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

Overview

MCS1806GS-3-20-P from Monolithic Power Systems is a galvanically isolated linear Hall-effect current sensor with ±20A bidirectional sensing range, 3.3V single supply, 66mV/A sensitivity, ±2.5% total output error over -40°C to +125°C, and 3kVRMS isolation rating. It replaces optocouplers in motor control feedback loops, inverter phase-leg monitoring, and over-current protection circuits where compact SOIC-8 footprint and immunity to stray magnetic fields are critical.

For engineers reviewing the MCS1806GS-3-20-P datasheet, MCS1806GS-3-20-P pinout, MCS1806GS-3-20-P application, or MCS1806GS-3-20-P equivalent, key selection criteria include its 0.9mΩ internal conductor resistance, adjustable 100kHz bandwidth via external FILT capacitor, ratiometric analog output referenced to VCC/2, and factory-trimmed accuracy without external calibration.

Technical Context

The device uses a differential Hall array architecture with two spatially separated sensing points (PMCF1 = 0.6mT/A, PMCF2 = 0.3mT/A) to reject common-mode magnetic interference. Its spinning current technique minimizes offset drift, achieving ±10mV max offset voltage over temperature.

Galvanic isolation is achieved via integrated high-voltage barrier between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), rated for 3kVRMS dielectric strength and 500VRMS working voltage per IEC62368-1. The internal 1.5kΩ filter resistor and 1nF capacitor enable bandwidth adjustment up to 100kHz using an external CF capacitor.

Key Specifications

Pinout & Package

SOIC-8 package (5mm × 4mm, 1.57mm height) with creepage and clearance ≥4.2mm between primary and secondary sides for reinforced isolation compliance.

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 TMC1100-20A, MCS1806GS-3-20-P delivers optimal balance of 3kVRMS isolation, SOIC-8 compactness, and factory-trimmed ±2.5% accuracy-making it preferred for space-constrained industrial inverters and automotive OBCs requiring IEC62368-1 compliance.

Availability

MCS1806GS-3-20-P is available at Aetrix Electronics and suitable for motor controls, switch-mode power supplies, and automotive on-board chargers requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1806GS-3-20-P 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 solutions optimized for high-efficiency motor drives, renewable energy inverters, and automotive electrification systems where accuracy, size, and safety certification are critical.

FAQ

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

The device guarantees ±2.5% total output error and linear response across its optimized range of ±20A. While it continues to provide proportional output beyond ±20A, nonlinearity increases outside this range due to magnetic saturation effects in the Hall sensing structure.

How does the FILT pin affect bandwidth and noise performance?

Connecting an external capacitor (CF) between FILT and GND forms a first-order RC filter with internal RFI (1.5kΩ) and CFI (1nF). This reduces bandwidth per fBW = 1/(2π × RFI × (CF + CFI)) and lowers input-referred noise from 200µA/√Hz to 50mA(RMS) at 60kHz, enabling SNR optimization for specific switching frequencies.

Can MCS1806GS-3-20-P be used with 5V supply instead of 3.3V?

No - MCS1806GS-3-20-P is specifically configured for 3.3V operation (VCC = 3.0–3.6V). Using 5V exceeds absolute maximum ratings and risks permanent damage. For 5V systems, select MCS1806GS-5-20-P, which has 100mV/A sensitivity and 4.5–5.5V supply range.

What is the thermal impact of 20A continuous current on the SOIC-8 package?

At ±20A DC, self-heating raises junction temperature by ~45°C above ambient on a standard 2-layer evaluation board. With TA = 25°C, TJ ≈ 70°C - well below the 165°C maximum. Thermal performance improves significantly with increased copper area or forced airflow.

Does the device require external zero-current calibration?

No - the MCS1806GS-3-20-P is factory-trimmed for zero-current output (VOUT(Q) = VCC/2 ±10mV) and sensitivity (66mV/A). No external calibration is needed; offset and gain errors are fully characterized and compensated during production test.

How is galvanic isolation verified in production?

Every unit undergoes 100% production testing per IEC62368-1, applying 3000VRMS for 60 seconds between primary (IP+/IP−) and secondary (VCC/VOUT/FILT/GND) terminals. Dielectric surge strength is validated separately at 6000V per IEC61000-4-5.

What PCB layout practices maximize isolation integrity and thermal performance?

Maintain ≥4.2mm creepage/clearance between primary and secondary copper, use internal ground planes only on signal-side layers, place 1µF bypass capacitor within 2mm of VCC pin, and extend IP+/IP− traces with ≥1oz copper and ≥2mm width to minimize resistance and inductance.