ADC3683EVM

www.ti.com Abstract User’s Guide ADC368xEVM Evaluation Module Abstract This user’s guide describes the characteristics, operation, and use of the ADC368x evaluation module (EVM). This user's guide discusses how to set up and configure the software and hardware, and reviews various aspects of the program operation. Throughout this document, the terms evaluation board, evaluation module, and EVM are synonymous with the ADC368xEVM. In the following sections of this document, the ADC368x evaluation board is referred to as the EVM and the ADC368x devices are referred to as the ADC devices, respectively. This document applies only to the ADC3683EVM and ADC3682EVM. Table of Contents Abstract...................................................................................................................................................................................... 1 1 Introduction.............................................................................................................................................................................2 2 Equipment............................................................................................................................................................................... 2 2.1 ADC368xEVM Functionality...............................................................................................................................................2 2.2 Evaluation Board Feature Identification Summary.............................................................................................................4 2.3 Required Equipment.......................................................................................................................................................... 5 3 Setup Procedure..................................................................................................................................................................... 6 3.1 Install High-Speed Data Converter (HSDC) Pro Software................................................................................................. 6 3.2 Install ADC35XXEVM GUI 1.0 Software............................................................................................................................ 6 3.3 Connect the ADC368xEVM and TSW1400EVM................................................................................................................6 3.4 Connect the Power Supply and Mini-USB Connections.................................................................................................... 7 3.5 Connect the Clocks and Analog Input................................................................................................................................7 4 ADC GUI Configuration.......................................................................................................................................................... 8 4.1 Bypass Mode..................................................................................................................................................................... 9 4.2 Real Decimation Mode.....................................................................................................................................................13 4.3 Complex Decimation Mode.............................................................................................................................................. 16 5 Onboard Clocking Hardware Setup.................................................................................................................................... 20 5.1 Hardware Modfications.................................................................................................................................................... 21 5.2 Onboard Clock: ADC35XX GUI Real Decimation Mode ................................................................................................. 23 6 FDA Configuration................................................................................................................................................................24 7 ADC36xxEVM Power Monitor.............................................................................................................................................. 26 8 Test Pattern........................................................................................................................................................................... 