EVAL-AD7723CB AD7723 AD780 AD8047 74FCT162374 74FCT162244 AD8041 J18-J23

Evaluation Board for 16-Bit, 1.2 MSPS CMOS, Sigma-Delta ADC EVAL-AD7723CB The AD7723 can operate with it's internal reference or

a Evaluation Board for 16-Bit, 1.2 MSPS CMOS, Sigma-Delta ADC EVAL-AD7723CB EVAL-AD7723CB The AD7723 AD7723 can operate with it's internal reference or the on-board AD780 AD780 precision bandgap reference can be used as an external reference. The analog input is conditioned using 2 AD8047 AD8047 op-amps and this circuit can be configured to drive the AD7723 AD7723 with complimentary signals. The EVAL-AD7723CB EVAL-AD7723CB offers the flexibility of using an external sampling clock, an on-board CMOS clock oscillator, or the AD7723 AD7723's crystal oscillator circuit. The board can be configured for either parallel or serial mode operation. In parallel mode, a 16-bit register, 74FCT162374 74FCT162374, latches the conversion results to a 40 pin IDC connector (P5). In serial mode, the AD7723 AD7723's serial interface signals are buffered with a 74FCT162244 74FCT162244 and are available from a 20-pin header (P4). The EVAL-AD7723CB EVAL-AD7723CB is ideal for use as a stand-alone unit or with the EVAL-CONTROL BOARD which is available from Analog Devices under the order entry "EVAL-CONTROL BOARD". Software is provided with the evaluation board package to allow analysis of the ADC's performance when using the EVAL-CONTROL BOARD. A 96-pin DIN connector (P1) interfaces the control board directly to the EVAL-AD7723CB EVAL-AD7723CB. The evaluation board uses extensive power and ground planes to minimize high frequency noise interference from the on-board clocks or any other source. The AGND plane is kept separate from the DGND plane and is joined under the AD7723 AD7723. It is not recommended to connect the AGND and D GND ground planes elsewhere to avoid ground loop problems. FEATURES Full-Featured Evaluation Board for the AD7723 AD7723 EVAL-CONTROL BOARD Compatible Stand Alone Capability Versatile Analog Signal Conditioning Circuit On-Board 2.5V Reference Crystal or CMOS Clock Oscillator Sampling Clock Serial or Parallel Conversion Data Interface Various Linking Options PC Software for Control and Data Analysis when used with EVAL-CONTROL BOARD Patch-work Area for User Expansion INTRODUCTION This Technical Note describes the evaluation board for the AD7723 AD7723 16-Bit, 1.2MSPS, CMOS, Sigma-Delta ADC. The AD7723 AD7723 evaluation board is designed to demonstrate the AD7723 AD7723's performance and to provide a flexible interface for a variety of applications. Full data on the AD7723 AD7723 is available in the AD7723 AD7723 data sheet available from Analog Devices and should be consulted in conjunction with this Technical Note when using the Evaluation Board. FIG. 1: 96 Pin DIN Connector VCC DGND FUNCTIONAL BLOCK DIAGRAM -VS Parallel Interface AGND+VS A D 77 23 AD C Serial Interface 16 Bit Data Register 40 pin IDC Connector 16 Bit Line Driver/Buffer Analog Input Signal Conditioning Voltage Reference Sampling Clock 20 pin header REV. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/3268703 EVAL-AD7723CB EVAL-AD7723CB Link and Switch Options There are 37 link options which must be set for the required operating setup before using the evaluation board. The functions of these options are outlined below. Link No. Function. J1 J2 Both of these links must be used together. These links are in place when using an AIN signal that is biased around 0V. These links are removed when using an AIN signal that is biased around 2.5V. The noise floor of high quality signal sources will, in most cases, be higher than the actual noise floor of the AD7723 AD7723. For this reason, it is important that the signal source should be filtered using a bandpass or, for low frequency signals, a lowpass filter before being applied to the signal input of the evaluation board. For low frequency signal sources, a simple RC lowpass filter is sufficient to demonstrate the very low noise floor of the AD7723 AD7723. J3 This link selects the clock source for the AD7723 AD7723. In position "B" the on-board CMOS clock oscillator is selected. In position "A" an external sampling clock connected to SK2 is selected. To use the AD7723 AD7723's crystal oscillator circuit, J3 must be removed and a 19.6MHz quartz crystal must be inserted in position Y1, two 33pF ceramic (0603 case) capacitors must be inserted in positions C13 & C14 and a 1M resistor (0805 case) must be inserted in position R12. J4 This link is used to select the source of the AVDD power plane. In position "A" the AVDD power plane is supplied from the external power terminal P2. In position "B" the AV DD power plane is supplied by the EVALCONTROL BOARD. J5 This link is used to choose the power source for the positive supply pin of the op-amps (V+). When connecting to the EVAL-CONTROL BOARD, this link must be removed if using the AD8047 AD8047 op-amps supplied with the evaluation board. In this case, an external +7.5V must be supplied via the "+VS" pin of P2. If using AD8041 AD8041 op-amps (not supplied), this link can remain in place and the EVAL-CONTROL BOARD can supply the required +5V. Please note that using AD8041 AD8041 op-amps causes a 2dB degradation in the ADC's SNR. J6 This link is used to choose the power source for the negative supply pin of the op-amps (V-). When connecting to the EVAL-CONTROL BOARD, this link must be removed if using the AD8047 AD8047 op-amps supplied with the evaluation board. In this case, an external -2.5V must be supplied via the "-VS" pin of P2. If using AD8041 AD8041 op-amps (not supplied), this link can remain in place and the EVAL-CONTROL BOARD supplies -5V. Although the EVAL-CONTROL BOARD supplies a dual 5V power supply to the AD7723 AD7723 evaluation board, the AD8041 AD8041 only requires a single 5V power supply when being used with the AD7723 AD7723. Please note that using AD8041 AD8041 op-amps causes a 2dB degradation in the ADC's SNR. J7 J8 J9 J10 These jumpers allow operation with either the internal reference of the AD7723 AD7723 or the AD780 AD780 external reference. To operate the board using the internal reference of the AD7723 AD7723, both links, J9 & J10 must be removed and both links, J7 & J8 must be in position "A". To operate the board using the external reference(AD780 AD780), both links, J9 & J10 must be in place, link J7 must be in position "B" and remove link J8. J11 This link selects the reference voltage from the AD780 AD780 Voltage reference. When this link is "in place" the AD780 AD780 produces a +3V reference. When this link is "removed" the AD780 AD780 produces a +2.5V reference. J12 J13 These links are used to select serial mode or parallel mode operation. J12 corresponds to MODE1 while J13 corresponds to MODE2. With a link in position "A", the corresponding MODE pin is tied to AVDD while the pin is tied to GND when its corresponding link is in position "B". With both of these links in position "B" the AD7723 AD7723 is configured for serial operation. Any other combination of these links selects parallel mode operation, the polarity of the MODE pins determining whether decimate by 16 mode, decimate by 32 mode (lowpass) or bandpass mode is selected. See Table1 and Table2 on the AD7723 AD7723 Data Sheet for further information. Note that the AD7723 AD7723 can only be used in Decimate by 32 mode when interfaced to the EVAL-CONTROL BOARD and running on a 19.2 MHz clock. To interface the AD7723 AD7723 to the EVALCONTROL BOARD in Decimate by 16 mode, the master clock must be reduced to less than 16 MHz. J14 J15 These two links are used together in parallel mode operation to select how the conversion data is latched into the 16-bit data register (U7). With the header shunt installed in J15, conversion results are latched on the falling edge of the DRDY output. With the header shunt installed in J14, conversion results are latched on the rising edge of the DRDY output. J16 J17 In serial mode operation, J16 must be removed and J17 must be in position"B". In parallel mode operation, J16 is inserted and J17 is removed. J18-J23 J18-J23 Data pins DB0 to DB3, DB14 and DB15 are connected to links J18-J23 J18-J23. These pins are not used in serial mode and should be tied to GND. Inserting the links ties these pins to GND. In parallel mode, remove these links. 