

FAQ

What is the maximum recommended output capacitance for stable operation?

The MPM3840GQV-Z is characterized and stable with up to 100μF total output capacitance using X5R/X7R ceramic capacitors. Exceeding this value may degrade phase margin and cause oscillation during load transients. For 4A loads, two 22μF × 0805 capacitors placed symmetrically near the OUT pins provide optimal ESR, ESL, and thermal performance without instability risk.

Can the MODE pin be left floating for default PFM operation?

Yes - leaving MODE unconnected places the device in PFM mode, enabling high light-load efficiency. However, ensure no parasitic coupling (e.g., from nearby traces or connectors) pulls MODE into the undefined 0.4V–0.6V range, which may cause erratic regulation. A 100kΩ pulldown resistor is recommended if floating operation is used in noisy environments.

Does the integrated inductor have a specified saturation current?

Yes - the internal inductor is rated for 6.5A peak saturation current (per datasheet Figure 5 and electrical characteristics table). This provides 1.6× headroom above the 4A continuous rating and supports transient peaks up to 5.5A without core saturation or regulation loss.

How does the RAMP pin improve transient response?

The RAMP pin injects a controlled slope signal into the COT comparator, counteracting variations in on-time caused by input/output voltage changes. Adding a 22pF ceramic capacitor between RAMP and OUT increases the effective ramp slope, reducing output voltage deviation during 0→4A load steps by up to 30% compared to no RAMP capacitor.

Is the PG pin compatible with 1.8V logic systems?

No - PG is an open-drain output with internal 500kΩ pull-up to VIN, so its high-state voltage equals VIN (up to 5.5V). To interface with 1.8V logic, add a resistive divider (e.g., 200kΩ + 100kΩ) or level-shifting buffer; direct connection risks damaging downstream 1.8V inputs.

What thermal derating applies above 85°C ambient?

With θJA = 46°C/W on a 4-layer PCB, the device delivers full 4A up to +85°C ambient. Above that, output current must be linearly reduced: at +100°C ambient, max continuous current is ~3.3A; at +125°C, it drops to ~2.1A. Thermal shutdown activates at 150°C junction temperature with 20°C hysteresis.

Can the MPM3840GQV-Z operate with ceramic input capacitors only?

Yes - the datasheet specifies 22μF X5R/X7R ceramic capacitors as sufficient for most applications. Use two 10μF 0805 capacitors placed adjacent to VIN and GND pins. Avoid high-DC-bias dielectrics (e.g., Y5V); ensure total capacitance remains ≥15μF after DC bias derating at 5.5V.