27 SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 1 www.ti.com Introduction 1 Introduction The ADC36xxEVM is an evaluation board used to evaluate the ADC368x analog-to-digital converters (ADC) from Texas Instruments. The ADC368x uses a serial LVDS interface to output the digital data. The serialized LVDS interface supports output rates to 1 Gbps. The ADC368x can be operated in 'oversampling + decimating' mode using the internal decimation filter in order to improve the dynamic range and relax external anti-aliasing filter. The ADC368xEVM is equipped with the following features: • • • • • • Transformer and FDA coupled analog inputs CDCE6214 clocking solution for on-board clocking Transformer coupled or single-ended clock inputs INA226 current shunt monitors for evaluating power consumption Power over mini-USB FMC connector By default, the EVM is configured to receive external inputs for the sampling clock and analog input via ACcoupled, transformer (balun) inputs. These transformers perform single-ended to differential conversion, and provide a low noise/distortion passive input. To exercise the full performance capabilities of this high performance SAR ADC, it is recommended to evaluate the ADC in the default configuration, and then evaluate in other configurations (like onboard clocking or FDA input), as required. 2 Equipment This hardware setup procedure is written with the intent to use external clocking (sample clock and DCLKIN) and transformer coupled analog inputs. Using onboard clocking and FDA driven analog inputs is an option, and instructions are provided toward the end of this document to make the required hardware/software modifications. 2.1 ADC368xEVM Functionality The ADC368xEVM receives power from the USB 2.0, +5 V rail, and is then converted to +3.3 VDC and +1.8 VDC. The ADC receives +1.8 VDC from the TPS62231 DC-DC converter. The power consumption of the 1.8 V rail can be monitored (using the INA226) in the ADC35xxEVM GUI. USB-to-SPI communication is established using the FTDI (FT4234H). The ADC clocks can be supplied externally or from the onboard PLL/Distributor CDCE6214 (high quality external clocks are used to acheive best AC performance). The analog input can be AC coupled through the Balun (ADT1-6T+) input, or DC (or AC) coupled with the onboard FDA (THS4541). The analog input is 3.2 Vpp, and is driven a -1 dBFS (~2.8 Vpp) in all examples in this user's guide. The ADC368x family has a +1.6 V voltage reference (VREF), and can be supplied internally or externally. By default, the EVM is configured to supply an external voltage reference using the REF3318 (divided down to +1.6V) and the OPA837 high speed amplifier to drive the voltage reference. At any time, the VREF can be changed to internal reference by SPI write. The ADC368x family uses an unbuffered analog input, so a glitch filter is required to attenuate the ADC sampling glitch from when the sampling capacitors switch (sample/hold). The glitch filter acts as a low pass filter with an corner frequency (Fc) at 30 MHz (accepts DC to 30 MHz). The ADC368xEVM LVDS output data is routed to an FMC connector, and then connected to the LVDS Interposer card. This interposer card then maps to the TSW1400EVM's HSMC connector in order to capture the ADC368xEVM SLVDS clock and data signals. 2 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated Equipment www.ti.com Figure 2-1. ADC36xxEVM block diagram: Balun input Figure 2-2. ADC36xxEVM block diagram: FDA input SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 3 Equipment www.ti.com 2.2 Evaluation Board Feature Identification Summary Figure 2-3. ADC368xEVM Feature Identification Ensure that jumper J16 is shunted in the 2-3 position. This allows 5 V to be supplied to the ADC368xEVM through the mini-USB connector. If an external 5-V supply is desired, J16 must be shunted in the 1-2 position, and the external 5 V can be connected to the test point labeled "+5 EXT". The USB data connection will still be connected for SPI communications. J13 is tied to the REFBUF pin. It can be left floating, or can be tied to 1.8V (shunt pins 2-3) for normal operation. J14 is tied to the PDN/SYNC pin. It can be left floating for tied to ground (shunt pins 1-2) for normal operation. To power down the ADC, tied to 1.8V (shunt pins 2-3). The ADC may also be powered down via SPI. 4 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated Equipment www.ti.com Figure 2-4. LVDS Interposer 2.3 Required Equipment • The following equipment is included in the EVM evaluation kit: – ADC368xEVM Evaluation board (EVM) – LVDS FPGA Interposer Card – Mini-USB cable The following equipment is not included in the EVM evaluation kit, but is required for evaluation of this EVM: • TSW1400EVM data capture board and related items • HSDC Pro software • PC running Microsoft® Windows® 7, or 10 • One low-noise signal generator for the analog input (If using onboard clock option, no additiona signal generators are required). • Two low-noise signal generators for the sample clock and DCLKIN. (These two signal generators must share the same reference frequency). TI