Monolithic Power Systems Inc. MPQ2490DS-LF-Z

Overview

MPQ2490DS-LF-Z from Monolithic Power Systems is an industrial-grade, current-mode synchronous step-down DC/DC converter with programmable output current limit. It delivers 1.5A continuous output over 4.5V–36V input, regulates output from 0.8V to 15V, operates at fixed 700kHz, and integrates a 0.25Ω internal MOSFET-used in automotive cigarette lighter adapters and industrial power supplies.

For engineers reviewing the MPQ2490DS-LF-Z datasheet, MPQ2490DS-LF-Z pinout, MPQ2490DS-LF-Z application, or MPQ2490DS-LF-Z equivalent, key selection criteria include programmable current limit via ISP/ISN sensing, thermal shutdown behavior, cycle-by-cycle overcurrent protection, and QFN10 (3×3mm) layout constraints for high-current switching nodes.

Technical Context

The MPQ2490DS-LF-Z implements a peak-current-mode control architecture with integrated error amplifier, slope compensation, and PWM comparator driving a single high-side N-channel MOSFET. Its feedback loop references a precision 0.805V bandgap (±1.25% over temperature), while the current-limit loop activates when V_ISP–V_ISN reaches 100mV, pulling down the SS pin to fold back output voltage.

It features a dedicated bootstrap circuit (BST–SW) enabling high-side gate drive, open-drain PGOOD monitoring referenced to 90% of FB voltage, and EN-controlled startup with 3.3V UVLO threshold and 200mV hysteresis-enabling robust operation in noisy industrial 12V/24V bus environments.

Key Specifications

Pinout & Package

MPQ2490DS-LF-Z is housed in a thermally enhanced QFN10 package (3mm × 3mm, 0.75mm height) with exposed thermal pad on underside-must be soldered to PCB ground plane for thermal performance and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ2490DS-LF-Z, MP2451DT-LF-Z trades current-programmability for higher switching frequency and fixed 2A capability, while LM5164QPWPRQ1 adds automotive qualification and wider input range but removes integrated current-limit sensing-making MPQ2490 the optimal choice for industrial and consumer applications requiring flexible, lossless current limiting in compact 36V systems.

Availability

MPQ2490DS-LF-Z is available at Aetrix Electronics and suitable for industrial power supplies, automotive cigarette lighter adapters, and USB power supplies requiring stable component supply, RoHS-compliant packaging, and extended temperature operation (–40°C to +85°C).

Supply support for MPQ2490DS-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 interface applications.

The MPQ2490 belongs to MPS's industrial-grade DC/DC converter product line, designed specifically for ruggedized power conversion in harsh environments-including factory automation, transportation, and outdoor equipment-where wide input range, programmable protection, and thermal resilience are mandatory.

FAQ

What is the function of the SS pin on MPQ2490DS-LF-Z?

The SS (soft-start) pin controls both startup ramp rate and current-limit loop compensation. An external capacitor (typically 100nF) connected from SS to GND sets the soft-start time and dominates the bandwidth of the current-regulation loop, ensuring stable transition into constant-current mode during overload events without oscillation.

Can MPQ2490DS-LF-Z operate with inductor DCR current sensing?

Yes-MPQ2490DS-LF-Z supports Kelvin-connected inductor DCR sensing via ISP and ISN pins. The device uses the voltage drop across the winding's DC resistance to trigger current limiting at 100mV, eliminating external sense resistors and associated power loss, provided DCR matching and layout symmetry meet datasheet layout guidelines.

What is the minimum recommended input capacitance for MPQ2490DS-LF-Z?

The minimum recommended input capacitance is 4.7μF ceramic (X5R or X7R dielectric), placed as close as possible to VIN and GND pins. This value suppresses high-frequency switching noise and limits input voltage spikes during transient load steps; larger values (e.g., 10μF) improve hold-up during brief input dips.

Does MPQ2490DS-LF-Z require an external bootstrap diode?

No-MPQ2490DS-LF-Z includes an on-chip bootstrap regulator that charges the BST capacitor from VIN. An external diode is optional and only needed if the internal regulator cannot maintain sufficient gate drive under heavy load or low-VIN conditions (e.g., VIN < 6V); typical designs use only a 0.1μF ceramic capacitor between BST and SW.

How does PGOOD behave during undervoltage or overcurrent conditions?

PGOOD goes low when FB falls below 90% of the 0.805V reference (i.e., <0.72V), indicating loss of regulation due to input undervoltage, overload, or short circuit. It remains low until FB recovers above threshold; its open-drain structure requires an external pull-up resistor to the system rail it monitors.

What thermal design considerations apply to the QFN10 package?

The exposed thermal pad must be soldered to a minimum 100mm² copper pour tied to internal/external GND planes via ≥4 thermal vias (0.3mm diameter). Without this, θ_JA rises from 50°C/W to >80°C/W, causing premature thermal shutdown at ≤1A load-especially critical in enclosed industrial enclosures with limited airflow.