Monolithic Power Systems Inc. MCS1801GS-25-Z

Overview

MCS1801GS-25-Z from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±25A DC/AC sensing with 80 mV/A sensitivity, ±3% total output error over -40°C to +125°C, and 1.2 mΩ primary conductor resistance. It delivers ratiometric analog output referenced to 5V supply, features differential Hall sensing for stray-field immunity, and replaces optocouplers in high-reliability motor control and power supply monitoring.

For engineers reviewing the MCS1801GS-25-Z datasheet, MCS1801GS-25-Z pinout, MCS1801GS-25-Z application, or MCS1801GS-25-Z equivalent, key selection criteria include its 200 VRMS working isolation voltage, 4 µs output rise time, adjustable bandwidth up to 100 kHz via external FILT capacitor, and SOIC-8 package compatibility with space-constrained PCB layouts.

Technical Context

The MCS1801GS-25-Z integrates two matched Hall plates (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A) with spinning current offset cancellation and dynamic offset trimming to achieve ±15 mV offset voltage over temperature. Its internal 1.5 kΩ filter resistor and 1 nF capacitor enable bandwidth tuning from <10 kHz to 100 kHz using an external CF capacitor on the FILT pin.

Galvanic isolation is achieved via physical separation of primary current path (IP+/IP−) and signal pins (VCC/VOUT/FILT/GND), with 4.2 mm creepage and clearance per IEC 62368-1, supporting 1000 VRMS withstand voltage and 200 VRMS working voltage for basic insulation. The device operates from 4.5–5.5 V and draws 8.5–10.5 mA quiescent current.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm, JEDEC MS-012 AA), surface-mount, lead-free/halogen-free, MSL Level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear Hall-effect current sensing applications.

Compared with ACS724LMATR-25AB-T and TLE4971-25S4, the MCS1801GS-25-Z uniquely combines adjustable analog bandwidth, lowest conductor resistance, and certified 200 VRMS working isolation-making it optimal for high-efficiency, safety-certified analog control loops.

Availability

MCS1801GS-25-Z is available at Aetrix Electronics and suitable for motor control feedback, switch-mode power supply monitoring, and industrial over-current protection requiring stable component supply, consistent parametric performance, and long-lifecycle availability.

Supply support for MCS1801GS-25-Z 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 MCS1801 product line delivers isolated current sensing solutions targeting high-reliability industrial, automotive, and computing power systems where galvanic isolation, temperature stability, and minimal board area are critical design constraints.

FAQ

What is the maximum continuous primary current the MCS1801GS-25-Z can handle without damage?

The device supports continuous primary currents up to ±25 A within its specified accuracy range. Absolute maximum transient current is 250 A (10 ms pulse), per IEC 62368-1 testing. Sustained operation above ±25 A increases nonlinearity beyond ±3% and risks exceeding 165°C junction temperature-thermal design must verify copper area and airflow per Figure 10.

How does the FILT pin affect bandwidth, and what capacitor value achieves 50 kHz?

The FILT pin forms an RC filter with internal 1.5 kΩ resistance and 1 nF capacitance. Using Equation fBW = 1/(2π × RFi × (CFi + CF)), a 1.1 nF external capacitor yields ~50 kHz. Values below 100 pF yield near-maximum 100 kHz; >10 nF reduces bandwidth to <10 kHz. FILT may be left floating for default 100 kHz operation.

Is the MCS1801GS-25-Z UL-certified, and what standards does it meet?

Yes-the MCS1801GS-25-Z carries UL recognition under file E337622, compliant with UL 62368-1 for basic insulation. It achieves 1000 VRMS withstand voltage (60 s) and 200 VRMS working voltage per IEC 62368-1, with 4.2 mm external creepage and clearance. Certification applies to the SOIC-8 package configuration as shipped.

Can the MCS1801GS-25-Z measure bidirectional DC current, and what is the zero-current output voltage?

Yes-it provides true bidirectional sensing with VOUT = VCC/2 (2.5 V nominal at 5 V supply) at IP = 0 A. Output swings ±2 V around this midpoint for ±25 A, delivering 80 mV/A sensitivity. The ratiometric design ensures VOUT(Q) tracks VCC variations between 4.5–5.5 V, maintaining zero-point accuracy without external calibration.

What PCB layout practices minimize self-heating and improve thermal performance?

Mount the SOIC-8 on ≥2200 mm² of 4 oz (139 µm) copper connected to IP+/IP− pins on both top/bottom layers, with thermal vias linking planes. Avoid narrow traces-primary current paths must sustain ≥25 A continuously. Per Figure 11, die temperature rise is <40°C at 25 A DC with this layout; reduce copper area only after validating junction temperature stays ≤125°C.

Does the MCS1801GS-25-Z require external calibration for production use?

No-factory trimming ensures ±2.5% sensitivity error and ±15 mV offset voltage over temperature, meeting ±3% total output error without user calibration. For applications demanding <1% error, one-time end-of-line gain/offset correction using known current stimulus is optional but not required for most industrial motor or PSU designs.

How does the differential Hall architecture reject external magnetic interference?

Two physically separated Hall plates sense orthogonal components of the same magnetic field generated by IP. Stray uniform fields induce equal voltages in both plates, which cancel in the differential amplifier stage. Asymmetric conductor geometry ensures only the primary current's field produces a net differential signal-verified by ±1% Hall plate matching and <0.5% nonlinearity.