2 REV. A EVAL-AD7723CB EVAL-AD7723CB J24 When "in place" this link bypasses the 50 resistor on the Vin socket, SK1. A 440 resistor is used between the AD8047 AD8047 op-amp and the signal source. This 440 resistor is made up using a 50 resistor and a 390 resistor. When a signal source which has a source resistance of 50 is used, the 50 present on the evaluation board can be bypassed. J25-J28 J25-J28 These links are connected to pins TSI/DB10 TSI/DB10, SLP/DB11 SLP/DB11, SLDR/DB12 SLDR/DB12 and SCR/DB13 SCR/DB13. When the AD7723 AD7723 is configured for parallel mode operation, links J25-J28 J25-J28 are removed as the above pins are configured as digital outputs. When the AD7723 AD7723 is configured for serial mode operation, the above pins are configured as inputs and, are used to select the decimate by 16 mode, decimate by 32 mode (lowpass) or bandpass mode. With a link in position "A", the corresponding pin is tied to AVDD. With a link is position "B" the corresponding pin is tied to GND. Consult the datasheet (Table 1) for information on selecting the different modes. J29 Set to position "A" to disable the on-chip crystal oscillator amplifier to allow use of an external clock source. Set to position "B" when using an external crystal between the CLKIN and XTAL pins. J30 Set link to position "A" to select the half power mode. With HALF-PWR set to 1, the AD7723 AD7723 can be operated with a CLKIN of 10MHz maximum. Otherwise set link to position "B". J31 This link must always be set to position "B". J32 Selects either bipolar or unipolar analog input range. Position "A" for unipolar operation and position "B" for bipolar operation. J33 Used to connect the AGND and DGND planes. J34 This link is tied to DVDD/CS. In serial mode, this pin is configured as DVDD. The link must be set to position "A" so that DVDD/CS is tied high. In parallel mode, this pin operates as a Chip Select Digital input. In this mode, the link must be set to position "B" so that CS is tied low. J35 This selects the power source for the digital circuitry on the eval board. When it is removed, power must be supplied via the 2-pin header P6. Power can be supplied from the EVAL-CONTROL BOARD when this header is in place. J36 J37 These links must be in place if using AD8041 AD8041 op-amps. They connect the AD8041 AD8041's DISABLE pin to logic high. REV. A 3 EVAL-AD7723CB EVAL-AD7723CB SET-UP CONDITIONS Care should be taken before applying power and signals to the evaluation board to ensure that all link positions are as per the required operating mode. Table I shows the position in which all the links are set when the evaluation board is packaged. Table I. Initial Link and Switch Positions Link No. Position J1 J2 IN Function. Set for AIN signal biased around 0V. J3 B Selects the on-board CMOS 20MHz clock oscillator as the clock source for the evaluation board. J4 B The AVDD power plane is supplied from the Eval-Control Board. J5 J6 OUT +7.5V/-2.5V to be supplied at P2 for AD8047 AD8047 op-amps supply. J7 J8 J9 J10 J7-B, J8-OUT, J9-IN, J10- IN Board is set to use the external reference, AD780 AD780. J11 OUT AD780 AD780 set to supply +2.5V reference. J12 J13 A B Parallel mode (lowpass Decimate by 32) operation selected. J14 J15 J14-OUT J14-OUT, J15-IN J15-IN In Parallel mode operation, data is latched on the falling edge of DRDY. J16 J17 J16-IN J16-IN, J17-OUT J17-OUT Set for parallel mode operation. J18-J23 J18-J23 OUT Set for parallel mode operation. J24 IN Resistor R1 is bypassed. J25-J28 J25-J28 OUT Set for parallel mode operation. J29 A Board is set to use the on-board 20MHz CMOS clock oscillator (AD7723 AD7723's on-chip crystal oscillator amplifier is disabled). J30 B Normal operation mode (HALF_PWR = 0). J31 B Always set to position "B". J32 B Bipolar analog input range selected. J33 IN AGND and DGND planes connected at P1. J34 B AD7723 AD7723's CS active in parallel mode. J35 IN Digital power is supplied from the Eval-Control Board. J36 J37 OUT Must be out when using AD8047 AD8047 op-amps. CONNECTORS There are six connectors on the AD7723 AD7723 board as outlined in Table IV. TABLE IV. Connector P6 evaluation CONNECTOR