Monolithic Power Systems Inc. MP9447GL-P

Overview

MP9447GL-P from Monolithic Power Systems is a fully-integrated, synchronous step-down DC/DC converter delivering 5A continuous output current across a 4.5V–36V input range. It integrates 65mΩ high-side and 30mΩ low-side MOSFETs, supports 200kHz–650kHz programmable switching frequency, and features fast transient response with 1.5% reference voltage accuracy-used in USB power supplies and cigarette lighter adapters.

For engineers reviewing the MP9447GL-P datasheet, MP9447GL-P pinout, MP9447GL-P application, or MP9447GL-P equivalent, key selection criteria include input voltage range compatibility, thermal shutdown threshold (165°C), soft-start programmability, integrated MOSFET R_DS(on), and QFN-25 (3mm×4mm) package layout requirements.

Technical Context

The MP9447GL-P operates in continuous-conduction mode (CCM) at heavy loads with fixed-frequency PWM control, where ON-time is determined by input voltage and external FREQ resistor. Its proprietary switching-loss-reduction technology minimizes conduction and gate-drive losses across the full load range.

At light loads, it enters skip mode to maintain high efficiency, with LS-FET driver entering tri-state and current modulation limiting inductor current to <−1mA. Internal bootstrap charging enables low-dropout operation, and UVLO (4.0V rising threshold) ensures reliable startup under varying input conditions.

Key Specifications

Pinout & Package

MP9447GL-P uses a thermally enhanced 25-pin QFN package (3mm × 4mm) with an exposed thermal pad on the underside. The package supports high-current routing via dedicated IN, SW, and PGND pins distributed across multiple locations for optimal thermal and EMI performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP9447GL-P, MP2451DT-LF-Z trades current capability and flexibility for footprint reduction, while TPS54560BQPWPRQ1 adds automotive qualification and higher input voltage at the cost of increased BOM complexity and layout effort.

Availability

MP9447GL-P is available at Aetrix Electronics and suitable for USB power supplies, cigarette lighter adapters, and industrial IoT sensor hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP9447GL-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 core expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MP9447 belongs to MPS's high-efficiency, wide-input synchronous buck converter product line, designed specifically for demanding consumer, automotive, and industrial applications requiring compact size, fast transient response, and robust protection.

FAQ

What is the recommended input capacitor configuration for MP9447GL-P?

Use ≥10μF X5R/X7R ceramic capacitors placed directly at the IN pins, with RMS current rating exceeding half the maximum load current (≥2.5A). Place capacitors within 3mm of IN/PGND pins using wide traces and ≥4 thermal vias to the ground plane to minimize high-frequency loop inductance and input ripple.

Does MP9447GL-P require an external ramp compensation network?

Yes, when using low-ESR ceramic output capacitors - a resistor (R4) and capacitor (C4) network must be added to the FB pin to stabilize the control loop. For POSCAP or electrolytic capacitors with ≥12mΩ ESR, external ramp is not required per datasheet Section 10.2.

How is the soft-start time calculated for MP9447GL-P?

Soft-start time (in ms) = (C_SS in nF × 0.815V) / 8.5μA. For example, a 47nF capacitor yields ~4.5ms ramp time. Minimum C_SS is 4.7nF if output capacitance exceeds 330μF to avoid current-limit triggering during startup.

What is the function of the NC pin (Pin 6) on MP9447GL-P?

Pin 6 is a no-connect terminal and must remain unconnected and floating. Connecting it to any potential - including GND or VCC - may cause unpredictable behavior or damage due to internal test structure coupling. Do not route traces or place solder mask openings near this pin.

Can MP9447GL-P operate with 100% duty cycle?

No - MP9447GL-P cannot achieve true 100% duty cycle due to bootstrap capacitor charging requirement. However, its bootstrap refresh circuit enables operation up to ~95% duty cycle (V_OUT ≈ 0.9×V_IN) by periodically discharging the LS-FET to recharge BST during low-load or light-load conditions.

What is the thermal resistance (θ_JA) of MP9447GL-P in standard layout?

The typical junction-to-ambient thermal resistance is 48°C/W when mounted on a 4-layer JEDEC-standard PCB (JESD51-7) with 2oz copper, 1in² exposed thermal pad connected to internal ground planes via ≥9 vias. Actual θ_JA varies with PCB stackup and copper area.

How does the MP9447GL-P respond to a short-circuit condition?

Upon detecting V_FB < 0.4075V (50% of 815mV reference), MP9447GL-P triggers hiccup-mode short-circuit protection: it disables switching for ~10ms, then attempts restart. This cycle repeats until fault clears, limiting average power dissipation and preventing thermal runaway.