User's Guide SBAU149B – June 2009 – Revised May 2011 ADS1146EVM, ADS1246EVM, ADS1146EVM-PDK, ADS1246EVM-PDK ADS1246EVM (Left) and ADS1246EVM-PDK (Right) This user's guide describes the characteristics, operation, and use of the ADS1146EVM and ADS1246EVM, both by themselves and as part of the ADS1146EVM-PDK or ADS1246EVM-PDK. These evaluation modules (EVMs) are evaluation boards for the ADS1246, a 24-bit delta-sigma analog-to-digital converter (ADC), and the ADS1146, a 16-bit version of the ADS1246.
www.ti.com 1 2 3 4 5 6 7 8 9 10 Contents EVM Overview ............................................................................................................... 3 Analog Interface ............................................................................................................. 4 Digital Interface .............................................................................................................. 4 Power Supplies ...................................................................
EVM Overview www.ti.com 1 EVM Overview 1.1 Features ADS1146EVM/ADS1246EVM Features: • Contains all support circuitry needed for the ADS1146/ADS1246 • ±2.
Analog Interface 2 www.ti.com Analog Interface For maximum flexibility, the ADS1246EVM is designed for easy interfacing to multiple analog sources. Samtec part numbers SSW-110-22-F-D-VS-K and TSM-110-01-T-DV-P provide a convenient 10-pin, dual-row, header/socket combination at J8. This header/socket provides access to the analog input pins of the ADS1246. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connector options.
Power Supplies www.ti.com Table 2. J7: Serial Interface Pins (continued) Pin No. Pin Name Signal Name I/O Type Pullup J7.13 DR DOUT/DRDY Out None J7.14 GPIO4 Unused — None J7.15 INT DRDY Out None J7.16 SCL SCL I2C High I2C clock J7.17 TOUT CLK In None Can be used to provide a clock from a processor Digital ground J7.18 DGND DGND In/Out None J7.19 GPIO5 CLK Select — None J7.
Voltage Reference 4.1 www.ti.com Power Options J10 is arranged as five rows, each of which can be shorted. Table 4 lists the power option details for J10. For normal operation, J10.1-2, J10.3-4, and J10.5-6 must be connected (direct or through an ammeter), and either (or both) of J10.7-8 and J10.9-10 must be connected; otherwise, the board will not function. Table 4. J10 Configuration: Power Options 5 Row Name 1-2 ADC AVDD AVDD supply current measurement point for the ADC.
Clock Source www.ti.com 6 Clock Source The ADS1246 has an internal clock or can be provided an external clock. The EVM uses the internal clock mode only. Provision is made on the EVM circuit board, however, for an external clock source. A footprint is provided at U8 for a crystal oscillator to be mounted on the board. An external clock may also be provided by a processor on the TOUT pin (J7.17), or an external clock source connected to J9.1 (ground) and J9.2 (signal).
ADS1246EVM-PDK Kit Operation 7.3 www.ti.com Default Jumper Settings and Switch Positions Figure 3 shows the jumpers found on the EVM and the respective factory default conditions for each. Figure 3. ADS1246EVM Default Jumper Locations Table 6 lists the switches found on the EVM and the respective factory default conditions for each. Table 6.
ADS1246EVM-PDK Kit Operation www.ti.com 8.1 Installing the ADCPro Software CAUTION Do not connect the ADS1246EVM-PDK before installing the software on a suitable PC. Failure to observe this caution may cause Microsoft Windows to not recognize the ADS1246EVM-PDK as a connected device. The CD-ROM shipped with the ADS1246EVM contains an installer for ADCPro as well as an installer for the ADS1246EVM plug-in. The latest software is available from the TI website at http://www.ti.com/.
