Monolithic Power Systems Inc. MP8715DN-LF-Z

Overview

MP8715DN-LF-Z from Monolithic Power Systems is a 500 kHz fixed-frequency synchronous step-down DC/DC converter supporting 100% duty cycle operation, delivering up to 4 A continuous output current from a 4.5 V–21 V input range with adjustable output voltage (0.8 V to VIN). It integrates 120 mΩ high-side and 50 mΩ low-side MOSFETs, features internal compensation, power-good indication, and frequency synchronization-used in µP/FPGA core supplies and telecom point-of-load regulation.

For engineers reviewing the MP8715DN-LF-Z datasheet, MP8715DN-LF-Z pinout, MP8715DN-LF-Z application, or MP8715DN-LF-Z equivalent, key selection considerations include its 100% duty cycle capability for low-dropout operation, thermal shutdown at 150°C, POK open-drain signaling, external soft-start timing control, and dual-package availability (SOIC8E with exposed pad).

Technical Context

The MP8715 operates in fixed-frequency peak-current-mode control with internal 5.1 V bias regulator, enabling stable operation across 4.5 V–21 V input. Its error amplifier compares FB voltage against a 0.805 V reference and drives an internal compensation network, eliminating need for external compensation components.

It implements cycle-by-cycle overcurrent protection with hiccup mode recovery, thermal shutdown at 150°C (130°C hysteresis), and bootstrap-driven high-side gate drive with 2.8 V BST UVLO. The EN/SYNC pin supports enable control, automatic startup via resistor divider, or external clock synchronization from 300 kHz to 2 MHz.

Key Specifications

Pinout & Package

MP8715DN-LF-Z is packaged in an 8-pin SOIC with exposed thermal pad (SOIC8E), optimized for thermal performance in space-constrained PCB layouts. The exposed pad must be soldered to a thermal plane for effective heat dissipation (θ_JA = 50°C/W, θ_JC = 10°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP8715DN-LF-Z, MPQ8715GD-AEC1 adds automotive qualification without altering core functionality, while MP8770GQ trades 100% duty cycle and POK for higher current and frequency-making MP8715DN-LF-Z optimal for cost-sensitive, non-automotive POLs requiring dropout headroom and system sequencing.

Availability

MP8715DN-LF-Z is available at Aetrix Electronics and suitable for µP/FPGA core supplies, telecom point-of-load regulators, and cable eMTA power rails requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP8715DN-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 specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan.

The MP8715 belongs to MPS's high-efficiency synchronous buck converter product line, engineered for compact, thermally robust DC/DC conversion in networking, computing, and consumer electronics with emphasis on ease of use and minimal external components.

FAQ

What is the maximum allowable input voltage for MP8715DN-LF-Z?

The absolute maximum input voltage is 23 V, but the recommended operating range is 4.5 V to 21 V. Operation above 21 V risks exceeding internal device stress limits and may trigger overvoltage protection or permanent damage. Input ripple must stay within this window even during transients.

Can MP8715DN-LF-Z operate with 100% duty cycle at full 4 A load?

Yes-it supports true 100% duty cycle operation across its full 4 A load range when V_OUT ≥ V_IN − (I_LOAD × R_{DS(on)_HS}). At 4 A and 120 mΩ, dropout is limited to 480 mV, enabling stable regulation down to V_OUT = V_IN − 0.48 V with proper thermal management.

Is external compensation required for stable loop operation?

No-MP8715DN-LF-Z uses fully internal compensation. Its error amplifier and PWM comparator are factory-tuned to work with standard ceramic output capacitors (22 µF typical), eliminating external compensation components and reducing design risk and bill-of-materials count.

How does the POK pin behave during startup and fault conditions?

POK remains low until FB reaches 90% of its reference (0.725 V for nominal 0.805 V), then transitions to high-impedance open-drain state. During output undervoltage (FB < 0.685 V), it pulls low again. No external pull-up is strictly required, but a 10 kΩ resistor to system rail ensures defined logic levels.

What thermal derating applies when using the SOIC8E package without forced airflow?

In still air on a 4-layer PCB with 2 in² copper pour connected to the exposed pad, MP8715DN-LF-Z delivers full 4 A up to 65°C ambient. Above that, output current must be linearly reduced-e.g., to ~3.2 A at 85°C ambient-to maintain junction temperature ≤125°C.

Does MP8715DN-LF-Z support spread-spectrum frequency modulation?

No-MP8715DN-LF-Z offers only fixed 500 kHz operation or synchronization to an external clock (0.3–2 MHz). It does not implement internal spread-spectrum modulation; EMI reduction must be achieved via layout optimization, filtering, or external clock dithering.

What is the minimum output voltage achievable with MP8715DN-LF-Z?

The minimum regulated output voltage is 0.8 V, set by the internal 0.805 V feedback reference and tolerance. With a precision resistor divider (e.g., 4.99 kΩ + 10.2 kΩ), 1.2 V is typical; lower outputs require tighter resistor matching and attention to FB pin leakage (<50 nA).