Monolithic Power Systems Inc. MCS1801GS-25-P

Overview

MCS1801GS-25-P from Monolithic Power Systems is a galvanically isolated, linear Hall-effect current sensor optimized for ±25A DC/AC current sensing with 80 mV/A sensitivity, ±3% total output error over –40°C to +125°C, and 200 VRMS working voltage for basic isolation. It integrates differential Hall plates, spinning-current offset cancellation, and an SOIC-8 package with internal 1.2 mΩ conductor resistance-used in motor control feedback loops, SMPS overcurrent protection, and automotive battery monitoring.

For engineers reviewing the MCS1801GS-25-P datasheet, MCS1801GS-25-P pinout, MCS1801GS-25-P application, or MCS1801GS-25-P equivalent, key selection criteria include its ratiometric 5V analog output, adjustable bandwidth up to 100 kHz via external FILT capacitor, 4 µs rise time, and immunity to stray magnetic fields enabled by differential sensing architecture.

Technical Context

The device implements a dual-Hall transducer array with asymmetric primary conductor geometry, generating distinct vertical magnetic fields (PMCF1 = 0.6 mT/A, PMCF2 = 0.3 mT/A) at two sensing points; their difference is converted to a proportional voltage output. Internal dynamic offset cancellation uses spinning current technique to achieve <±15 mV offset drift over temperature.

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/clearance and 1000 VRMS withstand voltage per IEC62368-1. Bandwidth is set either by internal RC filter (1.5 kΩ / 1 nF) or externally via capacitor on FILT pin, enabling tradeoff between noise and response speed.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm, JEDEC MS-012 AA), surface-mount, RoHS-compliant, with exposed primary conductor terminals and signal-side isolation barrier.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-20AU-T and TLE4971-25U5-S, the MCS1801GS-25-P delivers superior thermal stability (±15 mV offset drift), configurable bandwidth via passive FILT pin, and true analog drop-in compatibility in SOIC-8-making it optimal for space-constrained, high-reliability analog feedback loops.

Availability

MCS1801GS-25-P is available at Aetrix Electronics and suitable for motor control feedback, switch-mode power supply protection, and automotive battery management requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MCS1801GS-25-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.

The MCS1801 product line delivers isolated current sensing solutions targeting space-constrained, high-temperature industrial and automotive applications where reliability, accuracy, and ease of integration are critical.

FAQ

What is the maximum continuous primary current the MCS1801GS-25-P can handle without exceeding junction temperature limits?

The device supports continuous ±25 A with ≤100°C die temperature rise when mounted on a 2200 mm², 4 oz copper PCB per MPS evaluation layout. Self-heating performance depends on copper area, thermal vias, and ambient temperature; at 25°C ambient and full 25 A DC, junction temperature remains below 125°C with proper layout.

How does the FILT pin affect noise and bandwidth, and what capacitor value should be used for 20 kHz operation?

FILT sets bandwidth using internal 1.5 kΩ resistor and 1 nF capacitor plus external CF. For 20 kHz (3 dB), CF ≈ 4.7 nF per fBW = 1/(2π × RFi × (CFi + CF)). This reduces input-referred noise from 50 mA(RMS) at 60 kHz to ~22 mA(RMS), improving resolution in low-frequency motor control applications.

Is the MCS1801GS-25-P certified for reinforced or basic isolation, and which safety standards does it meet?

It is certified for basic isolation per IEC62368-1, with 200 VRMS working voltage and 1000 VRMS withstand voltage (60 s). It is not rated for reinforced isolation. UL certification is included per revision 1.1; no additional agency approvals (e.g., VDE, CSA) are claimed in the datasheet.

Can the MCS1801GS-25-P measure bidirectional AC current, and what is its minimum resolvable current at 25°C?

Yes-it outputs a ratiometric analog voltage centered at VCC/2 (2.5 V), swinging ±200 mV for ±25 A, enabling true bidirectional AC/DC measurement. At 25°C with FILT disconnected, input-referred noise is 200 μA(RMS)/√Hz; with 60 kHz bandwidth, minimum resolvable RMS current is ~50 mA.

What is the purpose of the dual IP+ and dual IP− pins, and how should they be routed on the PCB?

Pins 1&2 (IP+) and 3&4 (IP−) are internally shorted to minimize inductance and distribute current evenly across the primary conductor. They must be connected to wide, low-inductance copper traces-ideally symmetric 4 oz planes with thermal vias-to maintain 1.2 mΩ resistance and prevent localized heating or magnetic field asymmetry.

Does the MCS1801GS-25-P require external calibration, and how is factory trimming implemented?

No external calibration is required. Sensitivity and offset are factory-trimmed using laser or fuse-based methods during wafer test; typical total output error is ±3% over temperature without user adjustment. Trim data is stored permanently in on-die nonvolatile elements and applied automatically during operation.

What is the propagation delay and how does it impact real-time overcurrent protection?

Propagation delay is 1.5 µs-the time between 20% of primary current step and 20% of VOUT response. Combined with 4 µs rise time and 5 µs response time, this enables detection and shutdown of overcurrent events within <10 µs, supporting fast-acting protection in SiC/GaN-based power stages.