AD7923 Analog Devices, AD7923 Datasheet
AD7923
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AD7923 Summary of contents
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... CONTROL LOGIC AD7923 GND Figure 1. High Throughput with Low Power Consumption. The AD7923 offers up to 200 kSPS throughput rates. At the maximum throughput rate with 3 V supplies, the AD7923 dissipates just 3 power. Four Single-Ended Inputs with a Channel Sequencer. Single-Supply Operation with V Function ...
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... Change to Reference Section ........................................................ 16 Changes to Ordering Guide .......................................................... 24 11/02—Revision 0: Initial Version Typical Connection Diagram ................................................... 16 Modes of Operation ................................................................... 17 Powering Up the AD7923 ......................................................... 18 Power vs. Throughput Rate....................................................... 19 Serial Interface ............................................................................ 20 Microprocessor Interfacing....................................................... 21 Application Hints ........................................................................... 23 Grounding and Layout .............................................................. 23 Evaluating the AD7923 Performance ...................................... 23 Outline Dimensions ....................................................................... 24 Ordering Guide .......................................................................... 24 Automotive Products ................................................................. 24 Rev Page ...
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... Straight binary output coding Typ ±0.5 LSB −REF to +REF biased about REF IN IN complement output coding Typ ±0.8 LSB Range bit set to 1 Range bit set 4. 5. ±1% specified performance f = 200 kSPS SAMPLE Typ 10 nA DRIVE AD7923 with twos IN ...
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... AD7923 Parameter LOGIC OUTPUTS Output High Voltage Output Low Voltage Floating-State Leakage Current Floating-State Output Capacitance 3 Output Coding CONVERSION RATE Conversion Time Track-and-Hold Acquisition Time Throughput Rate POWER REQUIREMENTS DRIVE During Conversion Normal Mode (Static) Normal Mode (Operational) f ...
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... 200μ OUTPUT PIN C L 50pF 200μ Figure 2. Load Circuit for Digital Output Timing Specification Rev Page and timed from a voltage level of 1.6 V. See Figure DRIVE , is the true bus relinquish 8 1.6V AD7923 ...
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... AD7923 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter AV to AGND AGND DRIVE Analog Input Voltage to AGND Digital Input Voltage to AGND Digital Output Voltage to AGND REF to AGND IN Input Current to Any Pin Except 1 Supplies Operating Temperature Range Commercial (B Version) ...
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... DOUT Data Out. Logic Output. The conversion result from the AD7923 is provided on this output pin as a serial data stream. The AD7923 serial data stream consists of two leading 0s, and two address bits indicating which channel the conversion result corresponds to, followed by 12 bits of conversion data, MSB first. The output coding can be selected as straight binary or twos complement via the coding bit in the control register ...
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... AD7923 TYPICAL PERFORMANCE CHARACTERISTICS –10 –30 –50 –70 –90 –110 FREQUENCY (kHz) Figure 4. Dynamic Performance at 200 kSPS 200kSPS SAMPLE T = 25°C A RANGE = 0V TO REF INPUT FREQUENCY (kHz) Figure 5. SINAD vs. Analog Input Frequency for Various Supply Voltages at ...
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... DRIVE TEMP = 25 ° C 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 512 1024 1536 2048 2560 3072 CODE Figure 10. Typical DNL 3584 4096 Rev Page AD7923 ...
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... It defined IN Figure 6 shows the power supply rejection ratio vs. supply ripple frequency for the AD7923 with no decoupling. The power sup- ply rejection ratio is defined as the ratio of the power in the ADC output at full-scale frequency the power of a 200 mV p-p sine wave applied to the ADC AV PSSR (dB) = 10log(Pf/ equal to the power at frequency f in the ADC output ...
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... The theoretical SINAD ratio for an ideal N-bit converter with a sine wave input is given by SINAD = (6.02N + 1.76) dB Thus for a 12-bit converter, this is 74 dB. Total Harmonic Distortion (THD) THD is the ratio of the rms sum of harmonics to the fundamental. For the AD7923 defined THD ( ...
