Texas Instruments BoosterPack BOOSTXL-ADS7841-Q1 User manual

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BOOSTXL-ADS7841-Q1 BoosterPack™ User's Guide
User's Guide
SNAU229–December 2017
BOOSTXL-ADS7841-Q1 BoosterPack™ User's Guide
The ADS7841-Q1 BoosterPack™ (BOOSTXL-ADS7841-Q1) allows users to evaluate the functionality of
Texas Instruments' ADS7841-Q1 SAR ADC. The ADS7841-Q1 is a 12-bit, 4-channel, automotive qualified
SAR ADC. This user’s guide describes both the hardware platform with an ADS7841-Q1 device, and the
graphical user interface (GUI) software used to configure the various modes of operation of this device.
Contents
1 Introduction ................................................................................................................... 2
2 BOOSTXL-ADS7841-Q1 EVM Overview................................................................................. 4
3 BOOSTXL-ADS7841-Q1EVM EVM Setup ............................................................................... 6
4 BOOSTXL-ADS7841-Q1 EVM GUI Operation ......................................................................... 14
5 Bill of Materials, Printed-Circuit Board Layout, and Schematics..................................................... 19
List of Figures
1 BOOSTXL-ADS7841-Q1 EVM Block Diagram .......................................................................... 3
2 BOOSTXL-ADS7841-Q1EVM Top Level Overview..................................................................... 4
3 BOOSTXL-ADS7841-Q1 EVM GUI Installation.......................................................................... 6
4 BOOSTXL-ADS7841-Q1 EVM Driver Installation ....................................................................... 7
5 TM4C1294 LaunchPad™ Stellaris Virtual Serial Port and ICDI Driver............................................... 8
6 TM4C1294 LaunchPad™ Software Programming Setup .............................................................. 9
7 TM4C1294 LaunchPad™ selection in Configuration Tab............................................................. 10
8 TM4C1294 LaunchPad™ Programming Using LM Flash Programmer............................................. 11
9 TMC1294 LaunchPad™ VIA BoosterPack Driver ..................................................................... 12
10 BOOSTXL-ADS7841-Q1EVM stacked on TM4C1294 LaunchPad™ .............................................. 13
11 ADS7841-Q1EVM GUI Landing Page................................................................................... 14
12 AIN0 (Channel0) Voltage.................................................................................................. 15
13 AIN3 (Channel3) Voltage.................................................................................................. 16
14 Frequency Domain Analysis Page....................................................................................... 17
15 BOOSTXL-ADS7841-Q1 Top Layer Routing........................................................................... 20
16 BOOSTXL-ADS7841-Q1 Ground Layer................................................................................. 21
17 BOOSTXL-ADS7841-Q1 Power Layer.................................................................................. 22
18 BOOSTXL-ADS7841-Q1 Bottom Layer Routing....................................................................... 23
19 BOOSTXL-ADS7841-Q1 EVM Schematic Diagram................................................................... 24
List of Tables
1 Input Connector and Channel Configuration............................................................................. 4
2 Bill of Materials ............................................................................................................. 19
Trademarks
BoosterPack, LaunchPad, TM4C1294 LaunchPad are trademarks of Texas Instruments.

