Monolithic Power Systems Inc. MP28248GD-Z

Overview

MP28248GD-Z from Monolithic Power Systems is a fully-integrated, synchronous step-down DC/DC converter delivering 3A continuous output current with constant-on-time (COT) control. It operates from 4.2V to 20V input, regulates output from 0.815V to 13V, and integrates low-R_DS(ON) MOSFETs (120mΩ HS / 50mΩ LS) in a thermally enhanced QFN12 (2mm×3mm) package. It enables compact, high-efficiency power delivery in space-constrained networking and distributed power systems.

For engineers reviewing the MP28248GD-Z datasheet, MP28248GD-Z pinout, MP28248GD-Z application, or MP28248GD-Z equivalent, key selection considerations include its fast transient response via COT architecture, programmable switching frequency (via external R7), integrated protection suite (OCP, SCP, OVP, UVP, thermal shutdown), and soft-start/stop functionality with 14µA/4.5µA charge/discharge currents.

Technical Context

The MP28248GD-Z employs constant-on-time control with input-voltage feedforward, enabling rapid load-step response without external compensation. Its on-time is dynamically adjusted per cycle based on V_IN and R7 value, yielding stable switching frequency across input voltage range (e.g., ~500kHz at V_IN=12V, R7=200kΩ).

It supports dual-mode operation: continuous conduction mode (CCM) under heavy load with fixed-frequency PWM, and skip mode under light load to maintain >90% efficiency at 10mA. Protection logic includes cycle-by-cycle over-current detection, hiccup-mode short-circuit response triggered when V_FB < 0.4075V, and non-latching thermal shutdown at 150°C with 25°C hysteresis.

Key Specifications

Pinout & Package

MP28248GD-Z is housed in a thermally optimized QFN12 package (2mm × 3mm, 0.5mm pitch) with an exposed thermal pad (Pin 11) for enhanced heat dissipation. The package supports reflow soldering per JEDEC J-STD-020 and achieves θ_JA = 70°C/W on a 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP28248GD-Z, MP28164GQ-Z trades programmability and headroom for lower cost and smaller solution size, while TPS54332DR offers higher input voltage margin and voltage-mode flexibility at the expense of layout complexity and transient performance.

Availability

MP28248GD-Z is available at Aetrix Electronics and suitable for networking equipment power rails, distributed power architectures, industrial motor drive controllers, and telecom line card bias supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP28248GD-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 MP28248 belongs to MPS's high-efficiency, fast-transient synchronous buck converter product line, designed specifically for compact, high-density point-of-load regulation in networking, telecom, and industrial systems where thermal performance and transient response are critical.

FAQ

What is the minimum recommended output capacitance for stable operation?

The MP28248GD-Z requires ≥22µF of low-ESR ceramic output capacitance for stable PWM operation with external ramp compensation. When using large-ESR electrolytic or POSCAP outputs, a parallel 10µF ceramic capacitor is mandatory to suppress ESL-induced ringing and ensure reliable short-circuit protection triggering.

How does the bootstrap capacitor value affect startup reliability?

A 0.1µF X7R ceramic capacitor between BST and SW pins ensures sufficient gate drive voltage (>5V) for the high-side MOSFET across the full input range. Values below 0.068µF risk insufficient bootstrap voltage at V_IN = 4.2V, causing erratic switching or failure to start under heavy load.

Can the MP28248GD-Z operate without an external soft-start capacitor?

No - the SS pin requires an external capacitor to control ramp rate. Omitting it causes uncontrolled inrush current, potentially tripping cycle-by-cycle over-current protection during startup. Minimum recommended value is 10nF for 580µs soft-start time; larger values prevent current-limit violations with high-output-capacitance loads.

What is the maximum allowable input voltage ripple amplitude?

Input ripple must remain below 10% of nominal V_IN (e.g., <1.2V_pp at 12V_IN) to prevent false triggering of the 3.1V UVLO hysteresis window. This requires ≥10µF X5R/X7R ceramic input capacitance placed within 2mm of the IN and GND pins with low-inductance layout.

Does the device support forced continuous conduction mode (FCCM)?

No - the MP28248GD-Z automatically transitions between CCM and skip mode based on load current. FCCM is not supported; however, selecting higher switching frequency (e.g., >600kHz) and lower inductance (e.g., 1.0µH) extends CCM operation to lighter loads, reducing output voltage ripple at the expense of light-load efficiency.

How is thermal performance affected by PCB copper area under the exposed pad?

Thermal resistance θ_JA improves from 70°C/W (2-layer board) to ≤45°C/W with ≥250mm² of 2oz copper connected to the exposed pad via ≥6 thermal vias (0.3mm diameter). Insufficient copper area causes junction temperature to exceed 125°C at 2.5A load, triggering thermal foldback before shutdown.

What happens during output short-circuit condition?

When V_FB drops below 0.4075V (50% of 815mV reference), the MP28248GD-Z immediately enters hiccup mode: it disables switching for 10ms, then attempts restart. This limits average short-circuit current to <150mA and junction temperature rise to <35°C, enabling safe recovery once fault is cleared.