ADS1246EVM-PDK Kit Operation 8.2 www.ti.com Setting Up the ADS1246EVM-PDK The ADS1246EVM-PDK contains both the ADS1246EVM and the MMB3 motherboard; however, the devices are shipped unconnected. Follow these steps to set up the ADS1246EVM-PDK. Step 1. Unpack the ADS1246EVM-PDK kit. Step 2. Set the switches on the MMB3 as described below, as shown in Figure 6. • Set switch SW4 to the right. • Set the DAC switch (SW5) to the OUT position (to the right). Figure 6.
ADS1246EVM-PDK Kit Operation www.ti.com Step 3. Plug the ADS1246EVM into the MMB3 as Figure 7 illustrates. Figure 7. Connecting ADS1246EVM to MMB3 CAUTION Do not misalign the pins when plugging the ADS1246EVM into the MMB3. Check the pin alignment carefully before applying power to the PDK. Step 4. Set the jumpers and switches on the ADS1246EVM as shown in Figure 3 (note that these settings are the factory-configured settings for the EVM).
ADS1246EVM-PDK Kit Operation 8.2.1 www.ti.com About the MMB3 The MMB3 is a Modular EVM System motherboard. It is designed around the MSP430F449, a low-power microcontroller from Texas Instruments. Figure 8 shows a block diagram of the MMB3. USB USB RESET +5VA -5VA +5VD PWR & VREF +3.3V +1.8V +10V TUSB3410 -10V Supplied to Daughtercard Power Connector LCD DISPLAY 2.
ADS1246EVM-PDK Kit Operation www.ti.com 8.3 EVM Power Supply The ADS1246EVM-PDK is powered completely from the USB connection on the MMB3. The MMB3 provides 3.3V and ±5V to the ADS1246EVM. 8.4 Running the Software and Download of Firmware to MMB3 NOTE: The software is continually under development. These instructions and screen images are current at the time of this writing, but may not exactly match future releases. The program for evaluating the ADS1246EVM-PDK is called ADCPro.
ADS1246EVM-PDK Kit Operation space Step 2. www.ti.com Select ADS1246EVM from the EVM drop-down menu. The ADS1246EVM-PDK plug-in appears in the left pane, as shown in Figure 10. Figure 10. ADS1246EVM-PDK Plug-In Display Window Step 3. 14 The ADS1246EVM-PDK plug-in window has a status area at the top of the screen. When the plug-in is first loaded, the plug-in searches for the board. You will see a series of messages in the status area indicating this action.
ADS1246EVM-PDK Kit Operation www.ti.com space Step 4. If the plug-in cannot connect to the EVM, you will see a window as shown in Figure 11. This message may indicate that the firmware is not loaded on the MMB3. You may select Retry Auto Connect; if that action fails, select Retry Manual Connect and specify the COM port to be used. Figure 11. Connection Timeout Step 5. The plug-in detects whether or not the board has the correct firmware loaded.
ADS1246EVM-PDK Kit Operation www.ti.com Switch the BSL switch (SW4) on the MMB3 to the BSL position (to the left) as instructed, then press OK. The plug-in downloads the firmware to the MMB3. This operation may take a couple of minutes, so the progress is updated in the message at the top of the ADS1246 plug-in window (as Figure 13 shows). The firmware is saved in flash memory on the MMB3, so this operation should only need to be performed once. Figure 13.
Evaluating Performance with the ADCPro Software www.ti.com 9 Evaluating Performance with the ADCPro Software The evaluation software is based on ADCPro, a program that operates using a variety of plug-ins. To use ADCPro, load an EVM plug-in and a test plug-in. To load an EVM plug-in, select it from the EVM menu. To load a test plug-in, select it from the Test menu. To unload a plug-in, select the Unload option from the corresponding menu. Only one of each kind of plug-in can be loaded at a time.
Evaluating Performance with the ADCPro Software 9.1.1 www.ti.com Configuration Tab This tab (shown in Figure 15) is the primary tab that controls the function of the multiplexer and power and reference settings in the ADS1246. The tab is divided into two sections: I/O Configuration and Supply Configuration. Figure 15.