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BOOSTXL-ADS7841-Q1 BoosterPack™ User's Guide
1 Introduction
The BOOSTXL-ADS7841-Q1 BoosterPack™ is a fully-assembled evaluation platform designed to
highlight the ADS7841-Q1 device features and its various modes of operations.
The BOOSTXL-ADS7841-Q1 EVM interfaces to the TM4C1294 LaunchPad™ Development Kit (EK-
TM4C1294XL). The Tiva C Series TM4C1294 MCU on the TM4C1294 LaunchPad™ communicates with
the ADS7841-Q1 through its SPI interface and acts as a USB-to-PC GUI communication bridge.
NOTE: The BOOSTXL-ADS7841-Q1 requires an external master controller to evaluate the
ADS7841-Q1.
The TM4C1294 LaunchPad™ is controlled by commands received from the BOOSTXL-ADS7841-Q1 EVM
GUI, and returns data to the GUI for display and analysis. If the TM4C1294 LaunchPad™ is not used, the
BoosterPack plug-in module format of the BOOSTXL-ADS7841-Q1 board allows an alternative external
host to communicate with the ADS7841-Q1.
The BOOSTXL-ADS7841-Q1 EVM incorporates all required circuitry and components with the following
features:
• ADS7841-Q1 12-bit, 4-channel, automotive qualified SAR ADC with SPI interface
• Optional low power voltage reference, TI’s REF5045A, to generate a 4.5-V reference for the ADS7841-
Q1 VREF pin when using 5.0 V from TM4C1294 LaunchPad™
• Optional precision, low noise, dual operational amplifier, TI's OPA2320, to generate buffered input for
the ADS7841-Q1 AIN0 and AIN2 pins
• Optional adjustable linear regulator, TI’s TPS79901, to generate stable 5V output voltage to power the
ADS7841-Q1 VCC pin when using the USB power from the TM4C1294 LaunchPad™
• SPI interface for communication and configuration of modes available on the ADS7841-Q1
Figure 1 shows the BOOSTXL-ADS7841-Q1 EVM architecture, identifying the key components and blocks
previously listed.

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Figure 1. BOOSTXL-ADS7841-Q1 EVM Block Diagram

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2 BOOSTXL-ADS7841-Q1 EVM Overview
Section 2 describes various onboard components that are used to interface analog input, digital interface,
and provide power supply to BOOSTXL-ADS7841-Q1 EVM. Figure 2 shows a BOOSTXL-ADS7841-Q1
EVM overview.
Figure 2. BOOSTXL-ADS7841-Q1EVM Top Level Overview
2.1 Connectors for Analog Input
The BOOSTXL-ADS7841-Q1 EVM is designed for easy interface to analog sources through a 100-mil
header. Connector J10 allows analog source connectivity. Table 1 lists the analog input connector and
input channel configuration.
Table 1. Input Connector and Channel Configuration
J10 Connector Pin Description
J10:1 Single-ended analog input for channel 0 of ADC
J10:2 Single-ended analog input for channel 1 of ADC
J10:3 Single-ended analog input for channel 2 of ADC
J10:4 Single-ended analog input for channel 3 of ADC
J10:1 - J10:2 Pseudo-Differential analog input for channel 0 - channel 1 of ADC
J10:2 - J10:1 Pseudo-Differential analog input for channel 1 - channel 0 of ADC
J10:3 - J10:4 Pseudo-Differential analog input for channel 2 - channel 3 of ADC
J10:4 - J10:3 Pseudo-Differential analog input for channel 3 - channel 2 of ADC
J10:5 and J10:6 BoosterPack ground

