Monolithic Power Systems Inc. MP2403DN-LF-Z

Overview

MP2403DN-LF-Z from Monolithic Power Systems is a monolithic synchronous step-down DC/DC converter integrating 150mΩ high-side and 80mΩ low-side MOSFETs, delivering 3A continuous output current across 4.6V–32V input range with fixed 250kHz switching frequency and 0.80V feedback reference. It regulates down to 0.80V output voltage and supports distributed power systems in industrial and computing applications.

For engineers reviewing the MP2403DN-LF-Z datasheet, MP2403DN-LF-Z pinout, MP2403DN-LF-Z application, or MP2403DN-LF-Z equivalent, key selection criteria include input UVLO threshold (3.95V), thermal shutdown (160°C), soft-start programmability via external capacitor, cycle-by-cycle overcurrent protection, and compatibility with low-ESR ceramic output capacitors.

Technical Context

The MP2403DN-LF-Z employs current-mode control architecture with internal transconductance error amplifier (820μA/V) and ramp-based PWM comparator for fast transient response and inherent cycle-by-cycle current limiting. Its 250kHz fixed-frequency oscillator enables predictable EMI filtering and stable loop compensation design.

It integrates dual N-channel MOSFETs with matched on-resistance (150mΩ HS / 80mΩ LS) and uses bootstrap gate drive (BS pin) powered by SW-to-BS capacitor to enable high-side switch operation above VIN. The device features 0.80V ±2.5% feedback reference, 1.3V EN rising threshold with 205mV hysteresis, and 1μA shutdown quiescent current.

Key Specifications

Pinout & Package

MP2403DN-LF-Z is housed in an 8-pin SOIC package with exposed thermal pad (SOIC8N), optimized for PCB heat dissipation. The exposed pad must be soldered to a dedicated ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with MP2451DT-LF-Z and TPS54302DDAR, MP2403DN-LF-Z delivers superior thermal performance via its exposed-pad SOIC8N package and higher current capability at lower switching frequency-making it optimal for industrial environments where reliability under sustained 3A load and elevated ambient temperatures is critical.

Availability

MP2403DN-LF-Z is available at Aetrix Electronics and suitable for distributed power systems, industrial control units, and notebook pre-regulator designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MP2403DN-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 power ICs, headquartered in California and serving global industrial, computing, and automotive markets.

The MP2403 belongs to MPS's integrated synchronous buck converter product line, designed specifically for compact, high-efficiency DC/DC conversion in space- and thermal-constrained applications where external MOSFETs and complex compensation are undesirable.

FAQ

What is the minimum recommended input voltage for reliable operation?

The MP2403DN-LF-Z has a guaranteed operating input range starting at 4.6V. Its input under-voltage lockout (UVLO) activates at 3.95V (rising), so sustained operation below 4.6V risks instability or dropout. For cold-crank scenarios where input may dip to 6V, the device remains functional-but operation below 4.6V is outside specified conditions and not characterized.

Can the MP2403DN-LF-Z be used with ceramic output capacitors only?

Yes-the MP2403DN-LF-Z is explicitly designed for stability with low-ESR ceramic capacitors (X5R/X7R). Its current-mode control and compensation architecture accommodate wide ESR ranges, and typical designs use 22–100μF MLCCs without additional bulk electrolytics. The datasheet confirms stable operation with 0.5–5mΩ ESR values.

How is the soft-start time calculated for a given SS capacitor value?

Soft-start time is linearly proportional to the SS-to-GND capacitor: t_SS ≈ C_SS × 150ms/μF. For example, a 0.1μF capacitor yields ~15ms soft-start. This relationship is derived from the internal 6μA soft-start current source charging the external capacitor to 0.8V, per the Electrical Characteristics table.

Is an external bootstrap diode required for proper operation?

No-an external bootstrap diode is optional and only recommended for high-duty-cycle applications (e.g., V_OUT ≥ 5V with V_IN ≤ 7.7V, where D > 65%). The internal charge pump suffices for most configurations; adding an IN4148 from V_OUT to BS improves efficiency by ~0.5–1% in those specific cases.

What is the maximum allowable output voltage, and how is it set?

The MP2403DN-LF-Z supports output voltages up to 28V, set by the FB resistive divider: V_OUT = 0.80V × (1 + R1/R2). With R2 = 10kΩ, R1 = 340kΩ yields 28V. The upper limit is constrained by internal OVP (trip at 0.95V on FB, i.e., 28V × 0.95/0.80 ≈ 33.25V at output), ensuring safe operation within absolute max ratings.

Does the device support synchronization to an external clock?

No-the MP2403DN-LF-Z uses a fixed internal 250kHz oscillator and does not provide SYNC or CLKIN functionality. Frequency variation is limited to ±12% over temperature and input voltage; for synchronized multi-phase or noise-sensitive applications, consider MPS's MPQ447x or TPS54xxx families with external sync capability.

How should the exposed thermal pad be connected on the PCB?

The exposed pad must be soldered to a dedicated internal or bottom-layer copper pour connected directly to the main GND net. Recommended solder stencil aperture is 2.80mm × 3.82mm (10.7mm²); thermal vias (≥4×0.3mm diameter) should connect the pad to inner ground planes to achieve θ_JA ≤ 50°C/W per JEDEC JESD51-7 4-layer board standard.