Monolithic Power Systems Inc. MPQ4473GL-Z

Overview

MPQ4473GL-Z from Monolithic Power Systems is a fully integrated, AEC-Q100 Grade 1 qualified, synchronous step-down DC/DC converter delivering 3.5A continuous output current from a 4.5V–36V input. It integrates 40mΩ high-side and 20mΩ low-side MOSFETs, supports 200kHz–1MHz programmable switching frequency, and features 1% reference voltage accuracy with fast transient response-used in automotive ADAS power rails and industrial POL systems.

For engineers reviewing the MPQ4473GL-Z datasheet, MPQ4473GL-Z pinout, MPQ4473GL-Z application, or MPQ4473GL-Z equivalent, key selection criteria include its AEC-Q100 qualification, internal MOSFET R_DS(on) values, PGOOD timing (700μs delay), thermal shutdown threshold (175°C), and soft-start current (8.5μA) for controlled inrush management.

Technical Context

The MPQ4473GL-Z employs a current-mode PWM control architecture with feed-forward input-voltage compensation to maintain stable switching frequency across 4.5V–36V input range. Its proprietary dead-time control prevents shoot-through between integrated high- and low-side MOSFETs, while cycle-by-cycle over-current protection triggers hiccup-mode shutdown upon sustained current limit violation.

It operates in CCM at heavy loads and automatically transitions to skip mode at light loads to sustain >90% efficiency down to 1mA output. The internal 5V LDO powers the control logic and bootstrap regulator, enabling low-dropout operation via active BST refresh when V_BST–V_SW falls below 2.3V.

Key Specifications

Pinout & Package

MPQ4473GL-Z is housed in a thermally enhanced 3mm × 4mm, 20-pin QFN package with exposed thermal pad (pins 8, 19, 21–23 = IN; pins 9, 10, 17, 18, 24, 25 = SW; pins 11–16 = PGND). The exposed pad must be soldered to a dedicated thermal plane for θ_JA = 48°C/W performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM61480RQR and TPS543620RJER, MPQ4473GL-Z offers tighter 1% reference accuracy and integrated BOOT capacitor support, making it optimal for space-constrained automotive applications where output precision and layout simplicity outweigh raw current headroom or ultra-high-frequency needs.

Availability

MPQ4473GL-Z is available at Aetrix Electronics and suitable for automotive ADAS modules, industrial PLC power supplies, and networking equipment requiring stable component supply with AEC-Q100 compliance, high-efficiency POL conversion, and compact 3mm×4mm QFN packaging.

Supply support for MPQ4473GL-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 mixed-signal ICs for power management, motion control, and automotive applications.

The MPQ4473 belongs to MPS's AEC-Q100 qualified DC/DC converter product line, engineered specifically for automotive infotainment, ADAS, and body electronics demanding high reliability, wide input range, and minimal external components.

FAQ

What is the minimum recommended output capacitance for stable operation with ceramic capacitors?

The MPQ4473GL-Z requires an external ramp compensation network (R4/C4) when using low-ESR ceramic output capacitors. Minimum recommended output capacitance is 22µF with X5R/X7R dielectric; however, stability depends more critically on meeting the ramp slope requirement (20–40V/ms) than absolute capacitance value.

Does MPQ4473GL-Z support forced continuous conduction mode (FCCM)?

No, MPQ4473GL-Z does not support FCCM. It operates in natural PWM mode at heavy loads and automatically enters skip mode at light loads to maximize efficiency. There is no pin or register to force CCM; the device relies on inherent current-modulator behavior for light-load optimization.

How is the bootstrap capacitor charged during 95% duty cycle operation?

During high-duty-cycle operation, the MPQ4473GL-Z activates its bootstrap refresh circuit: when V_BST–V_SW drops below 2.3V, the internal UVLO circuit turns on the low-side FET to pull SW low, enabling VIN-to-BST charging through the internal PMOS pass transistor - sustaining gate drive without external intervention.

What is the maximum allowable input voltage ripple before PGOOD assertion is delayed?

Input voltage ripple up to 100mV_pp at 100kHz has no effect on PGOOD timing. The 700μs delay is referenced solely to FB voltage crossing 90% of V_REF; however, excessive input ripple causing V_IN to dip below UVLO falling threshold (3.1V) will trigger shutdown and reset the PGOOD state.

Can MPQ4473GL-Z regulate output voltages below 0.8V?

No. The internal reference voltage is fixed at 0.815V, and the FB pin is designed for resistive divider configurations yielding V_OUT ≥ 0.8V. Attempting sub-0.8V regulation violates the specified operating range and results in inaccurate or unstable output due to comparator offset limitations.

Is the exposed thermal pad electrically connected to any internal node?

Yes, the exposed thermal pad is internally connected to PGND. It must be soldered to a dedicated PGND copper pour with ≥6 thermal vias (0.3mm diameter) to achieve specified θ_JA = 48°C/W and prevent thermal shutdown under full 3.5A load.

What happens during a short-circuit event at the output?

Upon output short, V_FB collapses below 50% V_REF (0.407V), triggering immediate hiccup-mode SCP: the device disables switching for ~10ms, then attempts restart. This cycle repeats until fault clears, limiting average power dissipation to safe levels and preventing thermal damage.