Monolithic Power Systems Inc. MPM3805GQB-25-P

Overview

MPM3805GQB-25-P from Monolithic Power Systems is a fixed-output 2.5V, 0.6A synchronous step-down DC-DC power module with integrated inductor and MOSFETs in a QFN-12 (2.5mm×3.0mm×0.9mm) package. It operates from 2.5V–6V input, delivers ±1.25% output accuracy at 10mA, features 17μA quiescent current, constant-on-time control for fast transient response, and includes power good (PG), enable (EN), and thermal shutdown protection. It serves as a compact, low-noise local regulator for FPGA I/O rails.

For engineers reviewing the MPM3805GQB-25-P datasheet, MPM3805GQB-25-P pinout, MPM3805GQB-25-P application, or MPM3805GQB-25-P equivalent, key selection criteria include fixed 2.5V output tolerance, 0.6A continuous load capability, QFN-12 thermal performance (θJA = 65°C/W), PG open-drain logic compatibility, and EN voltage thresholds (1.2V high / 0.4V low) for sequencing in space-constrained embedded systems.

Technical Context

The MPM3805GQB-25-P implements a constant-on-time (COT) control architecture with input-voltage feedforward to maintain switching frequency stability across input and output conditions-typical range 2.8–4.2MHz at VOUT=1.2V. Its internal 0.47μH inductor and matched 110mΩ/70mΩ P/N-channel MOSFETs enable full integration while supporting 100% duty-cycle operation in dropout.

Fault management includes cycle-by-cycle over-current limiting (1.0A min), hiccup-mode short-circuit recovery, thermal shutdown at 150°C with 30°C hysteresis, and ±10% power-good window referenced to internal 0.6V feedback threshold. The PG pin uses a 550kΩ internal pull-up to VIN and sinks ≥1mA at 0.4V low level.

Key Specifications

Pinout & Package

MPM3805GQB-25-P is housed in a thermally enhanced QFN-12 package (2.5mm × 3.0mm × 0.9mm) with exposed thermal pad (pins 3–4 connected internally to SW node and tied to copper pour for heat dissipation). The package supports reflow soldering per JEDEC J-STD-020 and achieves θJA = 65°C/W on a 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSM1052-2.5 and RT7297CHZSP, MPM3805GQB-25-P uniquely combines fixed 2.5V accuracy, integrated remote sensing (OUT_S), PG signaling, and 0.6A capability in the smallest footprint (7.5mm²), making it optimal for high-density, sequenced, and thermally constrained applications.

Availability

MPM3805GQB-25-P is available at Aetrix Electronics and suitable for FPGA I/O power, portable instrument subsystems, and SSD interface voltage regulation requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for MPM3805GQB-25-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 over two decades of leadership in DC-DC conversion, motor drivers, and LED lighting solutions.

The MPM3805 product line delivers fully integrated, surface-mount power modules targeting space- and efficiency-critical applications in portable electronics, industrial controls, and computing infrastructure-designed to replace discrete buck regulators with minimal external components.

FAQ

What is the recommended input capacitor for MPM3805GQB-25-P?

A 10μF X5R/X7R ceramic capacitor placed immediately adjacent to the VIN and PGND pins is recommended for most applications. For systems with higher output voltage or demanding transient response, a 22μF unit improves stability. The capacitor must support RMS current ≥0.3A and be rated for ≥6.5V DC working voltage per absolute maximum ratings.

Does MPM3805GQB-25-P require external feedback resistors?

No. The "-25" suffix denotes a fixed 2.5V output version; Pin 10 (FB) is internally connected and must remain unconnected. Only input and output capacitors are required-no external resistors needed for regulation, simplifying design and reducing component count.

How does the OUT_S pin improve regulation accuracy?

OUT_S provides remote voltage sensing at the load point, compensating for IR drop across PCB traces between the module's OUT pin and the actual load. This maintains ±1.25% output accuracy under full 0.6A load, critical for noise-sensitive analog or high-speed digital interfaces where local regulation errors exceed specification limits.

What thermal derating applies above 25°C ambient?

With θJA = 65°C/W on a 4-layer board, maximum continuous output current decreases linearly above 25°C: at 60°C ambient, derated current is 0.48A; at 85°C, it drops to 0.36A. Full 0.6A is guaranteed only up to 60°C case temperature-ensure adequate copper pour and airflow per MPS AN-042 layout guidelines.

Can MPM3805GQB-25-P operate with input voltage equal to output voltage?

Yes. Its 100% duty-cycle capability allows regulation down to VIN = VOUT = 2.5V, enabling operation during battery discharge to endpoint voltage. This avoids brownout resets in Li-ion systems where cell voltage falls from 4.2V to 2.5V, maintaining uninterrupted 2.5V rail integrity.

Is the PG pin compatible with 1.8V logic systems?

Yes. PG is an open-drain output with internal 550kΩ pull-up to VIN. When VIN ≥ 3.3V, PG logic-high exceeds 2.4V-safe for 1.8V I/O with appropriate level-shifting or direct connection if host GPIO tolerates 3.3V. For VIN = 2.5V, PG high is ~2.5V, requiring external pull-down or buffer for 1.8V-safe interfacing.

What is the soft-start duration and how is it controlled?

The built-in soft-start ramps output voltage over 1.5ms (typical) to prevent inrush current and output overshoot. Duration is fixed and not user-adjustable; it begins at EN assertion and ends when FB reaches regulation. No external capacitor is needed-soft-start timing is implemented entirely within the IC's internal circuitry.