Monolithic Power Systems Inc. MCS1806GS-3-40-Z

Overview

MCS1806GS-3-40-Z from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±40A bidirectional DC/AC sensing with 3.3V single supply, 33 mV/A sensitivity, ±2.5% total output error, and 3kVRMS isolation. It replaces optocouplers in motor control and power supply feedback loops where compact SOIC-8 footprint and immunity to stray magnetic fields are critical.

For engineers reviewing the MCS1806GS-3-40-Z datasheet, MCS1806GS-3-40-Z pinout, MCS1806GS-3-40-Z application, or MCS1806GS-3-40-Z equivalent, key selection criteria include its 0.9mΩ internal conductor resistance, adjustable 100kHz bandwidth via external FILT capacitor, ratiometric analog output, and guaranteed 500VRMS working voltage under IEC62368-1.

Technical Context

The MCS1806GS-3-40-Z implements differential Hall sensing with two integrated transducers (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A) to cancel external magnetic interference. Its spinning current technique ensures stable offset drift of ±10 mV over -40°C to +125°C junction temperature.

Galvanic isolation is achieved via reinforced insulation between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), enabling safe measurement of high-side or floating currents up to 500VRMS working voltage and 6000V surge withstand per IEC61000-4-5.

Key Specifications

Pinout & Package

SOIC-8 package (5mm × 4mm, 1.27mm pitch) with reinforced creepage/clearance ≥4.2 mm between primary and signal sides.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar isolated current sensing applications.

Compared with ACS724LLCTR-40AB-T and TMC1100A10XUMA1, the MCS1806GS-3-40-Z delivers superior isolation margin (3kVRMS vs. 2.4kVRMS), tighter accuracy (±2.5% vs. ±3%), and design flexibility via FILT-adjustable bandwidth-all in the same SOIC-8 footprint.

Availability

MCS1806GS-3-40-Z is available at Aetrix Electronics and suitable for motor controls, switch-mode power supplies, and over-current fault protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1806GS-3-40-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 precision analog sensors.

The MCS1806 product line targets high-reliability current sensing in industrial motor drives, renewable energy inverters, and automotive on-board chargers-emphasizing galvanic isolation, wide temperature operation, and minimal external component count.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-40-Z can handle without derating?

The device supports ±40A continuous primary current within its specified accuracy range. At 40A, self-heating raises junction temperature; thermal performance depends on PCB copper area and ambient conditions. With 2oz copper and 25°C ambient, typical ΔTJ is ~35°C-well below the 165°C absolute max, provided adequate heatsinking is applied.

Can the MCS1806GS-3-40-Z measure AC current waveforms accurately?

Yes. Its linear Hall architecture and 100kHz bandwidth support accurate measurement of sinusoidal, square, and pulsed AC waveforms up to 40A peak. Total output error remains ≤±2.5% across −40°C to +125°C, and ratiometric output ensures consistent scaling regardless of supply ripple.

How does the FILT pin affect noise and bandwidth tradeoffs?

Connecting a capacitor (CF) between FILT and GND forms a first-order RC filter with internal RFI (1.5kΩ) and CFI (1nF). For example, a 1nF CF yields ~106kHz bandwidth; a 10nF CF reduces it to ~10.6kHz, lowering output noise by ~3× while increasing response time proportionally.

Is external calibration required to achieve ±2.5% accuracy?

No. The MCS1806GS-3-40-Z is factory-trimmed for sensitivity and offset. Its ±2.5% total output error specification includes contributions from sensitivity error (±2%), offset voltage (±10mV), and nonlinearity (0.5%) across the full temperature and current range-no user calibration is needed.

What is the minimum recommended bypass capacitance on the VCC pin?

A 1µF low-ESR ceramic capacitor is required directly between VCC and GND, placed as close as possible to the VCC pin. This stabilizes the internal regulator, suppresses switching noise from adjacent circuits, and ensures clean power for the Hall sensor and analog front-end.

Does the device support bidirectional current sensing out-of-the-box?

Yes. The ratiometric output centers at VCC/2 (1.65V at 3.3V supply), producing positive voltage excursions for current in the IP+→IP− direction and negative excursions for reverse flow. No external level-shifting or biasing is required for full ±40A bidirectional measurement.

What safety certifications apply to the MCS1806GS-3-40-Z's isolation barrier?

The isolation barrier is type-tested to IEC62368-1 for 3000VRMS withstand voltage (60s) and IEC61000-4-5 for 6000V surge (1.2/50µs). External clearance and creepage are both ≥4.2mm, satisfying reinforced insulation requirements for functional safety applications up to 500VRMS working voltage.