Texas Instruments DRV5055EVM User Manual

User's Guide

SLYU047A–April 2018–Revised May 2018

DRV5055EVM

This user’s guide describes the characteristics, operation, and use of the DRV5055 evaluation module
(EVM). This EVM is designed to evaluate the performance of the DRV5055 ratiometric, linear, Hall effect
sensors. Throughout this document, the terms evaluation board, evaluation module, and EVM are
synonymous with the DRV5055EVM. This document includes a schematic, reference printed circuit board
(PCB) layouts, and a complete bill of materials (BOM).

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DRV5055EVM

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Contents

1 Overview...................................................................................................................... 3

2 Operation ..................................................................................................................... 4

3 Hardware...................................................................................................................... 5

4 Schematics, PCB Layout, and Bill of Materials .......................................................................... 8

List of Figures

1 Microcontroller Source Code Operation .................................................................................. 5

2 Schematic for DRV5055 Devices Gain Variants A1 to A4 (Right to Left)............................................ 8

3 Schematic of LCD for Measurement Display, Microcontroller for Data Processing, and Switch for

Expanding GPIO Functionality ............................................................................................ 9

4 Schematic of Push-Button User Input, Slider Switch User Input, and Programming Input....................... 10

5 Schematic of LED and Indicators and Slider Switch Status Reader ................................................ 11

6 Schematic of Supply Input and Power Conditioning................................................................... 11

7 Top Overlay................................................................................................................. 12

8 Top Layer ................................................................................................................... 12

9 Bottom Overlay ............................................................................................................. 12

10 Bottom Layer................................................................................................................ 12

List of Tables

1 DRV5055 Device Summary ................................................................................................ 3

2 Kit Contents .................................................................................................................. 3

3 Related Documentation..................................................................................................... 3

4 Bill of Materials ............................................................................................................. 13

Trademarks

All trademarks are the property of their respective owners.

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1 Overview

The DRV5055 family of linear Hall effect sensors sense magnetic fields ranging from 21 mT to 176 mT,
depending on device and supply voltage. For each device, four gains are available. For the DRV5055, the
gains at 3.3 V VCCinclude: 7.5 mV/mT, 15 mV/mT, 30 mV/mT, and 60 mV/mT. These devices operate
from a single 3-V to 5.5-V power supply, drawing a maximum of 10 mA of supply current. These devices
are currently available in a 3-pin SOT-23 or 3-pin TO-92 package. Table 1 lists available gain options.

Overview

Table 1. DRV5055 Device Summary

Product Gain at 3.3V V

DRV5055A1 60 mV/mT
DRV5055A2 30 mV/mT
DRV5055A3 15 mV/mT
DRV5055A4 7.5 mV/mT

1.1 Kit Contents

Table 2 lists the contents of the DRV5055EVM kit. Contact the nearest Texas Instruments Product
Information Center if any component is missing. Click the links in Table 3 for further information on the

DRV5055. The device name links to the product web folder on www.ti.com. The literature number links to
the user's guide PDF.

Table 2. Kit Contents

Item Quantity

DRV5055EVM test board 1

Cylindrical magnet 1

USB cable 1

1.2 Related Documentation From Texas Instruments

This EVM user's guide provides information regarding TI's integrated circuits used in the assembly of the
DRV5055EVM. This user's guide is available from the TI website under literature number SLYU047. Any
letter appended to the literature number corresponds to the document revision that is current at the time of
the writing of this document. Newer revisions are available from www.ti.com or the Texas Instruments'
Literature Response Center at [phone] or the Product Information Center at [phone]. When
ordering, identify the document by both title and literature number. Table 3 lists documentation related to
the DRV5055EVM.

CC

DRV5055-Q1 data sheet SBAS639

SN74LVC1G17 data sheet SCES351

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Table 3. Related Documentation

Document Title

DRV5055 data sheet SBAS640

TCA9535 data sheet SCPS201

LP5907 data sheet SNVS798

TS5A23159 data sheet SCDS201

Copyright © 2018, Texas Instruments Incorporated

Document Literature

Number

DRV5055EVM

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Operation

2 Operation

2.1 Quick Start Setup

The following instructions describe how to set up and use the DRV5055EVM.

Step 1. Insert the USB cable into the EVM onboard USB receptacle.
Step 2. For proper calibration, make certain that there are no magnets within a few feet of the EVM

when the EVM powers up.

Step 3. Plug the USB cable into any USB power adapter (for example, laptop, desktop, power bank,

and so on). LED D13 on the far bottom right of the board indicates the board is powered,
calibrated, and is taking sample measurements from the DRV5055A1 (default EVM startup
device).

2.2 Measurements

The DRV5055EVM measures a magnetic field with multiple devices and the respective gain variants.
Push-button S1 selects the different gain variants of the DRV5055 devices. The devices are arranged
such that gain variants increase sequentially from right to left. The LCD displays the measurement
corresponding to the selected device. The measurement format is adjusted by the slide switch labeled
Display Mode (K1).