FUNCTIONS SOCKETS Function P1 There are 2 input sockets relevant to the operation of the AD7723 AD7723 on this evaluation board. The function of these sockets is outlined in Table III. 96-Way DIN Connector used to interface to the Eval-Control board. P2 3-Way Terminal Block used to supply analog power and ground. (+7.5V, -2.5V and 0V) when these are not supplied by the EVAL-CONTROL BOARD. P3 Table III. Socket Functions Socket P5 50 SMB socket for Analog input signal. SK2 20-Way Header used to access the AD7723 AD7723 serial interface signals when interfacing to systems other than the EVAL_CONTROL BOARD. Function SK1 10-Way Header P4 2-Way Terminal Block used to supply Digital power and ground. (+5V and 0V) when these are not being supplied by the EVAL-CONTROL BOARD. 50 SMB socket for external sampling clock input. Suitable cables for these sockets are available from Pasternack Enterprises. 40-Way IDC Connector used in parallel mode to interface to systems other than the EVAL_CONTROL BOARD. 4 REV. A EVAL-AD7723CB EVAL-AD7723CB INTERFACING TO THE EVAL-AD7723CB EVAL-AD7723CB CS Chip Select. The EVAL-AD7723CB EVAL-AD7723CB is designed to be interfaced to the EVAL-CONTROL BOARD or to operate as a stand-alone unit. +5VD Digital +5V supply. These lines are connected to the VCC supply via link J35 A GND Analog Ground. These lines are connected to the AGND plane on the evaluation board. -5V Analog -5V Supply. These lines are connected to the V- supply for the op-amps via link J6 if using AD8041 AD8041 op-amps. +5V Analog +5V Supply. These lines are connected tothe V+ supply for the op-amps via link J5 if using AD8041 AD8041 op-amps and to the AVDD supply for the AD7723 AD7723 via link J4. EVAL-CONTROL BOARD The EVAL-CONTROL BOARD is available from Analog Devices under the order entry "EVAL-CONTROL BOARD". When operated with this control board, all supplies (except +7.2V/-2.5V for AD8047 AD8047 op-amps) and control signals for operating the AD7723 AD7723 are provided by the EVAL-CONTROL BOARD when it is run under control of the AD7723 AD7723 software which is provided with the AD7723 AD7723 evaluation board package. This EVAL-CONTROL BOARD will also operate with all Analog Devices evaluation boards which end with the letters CB in their title. The 96-way connector on the EVAL-AD7723CB EVAL-AD7723CB plugs directly into the 96-way connector on the EVAL-CONTROL BOARD. No power supplies (except +7.2V/-2.5V for AD8047 AD8047 op-amps) are required in the system. The EVAL-CONTROL BOARD generates all the required supplies for itself and the EVAL-AD7723CB EVAL-AD7723CB. The EVALCONTROL BOARD is powered from a 12V ac transformer. This is a standard 12V ac transformer capable of supplying 1A current and is available as an accessory from Analog Devices under the following part numbers: EVAL-110VAC-US EVAL-110VAC-US: For use in the U.S. or Japan EVAL-220VAC-UK EVAL-220VAC-UK: For use in the U.K. EVAL-220VAC-EU EVAL-220VAC-EU: For use in Europe Table II. 96-Way Connector Pin Functions. ROW A ROWB ROWC 1 2 D0 3 4 D1 DGND DGND 5 6 DGND D2 D3 7 8 D4 +5VD 9 +5VD +5VD D5 10 D6 These transformers are also available from other suppliers including Digikey (U.S.) and Campbell Collins (U.K.). 11 Connection between the EVAL-CONTROL BOARD and the serial port of a PC is via a standard RS-232 RS-232 cable which is provided as part of the EVAL-CONTROL BOARD package. Please refer to the manual which accompanies the EVAL-CONTROL BOARD for more details on the EVALCONTROL BOARD package. 13 EVAL-CONTROL BOARD INTERFACING 18 Interfacing to the EVAL-CONTROL BOARD is via a 96way connector, P1. The pinout for the P1 connector is shown in Figure 2 and its pin designations are given in Table I I 19 CS D7 DGND DGND DGND D8 14 D9 15 D10 16 DGND D12 DGND DGND D11 17 IRQ2 D13 D14 D15 32 A B C 1 32 Figure 2: Pin Configuration for the 96-Way Connector, P1 96-Way Connector Pin Description D0-D15 D0-D15 Data Bus. D GND Digital Ground. These lines are connected to the DGND plane on the evaluation board. It allows the user to provide the digital supply via the connector along with the other digital signals. IRQ2 REV. A Interrupt Request 2. 