Monolithic Power Systems Inc. MP18851-A4BGLU-Z

Overview

MP18851-A4BGLU-Z from Monolithic Power Systems is an isolated, dual-input, independent dual-channel gate driver IC with 4A peak source/sink current per channel, 50ns typical propagation delay, and >100kV/µs common-mode transient immunity (CMTI). It uses capacitive isolation to achieve 2.5kVRMS withstand voltage (LGA-13 package) and supports 3.3V/5V logic interfaces. It drives high-side/low-side MOSFETs or IGBTs in isolated DC/DC converters.

For engineers reviewing the MP18851-A4BGLU-Z datasheet, MP18851-A4BGLU-Z pinout, MP18851-A4BGLU-Z application, or MP18851-A4BGLU-Z equivalent, this device delivers precise timing control, robust isolation for 600VRMS mains-referenced systems, UVLO-configurable secondary supplies (5V threshold), and LGA-13 thermal performance suitable for high-density power modules.

Technical Context

The MP18851-A4BGLU-Z implements fully independent dual-channel gate drive with separate input-side (VDDI/GNDI) and two isolated output-side domains (VDDA/VSSA and VDDB/VSSB), enabling half-bridge or dual independent topologies. Its proprietary capacitive isolation barrier provides functional isolation between secondary drivers (700VDC for LGA-13) and meets DIN EN IEC 60747-17 (VDE 0884-17) with 3535VPK reinforced rating.

It features dual enable/disabled logic inputs (EN/DIS), TTL/CMOS-compatible INA/INB with internal pull-downs, and per-channel under-voltage lockout on both primary (2.6V typ) and secondary sides (5V UVLO threshold for -A4B variant). Propagation delay matching is ≤6ns, and pulse-width distortion is ≤6ns - critical for synchronous rectification and phase-shifted full-bridge designs.

Key Specifications

Pinout & Package

LGA-13 (5mm × 5mm) package with exposed thermal pad; RoHS-compliant, halogen-free, MSL Level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si823H4BB-IS and ADUM4223BRIZ, MP18851-A4BGLU-Z uniquely combines LGA-13 thermal efficiency, 4A drive strength, independent VSSA/VSSB domains, and 5V UVLO configurability - making it optimal for high-power density, high-reliability isolated converters where layout space and thermal headroom are constrained.

Availability

MP18851-A4BGLU-Z is available at Aetrix Electronics and suitable for isolated DC/DC converters, photovoltaic string inverters, and industrial AC/DC adapters requiring stable component supply, long-term lifecycle support, and traceable sourcing for safety-critical designs.

Supply support for MP18851-A4BGLU-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, including DC/DC converters, LED drivers, and isolated gate drivers - with global manufacturing and quality certifications.

The MP18851 product line targets high-efficiency, high-density isolated power conversion systems, delivering robust capacitive isolation, precise timing, and flexible configuration for next-generation industrial, renewable energy, and automotive auxiliary power architectures.

FAQ

What does the "A4B" suffix indicate in MP18851-A4BGLU-Z?

The "A4B" denotes the UVLO threshold configuration: "A" specifies 3V logic compatibility on the input side, "4" indicates 4A peak output current per channel, and "B" sets the secondary-side UVLO threshold to 5V (min 5.0V, typ 5.5V, max 6.0V) - ensuring gate drive remains active only when VDDA/VDDB exceeds safe MOSFET turn-on voltage.

Can MP18851-A4BGLU-Z drive SiC MOSFETs directly?

Yes - its 4A peak source/sink current, 50ns propagation delay, and 10ns rise/fall times (with 1.8nF load) meet the gate drive requirements of 650V–1200V SiC MOSFETs. The 30V maximum output supply allows ±15V gate bias for enhanced Miller immunity, and >100kV/µs CMTI prevents false triggering during fast dV/dt transitions.

How is isolation verified between the two output channels (VSSA and VSSB)?

Per datasheet Section 12, the LGA-13 package provides 700VDC functional isolation between VSSA and VSSB - confirmed by dielectric withstand testing at 700VDC for 60 seconds and validated via creepage/clearance measurements (3.5mm minimum surface and air gap). This enables independent grounding for multi-level topologies.

Does MP18851-A4BGLU-Z require external bootstrap diodes or capacitors?

No - it does not implement bootstrap gate drive. Instead, it provides fully isolated secondary-side supplies (VDDA/VSSA and VDDB/VSSB), each requiring a local bypass capacitor (low-ESR/ESL) placed near pins 8 and 11. No external diodes or floating supplies are needed, simplifying layout in isolated half-bridge or dual-driver configurations.

What is the role of the DIS pin versus the EN pin?

DIS is active-high and internally pulled low; asserting DIS high disables both outputs immediately. EN is active-high and internally pulled high; pulling EN low disables outputs. They provide complementary fail-safe control - DIS enables hardware-triggered shutdown (e.g., overtemperature fault), while EN supports MCU-based enable/disable sequencing.

Is thermal pad soldering mandatory for MP18851-A4BGLU-Z?

Yes - the exposed thermal pad (Pin 13) must be soldered to a PCB copper pour with ≥4 thermal vias (0.3mm diameter, filled) connecting to inner-layer ground planes. Without this, junction temperature exceeds 150°C at 1175mW dissipation, triggering thermal shutdown and violating safety limiting values per Section 13 of the datasheet.