Monolithic Power Systems Inc. MP4460DQ-LF-Z

Overview

MP4460DQ-LF-Z from Monolithic Power Systems is a non-synchronous step-down DC/DC converter IC with integrated 150mΩ high-side MOSFET, delivering up to 2.5A output current across a 3.8V–36V input range and adjustable 0.8V–30V output. It operates at programmable switching frequencies up to 4MHz, features 120µA quiescent current, and includes internal soft-start, thermal shutdown, and frequency foldback for automotive and industrial power conversion.

For engineers reviewing the MP4460DQ-LF-Z datasheet, MP4460DQ-LF-Z pinout, MP4460DQ-LF-Z application, or MP4460DQ-LF-Z equivalent, key selection criteria include its 4MHz programmability for EMI-sensitive AM radio/ADSL systems, 3mm × 3mm QFN10 package footprint, current-mode control loop stability, and bootstrap capacitor charging constraints in high-duty-cycle operation.

Technical Context

The MP4460DQ-LF-Z implements peak-current-mode control with an internal error amplifier (200V/V gain, 60µA/V transconductance) and cycle-by-cycle current limiting set by COMP voltage. Its oscillator frequency is resistor-programmable via the FREQ pin (e.g., 45kΩ → 2MHz; 18kΩ → 4MHz), and minimum on/off times are fixed at 100ns each.

It uses a floating high-side gate driver powered by a bootstrap capacitor between BST and SW pins, regulated to ~5V; startup relies on internal 1µA EN pull-up, while UVLO thresholds are 2.7–3.3V (rising) with 0.35V hysteresis. Thermal shutdown activates at 150°C with 15°C hysteresis.

Key Specifications

Pinout & Package

MP4460DQ-LF-Z is housed in a thermally enhanced 3mm × 3mm QFN-10 package with exposed thermal pad on underside for PCB-level heat dissipation (θ_JA = 50°C/W, θ_JC = 12°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4460DQ-LF-Z, MPQ4460DQ-LF-Z adds automotive qualification at identical cost and footprint, while LM5164QPWPRQ1 trades off output current and frequency flexibility for higher input voltage tolerance and different thermal characteristics.

Availability

MP4460DQ-LF-Z is available at Aetrix Electronics and suitable for automotive infotainment power, industrial PLC I/O modules, and battery-powered telematics units requiring stable component supply across extended temperature and voltage ranges.

Supply support for MP4460DQ-LF-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 expertise in DC/DC conversion and motor control.

The MP4460 belongs to MPS's high-frequency buck converter product line, designed specifically for space-constrained, EMI-sensitive applications in automotive, industrial, and telecom infrastructure where small magnetics and wide input range are critical.

FAQ

What is the minimum recommended input voltage for reliable startup?

The MP4460DQ-LF-Z requires VIN ≥ 3.8V to exit UVLO and initiate regulation. Below this, the internal 2.6V regulator cannot sustain bias currents, preventing soft-start activation. Startup is guaranteed at 4.0V with 100mV margin, and the device remains operational down to 3.0V before UVLO hysteresis triggers shutdown.

Can the MP4460DQ-LF-Z operate without an external bootstrap diode?

Yes-the MP4460DQ-LF-Z integrates a bootstrap charging circuit that uses VIN to charge the BST capacitor through an internal PMOS switch when SW is low. An external diode is only required in high-duty-cycle (>85%) applications where internal charging time is insufficient; typical 3.3V/12V designs function reliably with just a 0.1µF ceramic BST capacitor.

How does frequency foldback improve light-load efficiency?

At light loads, the MP4460DQ-LF-Z reduces switching frequency proportionally to load current, decreasing gate-driving and switching losses. This maintains >85% efficiency at 1mA output-unlike fixed-frequency converters whose efficiency collapses below 10% load-making it ideal for battery-backed standby circuits.

What is the maximum allowable output voltage ripple with ceramic output capacitors?

With a 22µF X7R ceramic capacitor and 10µH inductor at 4MHz, output ripple is typically ≤15mV_pp for a 3.3V/1A output. Ripple scales linearly with inductor value and inversely with capacitance; the datasheet provides closed-form equations accounting for C_OUT, L, f_SW, and V_IN/V_OUT ratio.

Is the EN pin compatible with open-drain microcontroller GPIOs?

Yes-the EN pin has a 1µA internal pull-up and accepts logic-low signals down to 0.3V. An open-drain GPIO sinking ≥1µA (e.g., standard CMOS output) can fully disable the device. No external pull-down resistor is needed, simplifying interface design for MCU-controlled power sequencing.

Does the MP4460DQ-LF-Z support synchronous rectification?

No-it is a non-synchronous buck converter requiring an external Schottky diode (e.g., B340A-13-F) between SW and GND. Synchronous operation would require a second actively controlled FET and dedicated gate driver, which the MP4460 does not integrate. Efficiency gains from sync rectification are offset by added complexity and BOM cost in its target 2.5A applications.

What thermal derating applies above 25°C ambient?

With θ_JA = 50°C/W, the MP4460DQ-LF-Z delivers full 2.5A up to +85°C ambient on a 4-layer PCB with 2oz copper and thermal vias to inner ground planes. Above 85°C, output current must be linearly reduced to maintain T_J ≤ 125°C; at 100°C ambient, max continuous current is ~1.8A.