IDT ZMID5201 Manual de usuario
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
1
April 6, 2018
Contents
1. Introduction...................................................................................................................................................................................................3
2. Inductive Sensing Technology Introduction..................................................................................................................................................3
2.1 Device Block Diagram .........................................................................................................................................................................6
3. Getting Started .............................................................................................................................................................................................7
3.1 LC Tank –Tx Front-End Tuning ..........................................................................................................................................................7
3.2 Device Initialization..............................................................................................................................................................................8
3.2.1 Output Mode Selection .........................................................................................................................................................8
3.3 Offset Check for Rx Coils ....................................................................................................................................................................9
3.4 Gain Stage Setting ............................................................................................................................................................................11
3.5 Input Amplitude Offset Compensation...............................................................................................................................................12
3.6 Output Calibration..............................................................................................................................................................................13
3.7Output Linearization ..........................................................................................................................................................................14
4. Internal Memory..........................................................................................................................................................................................17
5. Programming the ZMID520x EEPROM......................................................................................................................................................19
6. Glossary .....................................................................................................................................................................................................19
7. Revision History..........................................................................................................................................................................................20
List of Figures
Figure 1. Tx Loop Magnetic Field .......................................................................................................................................................................3
Figure 2. Current Paths and Shapes for Coils –Example for Linear Position Sensing ......................................................................................4
Figure 3. Geometrical Illustration for Coils and Target –Example for Linear Position Sensing..........................................................................5
Figure 4. Main Internal Functional Block Diagram..............................................................................................................................................6
Figure 5. ZMID520x Transmitter LC Tank..........................................................................................................................................................7
Figure 6. TX Oscillation and LF-U 5 Probe.........................................................................................................................................................8
Figure 7. ZMID520x EEPROM Memory Values –ZMID5203 Example for the Linear Output Mode Settings ..................................................9
Figure 8. ZMID520x EEPROM Gain Stage Setting –Example using the ZMID5203........................................................................................9
Figure 9. Coil Offset Reading –Example using the ZMID5203........................................................................................................................10
Figure 10. Magnitude for Gain Selection –Example for the ZMID5203 .............................................................................................................11
Figure 11. ZMID520x Input Amplitude Offset Compensation –Example for the ZMID5203 ..............................................................................12
Figure 12. Output Calibration..............................................................................................................................................................................13
Figure 13. Output Calibration Verification...........................................................................................................................................................14
Figure 14. Correction Mode Selection ................................................................................................................................................................14
Figure 15. Measured Value Readings for 9 Linearization Points........................................................................................................................15
Figure 16. Input Fields for the 9 Linearization Points Measured Values.............................................................................................................16
Figure 17. ZMID520x Internal Memory ...............................................................................................................................................................17
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
List of Tables
Table 1. EEPROM and Shadow RAM Contents..............................................................................................................................................17
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
1. Introduction
This document describes the procedures for setting up the IDT ZMID520x internal memory and transmitter (Tx) front-end in order to start
measurements with the device in user applications. It describes the settings needed to prepare the device for operation and then gives an
internal memory overview.
The steps provided here are needed when configuring a new device in a user application. These procedures can also be applied to any of the
ZMID520x application modules provided by IDT; however this is typically not needed because the sensor has been fully configured before the
module is shipped.
Recommendation: Read the ZMID520x Datasheet before using this document for a better understanding of the ZMID520x:
https://www.idt.com/document/dst/zmid520x-datasheet
Information on the OWI interface can be found in the ZMID520x Technical Brief –One Wire Interface (OWI).
2. Inductive Sensing Technology Introduction
This section provides some basic principles for inductive position sensing using the ZMID520x family of products, and it covers how the required
magnetic fields are generated.
In the application, an LC oscillator generates a magnetic field in the transmit wire loop. The frequency of the oscillation is tuned by the
capacitance Ct. The polarity of the magnetic field depends on the direction of the current in the loop.
Figure 1. Tx Loop Magnetic Field
ZMID520x
1
2
14
13
12
11
10
9
8
3
4
5
6
7
R1P
R1N
R2P
R2N
VDDT
EP
EN
Test_D
Test-Ena
VDDD
SOUT
VDDA
VSSE
VDDE Tx
I
I
ZMID520x
1
2
14
13
12
11
10
9
8
3
4
5
6
7
R1P
R1N
R2P
R2N
VDDT
EP
EN
Test_D
Test-Ena
VDDD
SOUT
VDDA
VSSE
VDDE Tx
I
I
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
The signal that is generated by the magnetic field of transmitter coil (Tx) is received by two receiver coils.