Step 1. Click the Device Select Switch until an LED indicates the device of interest is selected.
Step 2. Adjust the Display Mode slide switch to the measurement format of interest.
Step 3. Introduce magnetic stimulus (for example, the magnet included in the evaluation kit).

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Start Up

1. Set Up Microcontroller Registers

2. Calibrate Measurements

A: Number of Collected Samples < 32
B: Push-Button Pressed
C: 32 Samples Collected

Collect A2

Samples

Collect A3

Samples

B

A

A

A A

B B

B

Display Measurement

and Check Measurement Mode

C

C C C

Collect A1

Samples

Collect A4

Samples

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3 Hardware

The DRV5055 is a linear Hall effect magnetic-sense solution that provides ease of use and high
performance. The DRV5055EVM is intended to provide basic functional evaluation of this device family.
The fixture layout is not intended to be a model for the target circuit, nor is it laid out for electromagnetic
compatibility (EMC) testing. The DRV5055EVM consists of one PCB with each of the gain variants of the
DRV5055. The EVM kit also provides a USB cable for quick power-up, as well as a magnet for quick
qualitative assessment of the DRV5055 variants performance.

3.1 Features

The layout of the DRV5055EVM printed circuit board (PCB) is designed to provide the following features:

• Evaluation of all gain options for the DRV5055

• Easily access device pins through test points

• Easily read voltage, mT, and microcontroller ADC memory values from the onboard LCD

• Toggle between devices with a press of the Device Select Switch, push-button S1.
See the links in Table 3 for comprehensive information about the DRV5055 family of devices.

3.2 Theory of Operation

The DRV5055EVM is a plug and play board, requiring only that the user supply power and provide a
magnetic stimulus after the initial calibration. The ease of operation can be attributed to the onboard
microcontroller. The source code for the microcontroller is available on the DRV5055 web folder under

Tools and Software. The basic operation of the microcontroller source code is outlined in the state

machine diagram shown in Figure 1. Upon receiving power, the microcontroller registers are set up to
properly interact with the other devices on the board. Then, a preliminary measurement of each DRV5055
gain variant is taken. It is imperative that the magnetic stimulus of interest is not present at this time, as
this measurement sets the 0 point in the mT measurement display. After calibration is complete, the LED
for the DRV5055A1 powers on by default. At this point, the EVM microcontroller begins continuously
sampling the DRV5055A1. Pressing push-button S1 results in the EVM sampling the next adjacent device.
After every 32 samples are taken, the device calculates an average, and processes the data to fit the
format selected by the slider switch K1.

Hardware

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Figure 1. Microcontroller Source Code Operation

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DRV5055EVM

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Hardware

3.3 Circuitry

This section summarizes the DRV5055EVM components.

3.3.1 C1, J1, R1, and R2

J1 serves as the connector for an external MSP-FET Flash Emulation Tool to connect to the board.
C1, R1, and R2 are the additional passives required for the emulation tool to effectively communicate with

the MSP430FR4133 for the purposes of programming and debugging.
The MSPFETFlash can be obtained separately at http://www.ti.com/tool/MSP-FET. Alternatively, if an

MSP430FR4133 Launchpad is already available, that board can be configured to program the
DRV5055EVM microcontroller.

3.3.2 C2-C5, C29, C32, C36, C43

C2-C5 are the 1-µF supply bypass capacitors for the DRV5055.
C29, C32, C36, and C43 are the supply bypass capacitors for the MSP430FR4133, SN74LVC1G17,

LP5907MFX-3.3, TCA9535, and TS5A23159, respectively.

3.3.3 C8--C11, R3-R6

These components are used to form low-pass filters on the outputs of all of the DRV5055Ay devices,
where y = 1 to 4. The capacitors also allow the ADC input node to remain relatively stable throughout the
ADC sample transition.

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3.3.4 J2

J2 is the male USB connector that allows the device to be powered through a PC USB port or USB
adapter.

3.3.5 K1, R47, R48, R49

K1 serves as a slide switch that pulls GPIO extender TCA9535 GPIO pins P00, P01, and P02 either to
GND or to 3.3-V VCC through pullup resistors R47, R48, and R49.

3.3.6 R16 and S1

R16 is a pullup resistor that ties push-button switch S1 to the 3.3-V VCC when S1 is not pushed.

3.3.7 C55, R51, and U14

C55 and R51 form a low-pass filter with the push-button stimulus, and are used with SN74LVC1G17
Schmitt Trigger (U14) to mitigate the effects of debounce from the push-button.

3.3.8 U9-U12

U9-U12 Correspond to each of the gain variants of the DRV5055 device. The gains are arranged highest
to lowest with U9 being the A4 variant while U12 is the A1 variant.

3.3.9 U16 C33, C35, R19, R50

U16 is the LP590MFX-3.3 low dropout regulator (LDO) that converts the input voltage from the USB
power source to a stable 3.3 V.

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DRV5055EVM

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SLYU047A–April 2018–Revised May 2018

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