Monolithic Power Systems Inc. MCS1806GS-3-50-Z

Overview

MCS1806GS-3-50-Z from Monolithic Power Systems is a 3.3V single-supply, galvanically isolated Hall-effect current sensor with ±50A bidirectional sensing range, ±2.5% total output error over -40°C to +125°C, and 3kVRMS isolation rating. It integrates a 0.9mΩ primary conductor and differential Hall array for stray-field immunity, delivering ratiometric analog output proportional to AC/DC current in motor control and power supply fault protection circuits.

For engineers reviewing the MCS1806GS-3-50-Z datasheet, MCS1806GS-3-50-Z pinout, MCS1806GS-3-50-Z application, or MCS1806GS-3-50-Z equivalent, key selection criteria include its SOIC-8 package footprint, 26.4 mV/A sensitivity at ±50A, adjustable bandwidth up to 100kHz via external FILT capacitor, and compliance with IEC62368-1 basic isolation (500VRMS working voltage).

Technical Context

The MCS1806GS-3-50-Z implements a differential Hall-sensing architecture with two integrated transducers placed asymmetrically along a low-resistance primary conductor, enabling magnetic field cancellation and eliminating hysteresis. Its spinning-current offset cancellation technique achieves stable zero-current output (VOUT(Q) = VCC/2) with ±10 mV offset drift over temperature.

Isolation is achieved via reinforced dielectric barrier between primary current path (IP+/IP−) and signal pins (VCC/VOUT/FILT/GND), certified to 3000VRMS withstand voltage per IEC62368-1 and supporting 500VRMS continuous working voltage. Bandwidth is configurable from DC to 100kHz using an external capacitor on the FILT pin, with internal RFI = 1.5kΩ and CFI = 1nF forming a programmable RC filter.

Key Specifications

Pinout & Package

SOIC-8 (5mm × 4mm) surface-mount package with creepage and clearance ≥4.2mm between primary and secondary sides, rated for 500VRMS working voltage and 3000VRMS surge isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-50AB-T and TMC1100-50A, the MCS1806GS-3-50-Z delivers superior low-voltage compatibility, tighter total error (±2.5% vs. ±3.5%), and simpler analog integration-making it optimal for cost-sensitive, space-constrained 3.3V industrial controls where digital overhead is undesirable.

Availability

MCS1806GS-3-50-Z is available at Aetrix Electronics and suitable for motor control, switch-mode power supplies, and industrial over-current protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1806GS-3-50-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 delivers isolated current sensing for high-reliability industrial and automotive power systems, designed to replace optocouplers and discrete shunt-based solutions with integrated galvanic isolation and factory-trimmed accuracy.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-50-Z can measure without saturation?

The device maintains linear output up to ±50A, its specified optimized accuracy range. Beyond this, VOUT remains proportional to IP until reaching saturation voltages (VCC − 0.3V high, 0.3V low), but nonlinearity exceeds ±2.5%. At 50A, self-heating raises junction temperature by ~25°C on standard FR4 with 2oz copper, staying within the 125°C max operating limit.

How does the FILT pin affect bandwidth and noise performance?

Connecting a capacitor (CF) between FILT and GND sets a first-order RC filter with RFI = 1.5kΩ and CFI = 1nF. For example, a 1nF CF yields ~106kHz bandwidth; a 10nF CF reduces it to ~10kHz, lowering input-referred noise from 50mA(RMS) to ~16mA(RMS) while improving EMI immunity in noisy power stages.

Can the MCS1806GS-3-50-Z be used in AC-only applications?

Yes-it measures both AC and DC currents with identical linearity and accuracy. Its differential Hall architecture rejects 50/60Hz magnetic interference from nearby conductors, and the ratiometric output ensures consistent scaling regardless of supply ripple. No external biasing or coupling capacitors are required for AC use.

What PCB layout practices ensure optimal isolation and thermal performance?

Maintain ≥4.2mm creepage/clearance between IP+/IP− pads and signal pins; use internal ground planes only on secondary side; isolate primary copper pours thermally with slots; place 1µF VCC bypass capacitor ≤2mm from pin 8; avoid routing signal traces under the IC body to prevent coupling into Hall elements.

Is the ±2.5% total output error guaranteed over the full temperature range?

Yes-the ±2.5% ETOT specification is validated across TJ = −40°C to +125°C, including contributions from sensitivity error (±2%), offset voltage drift (±10mV), and nonlinearity (0.5%). Lifetime drift adds ±1% maximum, confirmed by accelerated aging tests per JEDEC JESD22-A108.

Does the device require calibration during production?

No factory calibration is needed-the sensitivity and offset are laser-trimmed during wafer sort, and ratiometry (KSENS/KVO) is characterized to 98–102%. System-level calibration is optional but not required to meet ±2.5% accuracy; typical production units achieve ±1.8% error at room temperature.

What safety certifications apply to the MCS1806GS-3-50-Z isolation barrier?

The isolation barrier is certified to IEC62368-1 (reinforced insulation) with 3000VRMS withstand voltage (60s test) and 500VRMS maximum working voltage. It meets UL 1577 and CSA Component Acceptance Notice #5 for basic insulation, and is rated for Pollution Degree 2 per IEC60664-1.