Monolithic Power Systems Inc. MP18851-A4CGY-Z

Overview

MP18851-A4CGY-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 capacitive isolation, supporting up to 30V secondary-side supply and operating across –40°C to +125°C for industrial DC/DC and AC/DC converters.

For engineers reviewing the MP18851-A4CGY-Z datasheet, MP18851-A4CGY-Z pinout, MP18851-A4CGY-Z application, or MP18851-A4CGY-Z equivalent, this part delivers verified functional isolation between secondary-side drivers (1500VDC), UL 1577–certified 5kVRMS input-to-output isolation (SOIC-16 WB), and configurable enable/disable logic for robust gate drive control in high-noise power systems.

Technical Context

The MP18851 employs MPS's proprietary capacitive-based isolation barrier to separate primary-side logic control (INA/INB, EN/DIS) from two fully independent secondary-side gate drivers (OUTA/VSSA/VDDA and OUTB/VSSB/VDDB), enabling split-ground configurations and half-bridge or dual-driver topologies. Each channel features dedicated UVLO thresholds (3V option for -A variant), internal pull-downs on INA/INB, and TTL/CMOS-compatible inputs.

Its architecture supports simultaneous or asynchronous switching with <6ns pulse-width distortion and <6ns channel-to-channel propagation delay matching. The SOIC-16 WB package provides reinforced insulation (5kVRMS, 6000VPK), while CMTI >100kV/µs ensures reliable operation under fast dv/dt transients in SiC/GaN-based converters.

Key Specifications

Pinout & Package

MP18851-A4CGY-Z is packaged in SOIC-16 WB (wide-body), providing 5kVRMS isolation and 8mm minimum creepage/clearance. Pin functions are validated per MPS MP18851 Rev. 1.0 datasheet (pp. 7–8).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si8273BD-D-IS and ADUM4223BRIZ, MP18851-A4CGY-Z uniquely combines 4A drive strength, 3V UVLO option, dual EN/DIS control, and 1500VDC inter-channel isolation - making it optimal for high-reliability SiC/GaN systems requiring flexible fault management and wide gate bias range.

Availability

MP18851-A4CGY-Z is available at Aetrix Electronics and suitable for industrial DC/DC converters, offline AC/DC power supplies, and solar inverters requiring stable component supply, long-term lifecycle support, and traceable sourcing for production ramp.

Supply support for MP18851-A4CGY-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 20 years of expertise in DC/DC conversion, motor control, and isolated gate drive solutions.

The MP18851 belongs to MPS's isolated gate driver product line, designed specifically for high-efficiency, high-density power systems using wide-bandgap semiconductors - emphasizing low propagation skew, ultra-high CMTI, and flexible configuration for SiC and GaN adoption.

FAQ

What is the isolation rating of MP18851-A4CGY-Z and which certifications does it hold?

MP18851-A4CGY-Z in SOIC-16 WB package provides 5kVRMS isolation for 60 seconds per UL 1577 and 6000VPK per DIN EN IEC 60747-17 (VDE 0884-17):2021-10. It also holds CQC certification per GB 4943.1-2011 and is rated for reinforced insulation up to 630VRMS working voltage.

Does MP18851-A4CGY-Z support independent control of each channel's UVLO threshold?

No - the "-A" suffix denotes a fixed 3V UVLO threshold on both VDDA and VDDB supplies. All channels share the same UVLO level; selectable thresholds (5V, 8V, etc.) are implemented via different part numbers (e.g., -B, -C), not programmable on the -A variant.

Can EN and DIS pins be used simultaneously, and what happens if both are asserted?

Yes - EN (active-high) and DIS (active-high) are logically OR'd internally. If either is asserted (high), the driver remains enabled; only when both are low does the device enter shutdown mode. This provides hardware-level redundancy for fail-safe operation.

What is the maximum recommended layout creepage distance between primary and secondary sides for MP18851-A4CGY-Z?

MPS specifies minimum external creepage of >8mm for SOIC-16 WB packages. PCB layout must maintain ≥8mm clearance across the isolation barrier (e.g., between pins 1–4 and pins 9–16), with conformal coating recommended for pollution degree 2 environments per IEC 60664-1.

Is MP18851-A4CGY-Z compatible with 1.2kV SiC MOSFETs requiring 20V gate drive?

Yes - its VDDA/VDDB supports up to 30V, and the 4A peak current ensures fast charging of large gate capacitances. With 1.3Ω typical source resistance and 50ns propagation delay, it meets turn-on requirements for 1.2kV SiC devices at 100kHz+ switching frequencies.

How does the MP18851 handle mismatched input signal timing between INA and INB?

Each channel operates independently - INA controls OUTA, INB controls OUTB, with no internal synchronization logic. Propagation delay matching is <6ns, so externally timed inputs retain sub-ns relative accuracy, enabling precise dead-time control in half-bridge configurations.

What thermal derating applies to MP18851-A4CGY-Z at 85°C ambient temperature?

In SOIC-16 WB package, safety limiting power drops to ~1800mW at 85°C ambient (per Fig. 14, p.14), and peak output current per channel reduces to ~75mA at 30V VDDA/VDDB. Full 4A drive is only guaranteed below 70°C ambient with adequate PCB copper area.