20 DGND DGND DGND 21 AGND AGND AGND 22 AGND AGND AGND 23 1 . 12 AGND AGND AGND 24 AGND AGND AGND 25 AGND AGND AGND 26 AGND AGND AGND 27 AGND 28 29 AGND AGND 30 AGND AGND AGND 31 -5V -5V -5V 32 +5V +5V +5V Note : The unused pins of the 96-way connector are not shown. 5 EVAL-AD7723CB EVAL-AD7723CB OPERATING AS A STAND-ALONE UNIT It is possible to operate the board as a stand-alone unit. When using the evaluation board as a stand alone unit, external supplies must be connected to the 3-way power connector (P2). If using AD8047 AD8047 op-amps (supplied on the Evaluation board), supplies of +7.5V/0V/-2.5V are required. If using AD8041 AD8041 op-amps (not supplied), supplies of +5V/0V are required. Plesse note that using AD8041 AD8041 op-amps will cause a 2dB degradation in the AD7723 AD7723's SNR. An external +5V and DGND (0V) must also be connected to the 2-pin power connector (P6). All power supplies are decoupled to the relevant ground plane with a 22uF tantalum capacitor and a 0.1uF ceramic capacitor. Each device power pin is also decoupled with a 0.1uF capacitor to the relevant ground plane. The board can be configured for either parallel or serial mode operation. In parallel mode, a 16-bit register, 74FCT162374 74FCT162374, latches the conversion results to a 40-pin IDC connector (P5). In serial mode, the AD7723 AD7723's serial interface signals are buffered with a 74FCT162244 74FCT162244 and are available from a 20-pin header (P4). The user must use their own connectors to interface to either of these connectors to gain access to the AD7723 AD7723 signals. Figure 3: Main Screen SOFTWARE DESCRIPTION Included in the EVAL-AD7723CB EVAL-AD7723CB evaluation board package is a PC-compatible disk which contains software for controlling and evaluating the performance of the AD7723 AD7723 when it is operated with the EVAL-CONTROL BOARD. The EVAL-AD7723CB EVAL-AD7723CB Demonstration/Evaluation Software runs under DOS 4.0 or later and requires a minimum of a 386based machine with 400kB of base RAM and 500kB of free hard disk space. The user interface on the PC is a dedicated program written especially for the AD7723 AD7723. The disk which accompanies the EVAL-AD7723CB EVAL-AD7723CB contains several files. The user should create a new directory on the main PC drive and label this "AD7723 AD7723". Then, all files on the EVAL-AD7723CB EVAL-AD7723CB disk should be copied into this directory. The Mouse Driver on the PC should be enabled before running the software. If this has not been loaded, the program will not run. To run the software, simply make the AD7723 AD7723 directory the current directory and type "go". When the evaluation program starts, the user sees the screen shown on Figure 3 (without any FFT or scope waveforms). This is the main screen and it is divided into three parts. The top part provides the main control interface for the AD7723 AD7723 evaluation software. The middle part of the main screen functions as a Digital Storage Oscilloscope and the bottom part of the main screen operates as either a Digital Spectrum Analyzer or a Histogram analyzer. 6 REV. A EVAL-AD7723CB EVAL-AD7723CB Each part of the screen has several buttons that can be pressed by using the mouse or the keyboard. To press a button using the mouse, simply use it to move the on-screen pointer to the button to be activated and click. To use the keyboard, simply press the appropriate key as highlighted on the button. Lower case letters must be used. When a button is pressed, it is highlighted on the screen. The next button can be highlighted by using the Tab key or the previous button by holding down the shift key and the Tab key together. The highlighted button can also be pressed by pressing the space bar. Pressing the ESC key halts any operation currently in progress. In this document, if a button can be activated from the keyboard then the key used is shown in bold in the button name. For example, "no prog" has the "p" highlighted in bold, indicating that the button can be activated by pressing the p key. Some buttons have a red indicator. A red indicator on the button means that the function associated with that button is on. Absence of the red