Monolithic Power Systems Inc. MCS1806GS-3-05-P

Overview

MCS1806GS-3-05-P from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±5A bidirectional DC/AC sensing with 3.3V single-supply operation, 264 mV/A sensitivity, ±2.5% total output error over –40°C to +125°C, and 3kVRMS isolation - deployed in motor control feedback loops and inverter phase-leg monitoring.

For engineers reviewing the MCS1806GS-3-05-P datasheet, MCS1806GS-3-05-P pinout, MCS1806GS-3-05-P application, or MCS1806GS-3-05-P equivalent, this device delivers ratiometric analog output, differential magnetic field immunity, factory-trimmed accuracy, and SOIC-8 footprint compatibility for space-constrained industrial power systems requiring stable current measurement under high dv/dt noise.

Technical Context

The MCS1806GS-3-05-P integrates two matched Hall plates with asymmetric primary conductor geometry to generate differential magnetic coupling (0.6 mT/A and 0.3 mT/A), enabling stray-field rejection via spinning current offset cancellation. Its internal 1.5 kΩ filter resistor and 1 nF capacitor set baseline bandwidth at 100 kHz when FILT is unconnected.

Galvanic isolation is achieved through reinforced dielectric barrier between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), rated for 3000 VRMS withstand voltage and 500 VRMS working voltage per IEC62368-1, with 4.2 mm creepage and clearance.

Key Specifications

Pinout & Package

SOIC-8 package (5 mm × 4 mm, 1.57 mm height) with gull-wing leads; primary current path isolated from signal side by internal molded insulation barrier.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS712ELCTR-05B-T and TMC1100-5A, the MCS1806GS-3-05-P uniquely combines 3.3V operation, ±2.5% accuracy over full automotive temperature range, analog ratiometric output, and user-adjustable bandwidth - making it optimal for analog-control-loop designs where supply headroom and noise immunity are constrained.

Availability

MCS1806GS-3-05-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 RoHS-compliant sourcing.

Supply support for MCS1806GS-3-05-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 design focus on efficiency, integration, and reliability for industrial, computing, and automotive markets.

The MCS1806 product line delivers isolated Hall-effect current sensors targeting high-density power conversion systems where galvanic isolation, low power loss, and analog interface simplicity are critical - particularly in inverters, motor drives, and battery management.

FAQ

What is the maximum continuous primary current the MCS1806GS-3-05-P can handle without exceeding junction temperature limits?

The device supports ±5A optimized range, but its 0.9 mΩ conductor enables safe continuous operation up to ±50A depending on PCB copper area and ambient temperature. At TA = 25°C with standard 2 oz copper on both sides, self-heating remains below 20°C at ±20A - verified per Figure 10 in the datasheet. Derating is required above 125°C ambient.

Can the MCS1806GS-3-05-P measure AC currents with high harmonic content, such as those found in VFD outputs?

Yes - its 100 kHz native bandwidth and differential Hall architecture reject common-mode magnetic interference from adjacent conductors. With FILT pin grounded via 10 nF capacitor, bandwidth reduces to ~10 kHz, effectively filtering 50th-order harmonics while preserving fundamental 50/60 Hz response with <0.1% gain error.

How does the ratiometric output behave if the 3.3V supply varies between 3.0V and 3.6V during operation?

VOUT scales linearly with VCC: zero-current output stays at VCC/2 (±15 mV), and sensitivity remains within 98–102% of nominal 264 mV/A across the full 3.0–3.6V range. This eliminates need for external voltage reference or software gain correction in systems with unregulated 3.3V rails.

Is external filtering required on the VOUT pin for use with a 12-bit SAR ADC?

No external RC filter is required - the internal 1.5 kΩ series resistance and 10 nF max capacitive load limit ensure stability with standard 12-bit ADC inputs. For noise-sensitive applications, a 100 Ω series resistor + 1 nF capacitor to GND at the ADC input reduces broadband noise without affecting 100 kHz signal fidelity.

What is the recommended PCB layout practice to maintain specified isolation and thermal performance?

Follow MPS layout guidelines: keep primary current traces wide (>2 mm) and straight between IP+ and IP− pins; isolate signal-side copper (GND, VOUT, FILT, VCC) from primary-side copper by ≥4.2 mm; use thermal vias under exposed pad (if present) and maximize inner-layer copper pour connected to GND for heat dissipation.

Does the MCS1806GS-3-05-P support bidirectional current measurement out-of-the-box?

Yes - VOUT is centered at VCC/2 (e.g., 1.65 V at 3.3 V supply), producing positive voltage for +IP and negative deviation for –IP. No external biasing or op-amp circuitry is needed; the full ±5A range maps linearly to ~0.825 V to ~2.475 V output swing with 264 mV/A gain.

How is the ±2.5% total output error distributed across temperature and current range?

At ±5A and –40°C to +125°C, ±2.5% includes ±2% sensitivity error, ±15 mV offset (±5.7 mA equivalent), and ±0.5% nonlinearity. Offset dominates near zero current; sensitivity error dominates near full scale. Lifetime drift adds ±1% total error over 10 years per datasheet Table 6.