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The analog input range is from GND to +VREF when configured as single-ended inputs. A maximum of
four single-ended inputs may be applied to J10, using pins J10:1 to J10:4. When configured for differential
mode operation, the positive analog input level has a range of -0.2V to VCC + 0.2V. The voltage on the
negative analog input is limited between -0.2V and 1.25V. A maximum of two pseudo-differential inputs
may be applied to J10, using pins J10:1 - J10:2, and J10:3 - J10:4.
The input to channel 0 can be optionally configured to use the OPA2320 buffer through 100ohm resistor
with an 560pF capacitor to GND. Jumper J8 can be placed on pins 1-2 to select this unity gain buffer
configuration of the OPA2320 and in this case channel 0 input is provided via SMA connector J7. A similar
configuration is available for channel 2 input as well by using Jumper J12 pins 1-2 and via SMA connector
J11.
By default, AIN3 is factory configured by Jumper J15 pins 1-2 and J15 pins 3-4 on the BOOSTXL-
ADS7841-Q1 EVM to measure a fraction of the 5V supply voltage using simple resistor divider circuit
formed by R35/R36 (see schematic in Figure 19 ). Please ensure Jumper J15 shunts are disconnected
when using J10.3 as AIN3 input.
2.2 Voltage Reference
The BOOSTXL-ADS7841-Q1 EVM has two sources for the reference voltage. Jumper J13 can select the
VREF voltage from either the REF5045A (U9) or from 5V VCC. The EVM is factory configured for use with
the REF5045A 4.5V reference (J13 pins 2-3).
2.3 Digital Interface
As noted in Section 1, the BOOSTXL-ADS7841-Q1 EVM interfaces with the TM4C1294 LaunchPad™,
which in turn communicates with the computer over USB. The two devices on the booster pack that the
TM4C1294 communicates with are the ADS7841-Q1 ADC (over SPI) and the EEPROM (over I2C). The
EEPROM comes preprogrammed with the information required to configure and initialize the BOOSTXL-
ADS7841-Q1 EVM platform every time on power up.
2.4 ADS7841-Q1EVM Digital I/O Interface
The BOOSTXL-ADS7841-Q1 EVM supports the SPI digital interface and functional modes as detailed in
the ADS7841-Q1EVM device data sheet (SBAS469). The TM4C1294 LaunchPad™ is operating at a 3.3-V
logic level and is connected to the 5.0-V digital I/O lines of the ADC through level shifter
(SN74LVC2T45QDCURQ1).
2.5 Power Supplies
The device supports a single supply with a wide range of operation. The VCC can operate from 2.7 V to
5.0 V. TI’s TPS79901 adjustable voltage regulator available onboard is configured to supply 5.0 V to
ADS7841-Q1 VCC pin on the BOOSTXL-ADS7841-Q1 EVM.

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3 BOOSTXL-ADS7841-Q1EVM EVM Setup
3.1 BOOSTXL-ADS7841-Q1 EVM Graphical User Interface Software Installation
The following steps describe the BOOSTXL-ADS7841-Q1 EVM GUI software installation:
1. Download the latest version of the EVM graphical user interface (GUI) installer from the Tools and
Software folder of the device, and run the GUI installer to install the EVM GUI software on your
windows PC.
2. Accept the License Agreements and follow the on-screen instructions to complete the installation (see
Figure 3).
Figure 3. BOOSTXL-ADS7841-Q1 EVM GUI Installation

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3. As a part of the BOOSTXL-ADS7841-Q1 EVM GUI installation, a prompt with a Device Driver
Installation Wizard appears on the screen (see Figure 4). Click the Next button to proceed, then click
the Finish button when the installation is complete.
Figure 4. BOOSTXL-ADS7841-Q1 EVM Driver Installation

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4. Open the computer's "Device Manager". You must be able to see the "Stellaris Virtual Serial Port" and
"Stellaris In-Circuit Debug Interface" as shown in Figure 5.
Figure 5. TM4C1294 LaunchPad™ Stellaris Virtual Serial Port and ICDI Driver

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3.2 LM Flash Programmer for TM4C1294 LaunchPad™ Software Programming
The TM4C1294 LaunchPad™ ships with a default firmware program flashed on its memory. When a
TM4C1294 LaunchPad™ is connected to the PC for the first time, its firmware needs to be updated for
communications with the BOOSTXL-ADS7841-Q1 EVM. The following steps describe the programming of
this firmware on the flash memory:
1. Download the latest version of LM Flash Programmer. The LM Flash Programmer is also included as
part of the BOOSTXL-ADS7841-Q1 EVM GUI installation in the following folder: C:\Program Files
(x86)\Texas Instruments\ADS7841\Firmware
2. Make sure the power select JP1 jumper on the TM4C1294 LaunchPad™ is on ICDI. Connect the
Debug USB port on the TM4C1294 LaunchPad™ to the PC with a micro USB cable as shown in
Figure 6. This must light the green power LED D0 on the TM4C1294 LaunchPad™.
Figure 6. TM4C1294 LaunchPad™ Software Programming Setup

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3. Launch the LM Flash Programmer. In the Configuration tab select TM4C1294XL LaunchPad from the
drop-down menu as shown in Figure 7.
Figure 7. TM4C1294 LaunchPad™ selection in Configuration Tab