Monolithic Power Systems Inc. MP1527DM-LF-Z

Overview

MP1527DM-LF-Z from Monolithic Power Systems is a 2A, 1.3MHz fixed-frequency current-mode step-up DC-DC converter in a 14-lead TSSOP package. It regulates output voltages from 3.3V to 25V with up to 93% efficiency, features internal 150mΩ MOSFET switch, cycle-by-cycle current limiting, and timer-latch fault protection. It is used in handheld computers, PCMCIA cards, and small LCD displays where compact size and noise-sensitive operation are critical.

For engineers reviewing the MP1527DM-LF-Z datasheet, MP1527DM-LF-Z pinout, MP1527DM-LF-Z application, or MP1527DM-LF-Z equivalent, key selection considerations include input voltage range (2.6V–25V), soft-start capacitor timing, FAULT pin latching behavior, FB regulation threshold (1.22V), and thermal shutdown at 160°C.

Technical Context

The MP1527DM-LF-Z employs fixed-frequency (1.3MHz) current-mode control with an internal transconductance error amplifier (300µA/V) and 400V/V gain, enabling stable loop compensation across wide VIN (2.6V–25V), VOUT (3.3V–25V), and load (up to 2A) ranges. Its architecture integrates a 2.4V LDO for internal bias (BP pin), soft-start via 2µA SS current source, and fault detection based on FB voltage falling below 1.098V.

It uses a single n-channel MOSFET switch (150mΩ typical at 5V IN) with peak current limit of 2.0A, operates in continuous conduction mode, and includes undervoltage lockout (2.4V rising threshold, 100mV hysteresis), thermal shutdown (160°C), and zero-current shutdown mode (<1.0µA quiescent current).

Key Specifications

Pinout & Package

MP1527DM-LF-Z is housed in a 14-lead TSSOP package (4.4mm × 5.0mm × 1.2mm), thermally enhanced with exposed power pad connected to PGND pins (pins 5 and 6). Pin 1 is marked by a dot; pin numbering follows standard TSSOP convention (counterclockwise from top-left corner).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP1527DR-LF-Z, the MP1527DM-LF-Z trades thermal performance for easier hand-soldering and legacy TSSOP compatibility; versus TPS61088RHLR, it offers wider VIN range and robust fault coordination at the cost of lower peak current and more complex loop compensation.

Availability

MP1527DM-LF-Z is available at Aetrix Electronics and suitable for handheld computing, PCMCIA expansion, and small LCD display applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP1527DM-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 headquartered in Los Gatos, CA, specializing in high-performance power management ICs for consumer, industrial, and automotive markets since 1997.

The MP1527 product line delivers compact, high-efficiency step-up converters targeting portable electronics with stringent size, noise, and battery-life requirements - emphasizing integration, thermal resilience, and system-level fault coordination.

FAQ

What is the minimum input voltage required for MP1527DM-LF-Z to start switching?

The device enters undervoltage lockout (UVLO) when VIN falls below 2.1V (rising threshold) and remains disabled until VIN exceeds 2.4V. Startup requires VIN ≥ 2.6V per recommended operating conditions, and the internal 2.4V LDO (BP pin) must be stable before regulation begins. A 10nF capacitor on BP ensures reliable startup down to 2.6V.

How does the FAULT pin behave during a short-circuit event?

When FB voltage drops below 1.098V (e.g., due to output short), the internal 2µA current source charges the SS capacitor. Once SS reaches 1.2V (~120ms with 10nF), FAULT is actively pulled low and the power switch disables. The latch persists until EN is cycled low-high or VIN is removed and reapplied.

Can MP1527DM-LF-Z drive multiple parallel LED strings directly?

No - it is a constant-voltage boost converter, not a constant-current LED driver. To drive multiple white LED strings, pair it with external current-sink ICs (e.g., TLC5916) or use discrete current-setting resistors. Figure 10 in the datasheet shows a reference design using MP1527 with 1N5819HW diode and 6-LED strings.

What is the purpose of separating SGND and PGND pins?

SGND carries low-current analog signals (FB, COMP, EN, SS) and serves as the reference for the error amplifier; PGND handles high di/dt switching currents from SW and internal FET. Separating them prevents ground bounce from corrupting feedback accuracy and improves regulation stability, especially at 1.3MHz switching.

Is an external Schottky diode mandatory, and what specs are critical?

Yes - the MP1527DM-LF-Z requires an external Schottky rectifier. Critical specs: reverse voltage ≥ VOUT (e.g., 20V for 18V output), average current ≥ max load current, peak current ≥ 2.5A (to handle 2A switch limit plus ripple), and low forward voltage (≤0.4V) to preserve efficiency. MBR0530 is a validated choice.

How does soft-start interact with the fault timer?

The same 2µA current source charges the SS capacitor during both soft-start and fault conditions. During startup, SS ramps until 1.2V to limit COMP voltage and control inrush; during fault, identical ramping triggers FAULT assertion at 1.2V. The external capacitor value (10–22nF) sets both durations: tSS ≈ 275ms × CSS(nF).

What layout guidance applies to the BP pin?

BP must be bypassed with ≥10nF ceramic capacitor directly between BP and SGND, placed within 2mm of the pin. No external load may be connected - even test points or pull-ups will destabilize the internal LDO and cause erratic regulation or startup failure.