Monolithic Power Systems Inc. MPM3805GQB-12-P

Overview

MPM3805GQB-12-P from Monolithic Power Systems is a fixed-output 1.2V, 0.6A synchronous step-down DC-DC power module with integrated inductor and MOSFETs, operating from 2.5V–6V input. It delivers regulated low-voltage I/O power in space-constrained portable electronics, features constant-on-time (COT) control for fast transient response, and includes EN, PG, thermal shutdown, and hiccup-mode short-circuit protection.

For engineers reviewing the MPM3805GQB-12-P datasheet, MPM3805GQB-12-P pinout, MPM3805GQB-12-P application, or MPM3805GQB-12-P equivalent, key selection criteria include its QFN-12 package footprint, 17μA quiescent current, ±10% power-good window, 1.2V ±2.5% output tolerance at 10mA, and 100% duty-cycle dropout capability in low-input scenarios.

Technical Context

The MPM3805GQB-12-P implements a constant-on-time (COT) control architecture with input voltage feed-forward to maintain stable switching frequency (2.8–4.2 MHz) across input and output variations. Its internal 0.47μH inductor and matched 110mΩ/70mΩ P/N-channel MOSFETs enable full integration in a 2.5mm × 3.0mm × 0.9mm QFN-12 package.

It integrates analog ground (AGND), power ground (PGND), and output sense (OUT_S) separation for noise immunity; uses an open-drain PG pin with 550kΩ internal pull-up to VIN and ±10% regulation window; and employs cycle-by-cycle current limiting (1.0A min) with thermal shutdown at 150°C and 30°C hysteresis.

Key Specifications

Pinout & Package

MPM3805GQB-12-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).

Key Features

Applications

Availability

MPM3805GQB-12-P is available at Aetrix Electronics and suitable for portable instrumentation, SSD/HDD controller power, and FPGA I/O bank supply requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for MPM3805GQB-12-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, headquartered in Kirkland, WA, with global design and support operations.

The MPM3805 series is part of MPS's integrated power module product line, designed specifically to replace discrete buck converters in space- and time-constrained applications by embedding inductors and MOSFETs without sacrificing efficiency or thermal performance.

Equivalent & Alternatives

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

Compared with TPS82671 and LTM8003-1.2, the MPM3805GQB-12-P uniquely balances ultra-small footprint (2.5mm × 3.0mm), integrated PG/OUT_S functionality, and industry-leading 65°C/W thermal resistance - making it optimal for portable, thermally constrained, and system-sequenced designs.

FAQ

What is the recommended input capacitor for MPM3805GQB-12-P?

A 10μF X5R/X7R ceramic capacitor placed within 1mm of VIN and PGND pins is recommended for most applications. For higher output voltages or noisy environments, a 22μF unit improves stability. An additional 0.1μF ceramic capacitor in parallel ensures high-frequency decoupling, especially when using bulk tantalum or electrolytic input capacitors.

Can MPM3805GQB-12-P operate with input voltage below 2.5V?

No - the absolute minimum operating input voltage is 2.5V per datasheet specifications. Below this, UVLO disables the device. The under-voltage lockout rising threshold is 2.15–2.48V, but guaranteed operation starts only at 2.5V. Attempting operation below this risks unstable regulation or failure to start.

Is the PG pin actively driven high or pulled up?

The PG pin is an open-drain output with a 550kΩ internal pull-up resistor to VIN. It is actively pulled low by an internal MOSFET when FB voltage deviates beyond ±10% of 1.2V; otherwise, it floats high via the pull-up. External pull-up is unnecessary and may interfere with timing.

Does MPM3805GQB-12-P require external compensation components?

No - the constant-on-time control architecture and internal compensation eliminate the need for external RC networks. Only input/output capacitors and (for adjustable versions) FB resistors are required. This simplifies design validation and reduces layout sensitivity compared to voltage-mode buck controllers.

What is the maximum ambient temperature for continuous 0.6A operation?

At TA = +85°C with standard 4-layer JEDEC PCB (JESD51-7), the device sustains 0.6A continuously due to θJA = 65°C/W and TJ(MAX) = 125°C. Derating is required above 85°C ambient; full 0.6A load is not sustainable at TA ≥ 100°C without enhanced heatsinking or airflow.

How does the OUT_S pin improve regulation accuracy?

OUT_S provides Kelvin sensing of the output voltage at the load, compensating for IR drop across PCB traces between the module and load. When connected directly to the load-side of the output capacitor, it enables ±1% regulation accuracy under varying load currents - critical for precision analog or high-speed digital interfaces.

Is MPM3805GQB-12-P RoHS-compliant and lead-free?

Yes - all MPM3805 variants are lead-free and fully compliant with the EU RoHS directive. MPS confirms green status on its official website under Products > Quality Assurance, and the device meets JEDEC J-STD-020 moisture sensitivity level 3 (MSL3) for standard SMT assembly.