Monolithic Power Systems Inc. MCS1806GS-5-40-P

Overview

MCS1806GS-5-40-P from Monolithic Power Systems is a galvanically isolated, bidirectional Hall-effect current sensor in SOIC-8 package, delivering ±2.5% total output error over –40°C to +125°C, 50 mV/A sensitivity at 5V supply, and 3kVRMS isolation for ±40A primary current sensing in motor control and power conversion systems.

For engineers reviewing the MCS1806GS-5-40-P datasheet, MCS1806GS-5-40-P pinout, MCS1806GS-5-40-P application, or MCS1806GS-5-40-P equivalent, key selection criteria include its differential Hall architecture for stray-field immunity, adjustable 100kHz bandwidth via external FILT capacitor, ratiometric analog output, and 0.9mΩ internal conductor resistance enabling low-loss current measurement without shunt resistors.

Technical Context

The MCS1806GS-5-40-P integrates two matched Hall plates with asymmetric primary conductor geometry to generate differential magnetic field sensing (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A), enabling rejection of uniform external magnetic interference. Its spinning current technique minimizes offset drift, while factory trimming ensures ±2.5% total output error across temperature and lifetime.

Galvanic isolation is achieved via reinforced insulation 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 device supports 4.5–5.5V operation, delivers 8.5–10.5mA supply current, and features propagation delay of 1.5µs and response time of 5µs under full-scale step input.

Key Specifications

Pinout & Package

SOIC-8 package (5mm × 4mm, 1.5mm height) with creepage and clearance ≥4.2mm between primary and secondary sides, supporting reinforced isolation. Primary current path occupies pins 1–4 (dual IP+ and dual IP–); signal side occupies pins 5–8 (GND, FILT, VOUT, VCC).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCB-40AB-T and TMC1100-50, the MCS1806GS-5-40-P uniquely combines 5V operation, 3kVRMS isolation, analog ratiometric output, and user-adjustable bandwidth in a compact SOIC-8 footprint-making it optimal for cost-sensitive, high-reliability analog control loops requiring design flexibility.

Availability

MCS1806GS-5-40-P is available at Aetrix Electronics and suitable for motor controls, switch-mode power supplies, automotive on-board chargers, and over-current fault protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1806GS-5-40-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, with expertise in DC/DC converters, LED drivers, and isolated sensing solutions.

The MCS1806 product line delivers monolithic, Hall-based isolated current sensors targeting space-constrained, high-efficiency power systems where accuracy, reliability, and safety-certified isolation are critical.

FAQ

What is the maximum continuous primary current the MCS1806GS-5-40-P can handle without exceeding junction temperature limits?

The device supports ±40A continuous primary current within its specified linear range. At this level and ambient temperature of 25°C on a standard evaluation board, self-heating raises junction temperature by ~45°C. To stay below the 165°C absolute maximum, ambient must remain ≤120°C or PCB copper area must be increased per MPS AN178 thermal guidelines.

How does the FILT pin affect bandwidth, and what capacitor value yields 20kHz cutoff?

The FILT pin forms an RC filter with internal RFI = 1.5kΩ and CFI = 1nF. Using fBW = 1/(2π × RFI × (CF + CFI)), a 5.3nF external capacitor yields ~20kHz bandwidth. Capacitor tolerance and PCB parasitics must be considered; use X7R/C0G ceramics with tight tolerance for stable performance.

Can the MCS1806GS-5-40-P measure DC current accurately in the presence of strong external magnetic fields?

Yes. Its differential Hall array cancels uniform external magnetic fields due to matched geometry and ±1% Hall plate matching. Testing shows <0.1% output deviation under 100 Gauss DC field - sufficient for operation near transformers or high-current traces without shielding.

Is the output voltage truly ratiometric, and how does supply variation impact measurement accuracy?

Yes. Sensitivity (KSENS = 98–102%) and zero-current output (KVO = 99–101%) track VCC across 4.5–5.5V. A 5% VCC change induces <0.5% gain error and <0.3% offset shift - negligible compared to the ±2.5% total error budget, enabling robust operation with unregulated 5V rails.

What is the recommended PCB layout practice to preserve isolation and minimize noise coupling?

Maintain ≥4.2mm creepage/clearance between IP+/IP– pads and signal-side pads; use separate primary and secondary ground planes with no vias bridging the isolation barrier; place 1µF bypass capacitor within 2mm of VCC pin; route FILT traces away from noisy switching nodes to avoid injecting noise into the filter node.

Does the MCS1806GS-5-40-P support bidirectional current sensing, and how is polarity indicated?

Yes. Output voltage centers at VCC/2 (2.5V nominal at 5V supply). Current in the IP+→IP– direction produces VOUT > VCC/2; reverse current produces VOUT < VCC/2. Full-scale swing is ±2V, enabling direct connection to single-supply ADCs with appropriate reference and input range.

What safety certifications apply to the MCS1806GS-5-40-P's isolation barrier?

The isolation barrier is type-tested per IEC62368-1 for 3000 VRMS withstand voltage and certified for 500 VRMS working voltage. It meets reinforced insulation requirements and is 100% production-tested for isolation integrity - documentation available in MPS Certificate of Compliance (CoC) #MPS-ISO-2022-08.