Texas Instruments PGA309EVM-USB User Manual

User's Guide

SBOU084–February 2010

PGA309EVM-USB

This user’s guide describes the characteristics, operation, and use of the PGA309EVM-USB evaluation module (EVM). This EVM is designed to evaluate the performance of the PGA309, a voltage output, programmable sensor conditioner. This document covers all pertinent areas involved to properly use this EVM board, allowing for user evaluation suitable to a variety of applications. This document also includes the physical printed circuit board (PCB) layout and circuit descriptions. A schematic of the

PGA309EVM-USB is available as a separate download from the TI web site.

Contents

1 Introduction and Overview ................................................................................................. 2

2 System Setup ................................................................................................................ 5

3 PGA309EVM-USB Hardware Setup .................................................................................... 16

4 PGA309EVM-USB Software Overview ................................................................................. 25

List of Figures

1 Hardware Included with the INA282-286EVM........................................................................... 3

2 PGA309EVM-USB Hardware Setup...................................................................................... 5

3 PGA309_Test_Board Block Diagram .................................................................................... 5

4 PGA309_Test_Board Schematic: Input Circuitry ....................................................................... 7

5 PGA309_Test_Board Schematic: Power, Reference, and Digital Connections.................................... 8

6 PGA309_Test_Board Schematic: Output Circuitry..................................................................... 9

7 PGA309_Test_Board Schematic: Sensor Emulator Circuitry........................................................ 10

8 PGA309_Test_Board Connections to USB-DAQ-Platform and EEPROM......................................... 11

9 Theory of Operation For USB-DAQ-Platform.......................................................................... 16

10 PGA309EVM-USB Typical Hardware Connections................................................................... 17

11 Connecting the Two EVM PCBs ........................................................................................ 18

12 Connecting Power to the EVM........................................................................................... 19

13 Connecting the USB Cable............................................................................................... 20

14 Default Jumper Settings (PGA309_Test_Board)...................................................................... 21

15 Default Jumper Settings (USB-DAQ-Platform) ........................................................................ 22

16 PGA309EVM-USB Software: Registers Tab........................................................................... 26

17 PGA309EVM-USB Software: EEPROM Tab .......................................................................... 27

18 PGA309EVM-USB Software: Block Diagram.......................................................................... 28

19 PGA309EVM-USB Software: Auto Calibrate Tab—Sensor Definition.............................................. 29

20 PGA309EVM-USB Software: Sensor Emulator Control Panel Tool................................................ 30

21 PGA309EVM-USB Software: Auto Calibrate Tab—PGA Setup..................................................... 31

22 PGA309EVM-USB Software: Auto Calibrate Tab—Two-Point Calibration and Linearization................... 32

23 PGA309EVM-USB Software: Auto Calibrate Tab—Temperature Error Compensation.......................... 33

24 PGA309EVM-USB Software: Auto Calibrate Tab—Post Cal Error Check......................................... 34

25 PGA309EVM-USB Software: Auto Calibrate Tab—DMM Options.................................................. 35

Microsoft, Windows are registered trademarks of Microsoft Corporation. I2C is a trademark of NXP Semiconductors. All other trademarks are the property of their respective owners.

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Introduction and Overview

1 PGA309 Test Board Parts List........................................................................................... 12

2 J1 Pinout (25-Pin Male DSUB) .......................................................................................... 14

3 J2 Pinout (25-Pin Female DSUB) ...................................................................................... 15

4 PGA309_Test_Board Jumper Functions: General.................................................................... 22

5 PGA309_Test_Board Jumper Functions: Miscellaneous Connections............................................. 23

6 PGA309_Test_Board Jumper Functions: Sensor Emulator Section ............................................... 23

7 USB-DAQ-Platform Jumper Settings ................................................................................... 24

1 Introduction and Overview

This document provides the information needed to set up and operate the PGA309EVM-USB evaluation module, a test platform for the PGA309 programmable sensor conditioner. For a more detailed description of the PGA309, refer to the product data sheet (SBOS292) available from the Texas Instruments web site at http://www.ti.com. Additional support documents are listed in the section of this guide entitled Related

Documentation from Texas Instruments.