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... DONTC Don’t care. 1 RANGE This bit selects the analog input range to be used on the AD7923 set to 0, the analog input range extends from × REF . set to 1, the analog input range extends from REF × REF ...
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... PM0 Mode 1 1 Normal operation. In this mode, the AD7923 remains in full power mode, regardless of the status of any of the logic inputs. This mode allows the fastest possible throughput rate from the AD7923 Full shutdown. In this mode, the AD7923 is in full shutdown mode with all circuitry on the AD7923 powering down. The AD7923 retains the information in the control register while in full shutdown ...
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... The AD7923 is a high speed, 4-channel, 12-bit single-supply ADC. The part can be operated from a 2 5.25 V supply. When operated from either supply, the AD7923 is capable of throughput rates of 200 kSPS. The conversion time can be as short as 800 ns when provided with a 20 MHz clock. ...
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... ADC TRANSFER FUNCTION The output coding of the AD7923 is either straight binary or twos complement, depending on the status of the LSB in the control register. The designed code transitions occur at succes- sive LSB values (for example, 1 LSB, 2 LSBs). The LSB size is REF /4096 for the AD7923. The ideal transfer characteristic ...
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... In Figure 19, REF IN decoupled 2.5 V supply from a reference source, the AD780, to provide an analog input range 2.5 V (if the range bit (if the range bit is 0). Although the AD7923 is connected the serial interface is connected microprocessor ...
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... When running the AD7923 with a 20 MHz clock, one dummy 16 SCLK transfer should be sufficient to ensure that the part is fully powered up. During this dummy transfer, the contents of the control register should remain unchanged, therefore the write bit should the DIN line ...
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... ADC in and out of the low power state by controlling the CS signal. POWERING UP THE AD7923 When supplies are first applied to the AD7923, the ADC can power up in any of the operating modes of the part. To ensure that the part is placed into the required operating mode, the user should perform a dummy cycle operation, as outlined in Figure 23 through Figure 25 ...
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... DIN LINE HIGH FOR FIRST DUMMY CONVERSION Figure 23. Placing the AD7923 into Normal Mode after Supplies are First Applied CS SCLK DOUT DIN Figure 24. Placing the AD7923 into Full Shutdown Mode after Supplies are First Applied PART IS IN UNKNOWN MODE AFTER POWER- ...
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... Sixteen serial clock cycles are required to perform the conver- sion process and to access data from the AD7923. For the AD7923, the 12 bits of data are preceded by two leading 0s and Channel Address Bits ADD1 and ADD0, identifying which channel the result corresponds to. CS going low clocks out the first leading read by the microcontroller or DSP on the first falling edge of SCLK ...
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... SCLK DOUT DIN MICROPROCESSOR INTERFACING The serial interface on the AD7923 allows the part to be directly connected to a range of many different microprocessors. This section explains how to interface the AD7923 with some of the more common microcontroller and DSP serial interface protocols. AD7923-to-TMS320C541 ...
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... SCLK edge. If the number of SCLKs between interrupts is an integer of N, equidistant sampling is implemented by the DSP. AD7923-to-DSP563xx The connection diagram in Figure 31 shows how the AD7923 can be connected to the synchronous serial interface (ESSI) of the DSP563xx family of DSPs from Motorola. Each ESSI (two 1 ...
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... All three AGND pins of the AD7923 should be sunk into the AGND plane. Digital and analog ground planes should be joined at only one place. If the AD7923 system where multiple devices require an AGND to DGND connection, the connection should still be made at one point only, a star ground point that should be established as close as possible to the AD7923 ...
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... The EVAL-CONTROL BRD2 is a complete unit allowing control and communicate with all Analog Devices evaluation boards ending in the CB designators. To order a complete evaluation kit, order the particular ADC evaluation board, for example, the EVAL-AD7923CB, the EVAL-CONTROL BRD2, and transformer. ...