Evaluating Performance with the ADCPro Software www.ti.com 9.1.1.1 I/O Configuration Section Each input channel can have a VBIAS applied to it. Checking the VBIAS box on a channel applies the VBIAS voltage, which is approximately half the value of the supply. You can test this option as shown in Figure 16, using one input tied to something close to ground (make sure you observe the common-mode restrictions listed in the ADS1246 device data sheet) as a reference for this signal. Figure 16.
Evaluating Performance with the ADCPro Software www.ti.com The System Monitor button allows you to access the internal system monitor channels of the ADS1246. When pressed, this button disables the other analog input channel controls, and the system monitor channel selections are enabled. You can select Offset, Gain, or Temperature as the channel to convert. Note that some of these channels are scaled by a factor when read; refer to the ADS1246 data sheet to determine these factors.
Evaluating Performance with the ADCPro Software www.ti.com 9.1.2 Cal Tab The Cal tab (shown in Figure 17) controls the calibration functions of the ADS1246. Figure 17. Cal Tab Pressing the Self Offset Calibrate button causes the ADS1246 to perform a self calibration; the offset and full-scale register values are then updated on the plug-in screen. You may also write to these registers by typing in hex values in the New fields, then press the Set button.
Evaluating Performance with the ADCPro Software 9.1.3 www.ti.com About Tab The About tab displays information about the EVM and software, as shown in Figure 18. Figure 18. About Tab The Plugin Version and Firmware Version indicators show the version numbers of the plug-in and firmware code, respectively. The ID indicator shows the value of the ID [3:0] bits in the ADS1246 ID register. The Notes indicator may show relevant notes about the plug-in or firmware code, if there are any.
Evaluating Performance with the ADCPro Software www.ti.com 9.1.4 Collecting Data Once you have configured the ADS1246 for your test scenario, press the ADCPro Acquire button to start the collection of the number of datapoints specified in the Test plug-in Block Size control. The ADS1246EVM-PDK plug-in disables all the front panel controls while acquiring, and displays a progress bar as shown in Figure 19. Figure 19.
Schematics and Layout 9.2 www.ti.com Troubleshooting If the ADS1246EVM plug-in cannot find the ADS1246EVM-PDK, press the USB RESET button on the MMB3 (refer to Figure 6) and try again. If ADCPro stops responding while the ADS1246EVM-PDK is connected, try unplugging the USB cable from the PDK. Unload and reload the plug-in before reapplying power to the PDK. 10 Schematics and Layout Schematics for the ADS1146EVM and ADS1246EVM are appended to this user's guide.
Revision History www.ti.com Table 7. ADS1146EVM/ADS1246EVM Bill of Materials (continued) Item No. Qty Value Ref Des Vendor Part Number 24 1 10kΩ R1 Resistor, Thick Film Chip 10kΩ, 5%, 1/10W, Size = 0603 Description Panasonic ERJ-3GEYJ103V 25 1 2kΩ R2 Resistor, Thick Film Chip 2kΩ, 1%, 1/16W, Size = 0603 Panasonic ERJ-3EKF2001V 26 4 47Ω R3, R4, R7, R10 Resistor, Thick Film Chip 47Ω, 5%, 1/10W, Size = 0603 Panasonic ERJ-3GEYJ470V 27 2 2.7kΩ R5, R6 Resistor, Thick Film Chip 2.
1 2 3 4 5 150nF DVDD 4 VIN TEMP GND C1 1uF VOUT TRIM 6 C4 22uF 5 C5 22uF 0.1uF 0.1uF U12 5 C15 0.1uF -5V 4 TP1 AVSS REF5020ID D VDD RESET CT GND MR 1 2 3 TPS3836DBV C22 10uF AVDD DVDD J7 DVDD R15 0 C21 10uF 10uF 1 5 6 10 R14 0 1 3 5 7 9 11 13 15 17 19 C23 12 16 15 13 14 11 4 R10 GPIO0 DGND GPIO1 GPIO2 DGND GPIO3 GPIO4 SCL DGND SDA R5 2.
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