indicator light means that the function associated with the button is off. The on/off status of these buttons is changed simply by selecting the button. matically downloaded to the ADSP-2111 ADSP-2111. However, if the "no prog" button is on, then the .HIP file is not downloaded to the ADSP-2111 ADSP-2111. The AD7723 AD7723 is running from the 20MHz on-board crystal clock and is configured to operate in "decimate by 32 Lowpass" mode on the evaluation board when it is packaged in the evaluation board package. Because of this the sampling frequency (fsamp) must be set to 625KHz using the mouse and keyboard. If other master clock frequencies are used, the sampling frequency must be changed accordingly. The number of samples is also chosen using the mouse or keyboard. When evaluating SNR, use 1024 samples to see the full performance of the part. In addition, the number of signal drop bins used in the fft (Digital Spectrum Analyzer) should be 9. For optimum THD measurements, 4096 samples should be used. The "Analog in" section shows the analog input range and DC offset voltage. Main Screen The top left part of the main screen contains eight buttons which are selected using the mouse or by using the function keys from the keyboard. These buttons and the actions they perform are: F1: Info. This button shows information on the software. F2: Samp. When this key is pressed, the software causes the AD7723 AD7723 to perform a number of conversions as determined by the setup menu (see above). The data from these conversions is then analyzed by the AD7723 AD7723 evaluation software. Another set of samples may be taken by pressing the F3 key again. F4: Figure 4: Setup Menu Screen Setup. This button activates the setup menu. F3: Cont. Pressing this button causes the software to repeatedly perform conversions and analyze them. Once the conversions and analysis has been done for one set of samples, the software automatically repeats the process. It continues to do this until the ESC key is pressed. F5: Save. This saves a set of samples to a file for use either at a later date or with other software. The samples can be saved either as "volts", "ints" or "binary". The format of all these files is ASCII text. Note that the AD7723 AD7723 software can only load files saved in the "ints" format. Files saved in the "volts" and "ints" formats can be used with packages such as Mathcad. Files saved in the "binary" format are for viewing purposes only. F6: Load. This allows the user to load data from a file with a .DAT extension. Only data that was saved as ints can be loaded and analyzed. A configuration file must be loaded via the "F2 Setup" menu before the data file can be analyzed. If there is no EVAL-CONTROL BOARD connected to the PC, then the "no prog" button in the "F2 Setup" menu must be on. Once a configuration file has been loaded, the data loaded from the .DAT file is analyzed according to the settings in the "F2 Setup" menu. Setting up the EVAL-CONTROL BOARD When the software is run, the "F2 Setup" button in the top left of the screen should be selected to pop up the setup menu (see fig. 4). This menu sets up the EVAL-CONTROL BOARD for use with the EVAL-AD7723CB EVAL-AD7723CB. Firstly, the configuration file must be loaded by selecting "AD7723 AD7723" with the mouse or keyboard and pressing the "load" button. The configuration file contains the default configuration information for the EVAL-CONTROL BOARD, the Digital Spectrum Analyzer and the Digital Storage Oscilloscope. It also tells the AD7723 AD7723.EXE software which .HIP file to download to the ADSP-2111 ADSP-2111. The .HIP file contains the DSP code which is executed by the ADSP-2111 ADSP-2111. Normally, the "no prog" button is off, so when the configuration file is loaded, the .HIP file is autoREV. A 7 EVAL-AD7723CB EVAL-AD7723CB F7: Reset. Choosing this option resets the EVALCONTROL BOARD. F10: Quit. This quits the AD7723 AD7723 evaluation software and returns control to the operating system. Information Windows There are three information windows at the top of the main screen. The left-hand window is the configuration window and gives details about part being