Monolithic Power Systems Inc. MCS1805GS-320-B-P

Overview

MCS1805GS-320-B-P from Monolithic Power Systems is a bidirectional linear Hall-effect current sensor IC with galvanic isolation, ±20A sensing range, 66 mV/A sensitivity, 3 kVRMS isolation voltage, and integrated over-current detection (OCD) with 1 µs response time. It replaces optoisolators in motor control and power supply current monitoring where high accuracy, noise immunity, and compact SOIC-8 footprint are required.

For engineers reviewing the MCS1805GS-320-B-P datasheet, MCS1805GS-320-B-P pinout, MCS1805GS-320-B-P application, or MCS1805GS-320-B-P equivalent, this device delivers ratiometric analog output, differential magnetic field rejection, ±2.5% total accuracy across -40°C to +125°C, and factory-trimmed offset for minimal external calibration in isolated current-sensing designs.

Technical Context

The MCS1805GS-320-B-P uses a differential Hall array to cancel stray magnetic fields and employs spinning current technique for ultra-low offset drift. Its primary conductor (IP+/IP−) forms an integrated low-resistance path (1.2 mΩ), enabling direct high-current sampling without external shunts.

Galvanic isolation separates the 3.3V-powered signal side (VCC, VOUT, /OCD, GND) from the primary current path, achieving 3 kVRMS withstand voltage and 580 VRMS working voltage per IEC 62368-1. The OCD threshold is factory-set to 200% of IPMAX (±40 A), with 3–12% hysteresis and open-drain active-low output.

Key Specifications

Pinout & Package

Package: SOIC-8 (5 mm × 4 mm), surface-mount, with internal fusing on IP+ and IP− pins and creepage/clearance ≥4.2 mm between primary and signal sides.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-20AU-T and TB9052FG, the MCS1805GS-320-B-P uniquely combines bidirectional ±20 A sensing, integrated 1 µs OCD, ratiometric analog output, and SOIC-8 isolation-all in a single chip requiring zero external components for basic operation.

Availability

MCS1805GS-320-B-P is available at Aetrix Electronics and suitable for motor control, switch-mode power supplies, automotive battery management, and industrial load protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MCS1805GS-320-B-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 MCS1805 product line delivers isolated current sensing solutions optimized for space-constrained, high-reliability applications in motor drives, EV charging, and industrial power conversion-emphasizing integration, accuracy, and safety certification.

FAQ

What is the maximum continuous primary current the MCS1805GS-320-B-P can handle?

The device is rated for ±20 A bidirectional continuous current, with a primary conductor resistance of 1.2 mΩ and thermal design supporting sustained operation at full scale. Absolute maximum surge current is 3000 A (8 µs/20 µs pulse), and transient capability is 200 A (10 ms), per IEC 61000-4-5 testing.

Does the MCS1805GS-320-B-P require external calibration for accuracy?

No. The device is factory-trimmed for sensitivity, offset, and ratiometry, delivering ±2.5% total output error across -40°C to +125°C without user calibration. Only a 0.1–1 µF bypass capacitor on VCC and optional pull-up resistor on /OCD are required for basic operation.

How does the differential Hall array improve noise immunity?

The integrated dual-Hall transducer measures magnetic field difference between two spatially separated points, inherently rejecting uniform external gradients (e.g., from nearby inductors or busbars). This architecture achieves extreme low-noise density (100 µA(rms)/√Hz) and eliminates need for magnetic shielding in most layouts.

Can the /OCD pin drive a microcontroller GPIO directly?

Yes. The /OCD pin is an open-drain output with guaranteed low voltage ≤0.3 V at 4 mA sink current. A 10–500 kΩ pull-up resistor to VCC provides compatible logic levels for 3.3 V MCUs. No level-shifting or buffering is needed for standard digital input interfaces.

What is the meaning of "-B" and "-P" in MCS1805GS-320-B-P?

"B" denotes bidirectional current sensing (±20 A range); "P" indicates tape-and-reel packaging (per MPS part numbering convention). The "-320" specifies 3.3 V supply and 20 A rating; "GS" refers to green (halogen-free, RoHS-compliant) SOIC-8 package.

Is the MCS1805GS-320-B-P qualified for automotive applications?

It operates across −40°C to +125°C junction temperature and meets IEC 62368-1 reinforced isolation, but is not AEC-Q200 qualified. For automotive use, it is deployed in non-safety-critical subsystems (e.g., cabin HVAC, auxiliary power) where full qualification is not mandated.

What layout guidelines ensure optimal accuracy?

Keep primary current path (IP+/IP−) straight and centered; avoid routing noisy signals or high di/dt traces near the package edges. Use separate ground planes for primary and signal sides, connected only at a single point near GND pin. Place 0.1 µF ceramic capacitor <2 mm from VCC to GND.