Monolithic Power Systems Inc. MP24943DS-LF

Overview

MP24943DS-LF from Monolithic Power Systems is a monolithic 3A, 55V, 100kHz step-down DC/DC converter with programmable output over-voltage protection (OVP), fixed-frequency current-mode control, and integrated 0.15Ω high-side MOSFET. It operates from 4.5V to 55V input, delivers adjustable output from 0.8V to 45V, and targets automotive GPS and entertainment power supplies where wide VIN and robust fault protection are critical.

For engineers reviewing the MP24943DS-LF datasheet, MP24943DS-LF pinout, MP24943DS-LF application, or MP24943DS-LF equivalent, this device requires attention to SOIC8E package thermal pad grounding, external OVP resistor divider design (VO pin reference = 0.9V), soft-start capacitor sizing, and bootstrap capacitor placement for reliable 100kHz switching across temperature.

Technical Context

The MP24943DS-LF implements peak-current-mode control with internal slope compensation and a fixed 100kHz oscillator. Its error amplifier compares FB voltage against a precise 0.80V reference, while the VO pin monitors output via an external resistor divider referenced to 0.9V for programmable OVP triggering.

It integrates a 0.15Ω R_DS(ON) high-side MOSFET, uses an external bootstrap capacitor between BST and SW for gate drive, and features cycle-by-cycle current limiting, thermal shutdown at 150°C, and UVLO with 3.3V threshold and 200mV hysteresis.

Key Specifications

Pinout & Package

MP24943DS-LF is housed in an SOIC8E package with exposed thermal pad on the underside, requiring solder connection to PCB ground plane for optimal thermal performance (θ_JA = 50°C/W). Pin 2 (GND) and the exposed pad must be connected to the same low-impedance ground node.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164QDDARQ1 and TPS54360DGQR, MP24943DS-LF uniquely combines 55V rating, 3A output, fixed 100kHz operation, and a dedicated programmable OVP input (VO pin), making it optimal for automotive subsystems requiring both ruggedness and configurable fault protection without external components.

Availability

MP24943DS-LF is available at Aetrix Electronics and suitable for automotive GPS modules, infotainment head-units, and telematics trackers requiring stable component supply across extended temperature and high-reliability environments.

Supply support for MP24943DS-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP24943 belongs to MPS's automotive-grade buck converter product line, engineered specifically for harsh-environment DC/DC conversion in vehicles-emphasizing wide input range, integrated protection, and AEC-Q100-aligned reliability.

FAQ

What is the purpose of the VO pin, and how is it configured?

The VO pin monitors output voltage via an external resistor divider and compares it to an internal 0.90V reference. When the divided voltage exceeds 0.90V, the high-side switch shuts off after a short delay, and the soft-start capacitor discharges. To set a 6V OVP threshold, use R5 = 301kΩ and R6 = 680kΩ, yielding VO = 6V × (R6/(R5+R6)) = 0.90V.

Can MP24943DS-LF operate with input voltages below 4.5V?

No. The absolute minimum operating input voltage is 4.5V, defined by its UVLO rising threshold of 3.3V with 200mV hysteresis. Below 4.5V, the device remains disabled. It is not rated for start-stop or ultra-low-battery scenarios below this level.

Is an external bootstrap diode required for reliable operation?

An external bootstrap diode (e.g., BAT54) is recommended-not required-for applications with high duty cycle (>65%), output voltage >12V, or fixed 5V input sources. It ensures full gate drive voltage on the high-side MOSFET when the internal bootstrap regulator cannot sustain sufficient charge.

How does the SOIC8E package differ electrically from SOIC8?

The SOIC8E adds an exposed thermal pad connected internally to Pin 2 (GND). This reduces θ_JA from 90°C/W (SOIC8) to 50°C/W, enabling 2.5W continuous power dissipation vs. 1.38W. Electrically identical otherwise, but thermal pad must be soldered to a large GND copper area for spec-compliant performance.

What is the minimum recommended output capacitor ESR for stability?

The MP24943DS-LF is designed for ceramic output capacitors and does not require a minimum ESR. In fact, low-ESR X5R/X7R MLCCs (e.g., 22μF–100μF) are explicitly recommended. High-ESR capacitors like aluminum electrolytics may cause instability or excessive ripple due to phase margin degradation.

Does MP24943DS-LF support synchronization to an external clock?

No. The MP24943DS-LF uses a fixed internal 100kHz oscillator and does not provide a SYNC pin or frequency adjustment capability. For synchronized operation in multi-rail systems, external clocking is not supported; alternative parts like MPQ4333-AEC1 would be required.

What is the maximum achievable output voltage accuracy over temperature?

Over -40°C to +85°C, the feedback reference voltage (V_FB) varies from 0.78V to 0.82V (±2.5%), and the OVP reference (V_OVREF) varies from 0.88V to 0.96V (±4.4%). Combined with resistor tolerance, total output voltage accuracy is typically ±3% over temperature and line/load conditions.