The PGA309EVM-USB is an evaluation module that is used to fully evaluate the PGA309. The PGA309 is an integrated circuit that provides temperature compensation and linearization for bridge sensors. The PGA309EVM-USB consists of two PCBs. One board (the USB-DAQ-Platform) generates the digital signals required to communicate with the PGA309. The other board (the PGA309_Test_Board) contains the PGA309 device, as well as support and configuration circuitry.

Throughout this document, the abbreviation EVM and the term evaluation module are synonymous with the PGA309EVM-USB.

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List of Tables

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1.1 PGA309EVM-USB Hardware

Figure 1 shows the hardware included with the PGA309EVM-USB kit. Contact the factory if any

component is missing. It is highly recommended that you check the TI web site (at http://www.ti.com) to verify that you have the latest software. It is also recommended that you refer to the PGA309 User's Guide if you have questions about the PGA309 device itself.

The complete kit includes the following items:

• PGA309_Test_Board

• USB DAQ Platform Board

• USB cable

• 6V wall power-supply unit

• CD-ROM containing this user's guide and product software

Introduction and Overview

Figure 1. Hardware Included with the INA282-286EVM

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Introduction and Overview

1.2 Related Documentation from Texas Instruments

The following documents provides information regarding Texas Instruments integrated circuits used in the assembly of the PGA309EVM-USB. This user's guide is available from the TI web site under literature number SBOU084. 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 may be available from the TI web site at http://www.ti.com, or call the Texas Instruments Literature Response Center at (800) 477-8924 or the Product Information Center at (972) 644-5580. When ordering, identify the document by both title and literature number.

Document Literature Number

PGA309 SBOS292

USB DAQ Platform Users Guide SBOU056

PGA309 Users Guide SBOU024

OPA333 Product Data Sheet SBOS351

DAC8555 Product Data Sheet SLAS475

XTR117 Product Data Sheet SBOS344

PGA309EVM-USB Schematic SBOR010

Sensor-Emulator EVM Reference Guide SBOA102

1.3 If You Need Assistance

If you have questions about the PGA309EVM-USB evaluation module, send an e-mail to the Linear Application Team at precisionamps@list.ti.com. Include PGA309EVM-USB as the subject heading.

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1.4 Information About Cautions and Warnings

This document contains caution statements.

This is an example of a caution statement. A caution statement describes a situation that could potentially damage your software or equipment.

CAUTION

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USBDAQ

Platform

PGA309

TestBoard

EVM

Power

PGA309

V Supply Switched5.0VPower

DUT

One-WireInterface

25-Pin

MaleDSUBSignals

FromUSBDAQPlatform

25-Pin

FemaleDSUBSignals

FromUSBDAQPlatform

I C

Interface

4mAto20mA I/VConverter

Sensor

Connection

Sensor

Emulator

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2 System Setup

Figure 2 shows the system setup for the PGA309EVM. The PC runs software that communicates with the

USB-DAQ-Platform. The USB-DAQ-Platform generates the digital signals used to communicate with the PGA309_Test_Board. Connectors on the PGA309_Test_Board allow for connection to the bridge sensor.

System Setup

2.1 Theory of Operation for PGA309_Test_Board Hardware

Figure 2. PGA309EVM-USB Hardware Setup

Figure 3 shows the block diagram of the PGA309_Test_Board. The PGA309_Test_Board provides

connections to the I2C™, one-wire, analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) on the USB-DAQ-Platform. It also provides connection points for external connection of the bridge sensor. The PGA309_Test_Board has circuitry to convert the PGA309 voltage output to 4mA to 20mA current.

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Figure 3. PGA309_Test_Board Block Diagram

System Setup

The PGA309_Test_Board also has an onboard sensor emulator. The sensor emulator is a circuit that generates the same type of signals generated by a bridge sensor. The sensor emulator circuit is controlled by the PGA309EVM-USB software. Using the sensor emulator allows you to get a deeper understanding of the PGA309EVM-USB software and hardware more quickly. When the capabilities and functions of the PGA309EVM-USB are fully understood, you can connect the real-world sensor to the EVM and perform a full calibration.

Note that calibrations with real-world sensors are time-consuming because devices such as these are normally calibrated at multiple temperatures in an environmental chamber. It is not unusual for temperature calibration to require 12 hours.