If a metallic target is placed over the coils, the transmitted energy below the target is dissipated as eddy currents in the target and does not
induce a secondary voltage in the receiver coils in that area.
The two receiver coils are designed with a 90phase shift, and the transmitter coil surrounds them. The target is placed on top of them and
moves over a plane parallel to the plane containing all the coils, as shown in Figure 2 below. Depending on the coil’s shape, movement can be
linear, arc, or rotary. The same physical principle is valid for different coils (and target) shapes.
The position of the target will be indicated through the differential phase and the amplitude of the signals measured on the Rx coils by the
ZMID520x
Figure 2. Current Paths and Shapes for Coils –Example for Linear Position Sensing
Metallic Target
RxCos
RxSin
Tx
Sin Loop 1
(cw)
Sin Loop 2
(ccw)
Sin Loop 3
(cw)
Tx Loop
Cos Loop 2
(ccw)
Cos Loop 1
(cw)
The key parameters influencing the proper operation of coils with the ZMID520x are the following: the length and width of the Tx and Rx coils,
the size of the target, and the airgap between the target and the printed circuit board (PCB) where the coils are integrated. Figure 3 provides
an illustration of the length and width of the coils for linear position sensing.
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
Figure 3. Geometrical Illustration for Coils and Target –Example for Linear Position Sensing
Note: The following display was created by the ZMID520x Inductive Coil Design Tool Software.
IDT provides a software tool to support coil design as illustrated in Figure 3:
ZMID520x Inductive Coil Design Tool Software: https://www.idt.com/document/swr/zmid520x-inductive-coil-design-tool-software
ZMID520x User Guide –Inductive Coil Design Tool: https://www.idt.com/document/mas/zmid520x-user-guide-inductive-coil-design-tool
Reference designs for linear, arc and rotary position sensors are shown in the “Layout” section of the applicable Application Modules User
Manual available on the following application module product pages, which also provide relevant Gerber design files:
ZMID520xMLIN Application Module:
www.idt.com/products/sensor-products/position-sensors/zmid5201mlin-zmid5201-inductive-linear-application-module-analog-output
www.idt.com/products/sensor-products/position-sensors/zmid5202mlin-zmid5202-inductive-linear-application-module-pwm-output
www.idt.com/products/sensor-products/position-sensors/zmid5203mlin-zmid5203-inductive-linear-application-module-sent-output
ZMID520xMARC Application Module:
www.idt.com/products/sensor-products/position-sensors/zmid5201marc-zmid5201-inductive-arc-application-module-analog-output
www.idt.com/products/sensor-products/position-sensors/zmid5202marc-zmid5202-inductive-arc-application-module-pwm-output
www.idt.com/products/sensor-products/position-sensors/zmid5203marc-zmid5203-inductive-arc-application-module-sent-output
ZMID520xMROT Application Module:
www.idt.com/products/sensor-products/position-sensors/zmid5201mrot-zmid5201-inductive-rotary-application-module-analog-output
www.idt.com/products/sensor-products/position-sensors/zmid5202mrot-zmid5202-inductive-rotary-application-module-pwm-output
www.idt.com/products/sensor-products/position-sensors/zmid5203mrot-zmid5203-inductive-rotary-application-module-sent-output
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
2.1 Device Block Diagram
Refer to the ZMID520x Datasheet for the latest block diagram information.
The main building blocks include the following:
Power management: power-on-reset (POR) circuit and low drop-out (LDO) regulators for internal supplies.
Oscillator: generation of the transmit coil signal.
Analog front-end: demodulator and gain control for the receive signals.
Analog-to-digital converter (ADC): conversion into digital domain.
Digital signal processing: offset correction; conversion of sine and cosine signals into angle and magnitude; angle range adjustment; and
linearization.
EEPROM: nonvolatile storage of factory and user-programmable settings.
One-wire interface (OWI): programming of the chip through the output pin.
Interface options:
Analog output for ZMID5201
PWM output for ZMID5202
SENT output for ZMID5203
Protection: overvoltage, reverse polarity, short circuit protection.
Figure 4. Main Internal Functional Block Diagram
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
3. Getting Started
The following procedures require the ZMID520x EVK Application Software, which includes the graphical user interface (GUI) provided for the
ZMID520x Application Modules.
A complete description of the GUI is given in the ZMID520x Evaluation Kit User Manual, which is available on the IDT website via the following
link, and it includes instructions for downloading and installing the GUI: https://www.idt.com/document/man/zmid520x-evaluation-kit-user-
manual-application-modules.
3.1 LC Tank –Tx Front-End Tuning
The transmit circuitry for ZMID520x applications consists of an LC tank that is formed from the inductance of the transmitting coil and a capacitor
on the circuit board as shown in Figure 5.
