Monolithic Power Systems Inc. MP38900DL-B-LF-P

Overview

MP38900DL-B-LF-P from Monolithic Power Systems is a high-efficiency, fast-transient, 10A synchronous step-down converter in a QFN20 (3×4 mm) package. It integrates 27 mΩ high-side and 10 mΩ low-side MOSFETs, operates from 4.5 V to 16 V input, delivers adjustable 0.8 V–13 V output, and uses Constant-On-Time (COT) control for rapid load-step response in notebook I/O and POL systems.

For engineers reviewing the MP38900DL-B-LF-P datasheet, MP38900DL-B-LF-P pinout, MP38900DL-B-LF-P application, or MP38900DL-B-LF-P equivalent, key selection considerations include its built-in 5 V VCC regulator, hiccup-mode overcurrent protection, high-Z shutdown behavior, and thermal shutdown with 25 °C hysteresis - all critical for reliable POL implementation in space-constrained embedded power rails.

Technical Context

The MP38900DL-B-LF-P employs a proprietary Constant-On-Time (COT) control architecture that eliminates external compensation and enables sub-100 ns minimum off-time (100 ns typ.) and 300 ns one-shot on-time at 1.05 V output. Its internal bootstrap circuit supports high-side gate drive with a dedicated BST pin and requires a 1 μF capacitor between SW and BST.

It integrates full protection: cycle-by-cycle OCP (16.5 A limit), hiccup-mode fault recovery (MP38900-B variant), OVP (1.25 × V_FB), UVP (0.7 × V_FB), and thermal shutdown (150 °C trip, 125 °C restart). The FB pin monitors output via resistor divider with 815 mV ±8 mV reference voltage and 10–50 nA bias current.

Key Specifications

Pinout & Package

MP38900DL-B-LF-P is housed in a thermally enhanced QFN20 package (3 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad (Pin 11–16 PGND) for efficient heat dissipation in high-current applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP38900DL-B-LF-P, MPQ38900-AF-P adds automotive qualification but retains identical electrical specs and pinout, while MP2315GJ-Z trades current capability, programmability, and monitoring features for size and cost reduction - making each suitable for distinct reliability, performance, or integration constraints.

Availability

MP38900DL-B-LF-P is available at Aetrix Electronics and suitable for notebook I/O power, optical transceiver bias, and distributed POL systems requiring stable component supply amid end-of-life transitions and long production lifecycles.

Supply support for MP38900DL-B-LF-P 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 expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MP38900 series belongs to MPS's high-current, high-efficiency synchronous buck converter product line, designed specifically for demanding point-of-load applications in computing, networking, and optical infrastructure where small size, fast transient response, and integrated protection are essential.

FAQ

What is the difference between MP38900 and MP38900-B variants?

The MP38900-B integrates an internal 5 V VCC regulator and uses hiccup-mode overcurrent protection with high-Z shutdown, whereas the MP38900 requires external VCC bias, latches off during OCP, and uses soft shutdown. These differences make MP38900-B better suited for pre-biased outputs and automatic fault recovery in unattended systems.

Can MP38900DL-B-LF-P operate with ceramic output capacitors?

Yes - it supports ceramic output capacitors but requires external ramp compensation (R4/C4 network) on the FB pin to maintain stability in PWM mode due to low ESR. The datasheet provides equations for selecting R4 and C4 values based on VIN, VOUT, and switching frequency to ensure adequate VFB ripple slope.

What is the minimum recommended soft-start capacitor value?

The minimum recommended soft-start capacitor is 4.7 nF when output capacitance exceeds 330 μF. This prevents excessive inrush current and ensures controlled voltage ramp-up. For smaller output caps, the value can be scaled using C_SS = (t_SS × 8.5 μA) / 0.815 V, where t_SS is desired ramp time in milliseconds.

How does the PGOOD delay differ between MP38900 and MP38900-B?

MP38900's PGOOD delay is 0.5 × t_SS + 0.5 ms, making it dependent on soft-start time, while MP38900-B fixes the delay at 1.5 ms regardless of SS capacitor value. This simplifies timing validation in systems requiring deterministic power-good assertion.

Is MP38900DL-B-LF-P RoHS compliant and lead-free?

Yes - the "-LF" suffix confirms RoHS-compliant, lead-free packaging per EU Directive 2011/65/EU. All solderable terminations meet JEDEC J-STD-020 moisture sensitivity level 3 requirements, and the device is compatible with standard Pb-free reflow profiles.

What thermal derating applies above 25°C ambient?

With θ_JA = 48 °C/W, maximum power dissipation decreases linearly: P_D(MAX) = (150°C − T_A) / 48. At 85°C ambient, max continuous power drops to ~1.35 W. Layout with 2+ oz copper, thermal vias under the exposed pad, and airflow improves real-world thermal performance beyond this calculation.

Does MP38900DL-B-LF-P support output prebias startup?

Yes - its high-Z shutdown mode allows the output to remain floating when disabled, enabling safe startup into a precharged rail without reverse current or output collapse. This is confirmed by the datasheet's explicit support for prebias applications and absence of body-diode conduction path during disable.