recommends the following generators: • Rohde & Schwarz SMA100A • Rohde & Schwarz SMA100B A bandpass filter is required for the analog input signal due to most signal generators addition of phase noise or spurious components. A bandpass filter should also be used for the sample clock input. The DCLKIN input does not require a bandpass filter. If bandpass filters are not used, then the true performance of the ADC may not be seen clearly, and will be limited by the performance of the signal generators being used. The following recommended bandpass filter will have: • Bandpass filter, greater than or equal to 60-dB harmonic attenuation, less than or equal to 5% bandwidth, greater than 18-dBm power, less than 5-dB insertion loss • Signal-path cables, SMA SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 5 www.ti.com Setup Procedure 3 Setup Procedure This Setup Procedure will detail how to setup the ADC368xEVM hardware and software GUI required for evaluation using external sample and DCLKIN clocks. The clock rates in the following steps apply specifically to the ADC3683EVM, but example clock rates are provided for other EVM variants. 3.1 Install High-Speed Data Converter (HSDC) Pro Software Download the most recent version of the HSDC Pro software. Launch the executable, and accept the default installation options. Download and install the HSDC Pro Patch. This patch copies all the INI files required to the HSDC pro directory. 3.2 Install ADC35XXEVM GUI 1.0 Software Download the ADC35XXEVM GUI 1.0 software from the EVM tool folder at ADC3683EVM. Extract and run the executable file, and accept the default installation options. 3.3 Connect the ADC368xEVM and TSW1400EVM Connect the ADC368xEVM FMC connector to J4 of the LVDS Interposer Card. Connect J5 of the LVDS Interposer Card to J1 of the TSW1400EVM. Figure 3-1. ADC368xEVM Complete Setup (external clocks) 6 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com Setup Procedure 3.4 Connect the Power Supply and Mini-USB Connections Use the following steps to connect the power supply and mini-USB connections: 1. Connect the power cable to the TSW1400EVM at 5-V (minimum 3 A) power supply. Place the power switch (SW7) to the "On" position. 2. Connect the mini-USB cable to the TSW1400EVM (J2). 3. Connect the mini-USB cable to the ADC368xEVM (J16). 3.5 Connect the Clocks and Analog Input Use the following steps to connect the external ADC clocks and analog input. If onboard clocking is to be used, follow the instructions in the section Onboard Clocking Hardware Setup. The clock frequencies shown below are for the power on/default settings (bypass mode/non-decimation) for the ADC3683EVM, but the physical connections and signal power levels will remain the same for all ADC modes. • • For the sample clock (ADC3683EVM), set a signal generator to 65 MHz at a power level of +10 dBm. Connect to the SMA connector J4. A bandpass filter for the sample clock is recommended for best AC performance of the ADC368xEVM. For the DCLKIN clock (ADC3683EVM), set a signal generator to 292.5 MHz at a power level of +10 dBm. A bandpass filter is not required for the DCLKIN clock. External ADC sampling clock source and DCLKIN source must be frequency locked. If this is not performed, the captured data will appear scrambled. If using the onboard clocking option, the sampling clock and DCLKIN are frequency locked. • For the analog input, set a signal generator to 5 MHz at a power level of ~ +15 dBm. A bandpass filter is required to reduce harmonic and phase noise effects of the signal generator. SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 7 ADC GUI Configuration www.ti.com 4 ADC GUI Configuration A hardware reset should be performed before programming the ADC by toggling the push button switch S1. Also, a software reset may be performed at any time to reset the ADC registers to their default state. Figure 4-1. ADC35xx Software Reset 8 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com ADC GUI Configuration 4.1 Bypass Mode The following steps show how to configure the ADC368xEVM in Bypass mode with external sample clock and DCLKIN. These instructions show how to configure the ADC3683EVM, but apply to other EVM variants as well. 4.1.1 ADC35XXEVM GUI: Bypass Mode (2W) Configuration The following steps for Bypass (No Decimation) mode also apply to ADC3682EVM, but requires modification to the sample/DCLKIN clocks in accordance with the desired sample rate and bit resolution. For different sampling rates and bit resolutions, please use the tables for calculating the correct DCLKIN frequency for the desired sample rate and bit resolution. Table 4-1. 18-bit, Bypass Mode, Sample rate and DCLKIN examples (ADC3683EVM, ADC3682EVM) Interface Mode DCLKIN multiplier Example Sample Clock Required DCLKIN Frequency 2 Wire 4.5 45 MSPS 202.5 MHz 1 Wire 9 32 MSPS 288 MHz 1/2 Wire 18 10 MSPS 180 MHz Table 4-2. 