Monolithic Power Systems Inc. MP9841GL-P

Overview

MP9841GL-P from Monolithic Power Systems is a 36V, 1A synchronous step-down DC/DC converter with integrated 125mΩ high-side and 115mΩ low-side MOSFETs, 14μA no-load quiescent current, programmable 350kHz–2.5MHz switching frequency, and power-good (PG) output. It operates across 3.3V–36V input range and supports automotive and battery-powered systems requiring high efficiency at light load.

For engineers reviewing the MP9841GL-P datasheet, MP9841GL-P pinout, MP9841GL-P application, or MP9841GL-P equivalent, key selection criteria include its AEC-Q100 qualification, selectable forced CCM/AAM mode, 80ns minimum on-time, low-dropout operation, and QFN-16 (3mm×4mm) thermal performance with θJA = 48°C/W.

Technical Context

The MP9841GL-P uses peak-current-mode control with internal error amplifier and 0.8V feedback reference for precise output regulation. Its PLL-based oscillator enables synchronization to external clocks ≥250kHz above programmed frequency and supports in-phase or 180° out-of-phase operation via PHASE pin for multi-phase interleaving.

It integrates BST refresh logic for low-dropout operation up to ~100% duty cycle, hiccup-mode over-current protection, and thermal shutdown at 170°C with 20°C hysteresis. The BIAS pin allows external 5–18V supply to reduce VCC dissipation and improve efficiency under high VIN conditions.

Key Specifications

Pinout & Package

MP9841GL-P is housed in a thermally enhanced QFN-16 (3mm × 4mm, 0.5mm pitch) package with exposed thermal pad. Pin 1 is marked by dot; top marking includes "MP" prefix, year/week code, "9841", and lot number.

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, MP9841GL-P offers tighter light-load efficiency and integrated PHASE/SYNC flexibility for multi-phase designs; compared with LM61480RQR, it provides superior thermal performance in QFN-16 (48°C/W vs 55°C/W) and eliminates need for external bootstrap components.

Availability

MP9841GL-P is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC I/O modules, and battery-powered telematics requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for MP9841GL-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 MP9841 belongs to MPS's automotive-grade synchronous buck converter product line, engineered for high-reliability 12V/24V automotive and industrial power systems demanding ultra-low quiescent current, wide input range, and robust fault protection.

FAQ

What is the maximum allowable input voltage for MP9841GL-P?

The absolute maximum input voltage is 40V, but recommended operating range is 3.3V to 36V. Exceeding 36V risks violating safe operating area limits during transients unless external clamping is used. The device includes internal UVLO with 2.4–3.2V rising threshold and 150mV hysteresis to prevent erratic startup below minimum valid input.

How does the PHASE pin affect multi-converter operation?

The PHASE pin configures relative switching alignment between parallel MP9841GL-P units sharing the same SYNC clock: high forces in-phase operation, low forces 180° out-of-phase. This reduces total input current ripple amplitude by up to 50%, allowing smaller input bulk capacitors and lower EMI in multi-rail power systems like ADAS domain controllers.

Can MP9841GL-P operate without an external BIAS supply?

Yes - BIAS is optional. When unconnected or tied to GND, the internal VCC regulator powers all circuitry from VIN. However, connecting 5–18V to BIAS reduces power loss in the VCC LDO, improves full-load efficiency by ~1–2%, and lowers die temperature, especially at VIN > 15V. Floating BIAS is not recommended due to potential noise coupling.

What is the purpose of the BST refresh feature?

BST refresh actively monitors the BST-to-SW voltage and forces LS-FET conduction when it drops below 2.5V, recharging the bootstrap capacitor. This enables reliable high-side gate drive at duty cycles >95%, extending practical dropout performance and supporting applications like 24V→3.3V conversion where conventional buck regulators fail to regulate near minimum input.

How does AAM mode improve light-load efficiency?

In AAM mode, the MP9841GL-P enters discontinuous conduction mode (DCM) at light loads and transitions to power-save mode (PSM) at no load, reducing switching activity and drawing only 14μA. This avoids the fixed-frequency switching losses inherent in CCM, yielding >85% efficiency at 1mA load versus ~65% in forced CCM - critical for battery longevity in always-on devices.

Is MP9841GL-P pin-compatible with other MPS buck converters?

No - MP9841GL-P has a unique 16-pin QFN layout optimized for its PHASE/SYNC dual-function and BST architecture. While MPQ4420AGL-A-Z shares the same package outline and many pin functions, differences in SS, PG, and FREQ behavior require schematic and layout review. Direct substitution without validation is not recommended.

What thermal derating applies to the QFN-16 package?

With θJA = 48°C/W on a 4-layer JEDEC PCB, the MP9841GL-P delivers full 1A output up to +85°C ambient. Above that, output current must be linearly reduced: at +100°C ambient, max continuous current is ~0.7A; at +125°C, it drops to ~0.3A. Thermal pad soldering and copper pour area directly impact achievable current rating.