Monolithic Power Systems Inc. MP18851-A4BGY-Z

Overview

MP18851-A4BGY-Z from Monolithic Power Systems is an isolated, dual-input, independent dual-channel gate driver IC designed for high-voltage power stage control in isolated DC/DC and AC/DC converters. It delivers 4A peak source/sink current per channel, features 50ns typical propagation delay, >100kV/µs CMTI, and supports 2.8–5.5V primary-side VDDI and up to 30V secondary-side supply - enabling robust interfacing with 3.3V/5V controllers and wide-range MOSFET/IGBT gate drive.

For engineers reviewing the MP18851-A4BGY-Z datasheet, MP18851-A4BGY-Z pinout, MP18851-A4BGY-Z application, or MP18851-A4BGY-Z equivalent, this part serves as a safety-certified, capacitive-isolated solution for half-bridge, full-bridge, and inverter topologies requiring precise timing, high common-mode noise immunity, and dual independent output control with UVLO-configurable thresholds.

Technical Context

The MP18851 employs MPS's proprietary capacitive isolation barrier to achieve reinforced insulation (5kVRMS, SOIC-16 WB) and functional isolation between secondary-side drivers (1500VDC). Its dual-channel architecture supports either half-bridge (HS/LS) or dual independent configurations, with separate VDDA/VSSA and VDDB/VSSB supplies allowing floating ground references per channel.

Input logic accepts TTL/CMOS-compatible signals on INA/INB with internal pull-downs; enable/disable is implemented via EN (active-high, internal pull-up) or DIS (active-low, internal pull-down). Each channel includes dedicated under-voltage lockout (UVLO) with 5V threshold (–A4B variant), ensuring safe turn-off during supply brownout.

Key Specifications

Pinout & Package

MP18851-A4BGY-Z is packaged in SOIC-16 WB (wide-body), providing 5kVRMS isolation and 8mm creepage/clearance. Pin assignments are validated per MPS datasheet Rev. 1.0 (2022).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar isolated dual-channel gate driver applications.

Compared with Si8273BD-IS and UCC21540ADWKR, MP18851-A4BGY-Z uniquely combines dual independent enable/disable logic, 100kV/µs+ CMTI, and fully integrated isolated dual-channel architecture in a single SOIC-16 WB package - simplifying layout while meeting stringent industrial isolation and timing requirements.

Availability

MP18851-A4BGY-Z is available at Aetrix Electronics and suitable for half-bridge motor drives, isolated DC/DC converters, and offline AC/DC power supplies requiring stable component supply, long-term lifecycle assurance, and safety-certified isolation performance.

Supply support for MP18851-A4BGY-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 power management ICs, with design expertise in DC/DC conversion, gate driving, and isolation technologies.

The MP18851 product line delivers integrated, safety-certified isolated gate drivers targeting high-efficiency, high-density power conversion systems - particularly where reliability, timing precision, and regulatory compliance are critical.

FAQ

What is the isolation rating and certification status of MP18851-A4BGY-Z?

MP18851-A4BGY-Z in SOIC-16 WB package is UL 1577 certified for 5kVRMS (60s), VDE 0884-17 certified for 6000VPK, and CQC certified per GB 4943.1-2011. It provides reinforced insulation with 8mm creepage/clearance, validated for use in industrial and medical power supplies meeting IEC 62368-1.

How does the –A4B suffix define the UVLO behavior?

The "A4B" suffix indicates a 5V output-side UVLO threshold (VDDA_UVLO = 5.0V typ.) with 300mV hysteresis. When VDDA or VDDB falls below 5.0V, the corresponding channel output is disabled; recovery occurs only after voltage rises above 5.3V - preventing oscillation near threshold.

Can MP18851-A4BGY-Z drive both high-side and low-side switches in a half-bridge configuration?

Yes - its dual independent secondary-side supplies (VDDA/VSSA and VDDB/VSSB) allow one channel to drive the high-side switch (with VSSA referenced to switch source) and the other to drive the low-side switch (with VSSB grounded), supporting standard half-bridge topologies without external level shifters.

What is the difference between EN and DIS pins, and how should they be used?

EN is active-high (internal pull-up); DIS is active-low (internal pull-down). Either pin can independently enable/disable both channels. Use EN for system-level enable control; use DIS for hardware fault shutdown (e.g., connected to comparator output during overcurrent).

Does MP18851-A4BGY-Z support independent input logic for each channel?

Yes - INA controls OUTA and INB controls OUTB with no internal coupling. Each input accepts TTL/CMOS logic (1.6V high, 1.2V low thresholds) and features internal 200kΩ pull-down, enabling true independent dual-channel operation for asymmetrical PWM or phase-shifted control schemes.

What thermal derating applies to MP18851-A4BGY-Z at elevated ambient temperatures?

In SOIC-16 WB package, safety-limiting power decreases linearly from 2215mW at 25°C to zero at 150°C ambient. At 100°C ambient, maximum allowable power is ~1100mW per channel - requiring careful PCB copper area allocation and airflow planning for continuous 4A peak operation.

Is there a recommended bypass capacitor value for VDDI and VDDA/VDDB pins?

MPS specifies low-ESR/ESL ceramic capacitors placed as close as possible to respective pins: 0.1µF for VDDI (to GNDI) and 1µF for VDDA/VSSA and VDDB/VSSB pairs. Additional bulk capacitance (e.g., 10µF tantalum) may be added nearby for transient load support.