User's Guide SBAU192 – July 2011 ADS8638EVM-PDK ADS8638EVM-PDK This user's guide describes the characteristics, operation, and use of the ADS8638EVM, both by itself and as a part of the ADS8638EVM-PDK. This evaluation module (EVM) is designed to feature the ADS8638 but can also support the ADS8614, ADS8618, or ADS8634 if installed. This family of devices includes either an 8- or 12-bit, 1-MHz, multi-channel, successive approximation register (SAR) analog-to-digital converters (ADCs).
www.ti.com 1 2 3 4 5 6 7 8 Contents EVM Overview ............................................................................................................... 3 Analog Interface ............................................................................................................. 4 Digital Interface .............................................................................................................. 5 Power Supplies ........................................................................
EVM Overview www.ti.com 1 EVM Overview 1.
Analog Interface 2 www.ti.com Analog Interface For maximum flexibility, the ADS8638EVM 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 J1. This header/socket provides access to the analog input pins of the ADC. Consult Samtec at www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connector options.
Digital Interface www.ti.com 3 Digital Interface 3.1 Serial Data Interface 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 J2. This header/socket provides access to the digital control pins of the EVM. Consult Samtec at www.samtec.com or 1-800-SAMTEC- 9 for a variety of mating connector options. Table 2 describes the J2 serial interface pins. Table 2. J2: Serial Interface Header Pin Number 4 Signal Description J2.
EVM Operation 4.1 www.ti.com Power Options JP3 is in place for current measurement in order to regulate the power consumption of the ADS8638. When current measurement is not taking place, jumpers must be applied across many of the jumpers to properly power the ADC. Table 4 lists the power option details for JP3. Table 4. JP3 Configuration: Power Options Row Name Function 1-2 ADC HVDD Supply current measurement point for high voltage positive rail. Must be connected for operation.
ADS8638EVM-PDK Kit Operation www.ti.com 5.2 Digital Control The digital control signals can be applied directly to J2 (top or bottom side). The modular ADS8638EVM can also be connected directly to a DSP or microcontroller interface board, such as the 5-6K Interface or HPA-MCU Interface boards available from Texas Instruments, or the MMB0 if purchased as part of the ADS8638EVM-PDK.
ADS8638EVM-PDK Kit Operation www.ti.com Figure 2 and Figure 3 show a set of installation screens to pass through as the ADS86xxEVM-PDK plug-in is installed. Figure 2. ADS8638EVM-PDK Installer Continue through the pop-up screens until the plug-in is completely installed. Figure 3.
ADS8638EVM-PDK Kit Operation www.ti.com 6.2 Setting Up the ADS8638EVM-PDK The ADS8638EVM-PDK contains both the ADS8638EVM and the MMB0 motherboard; however, the devices are shipped unconnected. Follow these steps to set up the ADS8638EVM-PDK. Step 1. Unpack the ADS8638EVM-PDK kit. Step 2. Set the jumpers and switches on the MMB0 as shown in Figure 4. • Set the Boot Mode switch to USB. • Connect +5 V and +5 VA on jumper block J13B (if +5 V is supplied from J14 +5 VA).
ADS8638EVM-PDK Kit Operation Step 3. www.ti.com Plug the ADS8638EVM into the MMB0 as Figure 5 illustrates. Figure 5. Connecting ADS8638EVM to MMB0 Step 4. 6.2.1 Set the jumpers on the ADS8638EVM as shown in Figure 1 (note that these settings are the factory-configured default settings for the EVM). About the MMB0 The MMB0 is a Modular EVM System motherboard. It is designed around the TMS320VC5507, a DSP with an onboard USB interface from Texas Instruments. The MMB0 also has 16 MB of SDRAM installed.
ADS8638EVM-PDK Kit Operation www.ti.com 6.3 Connecting the Power Supply The ADS8638EVM-PDK requires multiple supplies to power the ADC to be used with the MMB0 motherboard. The ADS8638 requires two high-voltage supplies (±10 V to ±15 V), HVDD and HVEE, along with a +5-V supply to power the analog, AVDD, and +3.3 V to +5 V to power the digital circuitry, DVDD. When the MMB0 DSP is powered properly, LED D2 glows green. The green light indicates that the 3.3-V supply for the MMB0 is operating properly.
