Monolithic Power Systems Inc. MP9473GL-P

Overview

MP9473GL-P from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC converter delivering 3.5A continuous output current across a 4.5V–36V input range. It integrates 40mΩ high-side and 20mΩ low-side MOSFETs, supports adjustable output from 0.8V to 0.9×VIN, and features proprietary switching-loss-reduction technology for high efficiency (up to 95% at 3A, VIN=12V, VOUT=3.3V). It is deployed in notebook I/O power rails where fast transient response and compact 3mm×4mm QFN-20 packaging are critical.

For engineers reviewing the MP9473GL-P datasheet, MP9473GL-P pinout, MP9473GL-P application, or MP9473GL-P equivalent, key selection considerations include its programmable soft-start time (via external capacitor), 1% reference voltage accuracy, 200kHz–1MHz adjustable switching frequency, integrated thermal shutdown (175°C), and robust protection suite (SCP, OCP, UVP, PGOOD).

Technical Context

The MP9473GL-P operates in forced PWM mode at heavy loads and automatically transitions to skip-mode at light loads to maintain high efficiency across the full 0–3.5A output range. Its feed-forward-controlled on-time architecture ensures stable switching frequency over wide input-voltage variations, with frequency set via an external resistor (RFREQ) connected between FREQ and AGND.

It employs internal dead-time control to prevent shoot-through between high-side and low-side MOSFETs, and uses a bootstrap capacitor (0.1μF–1μF) between BST and SW to sustain gate drive for the high-side switch. The device enters low-dropout mode when VIN approaches VOUT, enabled by UVLO hysteresis (900mV) and bootstrap-refresh circuitry that sustains operation down to ~1.2V dropout.

Key Specifications

Pinout & Package

MP9473GL-P is housed in a thermally enhanced 3mm × 4mm, 20-pin QFN package with exposed thermal pads (pins 8,19,21,22,23 for IN; pins 9,10,17,18,24,25 for SW; pins 11–16 for PGND). The package supports high-current PCB routing via multiple vias to internal ground and power planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4473GQ-A, MP9473GL-P trades automotive qualification for lower unit cost and identical electrical performance in commercial environments; versus TPS54332DR, it integrates both MOSFETs and occupies 60% less PCB area while delivering 0.5A higher current capability.

Availability

MP9473GL-P is available at Aetrix Electronics and suitable for notebook systems, automotive infotainment units, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP9473GL-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 mixed-signal ICs for power management, motor drive, and automotive applications.

The MP9473 belongs to MPS's high-efficiency synchronous buck converter product line, designed specifically for compact, high-transient-response point-of-load regulation in space-constrained computing and communications equipment.

FAQ

What is the minimum recommended input capacitance for MP9473GL-P?

The minimum recommended input capacitance is 22μF ceramic (X5R/X7R), placed directly at the IN pins with low-ESR construction. For 3.5A output, a 47μF–100μF total (including bulk and high-frequency caps) is advised to limit input ripple to <100mV peak-to-peak under worst-case 2×VOUT condition.

Can MP9473GL-P operate with 100% duty cycle?

No - MP9473GL-P cannot achieve true 100% duty cycle due to bootstrap capacitor charging requirements. Minimum off-time is 100ns, and practical maximum duty cycle is ~95% at low VIN–VOUT differentials. For true 100% operation, a buck-boost or LDO solution is required.

How is the soft-start time calculated for a given CSS value?

Soft-start time (tSS) in milliseconds equals (CSS in nF × 0.815V) ÷ 8.5μA. For example, a 100nF capacitor yields tSS ≈ 9.6ms. If output capacitance exceeds 330μF, use ≥4.7nF to avoid current-limit tripping during ramp-up.

Does MP9473GL-P require external ramp compensation with ceramic output capacitors?

Yes - when using low-ESR ceramic output capacitors, external ramp compensation (R4/C4 network injected into FB) is required to ensure stability in PWM mode. Without it, VFB slope is insufficient for noise immunity, risking jitter and oscillation at light loads.

What is the thermal resistance (θJA) of the MP9473GL-P QFN package?

The junction-to-ambient thermal resistance (θJA) is 48°C/W, measured on a standard 4-layer JEDEC PCB per JESD51-7. With proper thermal pad soldering and 4+ thermal vias to inner ground planes, actual θJA in optimized layouts can reach ≤35°C/W.

How does the PGOOD pin behave during undervoltage lockout?

During UVLO (VIN < 3.1V falling), PGOOD is actively pulled LOW regardless of FB voltage. Once VIN rises above 4.0V, the device powers up, and PGOOD remains LOW until FB reaches 90% of 0.815V (≈0.734V) with 700μs delay - ensuring clean system reset sequencing.

Is the MP9473GL-P RoHS and halogen-free compliant?

Yes - MP9473GL-P is lead-free, halogen-free, and fully compliant with the EU RoHS Directive 2011/65/EU. Full compliance documentation, including material declarations and test reports, is available on the Monolithic Power Systems website under Quality Assurance.