Monolithic Power Systems Inc. MP2370DJ-LF-P

Overview

MP2370DJ-LF-P from Monolithic Power Systems is a monolithic step-down white LED driver IC with integrated 0.35Ω power MOSFET, delivering up to 1.2A peak output current across 4.5V–24V input range, operating at fixed 1.4MHz switching frequency, and featuring 0.15V current-sense threshold for precise LED current regulation in backlight and portable lighting systems.

For engineers reviewing the MP2370DJ-LF-P datasheet, MP2370DJ-LF-P pinout, MP2370DJ-LF-P application, or MP2370DJ-LF-P equivalent, key selection criteria include its TSOT23-6 package footprint, cycle-by-cycle overcurrent protection, thermal shutdown behavior, bootstrap capacitor requirement for high-side gate drive, and PWM dimming capability via EN pin with ≥240μs minimum on-time.

Technical Context

The MP2370DJ-LF-P implements current-mode control architecture with internal ramp compensation, enabling fast transient response and stable loop operation without external compensation components. Its error amplifier integrates the difference between FB voltage and 0.15V reference, directly modulating peak inductor current.

It uses a floating high-side N-channel MOSFET driver powered by an external BST capacitor charged through an internal diode; at low VIN (<5V), an external bootstrap diode is recommended to maintain gate drive strength. The device supports both cap-less and ceramic-output configurations with stability ensured by low-ESR capacitors.

Key Specifications

Pinout & Package

MP2370DJ-LF-P is housed in a TSOT23-6 package (2.9mm × 1.6mm × 0.9mm), optimized for space-constrained LED backlight and portable electronics. Pin layout follows JEDEC MO-193 AB standard with exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current step-down LED driver applications.

Compared with LM3409MM/NOPB and TPS61165DRVR, MP2370DJ-LF-P offers lower BOM count due to integrated MOSFET and fixed 0.15V sense voltage, simplifies design for mid-range input (4.5V–24V) buck LED drivers, and delivers superior thermal performance in TSOT23-6 with θ_JA = 220°C/W.

Availability

MP2370DJ-LF-P is available at Aetrix Electronics and suitable for smartphone backlight drivers, automotive interior lighting modules, portable medical display systems, and industrial HMI panel backlights requiring stable component supply and RoHS-compliant packaging.

Supply support for MP2370DJ-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 MP2370 belongs to MPS's White LED Driver product line, engineered for compact, efficient, and thermally robust constant-current regulation in portable and automotive lighting where space, efficiency, and reliability are critical.

FAQ

What is the minimum PWM dimming pulse width supported by MP2370DJ-LF-P?

The MP2370DJ-LF-P supports PWM dimming via the EN pin with a minimum recommended on-time of 240μs at 25°C to achieve linear dimming performance. At temperature extremes (−40°C to +125°C), this increases to 240μs due to internal timing variation. Shorter pulses may cause inconsistent LED turn-on or flicker.

Can MP2370DJ-LF-P operate without an output capacitor?

Yes - MP2370DJ-LF-P supports cap-less operation using a 680pF capacitor in the feedback loop (between FB and GND), as shown in Figure 3 of the datasheet. This configuration eliminates output capacitance while maintaining regulation stability, reducing cost and board area in space-sensitive designs.

Why is an external bootstrap diode recommended below 5V input?

Below 5V input, the internal bootstrap diode cannot sufficiently charge the BST capacitor to sustain full gate drive voltage for the internal MOSFET. Adding an external Schottky diode from IN to BST strengthens bootstrap charging, ensuring reliable 0.35Ω R_DS(on) performance and preventing current derating at low VIN.

What is the maximum continuous LED current achievable with MP2370DJ-LF-P?

The MP2370DJ-LF-P is rated for 1.2A peak output current, but continuous operation above 1A is limited by thermal constraints in the TSOT23-6 package (θ_JA = 220°C/W). For sustained 1A loads, PCB copper area and airflow must keep junction temperature below 150°C; duty cycle >35% further restricts max load to 1A per datasheet guidance.

How does the MP2370DJ-LF-P handle short-circuit conditions on the LED string?

Under LED short-circuit, the FB pin voltage collapses toward 0V, triggering fold-back mode where switching frequency drops from 1.4MHz to 700kHz and maximum duty cycle reduces to 87%. This limits power dissipation while maintaining regulation attempt - combined with cycle-by-cycle current limiting and thermal shutdown, it provides robust fault tolerance.

Is MP2370DJ-LF-P compatible with ceramic input capacitors only?

Yes - MP2370DJ-LF-P is specifically characterized for stability with low-ESR X5R/X7R ceramic input capacitors (e.g., 4.7μF). Electrolytic or tantalum capacitors are unnecessary and may degrade loop response due to higher ESR and ESL; ceramic types also improve reliability and lifetime in portable applications.

What is the purpose of the BST pin and how is it connected?

The BST pin supplies the floating gate drive voltage for the internal high-side MOSFET. It must be connected via a 0.1μF ceramic capacitor between BST and SW pins. During SW low phase, the capacitor charges through the internal bootstrap diode; during SW high phase, it provides gate voltage above VIN to fully enhance the MOSFET, ensuring low R_DS(on) conduction.