Monolithic Power Systems Inc. MP18851-A4BGSE-Z

Overview

MP18851-A4BGSE-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 drives high-side and low-side power switches in isolated half-bridge topologies using proprietary capacitive isolation, supporting 3.3V/5V logic inputs and up to 30V secondary-side supply voltage. Used in offline AC/DC converters requiring reinforced isolation and tight timing control.

For engineers reviewing the MP18851-A4BGSE-Z datasheet, MP18851-A4BGSE-Z pinout, MP18851-A4BGSE-Z application, or MP18851-A4BGSE-Z equivalent, this page delivers verified specifications, SOIC-16 WB package mapping, functional isolation ratings, UVLO threshold configuration (5V option), and real-world gate drive timing behavior - all critical for high-reliability isolated power stage design.

Technical Context

The MP18851-A4BGSE-Z implements two fully independent, isolated gate drivers sharing a single input-side control domain but with separate secondary-side grounds (VSSA/VSSB) and supplies (VDDA/VDDB). Its capacitive isolation barrier enables 5kVRMS withstand voltage (UL 1577) and 6000VPK reinforced insulation (VDE 0884-17) in the SOIC-16 WB package.

It supports dual-input logic (INA/INB) with TTL/CMOS compatibility, EN/DIS enable/disable control, and configurable UVLO thresholds - here set to 5V (–B suffix) on the output side. Propagation delay matching ≤6ns and pulse-width distortion ≤6ns ensure precise synchronous switching in phase-shifted or interleaved topologies.

Key Specifications

Pinout & Package

MP18851-A4BGSE-Z is supplied in SOIC-16 wide-body (WB) package, providing reinforced isolation and 8mm creepage/clearance between primary and secondary sides. Pin numbering follows standard SOIC-16 top-view orientation with pin 1 at top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si8273BD and UCC5390SCD, MP18851-A4BGSE-Z uniquely combines per-channel 5V UVLO configuration, 1500V functional isolation between outputs, and SOIC-16 WB packaging - making it optimal for cost-sensitive, safety-certified industrial AC/DC where secondary-supply sequencing and shoot-through prevention are critical.

Availability

MP18851-A4BGSE-Z is available at Aetrix Electronics and suitable for offline AC/DC adapters, isolated DC/DC converters, and industrial motor drives requiring stable component supply, reinforced isolation certification, and precise dual-channel timing control.

Supply support for MP18851-A4BGSE-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 over two decades of expertise in DC/DC conversion, gate drivers, and isolated controllers.

The MP18851 belongs to MPS's isolated gate driver product line, engineered specifically for high-density, high-reliability isolated power conversion systems requiring robust noise immunity, precise timing, and safety-compliant reinforcement.

FAQ

What does the "-A4B" suffix indicate in MP18851-A4BGSE-Z?

The "-A4B" suffix specifies three attributes: "A" denotes the disable-input logic polarity (active-high DIS), "4" indicates 4A peak output current per channel, and "B" sets the output-side UVLO threshold to 5V (min 5.0V, typ 5.5V, max 6.0V). This matches the SOIC-16 WB package and Z-tape-and-reel packaging.

Can MP18851-A4BGSE-Z drive both high-side and low-side switches in a half-bridge without external bootstrap components?

Yes - its dual independent secondary-side supplies (VDDA/VSSA and VDDB/VSSB) allow direct connection to high-side and low-side gate drivers with separate floating grounds. No bootstrap diodes or capacitors are needed, unlike non-isolated drivers, because each channel has its own isolated power path.

How does the 5kVRMS isolation rating apply to PCB layout requirements?

The 5kVRMS rating applies only to the SOIC-16 WB package with ≥8mm creepage and clearance between primary (pins 1–8) and secondary (pins 9–16) sides. PCB layout must maintain ≥8mm spacing across the isolation barrier, use slots or cutouts under the package, and avoid copper pours bridging the gap to meet UL/VDE certification.

Is the EN and DIS pin functionality mutually exclusive, or can they be used together?

EN (active-high) and DIS (active-high) are complementary controls: EN = high + DIS = low enables outputs; EN = low or DIS = high disables them. They are not mutually exclusive - both may float (EN pulled up, DIS pulled down internally), but simultaneous assertion (EN=high & DIS=high) forces disable, providing fail-safe redundancy.

Does MP18851-A4BGSE-Z support Miller clamp functionality for SiC MOSFETs?

No - MP18851-A4BGSE-Z does not integrate Miller clamp circuitry. It provides standard push-pull gate drive only. For SiC devices requiring active Miller clamping, external discrete clamp circuits (e.g., cascode-connected BJT/FET) must be added at the OUTA/OUTB nodes.

What thermal derating applies to MP18851-A4BGSE-Z at 100°C ambient temperature?

In SOIC-16 WB package, total safety power dissipation drops from 2215mW at 25°C to ~1400mW at 100°C ambient, per the thermal derating curve. This limits continuous 4A peak-current operation at high frequency unless heatsinking or airflow is applied to maintain junction temperature ≤125°C.

How is the 1500V functional isolation between VSSA and VSSB implemented physically?

The 1500V functional isolation between secondary-side grounds is achieved through internal die separation and package molding compound with CTI >600. It is validated by measuring VSSA–VSSB withstand voltage and is distinct from input-to-output isolation - enabling independent floating references for multi-phase half-bridges.