16-bit, Bypass Mode, Sample rate and DCLKIN examples (ADC3663EVM, ADC3662EVM). Interface Mode DCLKIN multiplier Example Sample Clock Required DCLKIN Frequency 2 Wire 4 65 MSPS 260 MHz 1 Wire 8 32 MSPS 256 MHz 1/2 Wire 16 10 MSPS 160 MHz For this example, ensure that the sampling clock (J9) and DCLKIN (J7) are connected before launching the ADC35XX EVM GUI. In this example for the ADC3683EVM, the sampling clock is 65 MHz, and the DCLKIN is 292.5 MHz. External ADC sampling clock source and DCLKIN source must be frequency locked. If this is not performed, the captured data will appear scrambled. If using the onboard clocking option, the sampling clock and DCLKIN are frequency locked. After launching the ADC35xx GUI perform the following steps: • • • • • Under Resolution, select "18 bit". Under Mode, select "2 Wire". Ensure that "CDC Enable" is red (disabled). To calculate the DCLKIN frequency, enter "65" in the Fs(MHz) field, and click calculate. This is informational only. Click "Configure" button. SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 9 ADC GUI Configuration www.ti.com Figure 4-2. ADC35xx EVM GUI settings for 2W Bypass Mode 10 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated ADC GUI Configuration www.ti.com 4.1.2 HSDC Pro: Bypass Mode After pressing "Configure" within the ADC35xx GUI perform the following steps to setup HSDC pro: • • Launch HSDC Pro Select the TSW1400 and click OK Figure 4-3. HSDC Pro: Connect to TSW1400 • • Click OK for the no firmware loaded prompt. Select “ADC3683_2W_18bit" to load firmware, and click "Yes". Figure 4-4. HSDC Pro ini file selection for 2W, 18-bit Bypass Mode • Enter "65M" in the box that says “ADC Output Data Rate” since the ADC is sampling at 65 MSPS. SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 11 ADC GUI Configuration • www.ti.com • Enter the input frequency of the input signal in the box that says "ADC Input Target Frequency" (5 MHz used in this example). Click "Capture" . • The analog input signal power may need to be adjusted to reach -1 dBFS. 12 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com ADC GUI Configuration 4.2 Real Decimation Mode The following software configuration steps will program the ADC368xEVM in 16x Real Decimation mode. 4.2.1 ADC35XX GUI: Real Decimation Mode Configuration (2W, 18bit) This procedure applies specifically to the ADC3683EVM, but can be applied to other sampling rates and bit resolutions. See tables for examples for clock rates in Real Decimation mode. Table 4-3. 18-bit, Real Decimation, Sample rate and DCLKIN examples Interface Mode DCLKIN multiplier Example Sample Clock Real Decimation Factor Required DCLKIN Frequency 2 Wire 4.5 45 MSPS 2 101.25 MHz 1 Wire 9 32 MSPS 8 36 MHz 1/2 Wire 18 10 MSPS 32 5.625 MHz Table 4-4. 16-bit, Real Decimation Sample rate and DCLKIN examples Interface Mode DCLKIN multiplier Example Sample Clock Real Decimation Factor Required DCLKIN Frequency 2 Wire 4 65 MSPS 2 130 MHz 1 Wire 8 32 MSPS 8 32 MHz 1/2 Wire 16 10 MSPS 32 5 MHz For this 16x Real Decimation example, apply a 65 MHz signal to J9 (sample clock) and a 18.28125 MHz signal to J7 (DCLKIN). External ADC sampling clock source and DCLKIN source must be frequency locked. If this is not performed, the captured data will appear scrambled. If using the onboard clocking option, the sampling clock and DCLKIN are frequency locked. Apply a 1 MHz signal to J2 (ensure bandpass filter is used to reduce harmonics and noise of signal generator). After launching the ADC35xx GUI perform the following steps: • • • • • • Under Resolution, select 18 bit. Under DDC, Select Real. For Decimation Factor, select 16. To calculate the DCLKIN frequency, enter "65" in the Fs(MHz) field, and click calculate. This is informational only. Ensure that "CDC Enable" is red (disabled). Click "Configure" SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 13 ADC GUI Configuration www.ti.com 4.2.2 HSDC Pro: Real Decimation Mode After pressing "Configure" within the ADC35xx GUI perform the following steps to setup HSDC pro: • • • • Launch HSDC Pro Select the TSW1400 and click OK Click OK for the no firmware loaded prompt. Select “ADC3683_2W_18bit” to load firmware, and click Yes. Figure 4-5. Real Decimation HSDC Pro INI File (2W, 18bit) • • • • • • 14 Click on the cog next to "ADC Output Data Rate". In the new dialogue box, enter "65M" in "ADC Sampling Rate" Enter "1M" in "ADC Input Frequency" Enter "16" in "Decimation" Click "OK" Click "Capture" ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated ADC GUI Configuration www.ti.com Figure 4-6. HSDC Pro Cog Wheel (Real Decimation) Figure 4-7. HSDC Pro 16x Real Decimation FFT (2W, 18 bit) SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 15 ADC GUI Configuration www.ti.com 4.3 Complex Decimation Mode The following software configuration steps will program the ADC368xEVM in Complex Decimation mode (32x) with a 10 MHz analog input and 9.9 MHz NCO. 4.3.1 ADC35XX GUI: Complex Decimation Configuration This procedure applies specifically to the ADC3683EVM, but can be applied to other sampling rates and bit resolutions. Table 4-5. 