Monolithic Power Systems Inc. MP1586EN-LF-P

Overview

MP1586EN-LF-P from Monolithic Power Systems is a non-synchronous step-down DC/DC converter IC with integrated 28V high-side MOSFET, delivering up to 3A output current, programmable 50–400kHz switching frequency, and 4.5–28V input range. It operates in current-mode control with internal soft-start, thermal shutdown, and UVLO, targeting automotive and industrial power rails where wide VIN and low quiescent current (115µA) are critical.

For engineers reviewing the MP1586EN-LF-P datasheet, MP1586EN-LF-P pinout, MP1586EN-LF-P application, or MP1586EN-LF-P equivalent, key selection considerations include its SOIC8E thermally enhanced package, bootstrap capacitor dependency for high-side gate drive, FREQ-pin programmability, and end-of-life status requiring migration planning to MP2338.

Technical Context

The MP1586EN-LF-P implements peak current-mode control with cycle-by-cycle current limiting and internal error amplifier (200 V/V gain, 60 µA/V transconductance). Its oscillator frequency is resistor-programmable via the FREQ pin, and it features a dedicated floating bootstrap driver regulated to ~5V with UVLO (2.2V rising threshold).

Startup includes internal soft-start (1.5ms ramp), blanking of current comparator during switch turn-on, and coordinated sequencing of reference, regulator, and power stage enablement. Shutdown is triggered by EN <1.2V, VIN <2.6V, or junction temperature >150°C with 15°C hysteresis.

Key Specifications

Pinout & Package

MP1586EN-LF-P is housed in a thermally enhanced SOIC8E package (8-pin, exposed thermal pad), optimized for surface-mount assembly and PCB heat dissipation. The exposed pad must be connected directly to a large GND copper area for θ_JA = 50°C/W performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP1586EN-LF-P, MP2338 offers superior efficiency and integration as a direct replacement, while LM2678 provides higher current and input voltage headroom at the cost of fixed frequency and reduced light-load performance.

Availability

MP1586EN-LF-P is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC power modules, and distributed telecom power supplies requiring stable component supply despite end-of-life status.

Supply support for MP1586EN-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 core expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MP1586 belongs to MPS's legacy high-voltage buck converter product line, designed specifically for ruggedized 12V/24V system power delivery in automotive and industrial environments before migration to synchronous platforms.

FAQ

Is MP1586EN-LF-P still in production?

No - MP1586EN-LF-P is officially marked End-of-Life (EOL) by Monolithic Power Systems. Datasheet Rev. 0.91 (2010) confirms EOL status and explicitly directs users to migrate to MP2338. Aetrix Electronics holds limited legacy stock for last-time buy and repair fulfillment, but no new wafer starts are planned.

Can MP1586EN-LF-P operate without an external Schottky diode?

No - MP1586EN-LF-P is a non-synchronous buck converter and requires an external Schottky diode (e.g., B340A-13-F or CMSH3-40MA) connected from SW to GND. Omitting it causes catastrophic failure due to lack of freewheeling path during high-side switch off-time.

What is the minimum recommended input voltage for reliable startup?

The minimum functional input voltage is 4.5V, but reliable startup requires VIN ≥ 3.0V to exit UVLO (rising threshold). Below 2.6V (falling threshold), the device remains disabled. For cold-crank scenarios, ensure VIN stays above 4.5V under load to maintain regulation and avoid thermal stress.

How does the bootstrap capacitor charge, and what value is required?

The BST capacitor (typically 0.1µF X7R ceramic) charges from VIN to SW through an internal PMOS when SW is low. It must sustain ~5V across BST–SW during high-side conduction. Insufficient charging occurs at high duty cycles (>65%) or low VIN–VOUT differential (<3V); adding an external bootstrap diode (e.g., BAT54) mitigates this.

Does MP1586EN-LF-P support remote sensing or output voltage trimming?

No - MP1586EN-LF-P uses single-point feedback via the FB pin and lacks dedicated remote sense inputs or trim pins. Output accuracy depends entirely on resistor divider tolerance and layout parasitics. For tighter regulation, use 0.5% or better resistors and route FB traces away from noisy nodes like SW.

What is the maximum allowable output capacitance?

No hard upper limit exists, but stability depends on ESR and zero placement. Ceramic outputs require C2 ≥ 2×22µF (per typical app note); larger values improve ripple but may shift compensation poles. If using high-ESR electrolytics, add C6 per Table 3 to cancel ESR zero and prevent oscillation.

Can EN pin be used to adjust UVLO threshold?

Yes - tying EN to VOUT via a resistor divider raises the effective UVLO threshold to VOUT + 3V, preventing premature shutdown during low-VIN transients. This technique is documented in the "External Bootstrap Diode" section and validated for automotive cold-crank immunity.