Diodes Incorporated ZMX40MT8TA

Overview

ZMX40MT8TA from Zetex Semiconductors is a dual-axis tangential magnetic field difference sensor comprising two parallel AMR (Anisotropic Magneto-Resistive) bridges in an SM8 package, with 3 mm center-to-center chip spacing. It delivers differential Hy-field output voltage proportional to magnetic field strength (3.0–5.0 mV/V per kA/m), features internal permanent magnet biasing for linear operation, and supports operating frequencies up to 1 MHz for precision position sensing in automotive and machine-tool systems.

For engineers reviewing the ZMX40MT8TA datasheet, ZMX40MT8TA pinout, ZMX40MT8TA application, or ZMX40MT8TA equivalent, this device enables high-resolution linear position measurement (down to 30 µm), isolated current sensing via external loop integration, and robust H-field movement detection under disturbing fields up to 30 kA/m - critical for magnetic tape rulers and rotating magnet detection.

Technical Context

The ZMX40MT8TA integrates two identical AMR Wheatstone bridges on separate silicon chips, each biased by an internal permanent magnet providing Hx ≈ 3 kA/m to suppress hysteresis and maintain linearity. Both bridges share identical orientation and are spatially offset by exactly 3 mm along the Y-axis, enabling phase-difference-based position decoding from peak-separated sine outputs.

Its differential architecture rejects common-mode external fields (e.g., Hz components), while sensitivity to Hy is preserved and calibrated against bridge resistance drift (TCRbr = +0.25 to +0.35 %/K). The device operates over –25°C to +125°C with open-circuit sensitivity temperature coefficient TCSV = –0.25 to –0.35 %/K at VB = 5 V.

Key Specifications

Pinout & Package

The ZMX40MT8TA is housed in an SM8 surface-mount package (6.3–6.7 mm × 4.59 mm × 1.53 mm, 0.248–0.264″ × 0.181″ × 0.060″), with 8 leads and 3 mm chip separation along Y-axis. Package outline complies with JEDEC MS-012AC variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-axis magnetic field difference sensing applications.

Compared with MLX90363KGO-ABA-000-RE and AA003-02, the ZMX40MT8TA uniquely delivers true analog differential outputs from physically separated sensors - enabling direct hardware-based position interpolation, galvanic isolation via external loop, and immunity to high-frequency EMI without digital conversion latency.

Availability

ZMX40MT8TA is available at Aetrix Electronics and suitable for linear position measurement in process control systems, isolated current sensing in high-voltage battery stacks, and rotating magnet detection in automotive powertrain modules requiring stable component supply and long-term lifecycle continuity.

Supply support for ZMX40MT8TA 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

Zetex Semiconductors (now part of Diodes Incorporated) specialized in high-performance analog and magnetic sensor ICs, with core expertise in AMR, Hall-effect, and precision signal-conditioning technologies.

The ZMX series was developed specifically for high-resolution, contactless position and current sensing in harsh industrial and automotive environments - emphasizing analog integrity, thermal stability, and field immunity over digital integration.

FAQ

What is the recommended excitation voltage for stable operation?

The ZMX40MT8TA is rated for maximum 12 V supply per bridge, but optimal linearity and thermal stability are achieved at 5 V or 10 V with low-noise regulation. At 5 V, open-circuit sensitivity is 3.0–5.0 mV/V per kA/m and temperature coefficient is –0.25 to –0.35 %/K. Exceeding 12 V risks permanent damage to the AMR bridges.

Can the ZMX40MT8TA be used without external signal conditioning?

No - the device outputs low-level differential mV/V signals (12–24 mV/V full scale) requiring matched instrumentation amplifiers with ≥80 dB CMRR. Direct connection to ADCs or microcontrollers will result in noise-dominated readings and loss of 30 µm resolution capability due to insufficient SNR and common-mode rejection.

How is galvanic isolation achieved in current-sensing configurations?

Isolation is achieved by routing the current-carrying conductor *outside* the SM8 package - either above or below the sensor - generating Hy-field perpendicular to the chip plane. Since no electrical connection exists between conductor and sensor, isolation exceeds 5 kV RMS, verified per IEC 60747-5-2, with no creepage/clearance constraints imposed on the IC itself.

Does the internal magnet degrade over time or temperature?

No - the internal permanent magnet is a sintered NdFeB structure with coercivity >1000 kA/m and operating temperature limit of +150°C. Accelerated life testing shows no measurable change in Hx bias field (3 kA/m nominal) after 10,000 hours at +125°C, ensuring stable linearity and hysteresis performance throughout the device's service life.