Monolithic Power Systems Inc. MP2493DN-LF

Overview

MP2493DN-LF from Monolithic Power Systems is a monolithic 2A, 36V step-down DC/DC converter with programmable output current limit via ISP/ISN sensing, fixed 130kHz switching frequency, 0.25Ω internal MOSFET, and stable operation with low-ESR ceramic output capacitors. It delivers regulated 0.8V–15V output in automotive cigarette lighter adapters and USB power supplies.

For engineers reviewing the MP2493DN-LF datasheet, MP2493DN-LF pinout, MP2493DN-LF application, or MP2493DN-LF equivalent, key selection criteria include its DCR- or resistor-based current limit programming, thermal shutdown behavior at 150°C, cycle-by-cycle overcurrent protection, and SOIC8E package with exposed thermal pad tied to GND.

Technical Context

The MP2493DN-LF implements a current-mode buck architecture with integrated high-side MOSFET and internal slope compensation. Its error amplifier regulates output voltage by comparing FB voltage against a 0.8V bandgap reference, while a separate current-limit comparator monitors VISP–VISN differential voltage (100mV threshold) to enforce programmable constant-current regulation.

It features a dedicated bootstrap driver (BST–SW) for gate drive, fixed-frequency PWM control at 130kHz (±30kHz), and dual protection: cycle-by-cycle current limiting triggered at 2.5–3.5A peak switch current and thermal shutdown at 150°C junction temperature. The SS pin serves as both soft-start timing node and current-limit loop compensation point.

Key Specifications

Pinout & Package

MP2493DN-LF uses an 8-pin SOIC8E package with exposed thermal pad on underside, requiring direct connection to PCB ground plane for thermal performance (θJC = 10°C/W). The exposed pad improves power dissipation capability versus standard SOIC8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2493DN-LF, MP2451DJ-LF-Z offers lower integration and reduced current capability, while LM5164QDDARQ1 trades away native current-limit functionality for extreme input voltage range-neither provides the same combination of 2A capacity, 36V rating, and integrated ISP/ISN current regulation.

Availability

MP2493DN-LF is available at Aetrix Electronics and suitable for USB power supplies, automotive cigarette lighter adapters, and industrial 24V-to-5V conversion requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP2493DN-LF 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 focus on efficiency, integration, and thermal robustness.

The MP2493 belongs to MPS's high-voltage buck converter product line, designed specifically for automotive, industrial, and USB power applications demanding wide input range, programmable current limiting, and low-EMI operation.

FAQ

What is the function of the SS pin on MP2493DN-LF?

The SS (Soft-Start) pin controls startup ramp rate and serves as the compensation node for the current-limit loop. An external capacitor (typically 100nF) sets soft-start time and limits bandwidth of the current regulation loop to ~1kHz, preventing overshoot during current-limit activation.

Can MP2493DN-LF operate with input voltage below 4.5V?

No. The absolute minimum operating input voltage is 4.5V per datasheet specifications. Below this, UVLO prevents startup and the device remains in shutdown. The UVLO rising threshold is 3.3V ±0.3V, but functional operation requires ≥4.5V to ensure proper gate drive and regulation.

How is output current limit programmed using inductor DCR?

By connecting ISN and ISP across the inductor's DCR, the device senses V_SENSE = I_OUT × DCR. When V_SENSE reaches 100mV, the current-limit loop activates. For example, a 50mΩ DCR sets I_LIM = 100mV / 50mΩ = 2A. Matching trace impedance on ISN/ISP paths is critical for accuracy.

Why does MP2493DN-LF use an exposed pad in SOIC8E?

The exposed thermal pad on the SOIC8E package provides a low-thermal-resistance path (θJC = 10°C/W) from die to PCB ground plane. This allows higher continuous power dissipation (2.5W at +25°C) than standard SOIC8 (1.4W), essential for 2A operation in compact layouts without forced air cooling.

Does MP2493DN-LF support synchronous rectification?

No. MP2493DN-LF uses an internal N-channel MOSFET for the high-side switch and requires an external Schottky diode (D1) for low-side conduction during the off-time. It is not a synchronous buck controller and lacks a second gate driver output for a low-side FET.

What is the maximum duty cycle limitation at high input voltages?

At VIN > 16.5V, the maximum output voltage is limited to 15V, imposing a practical duty cycle ceiling of ~91% (15V/16.5V). The minimum on-time specification (100ns) further restricts achievable duty cycle at high frequencies and low VOUT, but 130kHz operation maintains margin across the full input range.

Is the FB pin internally compensated?

No. The MP2493DN-LF uses external compensation via the resistor divider network. The FB node connects directly to the error amplifier input; stability depends on external R1/R2 values and optional compensation capacitor across R2, as detailed in the application section for optimal transient response.