Monolithic Power Systems Inc. MP2309DS-LF-P

Overview

MP2309DS-LF-P from Monolithic Power Systems is a monolithic synchronous buck regulator integrating 140mΩ high- and low-side N-channel MOSFETs, delivering 1A continuous output current across a 4.75V–23V input range. It features fixed 340kHz switching frequency, adjustable 0.923V–20V output via resistive feedback, cycle-by-cycle overcurrent protection, and 1μA shutdown quiescent current. Used in FPGA/DSP power supplies where compact size and ceramic-capacitor stability are critical.

For engineers reviewing the MP2309DS-LF-P datasheet, MP2309DS-LF-P pinout, MP2309DS-LF-P application, or MP2309DS-LF-P equivalent, key selection criteria include input voltage range compatibility (4.75–23V), output adjustability down to 0.923V, SOIC8 thermal performance (θJA = 90°C/W), and integrated MOSFET R_DS(ON) matching (140mΩ both sides).

Technical Context

The MP2309DS-LF-P employs current-mode control with internal transconductance error amplifier (G_EA = 800μA/V) and COMP-pin-based loop compensation. Its functional block includes a 340kHz oscillator, 0.923V precision feedback reference, and dual comparators for overvoltage (1.1V threshold) and input UVLO (4.1V nominal).

It uses bootstrap gate drive architecture requiring a capacitor between SW and BS pins to enable high-side N-MOSFET operation. The EN pin provides 1.5V typical turn-on threshold with 210mV hysteresis, while SS pin supports programmable soft-start via external capacitor (e.g., 0.1μF → 15ms).

Key Specifications

Pinout & Package

MP2309DS-LF-P is housed in an 8-pin SOIC package (MP2309_PD01_SOIC8), with exposed pad not present. Package dimensions conform to JEDEC MS-012AC, rated for –40°C to +85°C ambient operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2309DS-LF-P, MP2307DJ-LF-Z offers superior thermal performance in smaller footprint but sacrifices SOIC8 drop-in replacement capability, while TPS54202DRCT delivers higher current and flexibility at the cost of increased design complexity and component count.

Availability

MP2309DS-LF-P is available at Aetrix Electronics and suitable for FPGA power supplies, telecom auxiliary rails, notebook system rails, and green appliance control circuits requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP2309DS-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 mixed-signal ICs for power management, motion control, and automotive applications.

The MP2300-series targets cost-sensitive, space-constrained DC/DC conversion in computing, networking, and consumer electronics, emphasizing integration, efficiency, and ease of use with minimal external components.

FAQ

What is the minimum output voltage achievable with MP2309DS-LF-P?

The MP2309DS-LF-P supports output voltages as low as 0.923V, set by its internal feedback reference voltage. This value is guaranteed across temperature and line conditions per datasheet Electrical Characteristics table, enabling direct generation of sub-1V logic rails when paired with appropriate resistor dividers and low-ESR output capacitors.

Can MP2309DS-LF-P operate with only ceramic capacitors on input and output?

Yes - the MP2309DS-LF-P is explicitly characterized and stabilized with low-ESR ceramic capacitors. The datasheet confirms stability with 10μF X5R/X7R input and 22μF ceramic output capacitors, eliminating need for tantalum or electrolytic types and reducing board area and aging-related drift.

Is an external Schottky diode required for basic operation?

No - the MP2309DS-LF-P integrates synchronous rectification using internal MOSFETs, making an external Schottky diode optional. It may be added across SW–GND only to improve efficiency under specific high-duty-cycle conditions (e.g., 5V output from 12V input), per Application Information section.

How does the soft-start function behave when the SS pin is left unconnected?

Leaving the SS pin open disables the soft-start feature entirely, resulting in immediate output voltage ramp-up at enable. This is confirmed in the PIN FUNCTIONS table: "To disable the soft-start feature, leave SS unconnected." No pull-up or pull-down is internal; the pin floats high-impedance.

What is the purpose of the BS pin, and what capacitor value is recommended?

The BS pin supplies boosted gate drive voltage to the high-side MOSFET. A capacitor ≥0.01μF (typically 0.1μF ceramic) must connect between BS and SW to form the bootstrap reservoir. This ensures sufficient V_GS for full enhancement of the high-side switch during each switching cycle.

Does MP2309DS-LF-P include thermal shutdown protection?

Yes - the device incorporates internal thermal shutdown that activates at 160°C junction temperature, as specified in the Electrical Characteristics table. Once triggered, regulation halts until die temperature falls below hysteresis threshold, preventing permanent damage during sustained overload or poor heatsinking.

What is the recommended layout practice for the COMP pin?

The COMP pin requires careful routing: keep traces short and away from noisy nodes (e.g., SW, IN). Connect the compensation RC network (e.g., 7.5kΩ + 3.3nF) directly from COMP to GND with minimal parasitic inductance. Avoid vias or long traces to preserve loop stability and prevent oscillation.