Diodes Incorporated ZMZ20M

Overview

ZMZ20M from Zetex plc is an anisotropic magnetoresistive (AMR) linear magnetic field sensor in a 4-pin E-line surface-mount package, measuring the vertical component (Hy) of magnetic fields with open-circuit sensitivity of 3.0–7.0 (mV/V)/(kA/m). It integrates an internal permanent magnet to supply auxiliary field Hx (2.5 kA/m) for hysteresis suppression and delivers ratiometric output voltage proportional to Hy. Used in door interlocks, impeller-based fluid metering, and automotive engine position sensing.

For engineers reviewing the ZMZ20M datasheet, ZMZ20M pinout, ZMZ20M application, or ZMZ20M equivalent, key selection considerations include its 1.2–2.2 kΩ bridge resistance, ±50 µV/V hysteresis at Hy = 2 kA/m, -25°C to +125°C operating range, 0–1 MHz bandwidth, and requirement for perpendicular Hx biasing to maintain linearity.

Technical Context

The ZMZ20M implements a thin-film Permalloy Wheatstone bridge structure where resistance changes under Hy induce a differential output voltage scaled by supply voltage VB. Its operation requires a fixed internal Hx field (2.5 kA/m) orthogonal to Hy to saturate the AMR layer and eliminate magnetic hysteresis.

Electrical behavior is ratiometric: output voltage VO is expressed in mV/V, referenced to VB (max 12 V), enabling immunity to supply variation. Temperature coefficients are tightly specified-TCVoff (±3 µV/V/K), TCRbr (0.25–0.35 %/K), and TCSV (-0.25 to -0.35 %/K)-supporting stable performance across -25°C to +125°C.

Key Specifications

Pinout & Package

The ZMZ20M is housed in a 4-pin E-line SMD package (dimensions: 4.0–4.4 mm × 3.8–4.2 mm × 0.8–1.0 mm height) with gull-wing leads, optimized for automated placement and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC1501 and KMZ60, the ZMZ20M uniquely combines internal Hx biasing, E-line SMD packaging, and analog ratiometric output-making it optimal for cost-sensitive, space-constrained analog position sensing where external magnetics or digital interfaces are undesirable.

Availability

ZMZ20M is available at Aetrix Electronics and suitable for door interlocks, fluid metering systems, and automotive crankshaft position sensing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZMZ20M 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 plc was a UK-based semiconductor company specializing in high-performance analog and magnetic sensors, acquired by Diodes Incorporated in 2008; legacy Zetex products remain widely deployed in industrial and automotive systems.

The ZMZ series was engineered specifically for contactless linear position and speed measurement in harsh environments, emphasizing self-biased AMR architecture, wide temperature tolerance, and minimal external component requirements.

FAQ

What is the required orientation of the magnetic field for proper ZMZ20M operation?

The ZMZ20M measures the magnetic field component Hy perpendicular to the chip surface (vertical to the package top). A second field Hx must be applied parallel to the chip plane and orthogonal to Hy-this is supplied internally by a permanent magnet, so no external alignment is needed for Hx. Rotating the sensor 90° around the Hy axis invalidates operation.

Can ZMZ20M be used without external signal conditioning?

Yes-the ZMZ20M provides a fully conditioned Wheatstone bridge output that is ratiometric and DC-coupled. It can drive high-impedance ADC inputs directly. However, for noise-sensitive environments or long traces, a simple differential amplifier with gain ≥10 is recommended to resolve sub-mV signals within its ±1.5 mV/V offset window.

Does ZMZ20M require calibration for zero-field output?

Factory-trimmed offset voltage is ±1.5 mV/V at 25°C, but system-level calibration is recommended due to temperature drift (TCVoff ±3 µV/V/K) and mechanical stress effects. A one-point null adjustment at known zero-Hy condition improves accuracy over full temperature range, especially in precision metering applications.

How does supply voltage affect ZMZ20M output linearity and noise?

Output is strictly ratiometric: VO scales linearly with VB, preserving linearity across 5–12 V. Noise spectral density remains constant in nV/√Hz, but absolute noise amplitude increases with VB. Operating at 5 V reduces total output swing and power dissipation (PTOT ≤120 mW), while 12 V maximizes signal-to-noise ratio at the cost of thermal load.