Monolithic Power Systems Inc. MP8867GLE-Z

Overview

MP8867GLE-Z from Monolithic Power Systems is a high-frequency, synchronous step-down DC/DC converter with I²C programmability, delivering up to 8A output current across a 4.5V–17V input range. It features 0.6V–1.87V I²C-adjustable output voltage in 10mV steps, 1% reference accuracy, and integrated over-voltage, over-current hiccup, and thermal shutdown protections. Used in FPGA core supplies where dynamic voltage scaling and precise rail sequencing are required.

For engineers reviewing the MP8867GLE-Z datasheet, MP8867GLE-Z pinout, MP8867GLE-Z application, or MP8867GLE-Z equivalent, key selection considerations include I²C-configurable soft-start timing, external clock synchronization (200kHz–2MHz), open-drain power-good signaling, and QFN-14 (3×4mm) thermal performance with θ_JA = 48°C/W.

Technical Context

The MP8867GLE-Z implements current-mode control with internal high-side (30mΩ) and low-side (15mΩ) MOSFETs, enabling fast transient response and stable loop compensation without external compensation components. Its I²C interface controls not only output voltage but also switching frequency, power-save mode (PSM/FS), and voltage-slew rate-enabling dynamic V/f scaling in processor cores.

Three operating modes-CCM (default), AAM for light-load efficiency, and DCM for ultra-light loads-are selected via register bit MODE[0]. The internal 5V LDO (VCC) powers all logic and analog blocks, regulated from VIN across the full input range, with mandatory 0.47µF ceramic decoupling.

Key Specifications

Pinout & Package

MP8867GLE-Z is housed in a thermally enhanced QFN-14 package (3mm × 4mm, 0.5mm pitch) with exposed thermal pad. Pin 14 (AGND) and Pin 8 (PGND) must be connected separately to the system ground plane using multiple vias to minimize noise coupling and ensure stable feedback operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP8867GLE-Z, MP8859GQ-Z trades I²C flexibility for lower BOM cost and simpler layout, while TPS548D22RTQR adds telemetry and broader output range at the expense of higher design complexity and footprint.

Availability

MP8867GLE-Z is available at Aetrix Electronics and suitable for FPGA-based systems, ASIC power delivery, and distributed telecom power applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP8867GLE-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, headquartered in Kirkland, Washington, with global design and support operations.

The MP8867 belongs to MPS's high-current, digitally configurable DC/DC converter product line, designed specifically for dynamic voltage scaling in FPGA, ASIC, and multicore processor applications where precision, efficiency, and programmability are critical.

FAQ

What is the minimum recommended soft-start capacitor value for MP8867GLE-Z?

The soft-start capacitor (SS pin) is charged by a 10µA internal current source. For a typical 10ms ramp time at 1.2V output, a 83nF capacitor is calculated using C_SS = (T_SS × 10µA) / V_REF. A 100nF X7R ceramic capacitor is recommended to accommodate tolerance and temperature drift, placed within 2mm of the SS pin with short traces to AGND.

Can MP8867GLE-Z operate without I²C communication after initial configuration?

Yes. After power-up, MP8867GLE-Z defaults to FB-resistor control if no I²C activity is detected within ~100ms. The device retains its last programmed output voltage, frequency, and mode settings in volatile registers but reverts to analog feedback loop operation-ensuring robustness in systems with intermittent I²C bus access.

How does the MP8867GLE-Z handle output over-voltage conditions?

When FB or VOUT exceeds 120% of the reference voltage, MP8867GLE-Z activates linear discharge mode using an internal 35Ω resistor between VOUT and GND. This limits over-voltage to ≤127% VREF and holds it until VOUT drops below 105% VREF, at which point normal PWM operation resumes-no latch-off or manual reset required.

Is EN/SYNC pin 5V-tolerant when used for external clock synchronization?

No. EN/SYNC has an internal 5.7V Zener clamp, so applying >5.5V directly risks exceeding the 100µA absolute maximum current rating. For 12V clock sources, a ≥63kΩ pull-up resistor to VIN is required; for direct 3.3V/5V clocks, no series resistor is needed, and the pin safely accepts 200kHz–2MHz square waves with 50% duty cycle.

What is the purpose of separating PGND and AGND pins on the QFN-14 package?

PGND carries high di/dt return currents from the power switches, while AGND references sensitive analog circuits (error amplifier, I²C logic, DAC). Separating them prevents ground bounce from corrupting feedback accuracy or causing I²C communication errors. They must join at a single point near the input capacitor to maintain low-impedance return paths without creating ground loops.

Does MP8867GLE-Z support pre-biased output start-up, and how is it implemented?

Yes. During start-up with a pre-biased output, the internal SS capacitor charges until its voltage exceeds the sensed VOUT at FB/VOUT pin. Only then does the controller begin switching, ramping output monotonically from the pre-bias level. This avoids reverse current flow into the output capacitor and ensures glitch-free initialization in hot-swap or multi-rail systems.

What thermal derating applies to the 8A output rating in the QFN-14 package?

The 8A rating assumes θ_JA = 48°C/W on a 4-layer PCB with 2oz copper and thermal vias under the exposed pad. At ambient temperatures above 60°C or with reduced copper area, output current must be derated linearly: I_OUT = 8A × (1 − (T_A − 60)/65). At 100°C ambient, max continuous current drops to ~5.1A to maintain T_J ≤ 125°C.