AD7622 Analog Devices, AD7622 Datasheet
AD7622
Specifications of AD7622
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AD7622 Summary of contents
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... It features two very high sampling rate modes (wideband warp and warp) and a fast mode (normal) for asynchronous rate applications. The AD7622 is hardware factory calibrated and tested to ensure ac parameters, such as signal-to-noise ratio (SNR), in addition to the more traditional dc parameters of gain, offset, and linearity. ...
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... Multiplexed Inputs ..................................................................... 17 Driver Amplifier Choice ........................................................... 18 Voltage Reference Input ............................................................ 19 Power Supply............................................................................... 20 Conversion Control ................................................................... 20 Interfaces.......................................................................................... 21 Digital Interface.......................................................................... 21 Parallel Interface......................................................................... 21 Serial interface ............................................................................ 22 Master Serial Interface............................................................... 22 Slave Serial Interface .................................................................. 24 Microprocessor Interfacing....................................................... 26 Application Hints ........................................................................... 27 Layout .......................................................................................... 27 Evaluating the AD7622 Performance ...................................... 27 Outline Dimensions ....................................................................... 28 Ordering Guide .......................................................................... 28 Rev Page ...
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... AD7622 Unit Bits μA ns MSPS ms ns MSPS 4 LSB Bits LSB LSB LSB LSB ppm/°C LSB ppm/°C LSB ...
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... AD7622 Parameter REFBUFIN Output Voltage REFBUFIN Output Resistance EXTERNAL REFERENCE Voltage Range Current Drain REFERENCE BUFFER REFBUFIN Input Voltage Range REFBUFIN Input Current TEMPERATURE PIN Voltage Output Temperature Sensitivity Output Resistance DIGITAL INPUTS Logic Levels DIGITAL OUTPUTS ...
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... See Table 4 375/500 12 AD7622 Unit ...
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... AD7622 1 See the Conversion Control section. 2 All timings for wideband warp mode are the same as warp mode warp mode only, the maximum time between conversions is 1 ms; otherwise, there is no required maximum time. 4 See the Digital Interface section and the RESET section. ...
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... AGND − 0.3 V section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect ±0.3 V device reliability. −0 +2.7 V −0 +3.8 V ±2.8 V −3 +2.8 V −0 +5.5 V ±20 mA 700 mW 2.5 W 125°C –65°C to +125°C Rev Page AD7622 ...
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... When EXT/INT = high, slave mode. The output data is synchronized to an external clock signal, gated by CS, connected to the SCLK input AGND 1 PIN 1 AVDD IDENTIFIER 2 DGND 3 BYTESWAP 4 OB/2C 5 AD7622 WARP 6 TOP VIEW NORMAL 7 (Not to Scale) SER/PAR D2/DIVSCLK[0] 11 D3/DIVSCLK[1] ...
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... When SER/PAR = high, serial data output. In serial mode, this pin is used as the serial data output synchronized to SCLK. Conversion results are stored in an on-chip register. The AD7622 provides the conversion result, MSB first, from its internal shift register. The data format is determined by the logic level of OB/2C ...
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... AI Differential Positive Analog Input. 45 TEMP AO Temperature Sensor Analog Output. Normally, 278 mV @ 25°C with a temperature coefficient of 1 mV/°C. This pin can be used to measure the temperature of the AD7622. See the Temperature Sensor section. 46 REFBUFIN AI/O Internal Reference Output/Reference Buffer Input. When PDREF/PDBUF = low, the internal reference and buffer are enabled producing the 1.2 V (typical) band gap output on this pin, which needs external decoupling ...
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... CNVST input to when the input signal is held for a conversion. Transient Response The time required for the AD7622 to achieve its rated accuracy after a full-scale step function is applied to its input. Reference Voltage Temperature Coefficient It is derived from the typical shift of output voltage at 25° ...
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... AD7622 TYPICAL PERFORMANCE CHARACTERISTICS 1.50 1.00 0.50 0 –0.50 –1.00 –1.50 0 16384 32768 CODE Figure 6. Integral Nonlinearity vs. Code 250000 196433 200000 150000 100000 50000 27695 7FF8 7FF9 7FFA 7FFB 7FFC 7FFD 7FFE 7FFF CODES IN HEX Figure 7. Histogram of 261,120 Conversions Input at the Code Center (External Reference) 2 ...
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... TEMPERATURE (°C) Figure 16. SNR, SINAD, and ENOB vs. Temperature SFDR THD SECOND THIRD HARMONIC HARMONIC –35 – TEMPERATURE (°C) Figure 17. THD, Harmonics, and SFDR vs. Temperature AD7622 900 1000 16.0 15.5 15.0 14.5 14.0 105 125 120 110 100 105 125 ...