evaluated. It shows the name of the program that has been downloaded to the EVAL-CONTROL BOARD, the sampling frequency, the number of bits, the analog input range of the part and the output code format of the part. The right-hand large window is the Status window. This window provides feedback to the user as to what operations are currently being performed by the software and also displays error messages. Directly underneath the status window is a small window that shows the selected conversion sequence and the maximum and minimum values of the most recently captured samples for all channels in the conversion sequence. Test Mode At the top right of the main screen are the Test Mode buttons. These buttons determine what sort of testing is done on the samples captured by the software. Both an ac analysis and dc analysis can be performed. The function of these buttons are: fft plot Choosing this button causes the Digital Spectrum Analyzer to appear at the bottom of the screen. Histog ram: Choosing this button causes the Histogram Analyzer to be displayed at the bottom of the screen. There is one other button near the top of the screen, beside the "F10 Quit" button. This is: blackman-harris: When performing a Fourier transform of the sampled data, this button determines whether or not the data is windowed by a blackman-harris window before the transform. When this button is on, the data is windowed. When this button is off, the data isn't windowed. 8 REV. A EVAL-AD7723CB EVAL-AD7723CB Digital Storage Oscilloscope. When samples of data are captured, they are displayed on the Digital Storage Oscilloscope. If the blackman-harris button is turned on then the windowed data is also displayed on the oscilloscope. The 'scope has been designed to act in a similar way as a conventional oscilloscope. To the right of the oscilloscope are several buttons that control the manner in which data is displayed on the 'scope. The timebase for the oscilloscope is automatically chosen by the software if the Time/Div "Auto" button is on. The user can also select the timebase by clicking in the Time/Div window and scrolling up and down through the possible timebases. Similarly, the vertical scale of the oscilloscope is chosen automatically if the Volt/Div "Auto" button is on. The user also has the option of selecting the desired vertical scale in a similar manner to selecting the timebase. The other buttons associated with the oscilloscope are: ac When this button is on, the dc component of the sampled signal is removed and the signal is displayed. This has the effect of centering the signal vertically on the oscilloscope screen. When this button is off, the dc component is not removed and the signal is displayed with its horizontal axis corresponding to a code of 0. The ac display option is useful for zooming in on a low-level signal that has a large dc offset. d ual When the "dual" button is on, the oscilloscope screen is divided into two parts with the sampled data display centered on one horizontal axis and the windowed data display centered on another. When the "dual" button is off, both traces are centered on the same horizontal axis. 1 This button toggles the sampled data trace on and off. This button toggles the sampled data trace on and off. g rid This button toggles the grid display of the oscilloscope on and off. 2 axis This button toggles the axis display of the oscilloscope on and off Histogram Analyzer text This button toggles the text displayed on the oscilloscope screen on and off. line When the line button is on, the displayed samples are joined together by lines. When this button is off, the samples are displayed as points. The histogram analyzer counts the number of occurrences of each code in the captured samples and displays a histogram of these counts. The most frequently occurring code is displayed in the center of the histogram. The analyzer is normally used with a dc input signal and calculates the mean and the standard deviation of the sampled data. The mean and standard deviation are displayed in both volts and in units of the lsb size of the converter. The histogram gives a good indication of the dc noise