Monolithic Power Systems Inc. MCQ1806GS-3-20-AEC1-Z

Overview

MCQ1806GS-3-20-AEC1-Z from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified, galvanically isolated Hall-effect current sensor for bidirectional AC/DC current measurement up to ±20A, featuring ±2.5% total output error over -40°C to +125°C, 3kVRMS isolation voltage, 500VRMS working voltage, and 66mV/A sensitivity at 3.3V supply - deployed in automotive motor control and inverter phase-leg monitoring.

For engineers reviewing the MCQ1806GS-3-20-AEC1-Z datasheet, MCQ1806GS-3-20-AEC1-Z pinout, MCQ1806GS-3-20-AEC1-Z application, or MCQ1806GS-3-20-AEC1-Z equivalent, this page delivers verified technical context, SOIC-8 pin mapping, ratiometric analog output behavior, AEC-Q100 thermal and isolation compliance, and validated alternatives for high-reliability automotive current sensing.

Technical Context

The MCQ1806GS-3-20-AEC1-Z integrates a differential Hall array with spinning current offset cancellation to reject stray magnetic fields and achieve stable zero-current output (VOUT(Q) = VCC/2). Its primary conductor (0.9mΩ) carries current directly through the package, generating opposing magnetic fields sensed at two integrated Hall transducers (PMCF1 = 0.6mT/A, PMCF2 = 0.3mT/A), enabling precise differential field subtraction.

Isolation is achieved via reinforced dielectric barrier between primary current path (IP+/IP−) and signal side (VCC/VOUT/FILT/GND), certified to IEC62368-1 with 3000VRMS withstand voltage and 4.2mm creepage/clearance. Bandwidth is adjustable up to 100kHz via external capacitor on FILT pin, while ratiometric output ensures immunity to supply variation (KSENS = 98–102%, KVO = 99–101%).

Key Specifications

Pinout & Package

MCQ1806GS-3-20-AEC1-Z uses a standard SOIC-8 (5mm × 4mm) surface-mount package with reinforced creepage and clearance for reinforced isolation. Primary current terminals (IP+, IP−) are internally paralleled pairs on pins 1–2 and 3–4 respectively, electrically separated from signal-side pins by molded isolation barrier.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ACS724LLCTR-20AB-T and TLE4971-20S4, the MCQ1806GS-3-20-AEC1-Z offers optimal balance of AEC-Q100 Grade 1 compliance, 3.3V compatibility, low power (10.5mA), and minimal external components - making it ideal for space- and voltage-constrained automotive subsystems where analog simplicity and proven reliability are prioritized.

Availability

MCQ1806GS-3-20-AEC1-Z is available at Aetrix Electronics and suitable for automotive traction inverters, on-board chargers, electric power steering systems, and 48V mild hybrid DC-DC converters requiring stable component supply with full AEC-Q100 traceability and long-term lifecycle support.

Supply support for MCQ1806GS-3-20-AEC1-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, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MCQ1806 series belongs to MPS's automotive-grade isolated current sensor product line, engineered specifically for high-accuracy, high-isolation, low-power current monitoring in electric vehicle powertrain and charging systems.

FAQ

What is the maximum continuous primary current the MCQ1806GS-3-20-AEC1-Z can measure with guaranteed linearity?

The device maintains ±2.5% total output error across its optimized accuracy range of ±20A at TJ = −40°C to +125°C. Beyond ±20A, output remains proportional but nonlinearity increases - maximum continuous current is limited by thermal rise: at 20A DC, 0.9mΩ conductor dissipates 360mW, resulting in <10°C junction rise above ambient in typical PCB layout. Sustained operation above ±25A requires thermal derating per Figure 11 in the datasheet.

Can the MCQ1806GS-3-20-AEC1-Z be used with a 5V supply?

No - the "-3-" suffix denotes 3.3V supply optimization. Using 5V on VCC violates absolute maximum rating (6V limit) and risks permanent damage. For 5V systems, select MCQ1806GS-5-20-AEC1, which has identical ±20A range but 5V supply architecture, 100mV/A sensitivity, and adjusted internal biasing. Mixing supply variants causes incorrect offset and sensitivity.

How does the FILT pin affect noise and bandwidth in real-world designs?

Connecting a capacitor (CF) between FILT and GND sets the 3dB bandwidth: CF = 1nF → ~100kHz, CF = 10nF → ~10kHz. Larger CF reduces high-frequency noise (e.g., 50mA RMS with 1nF drops to 15mA RMS with 10nF) but increases propagation delay (tPD rises from 1.5µs to ~5µs). For OCP, use 1nF; for average current monitoring in noisy environments, use 4.7nF–10nF.

Is external calibration required to achieve ±2.5% accuracy?

No - the MCQ1806GS-3-20-AEC1-Z is factory-trimmed for sensitivity and offset across temperature. Total output error of ±2.5% is specified over −40°C to +125°C without system-level calibration. However, for applications demanding <1% error (e.g., revenue-grade metering), one-point gain/offset calibration at room temperature improves accuracy to ±0.5% over temperature.

What PCB layout practices ensure optimal magnetic immunity?

Route IP+ and IP− traces symmetrically and tightly coupled (≤0.2mm gap) beneath the package to minimize loop area and external field coupling. Keep signal traces (VOUT, FILT) ≥5mm from high-dI/dt paths. Avoid placing ferrite beads, inductors, or transformers within 10mm of the SOIC-8 body. Use ground pour under signal side only - no copper under IP+ or IP− pads to preserve magnetic field symmetry.

Does the MCQ1806GS-3-20-AEC1-Z support bidirectional current measurement out-of-the-box?

Yes - the ratiometric output centers at VCC/2 (1.65V at 3.3V), so VOUT > 1.65V indicates positive current (IP+ to IP−), and VOUT < 1.65V indicates negative current. No external level-shifting or dual-supply circuitry is needed. The ±20A range is symmetric, and total error remains ±2.5% for both directions across full temperature range.

What is the minimum recommended bypass capacitor on VCC, and why is placement critical?

A 1µF X7R ceramic capacitor with ≤100mΩ ESR is mandatory and must be placed ≤2mm from VCC pin with short, wide traces. This suppresses high-frequency switching noise from the internal Hall driver and regulator, preventing oscillation and output instability. Omitting or misplacing this capacitor causes VOUT ripple >50mV and increased offset drift - verified in MPS AN178 layout guidelines.