Monolithic Power Systems Inc. MP8759GD-P

Overview

MP8759GD-P from Monolithic Power Systems is a fully integrated, synchronous step-down DC/DC converter delivering 8A continuous and 10A peak output current across a 4.5V–26V input range. It employs adaptive constant-on-time (COT) control, features 117μA quiescent current, 1% reference voltage accuracy, and integrates high- and low-side MOSFETs with 25mΩ/12mΩ R_DS(ON) in a QFN-12 (2mm×3mm) package for compact point-of-load regulation in space-constrained systems.

For engineers reviewing the MP8759GD-P datasheet, MP8759GD-P pinout, MP8759GD-P application, or MP8759GD-P equivalent, key selection considerations include its ultrasonic mode (USM) for audible-noise-sensitive applications, DC auto-tune loop for tight load/line regulation, integrated output discharge, and robust protection suite including hiccup-mode OCP/OVP/UVP and thermal shutdown.

Technical Context

The MP8759GD-P implements adaptive COT control with internal ramp compensation and a DC auto-tune loop that dynamically adjusts the reference comparator input to minimize steady-state V_FB–V_REF error without degrading transient response. Its valley-current sensing OCP uses the low-side MOSFET's R_DS(ON) as the current-sense element, triggering cycle-by-cycle limiting at 10.5–13.5A.

It supports three operating modes via the MODE pin: forced PWM (>2.6V), PFM with ultrasonic mode (floating), and PFM without USM (grounded). The 700kHz switching frequency is maintained across input and load variations via COT timing, while light-load efficiency is enhanced by DCM entry, skip mode, and zero-current detection with LS-FET driver tri-state.

Key Specifications

Pinout & Package

MP8759GD-P is housed in a thermally enhanced QFN-12 package (2mm × 3mm, 0.5mm pitch) with exposed thermal pad for efficient PCB heat dissipation. Pin numbering follows standard top-view orientation with Pin 1 marked by dot or chamfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RTQ2132BGQW and TPS54821RHLR, MP8759GD-P uniquely combines 8A capability, ultrasonic mode, integrated output discharge, and 1% reference accuracy in a 2mm×3mm footprint-making it optimal for compact, noise-sensitive, high-reliability POL designs where board space and acoustic performance are critical.

Availability

MP8759GD-P is available at Aetrix Electronics and suitable for laptop computers, industrial PLC modules, flat-panel display power supplies, and networking switch ASIC core rails requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for MP8759GD-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, motor drive, and automotive applications.

The MP8759GD-P belongs to MPS' high-current synchronous buck converter product line, engineered for compact, high-efficiency point-of-load regulation in computing, consumer, and industrial systems demanding low IQ, fast transient response, and robust protection.

FAQ

What is the minimum recommended output capacitance for stable operation with MP8759GD-P?

The MP8759GD-P supports ceramic output capacitors down to 22μF total (e.g., two 10μF + one 2.2μF X7R) when using internal ramp compensation. For pure ceramic configurations requiring external ramp, ≥47μF is recommended. Electrolytic or POSCAPs allow smaller values (≥10μF) due to inherent ESR damping.

How does the DC auto-tune loop affect long-term output voltage accuracy?

The DC auto-tune loop continuously adjusts the internal reference comparator offset to maintain V_FB = V_REF over time and temperature. This corrects for resistor drift, PCB stress, and aging effects, ensuring output voltage remains within ±0.5% of nominal across –40°C to +125°C junction temperature and 10-year operational life.

Can MP8759GD-P operate with 100% duty cycle, and under what conditions?

Yes - MP8759GD-P supports extended duty cycle operation when V_IN – V_OUT < 2V. Its internal TON extension function increases on-time to maintain regulation, enabling use cases like 5V-to-3.3V or 12V-to-10V conversion without external linear post-regulation.

What is the purpose of the VOUT pin, and why must it be routed separately from PGND?

VOUT is a Kelvin sense connection for the output voltage, providing a dedicated low-noise path to the internal error amplifier. Routing it separately from PGND avoids IR drop and switching noise coupling, ensuring accurate feedback. It must be a >25mil trace with no vias and kept away from SW node to prevent regulation instability.

Does MP8759GD-P require external bootstrap diode, and how is BST capacitor selected?

No external diode is required - MP8759GD-P integrates bootstrap charging circuitry. A 0.1μF X7R ceramic capacitor (rated ≥16V) must be placed between BST and SW pins, with minimal trace length and direct connection to SW pad to ensure reliable high-side gate drive under all load conditions.

How does ultrasonic mode (USM) behave during no-load conditions?

In USM (MODE floating), the MP8759GD-P monitors SW node voltage. After ~30μs of both MOSFETs being off, it shrinks TON to maintain regulation while keeping f_SW >20kHz. If load drops further, it discharges V_OUT until FB falls below 102% V_REF, then halts switching entirely until FB rises to V_REF again.

What thermal derating applies to the QFN-12 package at 8A continuous load?

With standard 4-layer PCB (2oz copper, 1in² thermal pad area), the MP8759GD-P delivers full 8A up to +85°C ambient. Above this, output current must be reduced per θ_JA = 70°C/W: at +100°C ambient, max continuous current drops to ~5.5A to keep T_J ≤ 125°C.