performance of the ADC. The standard deviation shows directly the noise introduced in the conversion process. Figure 5 Histogram Screen REV. A 9 EVAL-AD7723CB EVAL-AD7723CB Figure 6. AD7723 AD7723 Evaluation Board Circuit Diagram (Sheet 1 of 3) 10 REV. A EVAL-AD7723CB EVAL-AD7723CB Figure 7. AD7723 AD7723 Evaluation Board Circuit Diagram (Sheet 2 of 3) REV. A 11 EVAL-AD7723CB EVAL-AD7723CB Figure 8. AD7723 AD7723 Evaluation Board Circuit Diagram (Sheet 3 of 3) 12 REV. A EVAL-AD7723CB EVAL-AD7723CB Figure 9: AD7723 AD7723 Evaluation Board Component Side Silkscreen Artwork Figure 10: AD7723 AD7723 Evaluation Board Solder Side Silkscreen Artwork REV. A 13 EVAL-AD7723CB EVAL-AD7723CB Figure 11: AD7723 AD7723 Evaluation Board Component Side Artwork (Layer 1) Figure 12: AD7723 AD7723 Evaluation Board Solder Side Artwork (Layer 4) 14 REV. A EVAL-AD7723CB EVAL-AD7723CB Figure 13: AD7723 AD7723 Evaluation Board Layer 2 (Ground Planes) Artwork Figure 14: AD7723 AD7723 Evaluation Board Layer 3 (Power Planes) Artwork REV. A 15 EVAL-AD7723CB EVAL-AD7723CB Qty Reference Designator Description/Value Manuf. No. Supplier No. 2 1 1 1 1 1 1 1 1 U1-2 U3 U4 U5 U6 U7 U8 U9 Y1 AD8047AN AD8047AN AD780 AD780 20MHz Crystal Oscillator 74AC00 74AC00 74AC04 74AC04 74FCT162374TPV 74FCT162374TPV 16 bit register 74FCT162244TPV 74FCT162244TPV 16 bit buffer AD7723 AD7723 19.6MHz Crystal ADI AD8047AN AD8047AN ADI AD780AN AD780AN IQD 20MHz IQXO-35BE IQXO-35BE Harris CD74AC00M CD74AC00M Harris CD74AC04M CD74AC04M Integrated Device Tech. Integrated Device Tech. ADI IQD 19.6MHz HC49 ADI ADI FEC 221-480 FEC 485-755 FEC 485-779 Hamilton Hallmark Hamilton Hallmark ADI IQD 2 L1 L2 RFI SUPPRES. BEAD 1 1 8 31 Unused capacitor spacing 220pF Ceramic 0805 Case 10uF 16V Tant. TAJ-B Case 0.1uF Ceramic 0805 Case AVX 08051A220JAT00J 08051A220JAT00J AVX TAJB106K016R TAJB106K016R AVX CM21X7R104K25VAT CM21X7R104K25VAT FEC 498-609 FEC 498-737 FEC 499-687 2 5 1 1 6 1 C1 C2 C3 C5 C7 C9 C11 C21 C38 C43 C4 C6 C8 C10 C12 C16 C18 C20 C22 C28-37 C28-37 C39 C40 C44 C49-57 C49-57 C13 C14 C15 C17 C19 C24 C48 C23 C25 C26 C41 C42 C45 C46 C47 C27 33pF Ceramic 0603 Case (unused) 22uF 16V Tant. TAJ-D Case 22nF Ceramic 0805 Case 220nF Ceramic 0805 Case 10nF Ceramic 0805 Case 1uF Ceramic 1206 Case AVX 06035A330JAT00J 06035A330JAT00J AVX TAJD226K016R TAJD226K016R AVX 08055C223KAT00J 08055C223KAT00J AVX CM21X7R224K16VAT CM21X7R224K16VAT AVX 08055C103KAT00J 08055C103KAT00J AVX CM316X7R106K16VAT CM316X7R106K16VAT FEC 498-555 FEC 498-749 FEC 578-198 FEC 499-699 FEC 499-225 FEC 499-71 1 1 4 2 1 1 1 1 1 6 2 R1 R2 R3 R5-R7 R4 R8 R9 R10 R11 R12 R13 R14-19 R14-19 R20-21 R20-21 51 5% 0.1W 0805 Case 390 5% 0.1W 0805 Case 220 5% 0.1W 0805 Case 27 5% 0.1W 0805 Case 20k 5% 0.1W 0805 Case 10k 5% 0.1W 0805 Case 1k 5% 0.1W 0805 Case 1M 5% 0.1W 0805 Case (unused) 20 5% 0.1W 0805 Case 4.7k 5% 0.1W 0805 Case 10 5% 0.1W 0805 Case Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp Multicomp FEC 771-181 FEC 613-046 FEC 613-010 FEC 612-900 FEC 771-791 FEC 613-216 FEC 613-095 FEC 613-459 FEC 771-132 FEC 613-174 FEC 612-856 1 1 1 1 1 1 2 21 P1 P2 P3 P4 P5 P6 SK1 SK2 J1 J2 J5 J6 J9-J11 J9-J11 J14-16 J14-16 J18-24 J18-24 J33 J35-37 J35-37 J3 J4 J7 J8 J12 J13 J17 J25-32 J25-32 J34 J1-J37 J1-J37 TP1 TP2 TP9-TP19 TP9-TP19 TP4 TP6 TP7 TP20 TP3 TP5 TP8 TP21 TP22 U1 U2 U3 DIN41612 DIN41612 C96 900 plug 3 Pin Power Connector 10 Way DIL Header 20 Way DIL Header 40 Way Shrouded Header 2 Pin Power Connector 50 Gold Plated PCB SMB Jack 2 Way Jumper Harting 0903-196-7921 Lumberg KRM3 Preci-Dip 892-90-010-10-802 Preci-Dip 892-90-020-10-802 3M 2540-6002UB 2540-6002UB Lumberg KRM2 Pasternack Enter. PE4174 PE4174 Preci-Dip 890-90-002-10-802 FEC 104-986 FEC 151-786 Futura Elect. Futura Elect. Digikey mhb40k-nb FEC 151-785 FEC 310-682 Futura Elect. 3 way jumper Shorting links White Testpoint Red Testpoint Black Testpoint Ultra low profile socket strip Preci-Dip 890-90-003-10-802 Preci-Dip 999-19-310-00 Keystone Cat. No. 5002 Keystone Cat. No. 5000 Keystone Cat. No. 5001 Preci-Dip 714-91-108-31-012 Futura Elect. Futura Elect. Futura Elect. Futura Elect. Futura Elect. Futura Elect. 16 37 13 4 5 3 16 FEC 108-267 REV. A