Monolithic Power Systems Inc. MCS1806GS-3-20-Z

Overview

MCS1806GS-3-20-Z from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±20A bidirectional DC/AC sensing with 3.3V single supply, 66 mV/A sensitivity, ±2.5% total output error over -40°C to +125°C, and 3kVRMS isolation-used in motor control feedback loops and inverter phase-current monitoring.

For engineers reviewing the MCS1806GS-3-20-Z datasheet, MCS1806GS-3-20-Z pinout, MCS1806GS-3-20-Z application, or MCS1806GS-3-20-Z equivalent, key selection criteria include primary conductor resistance (0.9 mΩ), adjustable bandwidth up to 100 kHz via FILT pin capacitor, ratiometric output scaling with VCC, immunity to stray magnetic fields via differential Hall array, and SOIC-8 footprint compatibility with space-constrained power stage layouts.

Technical Context

The MCS1806GS-3-20-Z implements a differential Hall-sensing architecture with two integrated transducers placed at asymmetric points along a low-resistance primary conductor (0.9 mΩ), generating magnetic field gradients proportional to current. Spinning current offset cancellation ensures stable zero-current output (VOUT(Q) = VCC/2) across temperature.

Galvanic isolation is achieved through internal molding and package-level creepage/clearance (4.2 mm), enabling replacement of optocouplers in high-side current sensing. Bandwidth is programmable from <10 kHz to 100 kHz using an external capacitor on the FILT pin, interfacing with internal 1.5 kΩ resistor and 1 nF capacitor.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm, 1.55 mm height), surface-mount, RoHS-compliant, MSL Level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-20AB-T and TMCS1100A1QDR, the MCS1806GS-3-20-Z delivers superior isolation (3kVRMS vs. ≤2.5kVRMS), tighter accuracy (±2.5% vs. ±3–5%), and SOIC-8 compatibility-making it optimal for space-constrained, safety-critical industrial and automotive power stages requiring long-term stability without recalibration.

Availability

MCS1806GS-3-20-Z is available at Aetrix Electronics and suitable for motor controls, switch-mode power supplies, and automotive onboard chargers requiring stable component supply, long-lifecycle support, and certified isolation performance.

Supply support for MCS1806GS-3-20-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 expertise in 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 electrification-designed to replace optocouplers with integrated, factory-calibrated Hall-effect isolation.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-20-Z can measure with guaranteed linearity?

The device guarantees ±2.5% total output error and linear response across its optimized range of ±20A. Beyond ±20A, output remains proportional but nonlinearity increases-maximum usable current is limited by junction temperature (165°C) and self-heating, typically allowing brief peaks up to ±35A with adequate PCB copper area.

How does the FILT pin affect bandwidth and noise performance?

Connecting a capacitor (CF) between FILT and GND forms a first-order RC filter with internal 1.5 kΩ resistance and 1 nF capacitance, lowering bandwidth per fBW = 1/(2π × RFI × (CF + CFI)). A 1 nF CF reduces bandwidth to ~100 kHz; 10 nF lowers it to ~10 kHz, reducing output noise (e.g., 50 mA RMS at 60 kHz) by ~10×.

Can the MCS1806GS-3-20-Z operate from a 5V supply?

No-the "-3-" suffix denotes the 3.3V supply variant. The 5V-compatible version is MCS1806GS-5-20-Z (100 mV/A sensitivity). Using 5V on MCS1806GS-3-20-Z exceeds the absolute maximum VCC rating (6V) but violates recommended operating conditions (3.0–3.6V), risking increased offset drift and premature failure.

What is the significance of the dual IP+ and IP− pins?

Pins 1&2 (IP+) and 3&4 (IP−) are internally shorted pairs to distribute high current and reduce current density at solder joints. This design lowers thermal stress and improves reliability under ±20A continuous operation, while maintaining 0.9 mΩ effective conductor resistance measured between any IP+ and IP− pair.

Does the MCS1806GS-3-20-Z require external calibration for production use?

No-factory trimming ensures ±2.5% total output error across -40°C to +125°C without user calibration. Offset voltage (±10 mV max) and sensitivity error (±2%) are pre-characterized; ratiometric behavior (KSENS/KVO = 98–102%) further eliminates need for supply-voltage compensation in most MCU-based systems.

How is isolation verified during manufacturing?

Every unit undergoes 100% production testing per IEC62368-1 for 3000 VRMS withstand isolation voltage (60-second test). Dielectric surge strength (6000 V) and working voltage (500 VRMS) are type-tested per IEC62368-1 and IEC61000-4-5, with external clearance and creepage both guaranteed at 4.2 mm.

What PCB layout practices maximize thermal performance?

Mount the SOIC-8 package on ≥2 oz copper with ≥200 mm² thermal pad connected to internal ground planes via ≥8 vias (0.3 mm diameter). Keep primary current traces wide (>2 mm) and symmetric across IP+/IP− pairs; avoid routing noisy signals near FILT or VOUT to preserve SNR.