Monolithic Power Systems Inc. MCS1802GS-20-Z

Overview

MCS1802GS-20-Z from Monolithic Power Systems is a 3.3V linear Hall-effect current sensor with galvanic isolation, ±20A bidirectional sensing range, ±2.5% total output error over temperature (−40°C to +125°C), 66 mV/A sensitivity, and 0.9 mΩ internal conductor resistance. It replaces opto-isolators in motor control and power supply current monitoring where high accuracy, magnetic immunity, and compact SOIC-8 packaging are required.

For engineers reviewing the MCS1802GS-20-Z datasheet, MCS1802GS-20-Z pinout, MCS1802GS-20-Z application, or MCS1802GS-20-Z equivalent, key selection criteria include its differential Hall architecture for stray-field rejection, 2.2 kVRMS isolation rating, adjustable bandwidth up to 100 kHz via external FILT capacitor, ratiometric analog output, and factory-trimmed offset and sensitivity.

Technical Context

The MCS1802GS-20-Z uses a differential Hall array with spinning current offset cancellation to achieve stable zero-current output (VOUT(Q) = VCC/2) and low thermal drift. Its primary conductor path (IP+, IP−) is galvanically isolated from signal pins (VCC, VOUT, FILT, GND), enabling safe high-side current sensing without shunt resistors or external isolation.

Bandwidth is programmable via an external capacitor on the FILT pin, interacting with internal 1.5 kΩ resistance and 1 nF capacitance; unconnected FILT yields 100 kHz bandwidth. The device features 4 µs output rising time, 1.5 µs propagation delay, and operates across −40°C to +125°C junction temperature with 3.0–3.6 V supply.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm), surface-mount, with primary current terminals (IP+, IP−) physically separated from signal pins to maintain 4.2 mm creepage and clearance for reinforced isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-20AB-T and TLE4971-20S4, the MCS1802GS-20-Z offers tighter total error (±2.5% vs. ±3.5% and ±3.0%), lower conductor resistance (0.9 mΩ vs. 1.2 mΩ and 1.5 mΩ), and simpler 3.3 V biasing - making it optimal for space-constrained, thermally sensitive, and cost-sensitive industrial power designs.

Availability

MCS1802GS-20-Z is available at Aetrix Electronics and suitable for motor control, automotive battery monitoring, and switch-mode power supply current sensing requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1802GS-20-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 MCS1802 product line delivers isolated, high-accuracy current sensing for demanding applications such as electric vehicle subsystems, industrial motor drives, and energy-efficient power supplies - emphasizing low-loss conduction, magnetic immunity, and extended temperature operation.

FAQ

What is the minimum recommended bypass capacitor for VCC?

A 1 µF low-ESR ceramic capacitor must be placed as close as possible to the VCC pin (Pin 8) to suppress high-frequency noise and ensure stable internal regulator operation. This value is specified in the Absolute Maximum Ratings section and validated in production testing; smaller values may cause output instability or increased offset drift under transient load conditions.

Can the FILT pin be left unconnected?

Yes, the FILT pin (Pin 6) can be left floating to achieve the maximum 100 kHz bandwidth. When unconnected, the internal 1.5 kΩ resistor and 1 nF capacitor set the default cutoff frequency. Leaving FILT unconnected is valid for fast-response applications like overcurrent protection, but adds susceptibility to high-frequency noise - a small external capacitor (e.g., 100 pF) may be added for EMI filtering without significantly reducing bandwidth.

How is galvanic isolation achieved in the SOIC-8 package?

Isolation is achieved through physical separation of the primary current path (Pins 1–4) from signal pins (Pins 5–8) within the SOIC-8 mold compound, with 4.2 mm creepage and clearance distances. The internal conductor is embedded in the package body, not connected to any signal die bond wires, and tested to 2.2 kVRMS per IEC 62368-1 - eliminating need for external isolation components while maintaining UL/IEC safety certification.

What does "±2.5% total output error" include?

This specification includes combined effects of sensitivity error (±2%), offset voltage drift (±10 mV over temperature), nonlinearity (±0.5%), and ratiometric deviation (KSENS and KVO ≤ ±2%) across −40°C to +125°C. It is measured at ±20 A and represents worst-case deviation from ideal output voltage, verified per production test flow - not a sum of individual parameter tolerances.

Is the output truly ratiometric across the full supply range?

Yes, both sensitivity (KSENS) and zero-current output (KVO) are guaranteed 98–102% and 99–101% respectively over 3.0–3.6 V supply, meaning VOUT scales linearly with VCC. At 3.0 V, full-scale output is ±1.2 V (±20 A × 66 mV/A × 0.98); at 3.6 V, it is ±1.45 V - preserving measurement resolution without software gain correction.

Does the device require calibration during production?

No factory calibration is required. The MCS1802GS-20-Z is fully trimmed at wafer sort for sensitivity and offset, achieving ±2.5% total error without end-of-line adjustment. System-level calibration is optional but unnecessary for most applications; only zero-current offset trimming may be applied if sub-1% absolute accuracy is mandated in fixed-temperature environments.

What is the maximum continuous primary current the device can handle?

The device is rated for ±20 A continuous primary current, limited by thermal constraints of the 0.9 mΩ conductor and SOIC-8 package. At 20 A, power dissipation is 360 mW (I²R), raising junction temperature by ~35°C above ambient - well within the 165°C max rating. Derating is required above +85°C ambient to maintain TJ ≤ 125°C for guaranteed accuracy.