Monolithic Power Systems Inc. MP1484EN-LF-Z

Overview

MP1484EN-LF-Z from Monolithic Power Systems is a monolithic synchronous buck regulator integrating 85mΩ high-side and low-side N-channel MOSFETs, delivering 3A continuous output current across a 4.75V–18V input range with fixed 340kHz switching frequency and adjustable 0.925V–20V output voltage. It employs current-mode control for fast transient response and cycle-by-cycle overcurrent protection, used in FPGA/ASIC core power supplies where compact, efficient DC-DC conversion is required.

For engineers reviewing the MP1484EN-LF-Z datasheet, MP1484EN-LF-Z pinout, MP1484EN-LF-Z application, or MP1484EN-LF-Z equivalent, this page provides verified technical context, validated pin functions, confirmed efficiency and thermal performance data, real-world application constraints (e.g., bootstrap capacitor requirement, soft-start timing), and two functionally comparable alternatives with documented parameter-level differences.

Technical Context

The MP1484EN-LF-Z implements current-mode control with an internal transconductance error amplifier (GEA = 820 µA/V) and COMP-pin-based loop compensation. Its 340kHz oscillator sets switching frequency, with short-circuit protection reducing frequency to 110kHz when FB = 0V.

It integrates dual 85mΩ MOSFETs and requires an external bootstrap capacitor (≥0.01µF) between SW and BS to drive the high-side gate above VIN. Input under-voltage lockout triggers at 4.05V (±210mV hysteresis), and EN shutdown occurs at 1.5V (±220mV hysteresis).

Key Specifications

Pinout & Package

MP1484EN-LF-Z uses an 8-pin SOIC package with exposed thermal pad (SOIC8N), rated for –20°C to +85°C ambient operation. The exposed pad must be soldered to a PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP1482DN-LF-Z, MP1484EN-LF-Z delivers 50% higher current in identical SOIC8 packaging; versus TPS54331DR, it offers integrated FETs and lower quiescent current but sacrifices input voltage headroom and frequency flexibility.

Availability

MP1484EN-LF-Z is available at Aetrix Electronics and suitable for FPGA power supplies, LCD TV main boards, green appliance control modules, and notebook SSD power delivery requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for MP1484EN-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 mixed-signal ICs for power management, motion control, and automotive applications.

The MP1484 belongs to MPS's mainstream synchronous buck converter product line, designed for cost-sensitive, space-constrained industrial and consumer power systems requiring integrated high-current regulation without external MOSFETs.

FAQ

What is the minimum recommended output capacitance for stable operation?

The datasheet specifies a minimum 20µF ceramic output capacitor for typical applications. This value ensures sufficient charge storage to maintain regulation during load transients and keeps output voltage ripple below 1% of VOUT at 3A load. Lower values may cause instability or excessive ripple, especially with high ESR capacitors.

Can MP1484EN-LF-Z operate with an input voltage below 4.75V?

No. The absolute minimum operating input voltage is 4.75V, enforced by an under-voltage lockout (UVLO) that disables switching below 4.05V (±210mV hysteresis). Attempting operation below this threshold results in no regulation and potential erratic behavior due to insufficient gate drive for internal MOSFETs.

Is an external Schottky diode required for proper operation?

No - the MP1484EN-LF-Z uses synchronous rectification and does not require an external diode. However, adding a Schottky diode (e.g., B130) from SW to GND can improve efficiency by ~1–2% under light loads by bypassing the low-side MOSFET's body diode conduction loss.

How is the soft-start time calculated from the SS capacitor value?

The soft-start period is determined by t_SS = C_SS × 6µA / 0.925V. With a 0.1µF capacitor, t_SS = 0.1µF × 6µA / 0.925V ≈ 15ms. This linear ramp controls COMP voltage rise, directly limiting output voltage slew rate and inrush current magnitude.

What thermal considerations apply to the exposed pad on the SOIC8N package?

The exposed pad must be soldered to a dedicated PCB copper area connected to GND. Thermal resistance θ_JA is 50°C/W with a 1"² 1oz copper pad; inadequate pad area or poor soldering increases junction temperature, potentially triggering thermal shutdown at sustained 3A loads above 60°C ambient.

Does MP1484EN-LF-Z support output voltages above 12V?

Yes - the device regulates outputs from 0.925V to 20V. For VOUT > 12V, ensure the input voltage remains within 4.75V–18V and verify that the feedback divider resistors (e.g., R1 = 121kΩ, R2 = 10kΩ for 12V) meet voltage rating and stability requirements per the datasheet's Table 1.

What happens if the BS capacitor is omitted or undersized?

Omission or undersizing (<0.01µF) of the BS-to-SW capacitor prevents proper high-side gate drive, causing the converter to fail to start or drop out under load. The high-side MOSFET cannot turn on fully, resulting in excessive conduction loss, thermal runaway, and possible device damage.