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

Overview

MCS1806GS-3-50-P from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±50A bidirectional DC/AC sensing with 3.3V single-supply operation, 26.4 mV/A sensitivity, ±2.5% total output error over -40°C to +125°C, and 3kVRMS isolation - deployed in motor control inverters and switch-mode power supply over-current protection circuits.

For engineers reviewing the MCS1806GS-3-50-P datasheet, MCS1806GS-3-50-P pinout, MCS1806GS-3-50-P application, or MCS1806GS-3-50-P equivalent, key selection criteria include primary conductor resistance (0.9 mΩ), adjustable bandwidth up to 100 kHz via external FILT capacitor, ratiometric output scaling with VCC, immunity to stray magnetic fields via differential Hall array, and SOIC-8 footprint compatibility with space-constrained PCB layouts.

Technical Context

The MCS1806GS-3-50-P implements a differential Hall-sensing architecture with two integrated transducers placed asymmetrically along a low-resistance primary conductor (0.9 mΩ), generating magnetic field gradients proportional to current magnitude and polarity. Its spinning current technique minimizes offset drift, while internal dynamic offset cancellation and factory trimming ensure ±2.5% accuracy across temperature.

Galvanic isolation is achieved via reinforced insulation between primary current terminals (IP+, IP−) and signal pins (VCC, VOUT, FILT, GND), rated for 3kVRMS dielectric surge strength and 500VRMS working voltage per IEC62368-1. Bandwidth is configurable from <10 kHz to 100 kHz using an external capacitor on the FILT pin, with internal RFI = 1.5 kΩ and CFI = 1 nF forming a first-order low-pass filter.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm, 1.57 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-50AB-T and TMC1100-50A, the MCS1806GS-3-50-P uniquely combines 3.3V operation, 3kVRMS isolation, and analog bandwidth configurability - making it optimal for space-constrained, safety-certified 3.3V industrial drives where analog simplicity and high isolation integrity are mandatory.

Availability

MCS1806GS-3-50-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 assurance, and traceable sourcing for production ramp-up.

Supply support for MCS1806GS-3-50-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 - headquartered in Kirkland, WA, with global design and support centers.

The MCS1806 product line delivers isolated Hall-effect current sensors targeting high-reliability industrial motor drives, renewable energy inverters, and automotive electrification systems - designed to replace optocouplers and shunt-based solutions with superior accuracy, bandwidth, and integration.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-50-P can measure without damage?

The device is rated for ±50A continuous primary current with guaranteed linearity and ±2.5% total error. It can withstand transient surges up to 3000A (8µs/20µs pulse) and 250A (10ms single peak) per IEC61000-4-5, but sustained operation beyond ±50A increases nonlinearity and self-heating - junction temperature must remain ≤165°C.

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 RFI = 1.5 kΩ and CFI = 1 nF. Increasing CF lowers bandwidth (e.g., 10 nF → ~10 kHz) and reduces output noise (e.g., 50 mA(RMS) at 60 kHz drops proportionally), enabling optimization for either high-speed control or low-noise energy measurement.

Can the MCS1806GS-3-50-P operate from a 3.0V supply?

Yes - the device operates across 3.0V to 3.6V per its recommended conditions. At 3.0V, VOUT(Q) = 1.5V nominal, full-scale output is ±1.32V, and UVLO releases at 2.5V. Performance specifications (accuracy, bandwidth, noise) remain valid across this range, verified from −40°C to +125°C.

What is the thermal impact of 50A DC current on the SOIC-8 package?

At 50A DC, self-heating raises junction temperature by ~45°C above ambient on the standard evaluation board (per Figure 10). With TA = 85°C, TJ ≈ 130°C - well below the 165°C limit. Board-level thermal design (copper area, thickness, airflow) directly impacts this delta; doubling PCB copper weight reduces ΔT by ~15°C.

Does the MCS1806GS-3-50-P require calibration for zero-current offset?

No - factory trimming achieves ±10 mV offset voltage (VOE) over −40°C to +125°C, translating to ±0.38A error at ±50A range. This is included in the ±2.5% total output error specification. System-level calibration is optional but not required for most industrial applications meeting IEC 61800-3 or UL 62368-1.

How is galvanic isolation physically implemented in the SOIC-8 package?

Isolation is achieved through reinforced creepage (4.2 mm) and clearance (4.2 mm) between primary (IP+/IP−) and signal (VCC/VOUT/FILT/GND) leads, plus internal molding compound with high dielectric strength. The 3000 VRMS withstand rating is 100% production-tested per IEC62368-1 - no internal transformer or capacitive coupler is used.

What is the minimum load impedance supported on the VOUT pin?

VOUT is specified for RL ≥ 4.7 kΩ to maintain accuracy and output swing (VCC − 0.3V / 0.3V). Driving lower impedances increases output error due to loading effects and may reduce bandwidth. For driving ADC inputs, a unity-gain buffer is recommended if source impedance exceeds 10 kΩ or if noise immunity is critical.