2.2 PGA309_Test_Board Connections

See Figure 4 for the input connections on the PGA309_Test_Board schematic. T1 provides the power connection for an external bridge sensor. T4 allows connections to each input of the external bridge sensor. T5 allows connection of the external temperature sensor. JMP7, JMP4, JMP5, and JMP6 allow users to select either the onboard sensor emulator or an external sensor. JMP12 allows users to choose between VSor V

The input is filtered with R3, R4, C14, C15, and C16. Note that C14 is ten times larger then C15, and C16 is used for good ac common-mode rejection. The cutoff frequency of this filter is 40.6Hz (f = 1/(2 p R3 C14)). This input filter is recommended in your final design if you have available board space.

has a 100pF capacitor and TEMPin has a 1nF capacitor. These components are also recommended

EXC

in your final design. Refer to Figure 5 to see the power, reference, and digital connections on the PGA309_Test_Board

schematic. T2 provides a connection for an external reference voltage. JMP1 and JMP2 allow users to select between the internal reference, an external reference, or power-supply reference. JMP7 and JMP8 allows users to connect the One-Wire signal to the PRG pin directly or through V

D2 is a transient voltage suppressor. It is useful in helping to prevent damage in an electrical overstress (EOS) condition. R5 is useful in preventing EOS damage to the output. C6 filters noise at the output. C5 filters the reference output. These components are recommended for your design if PCB space permits. C4 is a decoupling capacitor; it is required in the final design.

for the sensor power.

EXC

OUT

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System Setup

Figure 4. PGA309_Test_Board Schematic: Input Circuitry

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System Setup

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Figure 5. PGA309_Test_Board Schematic: Power, Reference, and Digital Connections

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Figure 6 shows the output section of the PGA309EVM_Test_Board. There are two output options: voltage

output and current output. The voltage output option is selected by placing JMP9 in the NC position. The current output option is selected by moving JMP9 to the V

to XTR position.

OUT

System Setup

Figure 6. PGA309_Test_Board Schematic: Output Circuitry

In voltage output mode, C10 = 10nF is connected to the PGA309 output. This capacitor is used for radio frequency interference (RFI) and electromagnetic interference (EMI) immunity. This component should be included in your design, if possible.

In current output mode, the PGA309 output is connected to a voltage-to-current (V-I) converter (XTR117). The sum of R6 and R8 convert the output voltage from the PGA309 to an input current for the XTR117. R7 can be used to create an input offset current using the reference. The total input current is IIN= V (R6 + R8) + V

/R7. The output current is equal to the input current times the current gain (x 100).

REF

D4 is used for reverse polarity protection. D3 is used for over-voltage transient protection. D3 was selected for low leakage. Leakage on D3 directly contributes to error. C11 is a decoupling capacitor and is required for proper operation. The external transistor, Q1, conducts the majority of the full-scale output current. Power dissipation in this transistor can approach 0.8W with high loop voltage (40V) and 20mA output current.

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OUT

System Setup

Figure 7 shows the sensor emulator circuit. The sensor emulator generates signals to help users evaluate

the PGA309. No part of this circuit is required in your final design. The sensor emulator uses a DAC8555 (U8) to generate an emulated temperature signal, common-mode signal, and differential signal. These signals can be controlled using software to produce levels that closely match real-world sensors.

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Figure 7. PGA309_Test_Board Schematic: Sensor Emulator Circuitry

The operational amplifier U4 and associated resistors is a differential amplifier with jumper selectable attenuation. The possible attenuations are 0.12 and 0.012. The attenuation produces a more accurate and stable emulated sensor output. For example, when the DAC outputs 3V, the sensor emulator outputs 3V ×

0.012 = 36mV (assuming that attenuation is set in the 0.012 position). Thus, the maximum output of the sensor emulator is 120mV/V and 12mV/V.

The op amp U6 buffers the emulated temperature signal. Resistors R16, R17, R18, and R19 are used to attenuate the DAC output for temperature emulation and to reference the temperature signal to supply or ground. JMP13 allows the resistor network to be bypassed for direct connection to the DAC (diode temperature sensor mode).

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Figure 8 illustrates the two 25-pin D-SUB connectors J1 and J2. These connectors provide all the signals

necessary to communicate with the PGA309. U5 is the EEPROM used to store the calibration look-up table used with the PGA309.

System Setup

Figure 8. PGA309_Test_Board Connections to USB-DAQ-Platform and EEPROM

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System Setup

2.3 PGA309_Test_Board Parts List

Table 1 describes the parts list for the PGA309_Test_Board.