Figure 5. ZMID520x Transmitter LC Tank
The objective of the Tx front-end tuning is to set the oscillation frequency in the range of operation specified in the ZMID520x Datasheet; a
typical value is approximately 3.5MHz.
The first step is to measure the inductance value of the Tx coil and verify that the value is within the limits specified in the ZMID520x Datasheet.
Once the inductor value is known, the capacitor value (Ct in Figure 5) can be calculated using Equation 1.
f = 1
2𝜋√ LC
Equation 1
Direct measurement of the frequency will confirm the exact value of the oscillation frequency.
If the measurement of the inductance of the printed circuit board coil (Lt in Figure 5) is not an option, a successive approximation approach can
be used; i.e., testing multiple Ct values until the resulting oscillation frequency is as close as possible to 3.5MHz. A capacitor value of 560pF is
generally a good starting point.
Recommendation: To ensure a good quality factor and low temperature drift for the LC tank circuit, use ceramic capacitors class C0G (C-zero-
G) ceramics also known as NP0 (negative-positive-zero). The capacitor must be placed close to the EP and EN pins on the ZMID520x.
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
Figure 6 shows the TX pin oscillation detected with a LF-U 5 Near-Field Probe from Langer EMV-Technik.
Figure 6. TX Oscillation and LF-U 5 Probe
3.2 Device Initialization
3.2.1 Output Mode Selection
The ZMID allows selecting one of two output modes: Linear or Modulo 360.
Linear: The Linear Output Mode is a non-repeating output mode in which the sensor output signal is clamped at the mechanical end
points.
Modulo 360: The Modulo 360 Output (Sawtooth Output) Mode is a repeating output mode in which the sensor output signal is not
clamped at the mechanical end points, but it is switched back to its origin.
See the ZMID520x Datasheet and ZMID520x EVK User Manual for further details.
In most linear and arc applications, the Linear Output Mode is recommended. For rotary applications, the Modulo 360 Mode is recommended.
To ensure a smooth and successful procedure, use the GUI and the instructions in the ZMID520x EVK User Manual to set the ZMID520x
EEPROM registers from 00HEX to 09HEX to the following values. Note: Ensure that the new values are stored in EEPROM using the “Write
EEPROM” function.
If using the Linear Output Mode, set the following register values as shown in Figure 7: register 00HEX = 2400 HEX; register 01HEX = 0400HEX;
and registers 02HEX through 09HEX = 0000HEX.
If using the Modulo 360 Output Mode, set register 00HEX = 0000HEX, register 01HEX = 0400HEX, registers 02HEX through 08HEX = 0000HEX,
and register 09HEX = 1000HEX.
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
Figure 7. ZMID520x EEPROM Memory Values –ZMID5203 Example for the Linear Output Mode Settings
Set these standard values
for registers 00HEX to 09HEX.
Remaining register values
might differ.
Write new values to the
ZMID520x EEPROM.
3.3 Offset Check for Rx Coils
The ZMID520x has a selectable input gain, which can be set via the GUI using the Gain_stage entry field found on the “INPUT” subtab under
the “CONFIGURE” tab as described in section 3.4. Before checking the offset of the Rx coils, set the Gain_stage value to a preliminary setting
of 6 using the entry field shown in the example for the ZMID5203 given in Figure 8, which is applicable to all ZMID520x ICs.
Save the new value in the ZMID520x EEPROM memory by clicking the “Write EEPROM” button,which updates register 0CHEX.
Figure 8. ZMID520x EEPROM Gain Stage Setting –Example using the ZMID5203
Set Gain_stage to 6.
Write new values to the
ZMID520x EEPROM.
ZMID520x User Guide for Getting Started
© 2018 Integrated Device Technology, Inc.
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April 6, 2018
Next, remove the target from the sensor board (distance between the target and the Rx coils must be greater than 20mm). With this condition,
use the GUI to read the “Sine” and “Cosine” values on the “INTERNAL VALUES” subtab under the “MAIN” tab as shown in the ZMID5203
example given in Figure 9.
For properly designed coils, typical offset values are below 100DEC for “Sine” and “Cosine” values as shown in the example in Figure 9.
The coil design should meet the criteria of having a maximum symmetry for the two Rx coils. See section 2 for the links for software and
documentation for the ZMID520x Inductive Coil Design Tool Software provided by IDT for addressing this requirement.
Figure 9. Coil Offset Reading –Example using the ZMID5203
Check that offset values
are within requirements.
Write new values to the
ZMID520x EEPROM.
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