18-bit, Complex Decimation, Sample rate and DCLKIN examples Interface Mode DCLKIN multiplier (Serialization Factor) Example Sample Clock Complex Decimation Factor Required DCLKIN Frequency 2 Wire 4.5 45 MSPS 2 202.5 MHz 1 Wire 9 32 MSPS 8 72 MHz 1/2 Wire 18 10 MSPS 32 11.25 MHz Table 4-6. 16-bit, Complex Decimation, Sample rate and DCLKIN examples Interface Mode DCLKIN multiplier (Serialization Factor) Example Sample Clock Complex Decimation Factor Required DCLKIN Frequency 2 Wire 4 65 MSPS 2 260 MHz 1 Wire 8 32 MSPS 8 64 MHz 1/2 Wire 16 10 MSPS 32 10 MHz For this 32x Complex Decimation example, apply a 65 MHz signal to J9 (sample clock) and a 18.28125 MHZ signal to J7 (DCLKIN). External ADC sampling clock source and DCLKIN source must be frequency locked. If this is not performed, the captured data will appear scrambled. If using the onboard clocking option, the sampling clock and DCLKIN are frequency locked. Apply a 10 MHz signal to J2 (ensure bandpass filter is used to reduce harmonics and noise of signal generator). An NCO of 9.9 MHz will be used to shift the 10 MHz input signal to -100 kHz. After launching the ADC35xxEVM GUI perform the following steps: • • • • • • • • 16 Under "Resolution", select "18 bit". Under "Mode", select "2 Wire" Under "DDC", Select "Complex". For "Decimation Factor", select "16". Ensure that "CDC Enable" is red (disabled). To calculate the DCLKIN frequency, enter "65" in the Fs(MHz) field, and click calculate. This is informational only. Under "FNCO A (MHz)" and "FNCO B (MHz)", enter "9.9" in the field. This field will then calculate to the nearest valid NCO value, and will auto-calculate the correct register values in the field next to it. Click "Configure". ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com ADC GUI Configuration 4.3.2 HSDC PRO: Complex Decimation Mode After pressing "Configure" within the ADC35xx GUI perform the following steps to setup HSDC pro: • • • • Launch HSDC Pro. Select the TSW1400 and click "OK". Click OK for the "no firmware loaded"prompt. Select “ADC3683_2W_18bit_Complex” to load firmware, and click Yes. Figure 4-8. Complex Decimation HSDC Pro INI file • • • • • • Click on the cog next to “ADC Output Data Rate”. In the new dialogue box, check the "Enable?" box. Under “ADC Sampling Rate”, enter "65M" Under “ADC Input Frequency”, enter "10M" Under "NCO", enter "9.9M" Under “Decimation”, enter "32". SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 17 ADC GUI Configuration • www.ti.com Click "OK". Figure 4-9. HSDC Pro Cog Parameters: 32x Complex Decimation Mode • • 18 Select "Complex FFT" Press "Capture" ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com ADC GUI Configuration Figure 4-10. HSDC Pro 32x Complex Decimation (2W, 18 bit) SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 19 www.ti.com Onboard Clocking Hardware Setup 5 Onboard Clocking Hardware Setup The onboard CDC is useful for general evaluation and relieves the user requirment of needing additional signal generators. However, the clock spurs and jitter of the CDCE6214 (due to 4.5 sample clock/DCLKIN relationship) begin to effect the optimal ADC AC performance. Looking at the image below, we can see that SNR/SFDR performance does degrade by several dBFS for the ADC3683EVM, however, using the onboard CDCE6214 relieves the user of providing the external sample clock and DCLKIN, and may be useful for verifying the SLVDS interface to an FPGA development kit. In practice, an appropriate filter may be used to reduce the effects of clock spurs and broad band phase noise in order to acheive full ADC performance. Figure 5-1. ADC3683EVM onboard clocking (CDCE6214: 65 MHz sample clock, 292.5 MHz DCLKIN) The following section shows how to configure and program the ADC368xEVM for onboard clock operation for Real Decimation Mode. Onboard clocking can be used for Bypass and Complex Decimation modes as well, and uses similar procedures that have been outlined in this document. When using onboard clocking, there are several different sampling rates to choose from (65MSPS, 25 MSPS and 10 MSPS) in Bypass and Decimation modes. The ADC35XX GUI does not support configuring the CDCE6214 to frequencies outside of these preset selections at this time. 20 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated Onboard Clocking Hardware Setup www.ti.com 5.1 Hardware Modfications The following hardware modifications must be made in