Monolithic Power Systems Inc. MCS1806GS-5-05-P

Overview

MCS1806GS-5-05-P from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±5A bidirectional DC/AC sensing with 400 mV/A sensitivity, ±2.5% total output error, and 3kVRMS isolation. It integrates differential Hall transducers, spinning-current offset cancellation, and an internal 0.9mΩ primary conductor-enabling high-accuracy current monitoring in motor control, SMPS over-current protection, and automotive power systems without magnetic hysteresis or external flux concentrators.

For engineers reviewing the MCS1806GS-5-05-P datasheet, MCS1806GS-5-05-P pinout, MCS1806GS-5-05-P application, or MCS1806GS-5-05-P equivalent, this device delivers ratiometric analog output, adjustable bandwidth up to 100kHz via external FILT capacitor, factory-trimmed accuracy across –40°C to +125°C, and SOIC-8 footprint compatibility with space-constrained PCB layouts requiring reinforced isolation.

Technical Context

The MCS1806GS-5-05-P implements a differential Hall array with two magnetically coupled sensing points (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A) to reject stray fields, paired with dynamic offset cancellation using spinning current technique. Its internal 1.5kΩ filter resistor and 1nF capacitor set baseline bandwidth at 100kHz when FILT is unconnected.

Galvanic isolation is achieved via reinforced insulation between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), certified to IEC62368-1 with 3000VRMS withstand voltage and 500VRMS working voltage. The device operates from 4.5–5.5V supply, draws 8.5–10.5mA, and features UVLO (2.5V threshold) and 90µs power-on time.

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 ACS712ELCTR-05B-T and TMCS1100A1QDR, the MCS1806GS-5-05-P uniquely combines IEC62368-1-certified 3000VRMS isolation, differential stray-field immunity, and guaranteed ±2.5% error across –40°C to +125°C - making it the only option qualified for automotive-grade OBC and industrial servo amplifier designs requiring long-term stability without recalibration.

Availability

MCS1806GS-5-05-P is available at Aetrix Electronics and suitable for motor controls, switch-mode power supplies, automotive on-board chargers, and battery management systems requiring stable component supply with full lifecycle support and traceable sourcing.

Supply support for MCS1806GS-5-05-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, including DC/DC converters, LED drivers, and isolated sensors - with emphasis on efficiency, integration, and reliability.

The MCS1806 series was designed specifically for high-accuracy, galvanically isolated current sensing in demanding industrial and automotive power conversion systems where optical isolation alternatives introduce latency, aging, and temperature drift.

FAQ

What is the maximum continuous primary current the MCS1806GS-5-05-P can handle without exceeding junction temperature limits?

The device supports continuous ±5A primary current within its specified accuracy range. At higher currents, self-heating must be evaluated: with 0.9mΩ conductor resistance, 10A produces ~90mW dissipation. Thermal performance depends on PCB copper area and ambient conditions; Figure 10 in the datasheet shows <10°C rise at 10A on the evaluation board after 10 minutes at 25°C ambient.

Can the MCS1806GS-5-05-P be used with a 3.3V supply?

No - the MCS1806GS-5-05-P is configured for 5V operation only. Its ordering code "-5-" denotes 5V supply optimization, with specified operating range 4.5–5.5V and UVLO threshold at 2.5V. For 3.3V systems, use MCS1806GS-3-05-P instead, which has different sensitivity (264 mV/A) and internal trimming.

How does the FILT pin affect noise performance and bandwidth?

Connecting a capacitor (CF) between FILT and GND forms a first-order RC filter with internal RFI (1.5kΩ) and CFI (1nF). For example, a 1nF CF yields ~106kHz bandwidth; 10nF reduces it to ~10kHz. This tradeoff directly lowers input-referred noise - e.g., 1nF gives 50mA(RMS) noise at 60kHz, while 100nF cuts noise by ~3× at the expense of slower response.

Is the zero-current output voltage (VOUT(Q)) truly centered at VCC/2 across temperature and supply variation?

Yes - VOUT(Q) is factory-trimmed to VCC/2 with ±15mV deviation over –40°C to +125°C and ±5mV over –40°C to +25°C. Ratiometry coefficients KVO (99–101%) confirm near-perfect scaling with VCC, ensuring consistent null point even with 4.5–5.5V supply tolerance.

Does the MCS1806GS-5-05-P require external calibration for production use?

No - the device is fully factory-trimmed for sensitivity, offset, and ratiometry. Total output error remains within ±2.5% across temperature and lifetime without user calibration. Only system-level gain/offset compensation may be needed if downstream ADC nonlinearity exceeds sensor error budget.

What is the minimum recommended PCB copper area for thermal management at 5A continuous?

MPS recommends ≥250mm² of 2oz copper connected to IP+/IP− pads per side for sustained 5A operation. The evaluation board uses 400mm² per layer; reducing copper below 200mm² increases thermal resistance and risks exceeding 125°C junction temperature under worst-case ambient conditions.

How does the differential Hall architecture improve immunity to external magnetic fields compared to single-point sensors?

The integrated dual Hall elements measure magnetic field gradients (B1 − B2) rather than absolute field strength. Because stray fields induce nearly identical flux at both points, their common-mode component cancels - achieving >40dB rejection of uniform 50Hz/60Hz interference and nearby inductor leakage fields, as verified in MPS application note AN178.