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... AD7622 93.0 SNR 92.5 SINAD 92.0 91.5 91.0 –60 –50 –40 –30 INPUT LEVEL (dB) Figure 18. SNR and SINAD vs. Input Level (Referred to Full Scale –55 –35 – TEMPERATURE (°C) Figure 19. Power-Down Operating Currents vs. Temperature –20 –10 0 DVDD OVDD, 3.3V OVDD, 2.5V AVDD 65 85 105 125 Rev ...
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... ADC that does not exhibit any pipeline or latency, making it ideal for multiple multiplexed channel applications. The AD7622 can operate from a single 2.5 V supply and interface to either 2.5 V digital logic housed in a 48-lead LQFP package or a tiny 48-lead LFCSP package, ...
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... AD7622 TRANSFER FUNCTIONS Using the OB/ 2C digital input, the AD7622 offers two output codings: straight binary and twos complement. The LSB size with V = 2.048 × 65536 which is 62.5 μV. Refer to REF REF Figure 23 and Table 7 for the ideal transfer characteristic. 111...111 111 ...
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... RC filter, as shown in Figure 24, does not settle in the required acquisition time, t These values are chosen to optimize the best SNR performance of the AD7622. To use the full 2 MSPS throughput in multiplexed applications, the RC should be adjusted to satisfy × RC time constant). However, lowering R and C increases ...
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... SNR by only 0.1 dB when using the RC filter in Figure 24, and by 1.3 dB without it. • The driver needs to have a THD performance suitable to that of the AD7622. Figure 14 gives the THD vs. frequency that the driver should exceed. The AD8021 almost all applications. The compensation capacitor that should have good linearity as an NPO ceramic or mica type ...
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... VOLTAGE REFERENCE INPUT The AD7622 allows the choice of either a very low temperature drift internal voltage reference, an external 1.2 V reference that can be buffered using the internal reference buffer external reference. Unlike many ADCs with internal references, the internal reference of the AD7622 provides excellent performance and can be used in almost all applications ...
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... SENSOR the power rails (that is, OVDD and OGND). AD7622 CONVERSION CONTROL The AD7622 is controlled by the CNVST input. A falling edge on CNVST is all that is necessary to initiate a conversion. Detailed timing diagrams of the conversion process are shown in Figure 31. Once initiated, it cannot be restarted or aborted, even by the power-down input, PD, until the conversion is complete ...
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... INTERFACES DIGITAL INTERFACE The AD7622 has a versatile digital interface that can be set up as either a serial or a parallel interface with the host system. The serial interface is multiplexed on the parallel data bus. The AD7622 digital interface also accommodates 2 logic with either OVDD at 2 3.3 V. OVDD defines the logic high output voltage ...
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... Internal Clock The AD7622 is configured to generate and provide the serial data clock SCLK when the EXT/ INT pin = low. The AD7622 also generates a SYNC signal to indicate to the host when the serial data is valid. The serial clock SCLK and the SYNC signal can be inverted ...
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... Figure 38. Master Serial Data Timing for Reading (Read Previous Conversion During Convert) RDC/SDIN = 0 INVSCLK = INVSYNC = D14 RDC/SDIN = 1 INVSCLK = INVSYNC = Rev Page AD7622 ...
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... Figure 40 and Figure 41 show the detailed timing diagrams of these methods. While the AD7622 is performing a bit decision important that voltage transients be avoided on digital input/output pins or degradation of the conversion result could occur. This is ...
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... X SDOUT D15 D14 t 16 Figure 41. Slave Serial Data Timing for Reading (Read Previous Conversion During Convert INVSCLK = D13 D1 D0 X13 X1 X0 INVSCLK = D13 D0 Rev Page AD7622 18 X15 X14 Y15 Y14 ...
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... Figure 42 shows an interface diagram between the AD7622 and an SPI-equipped DSP, the ADSP-219x. To accommodate the slower speed of the DSP, the AD7622 acts as a slave device and data must be read after conversion. This mode also allows the daisy-chain feature. The convert command can be initiated in response to an internal timer interrupt ...
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... Digital and analog ground planes should be joined in only one place, preferably underneath the AD7622 close as possible to the AD7622. If the AD7622 system where multiple devices require analog-to-digital ground connections, the connections should still be made at one point only, a star ground point, established as close as possible to the AD7622 ...
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... AD7622BCPZ −40°C to +85°C 1 AD7622BCPZRL −40°C to +85°C 1 AD7622BSTZ −40°C to +85°C 1 AD7622BSTZRL −40°C to +85°C 2 EVAL-AD7622CB 3 EVAL-CONTROL BRD3 Pb-free part. 2 This board can be used as a standalone evaluation board or in conjunction with the EVAL-CONTROL BRD3 for evaluation/demonstration purposes. ...