ADS8638EVM-PDK Kit Operation 6.4 www.ti.com Running the Software and Completing Driver Installation 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 ADS8638EVM-PDK is called ADCPro. This program uses plug-ins to communicate with the EVM. The ADS8638EVM-PDK plug-in is included in the ADS8638EVM-PDK package.
ADS8638EVM-PDK Kit Operation www.ti.com 6.4.2 USBStyx Driver Installation 1. Start the software by selecting ADCPro from the Windows Start menu. 2. Select ADS86xxEVM from the EVM drop-down menu. The ADS86xxEVM-PDK plug-in appears in the left pane. The setup is shown in Figure 8. Figure 8. ADS86xxEVM-PDK Plug-in 3. The ADS86xxEVM-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.
Evaluating Performance with the ADCPro Software 7 www.ti.com Evaluating Performance with the ADCPro Software The evaluation software is based on ADCPro, a program that operates using a variety of plug-ins. (The ADS8638EVM plug-in is installed as described in the Installation section). 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.
Evaluating Performance with the ADCPro Software www.ti.com 7.1.1 Plug-in Setup and The Device Config Tab When the ADS86xxEVM plug-in is first loaded, you must select the device from the Device Selection tab found in the basic settings window. The ADC options are not available on the plug-in until the device is selected. Use Figure 9 for reference. Figure 9. Device Configuration After the ADC has been selected, the tabs on the left become available, including the plug-in options to configure the ADC.
Evaluating Performance with the ADCPro Software www.ti.com The Data Rate control on the main plug-in window sets the data rate for the ADS8638. Changing the data rate controls the time between sequential conversions once the acquisition period begins. In the Basic Settings window, the Operating Mode and Input Range options are available. The plug-in was designed to only use auto-mode channel sequencing, and therefore manual mode is not selectable.
www.ti.com Evaluating Performance with the ADCPro Software Figure 10.
Evaluating Performance with the ADCPro Software 7.1.3 www.ti.com GPIO & Alarms Tab The GPIO & Alarms tab (as shown in Figure 11) includes some of the additional options found within the ADS8638. Here, the software provides access to setting the GPIO as either a power-down input or an alarm state output. This I/O line is routed to the onboard LED on the evaluation board to indicate when the alarm is active. Figure 11.
www.ti.com Evaluating Performance with the ADCPro Software After an acquisition, the Read Alarms button allows the user to read back the specific alarms that reported a fault. When the button is pressed, the firmware uses the sticky register read command; once the alarms are read, they are set back to zero. Each channel has two alarms, a high alarm and a low alarm; both are placed side by side in the alarm list.
EVM Bill of Materials, Schematic, and Layout 8 www.ti.com EVM Bill of Materials, Schematic, and Layout Table 5 contains a complete bill of materials for the modular ADS8638EVM. The schematic diagram is also provided for reference. Figure 12 through Figure 15 show the PCB layouts. 8.1 Parts List NOTE: All components should be compliant with the European Union Restriction on Use of Hazardous Substances (RoHS) Directive. Some part numbers may be either leaded or RoHS.
EVM Bill of Materials, Schematic, and Layout www.ti.com Table 5. Bill of Materials (continued) Item Qty Ref Des MFR Part Number 28 1 U2 Precision voltage reference 2.
EVM Bill of Materials, Schematic, and Layout www.ti.com Figure 13. ADS8638EVM PCB: Mid Layer Figure 14.
www.ti.com EVM Bill of Materials, Schematic, and Layout Figure 15.
1 2 3 4 5 6 +VA C12 10uF HVEE C6 HVDD +VBD C2 1uF (50V rated) 10uF 7 U4 U5 1uF C14 1nF OPA140 A 4 Y D 3 1 GND NC R15 470 SN74LVC1G17 12 11 10 9 DAUGHTER-ANALOG CS AIN1/NC SCLK AIN2/AIN0 SDI AIN3/AIN1 SDO 17 R2 JP1 33 R13 R14 10k 10k 33 18 19 J2A R5 PD/ALERT JP5 22 R7 GPIO VREFP 5 AINCOM VREFM R6 1 3 5 7 9 11 13 15 17 19 0 0 33 AIN7/NC TP3 R11 20 R1 U1 AIN6/NC 6 16 ADS86xx AIN5/AIN3 7 +3.
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