Table 1. PGA309 Test Board Parts List

Qty Value Ref Des Description Vendor Part Number

1 560pF C6 Panasonic - ECG ECJ-1VC1H561J

3 100pF C3 C5, C13 ECJ-1VC2A101J

6 0.1µF C4, C7, C8, C9, C14, C17 Kemet CC0603ZRY5V8BB104

2 .01µF C15, C16 AVX 06031C103KAT2A

1 1nF C18 Panasonic - ECG ECJ-1VB2A102K

2 10nF C10, C11 Kemet C0603C103K5RACTU

1 0.02µF C12 TDK Corporation C1608X7R2A223K 1 1000pF C2 Omit; not installed JOHANSON DIELECTRICS 501R18W102KV4E 4 100kΩ R11, R15, R18, R19 Susumu Co Ltd RGH1608-2C-P-104-B

2 1.2kΩ R12, R13 Susumu Co Ltd RGH1608-2C-P-122-B

5 10kΩ R8, R10, R14, R16, R17 Susumu Co Ltd RGH1608-2C-P-103-B

4 100Ω R5, R20, R21, R22 Yageo Corporation RC0603FR-07100RL

1 191kΩ R7 Yageo Corporation ERJ-3EKF1913V

1 11.3kΩ R6 Yageo Corporation ERJ-3EKF1132V

2 39.2kΩ R3, R4 Yageo Corporation RC0603FR-0739K2L

1 50kΩ R23 Sunsuma RR0816P-4992-D-68C

1 2.49kΩ R24 Sunsuma RR0816P-2491-D-39H 0 omit R1, R2, R9 Omit; not installed

1 PGA309 U1 Smart Programmable Sensor Texas Instruments PGA309AIPWT 1 BNC P1 Tyco Electronics/Amp 5227699-1

OPA333AID

2 U4 U6 IC Op Amp 1.8V 0-DRIFT SOT23-5 Texas Instruments OPA333AIDBVT 1 DAC8555 U3 IC DAC 16BIT QUAD 16-TSSOP Texas Instruments DAC8555IPW 1 24LC16BT U5 Microchip Technology 24LC16BT-I/OT

1 XTR117 U2 Texas Instruments XTR117AIDGKT

1 D2 ON Semiconductor P6SMB6.8AT3G

1 SMAJ43A D3 TVS 400W 43V Unidirectional SMA SMAJ43A-TP

1 BAS70TP D4 BAS70TPMSCT-ND

1 NPN Q1 Fairchild Semiconductor BCP55

5 ED300/2 T1, T2, T3, T4, T5 On-Shore Technology Inc ED300/2

BVT

6.8V TVS Zener Unidirectional 600W

transzorb 6.8V SMB

Capacitor, ceramic 560pF 50V NP0 0603

Capacitor, 0.1µF 25V, ceramic Y5V 0603

Capacitor, ceramic .01µF 10% 100V X7R 0603

Capacitor, 1000pF, 100V, ceramic X7R 0603

Capacitor, 10000pF, 50V, ceramic X7R 0603

Capacitor, ceramic 22000pF, 100V X7R 10%0603

Resistor, 100kΩ 1/6W 0.1% 0603 SMD

Resistor, 1.2kΩ 1/6W 0.1% 0603 SMD

Resistor, 10.0kΩ 1/6W 0.1% 0603 SMD

Resistor, 100kΩ 1/10W 1% 0603 SMD

Resistor, 191kΩ 1/10W 1% 0603 SMD

Resistor, 11.3kΩ 1/10W 1% 0603 SMD

Resistor, 39.2kΩ 1/10W 1% 0603 SMD

Resistor, 49.9kΩ 1/16W .5% 0603 SMD

Resistor, 2.49kΩ 1/16W .5% 0603 SMD

Connector, Jack BNC Vertical 50Ω PCB

IC SRL EEPROM 16K 2.5V SOT23-5

IC 4mA-20mA Current-Loop TX 8-MSOP

Micro Commercial

Components

Diode, Schottky 70V 200mA Micro Commercial SOT23 Components

IC, Transistor NPN SS GP 1.5A SOT223-4

2-Position Terminal Strip, Cage Clamp, 45º, 15A, Dove-tailed

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