Diodes Incorporated ZMY20MTC

Overview

ZMY20MTC from Zetex (now Diodes Incorporated) is a magneto-resistive magnetic field sensor in SOT223 package, measuring perpendicular magnetic field component Hy with 5.5 mV/V/kA/m typical open-circuit sensitivity, 12 V supply voltage, and internal permanent magnet providing stabilizing auxiliary field Hx. It enables precise linear/angular position sensing and electronic compass functions in automotive and industrial motion systems.

For engineers reviewing the ZMY20MTC datasheet, ZMY20MTC pinout, ZMY20MTC application, or ZMY20MTC equivalent, key selection considerations include its bridge-based analog output, built-in Hx biasing, ±30 kA/m disturbing field immunity, temperature-stable offset (<±1.5 mV/V), and 1 MHz bandwidth for dynamic field detection.

Technical Context

The ZMY20MTC integrates a thin-film permalloy Wheatstone bridge on silicon, where output voltage varies linearly with Hy under constant VB. Its operation requires no external bias magnet due to an integrated permanent magnet generating ~2 kA/m Hx orthogonal to Hy.

Electrical behavior is characterized by bridge resistance (1.7 kΩ typ), open-circuit sensitivity (5.5 mV/V/kA/m), and low hysteresis (<50 ppm/V). Temperature coefficients are specified for offset (±3 ppm/K), bridge resistance (+0.3 %/K), and sensitivity (−0.3 %/K), enabling compensated designs across −25°C to +125°C.

Key Specifications

Pinout & Package

Package: SOT223 (4-pin, single-gauge leadframe, heatsink tab). Dimensions: 6.7 × 3.7 × 1.8 mm (L × E1 × A), with exposed thermal pad connected to Pin 3 (V_B).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar magnetic field sensing applications.

Compared with SS49E and A1302, ZMY20MTC offers superior field resolution per volt (5.5 mV/V/kA/m vs. ~100 mV/mT), inherent bias stability, and true ratiometric analog output-making it optimal for precision analog position feedback in harsh, high-interference environments.

Availability

ZMY20MTC is available at Aetrix Electronics and suitable for linear position measurement, angular position measurement, and electronic compass applications requiring stable component supply across automotive, industrial automation, and navigation product lifecycles.

Supply support for ZMY20MTC 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 (acquired by Diodes Incorporated in 2008) specialized in high-performance analog and sensor ICs, with design heritage in magneto-resistive and bipolar technologies.

The ZMY series was developed specifically for contactless magnetic sensing in demanding motion-control applications, emphasizing stability, wide temperature operation, and self-contained biasing for simplified system integration.

FAQ

What is the function of the internal permanent magnet in ZMY20MTC?

The internal permanent magnet generates a fixed 2 kA/m auxiliary magnetic field (Hx) orthogonal to the sensitive axis (Hy). This biases the permalloy Wheatstone bridge into its linear operating region, eliminating the need for external magnets and ensuring repeatable sensitivity and zero-field offset across temperature and lifetime.

Can ZMY20MTC operate from a 5 V supply instead of 12 V?

No-ZMY20MTC is specified only for 12 V supply (VB = 12 V). Its bridge resistance (1.7 kΩ typ) and power dissipation limit (120 mW) define a minimum operating current (~7 mA); reducing VB lowers output signal amplitude proportionally and may fall outside guaranteed sensitivity and linearity specs per the datasheet.

How is thermal management handled in the SOT223 package?

The SOT223 package uses Pin 3 (VB) as both supply input and thermal connection to an exposed copper tab. Effective heat dissipation requires soldering this tab to ≥1 cm² of inner-layer or bottom-side PCB copper pour. With proper layout, the device sustains continuous 120 mW dissipation across −25°C to +125°C ambient.

Does ZMY20MTC require external signal conditioning for microcontroller ADC interfacing?

Yes-its differential analog output (Pins 1 & 2) requires amplification and level-shifting to match typical 0–3.3 V or 0–5 V ADC inputs. A simple instrumentation amplifier (e.g., AD620) with gain ~20–50 compensates for the 12–24 mV/V output range and rejects common-mode noise from long traces or noisy environments.