order to operate the ADC36xxEVM using an onboard sample and DCLKIN clocks. Onboard Sample Clock Modification: • DNI R46, R47 • Install R41, R51 (0-Ω resistor) Figure 5-2. ADC36xxEVM Onboard Sample clock modifications Onboard DCLKIN Modification: • Install R60 and R62 (0-Ω resistor) • DNI R35 and R36 SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 21 Onboard Clocking Hardware Setup www.ti.com Figure 5-3. ADC368xEVM Onboard DCLKIN modifications 22 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com Onboard Clocking Hardware Setup 5.2 Onboard Clock: ADC35XX GUI Real Decimation Mode To program the ADC36xxEVM with Onboard clocking, follow the steps written in the previous section titled "ADC35xx GUI: Real Decimation Configuration". The only differences that must be observed in the GUI is the "CDC Clock Enable" button must be enabled (Green), and the "Configure CDC" button must be clicked. The PLL_LOCK LED (D1) also illuminates to ensure CDCE6214 has been configured correctly. Figure 5-4. AD35xx EVM GUI: Onboard Clock 16x Real Decimation SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 23 FDA Configuration www.ti.com 6 FDA Configuration By default, the analog input is configured to use the balun input (AD1T-6T+) for both analog input channels, but can be modified to utilize the onboard FDA (THS4541). In terms of performance as compared with the balun input, SFDR is improves, but SNR performance degrades by a few dBFS. Figure 6-1. ADC3683EVM FDA Analog input (External Clocks, 65 MSPS) This procedure shows how to configure the FDA single-ended to diferential conversion for CHA. The same procedure can be performed for CHB (with the respective component designators). The edge launched SMA connector J1 receives the single-ended analog input signal. R1 can be replaced with a capacitor for AC coupling to FDA. Modify the following components to complete path to FDA (located on top of EVM). • Install: R1, R2, R14 (o ohm) 24 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated www.ti.com • FDA Configuration Remove (DNI): C3, C6, R7, R8 Figure 6-2. CHA FDA Component modification The FDA is setup with a gain of 2.5, and can be adjusted (R78, R84, R86 and R94) as the application requires. There is a 20 MHz LPF on the output of the FDA, and these components (C52, L11,L12 and C53) can be adjusted as the application requires. The termination resistors (R80, R81, R89 and R90) can be adjusted according to the source impedance. Figure 6-3. FDA schematic For further information on the THS4541 FDA, please refer to the THS4541 datasheet. SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 25 ADC36xxEVM Power Monitor www.ti.com 7 ADC36xxEVM Power Monitor The ADC368xEVM is equipped with on-board current shunt monitors that are able to measure the current consumption on the +1.8 VDC rails (AVDD and IOVDD). The user has the ability to read the ADC368xEVM power consumption on the front page of the ADC35XX EVM GUI. Click the "Measure Power" button to refresh the current values. This feature is useful for determining what mode/sampling speed offers the best power consumption for your application needs. Figure 7-1. ADC36xxEVM Power Meter 26 ADC368xEVM Evaluation Module SBAU360 – DECEMBER 2020 Submit Document Feedback Copyright © 2020 Texas Instruments Incorporated Test Pattern www.ti.com 8 Test Pattern It is often useful to utilize test patterns to help verify the correct reciept of digital data at the microcontroller or FPGA. A ramp pattern can be enabled by following these steps: • Click the yellow button "Analog Inputs and Clk" • Next to "Test Pattern CHA", click the drop down menu, and select "RAMP CUSTOM". This can be done for "Test Pattern CHB" as well. • In the field next to "Custom Pattern", – For 18 bit ramp mode (ADC3683EVM, ADC3682EVM), "1" must be entered in the "Custom Pattern" field. • The digital ramp pattern is now enabled on the ADC. The output of the ADC is now an 18 bit, incrementing ramp pattern. Figure 8-1. ADC36xxEVM 18-bit Ramp Pattern • In HSDC Pro, the ramp pattern can now be seen when data is captured. These same steps apply to any data output mode (Bypass, Real Decimation and Complex Decimation). – It may be necessary to increase the capture sample size to 524k to capture the entire ramp pattern in 18 bit mode. – In HSDC Pro, click "Data Capture Options" -> "Capture Option", and enter "524288" in the "# of samples (per channel)" field. SBAU360 – DECEMBER 2020 Submit Document Feedback ADC368xEVM Evaluation Module Copyright © 2020 Texas Instruments Incorporated 27 www.ti.com Trademarks Figure 8-2. HSDC Pro: Increase sample size Figure 8-3. HSDC Pro: ADC3683EVM Ramp Pattern (524k samples) Trademarks Microsoft® and Windows® are registered trademarks of Microsoft Corporation. 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