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

Overview

MCS1806GS-3-40-P 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 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-3-40-P datasheet, MCS1806GS-3-40-P pinout, MCS1806GS-3-40-P application, or MCS1806GS-3-40-P equivalent, key selection criteria include its 0.9mΩ internal conductor resistance, adjustable bandwidth up to 100kHz via external FILT capacitor, ratiometric analog output referenced to VCC/2, and guaranteed 500VRMS working voltage compliance per IEC62368-1.

Technical Context

The device implements differential Hall sensing with two integrated transducers (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A) to reject common-mode magnetic interference. Its spinning current technique minimizes offset drift, achieving ±10 mV max offset voltage over -40°C to +125°C operating junction temperature.

Galvanic isolation is achieved via reinforced insulation between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), with 4.2 mm creepage and clearance, 6000V surge withstand, and 100% production-tested 3000VRMS isolation. The internal 1.5kΩ filter resistor and 1nF capacitor enable bandwidth tuning from <10kHz to 100kHz using an external CF capacitor on FILT.

Key Specifications

Pinout & Package

Package: SOIC-8 (5mm × 4mm, 1.27mm pitch), 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-40AB-T and TMC1100-40A, MCS1806GS-3-40-P delivers superior isolation integrity (3kVRMS + 500VRMS working), lower thermal impact (0.9mΩ), and configurable bandwidth-making it optimal for safety-certified, thermally dense, and dynamically responsive power electronics.

Availability

MCS1806GS-3-40-P is available at Aetrix Electronics and suitable for motor control feedback, inverter phase-leg monitoring, and industrial SMPS over-current protection requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MCS1806GS-3-40-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 for high-reliability power conversion systems, emphasizing galvanic safety, thermal efficiency, and ease of integration in space-constrained industrial and automotive applications.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-40-P can measure with guaranteed linearity?

The device maintains ±2.5% total output error across its specified ±40A range at junction temperatures from −40°C to +125°C. Beyond ±40A, output remains proportional but nonlinearity increases-maximum usable current is limited by self-heating: at 40A DC, temperature rise is ~35°C above ambient on a standard evaluation board, so sustained >40A operation requires thermal derating based on PCB copper area and airflow.

How does the FILT pin affect bandwidth and noise performance?

The FILT pin connects to an external capacitor (CF) that forms a first-order RC filter with internal 1.5kΩ resistance and 1nF capacitance. With CF = 0 (floating), bandwidth is 100kHz and input-referred noise is 50mA(RMS) at 60kHz. Adding 10nF lowers bandwidth to ~10kHz and reduces noise to ~15mA(RMS), enabling cleaner measurements in noisy switch-mode environments at the cost of transient response speed.

Can MCS1806GS-3-40-P be used with a 5V supply?

No-MCS1806GS-3-40-P is factory-configured for 3.3V operation only. Its internal regulator, UVLO threshold (2.0–3.0V), and sensitivity calibration are optimized for 3.0–3.6V supply. For 5V systems, use MCS1806GS-5-40-P, which has 50mV/A sensitivity, different offset specs, and 4.5–5.5V operating range.

What is the recommended PCB layout for minimizing thermal stress?

Mount the SOIC-8 package directly on ≥2 oz copper with ≥100mm² thermal pad connected to internal ground plane via ≥8 thermal vias (0.3mm diameter). Keep primary current traces wide (>3mm) and short (<10mm) between IP+ and IP− pins. Avoid placing signal traces or components under the IC body to maximize heat dissipation through the package bottom into the PCB.

Does the device require calibration for zero-current output voltage (VOUT(Q))?

No-VOUT(Q) is factory trimmed to VCC/2 ±10mV over temperature, eliminating need for system-level null calibration. However, for highest accuracy, users should measure actual VOUT(Q) at operating temperature and subtract the deviation digitally in firmware, since thermal drift contributes up to ±10mV over −40°C to +125°C.

How is isolation verified during manufacturing?

Every unit undergoes 100% production testing per IEC62368-1 for 3000VRMS withstand isolation voltage for 60 seconds. Additionally, dielectric surge strength is validated at 6000V (1.2/50µs waveform) during qualification, and external creepage/clearance is measured at 4.2mm-exceeding minimum requirements for reinforced insulation in pollution degree 2 environments.

What is the propagation delay and how does it impact closed-loop control?

Propagation delay is 1.5µs-defined as time from 20% of primary current step to 20% of corresponding VOUT step. In FOC motor drives running at 20kHz PWM, this introduces <0.03° phase lag at 1kHz fundamental, well within typical control loop stability margins. Combined with 4µs rising time, it supports bandwidths up to 88kHz (0.35/tR), enabling high-fidelity current waveform capture.