Texas Instruments PGA309EVM-USB User Manual

5 (1)

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

www.ti.com

 

 

List of Tables

 

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

1Introduction 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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Introduction and Overview

1.1PGA309EVM-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'sguide and product software

Figure 1. Hardware Included with the INA282-286EVM

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1.2Related Documentation from Texas Instruments

The following documents provides information regarding Texas Instruments integrated circuits used in the assembly of the PGA309EVM-USB. This user'sguide 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

 

 

1.3If 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.

1.4Information About Cautions and Warnings

This document contains caution statements.

CAUTION

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

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System Setup

2System 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.

EVM

POWER

USB DAQ

PLATFORM

PGA309

TEST BOARD

Figure 2. PGA309EVM-USB Hardware Setup

2.1Theory of Operation for PGA309_Test_Board Hardware

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.

25-Pin Male DSUB Signals From USB DAQ Platform

VDUT Supply

 

Switched 5.0V Power

I2C

 

Interface

 

One-Wire Interface

PGA309

4mA to 20mA I/V Converter

Sensor

Emulator

25-Pin Female DSUB Signals From USB DAQ Platform

Sensor

Connection

Figure 3. PGA309_Test_Board Block Diagram

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System Setup

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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.

2.2PGA309_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 VS or VEXC for the sensor power.

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.

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

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.

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System Setup

Figure 4. PGA309_Test_Board Schematic: Input Circuitry

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

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System Setup

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 VOUT to XTR position.

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 = VOUT / (R6 + R8) + VREF/R7. The output current is equal to the input current times the current gain (x 100).

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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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.

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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System Setup

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.

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

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2.3PGA309_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

Capacitor, ceramic 560pF 50V NP0

Panasonic - ECG

ECJ-1VC1H561J

0603

 

 

 

 

 

 

 

 

 

 

 

3

100pF

C3 C5, C13

Capacitor, ceramic 560pF 50V NP0

 

ECJ-1VC2A101J

0603

 

 

 

 

 

 

 

 

 

 

 

 

6

0.1µF

C4, C7, C8, C9, C14, C17

Capacitor, 0.1µF 25V, ceramic Y5V

Kemet

CC0603ZRY5V8BB104

0603

 

 

 

 

 

 

 

 

 

 

 

2

.01µF

C15, C16

Capacitor, ceramic .01µF 10%

AVX

06031C103KAT2A

100V X7R 0603

 

 

 

 

 

 

 

 

 

 

 

1

1nF

C18

Capacitor, 1000pF, 100V, ceramic

Panasonic - ECG

ECJ-1VB2A102K

X7R 0603

 

 

 

 

 

 

 

 

 

 

 

2

10nF

C10, C11

Capacitor, 10000pF, 50V, ceramic

Kemet

C0603C103K5RACTU

X7R 0603

 

 

 

 

 

 

 

 

 

 

 

1

0.02µF

C12

Capacitor, ceramic 22000pF, 100V

TDK Corporation

C1608X7R2A223K

X7R 10%0603

 

 

 

 

 

 

 

 

 

 

 

1

1000pF

C2

Omit; not installed

JOHANSON DIELECTRICS

501R18W102KV4E

 

 

 

 

 

 

4

100kΩ

R11, R15, R18, R19

Resistor, 100kΩ 1/6W 0.1% 0603

Susumu Co Ltd

RGH1608-2C-P-104-B

SMD

 

 

 

 

 

 

 

 

 

 

 

2

1.2kΩ

R12, R13

Resistor, 1.2kΩ 1/6W 0.1% 0603

Susumu Co Ltd

RGH1608-2C-P-122-B

SMD

 

 

 

 

 

 

 

 

 

 

 

5

10kΩ

R8, R10, R14, R16, R17

Resistor, 10.0kΩ 1/6W 0.1% 0603

Susumu Co Ltd

RGH1608-2C-P-103-B

SMD

 

 

 

 

 

 

 

 

 

 

 

4

100Ω

R5, R20, R21, R22

Resistor, 100kΩ 1/10W 1% 0603

Yageo Corporation

RC0603FR-07100RL

SMD

 

 

 

 

 

 

 

 

 

 

 

1

191kΩ

R7

Resistor, 191kΩ 1/10W 1% 0603

Yageo Corporation

ERJ-3EKF1913V

SMD

 

 

 

 

 

 

 

 

 

 

 

1

11.3kΩ

R6

Resistor, 11.3kΩ 1/10W 1% 0603

Yageo Corporation

ERJ-3EKF1132V

SMD

 

 

 

 

 

 

 

 

 

 

 

2

39.2kΩ

R3, R4

Resistor, 39.2kΩ 1/10W 1% 0603

Yageo Corporation

RC0603FR-0739K2L

SMD

 

 

 

 

 

 

 

 

 

 

 

1

50kΩ

R23

Resistor, 49.9kΩ 1/16W .5% 0603

Sunsuma

RR0816P-4992-D-68C

SMD

 

 

 

 

 

 

 

 

 

 

 

1

2.49kΩ

R24

Resistor, 2.49kΩ 1/16W .5% 0603

Sunsuma

RR0816P-2491-D-39H

SMD

 

 

 

 

 

 

 

 

 

 

 

0

omit

R1, R2, R9

Omit; not installed

 

 

 

 

 

 

 

 

1

PGA309

U1

Smart Programmable Sensor

Texas Instruments

PGA309AIPWT

 

 

 

 

 

 

1

BNC

P1

Connector, Jack BNC Vertical 50Ω

Tyco Electronics/Amp

5227699-1

PCB

 

 

 

 

 

 

 

 

 

 

 

2

OPA333AID

U4 U6

IC Op Amp 1.8V 0-DRIFT SOT23-5

Texas Instruments

OPA333AIDBVT

BVT

 

 

 

 

 

 

 

 

 

 

 

1

DAC8555

U3

IC DAC 16BIT QUAD 16-TSSOP

Texas Instruments

DAC8555IPW

 

 

 

 

 

 

1

24LC16BT

U5

IC SRL EEPROM 16K 2.5V

Microchip Technology

24LC16BT-I/OT

SOT23-5

 

 

 

 

 

 

 

 

 

 

 

1

XTR117

U2

IC 4mA-20mA Current-Loop TX

Texas Instruments

XTR117AIDGKT

8-MSOP

 

 

 

 

 

 

 

 

 

 

 

1

6.8V

D2

TVS Zener Unidirectional 600W

ON Semiconductor

P6SMB6.8AT3G

transzorb

6.8V SMB

 

 

 

 

 

 

 

 

 

 

1

SMAJ43A

D3

TVS 400W 43V Unidirectional SMA

Micro Commercial

SMAJ43A-TP

Components

 

 

 

 

 

 

 

 

 

 

 

1

BAS70TP

D4

Diode, Schottky 70V 200mA

Micro Commercial

BAS70TPMSCT-ND

SOT23

Components

 

 

 

 

 

 

 

 

 

 

1

NPN

Q1

IC, Transistor NPN SS GP 1.5A

Fairchild Semiconductor

BCP55

SOT223-4

 

 

 

 

 

 

 

 

 

 

 

5

ED300/2

T1, T2, T3, T4, T5

2-Position Terminal Strip, Cage

On-Shore Technology Inc

ED300/2

Clamp, 45º, 15A, Dove-tailed

 

 

 

 

 

 

 

 

 

 

 

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