Monolithic Power Systems Inc. MP9473GL-Z

Overview

MP9473GL-Z 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 fast transient response with proprietary switching-loss-reduction technology for notebook I/O power and automotive subsystems.

For engineers reviewing the MP9473GL-Z datasheet, MP9473GL-Z pinout, MP9473GL-Z application, or MP9473GL-Z equivalent, key selection considerations include its 200kHz–1MHz programmable switching frequency, 1% reference voltage accuracy, thermal shutdown at 175°C, and integrated protection including SCP, OCP, UVP, and PGOOD with 700μs delay.

Technical Context

The MP9473GL-Z operates in continuous-conduction mode (CCM) under heavy load with fixed-frequency PWM control, where ON-time is determined by VIN and an external R_FREQ resistor. Its feed-forward architecture maintains stable switching frequency across input voltage variations while preserving V_OUT/V_IN duty ratio.

In light-load conditions, it enters skip mode-disabling HS-FET switching cycles when inductor current reaches zero-to sustain high efficiency. Internal dead-time control prevents shoot-through, and bootstrap charging enables low-dropout operation down to ~2.3V BST–SW differential.

Key Specifications

Pinout & Package

MP9473GL-Z is housed in a thermally enhanced 3mm × 4mm, 20-pin QFN package with exposed thermal pads (pins 8,19,21,22,23 = IN; pins 9,10,17,18,24,25 = SW; pins 11–16 = PGND). The exposed pads must be soldered to a large copper pour for optimal thermal performance and EMI reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP9473GL-Z, MP2451DT-LF-Z trades integration and protection for cost and footprint, while TPS54331DR offers greater loop tuning flexibility at the expense of higher component count and thermal resistance in SOIC-8 packaging.

Availability

MP9473GL-Z is available at Aetrix Electronics and suitable for automotive infotainment systems, notebook I/O power, industrial PLC modules, and optical transceiver bias supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MP9473GL-Z 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 MP9473 belongs to MPS's high-efficiency, fast-transient buck converter product line, designed specifically for demanding applications in automotive, computing, and industrial systems where input voltage range, thermal robustness, and protection integration are critical.

FAQ

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

The datasheet specifies that the input capacitor RMS current rating should exceed half the maximum load current (≥1.75A RMS for 3.5A output). For 24V_IN/3.3V_OUT, a 22μF X7R ceramic capacitor with 10V rating and low ESR is recommended, placed directly at the IN and PGND pins using multiple vias to minimize loop inductance.

Can MP9473GL-Z operate with ceramic output capacitors without external ramp compensation?

Yes, but only if the output capacitor ESR is sufficient to generate adequate V_FB ripple slope (15–30V/ms). With low-ESR ceramics, external ramp compensation (R₄/C₄) is required to stabilize the control loop in PWM mode; omission risks subharmonic oscillation and poor transient response.

How does the MP9473GL-Z handle short-circuit conditions?

It implements hiccup-mode short-circuit protection: cycle-by-cycle current limiting triggers after 100μs of consecutive overcurrent events. During a hard short, V_FB drops below 50% of reference (0.4075V), causing immediate hiccup entry-switching pauses for ~10ms before retrying-limiting average power dissipation and junction temperature rise.

Is the EN pin compatible with 1.8V logic microcontrollers?

No-the EN pin has a rising threshold of 1.0–1.4V (typ. 1.2V) and falling threshold of 0.7–0.99V (typ. 0.85V), making it incompatible with strict 1.8V GPIO. A level-shifter or pull-up to ≥2.5V is required for reliable enable/disable control from 1.8V systems.

What is the thermal resistance θ_JA for the MP9473GL-Z in standard JEDEC 4-layer PCB layout?

The datasheet specifies θ_JA = 48°C/W under JESD51-7 4-layer PCB conditions. Achieving this requires full connection of the exposed thermal pad to ≥200mm² internal or bottom-side copper pour with ≥6 thermal vias (0.3mm diameter, 0.5mm pitch), otherwise θ_JA degrades significantly.

Does MP9473GL-Z support forced PWM mode to eliminate audible noise?

No-it lacks a forced PWM pin or register setting. It automatically transitions between CCM (PWM) and skip mode based on load. To suppress sub-audible switching noise, select f_SW >25kHz (e.g., 300kHz minimum) and use ceramic output capacitors with low mechanical resonance.

How is output voltage accuracy affected by temperature and line regulation?

Over –40°C to +125°C, feedback voltage drift is ±5mV (±0.6%), and line regulation is ±0.05% across 4.5V–36V input. Combined with resistor divider tolerance, total output accuracy remains within ±1.5% over full operating range without trimming.