AD7720 Analog Devices, AD7720 Datasheet
AD7720
Specifications of AD7720
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AD7720 Summary of contents
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... VIN(–) MZERO GC BIP STBY One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 Fax: 781/326-8703 AD7720 AGND DVDD DGND REF1 AD7720 2.5V REFERENCE SIGMA-DELTA MODULATOR CLOCK CIRCUITRY CONTROL LOGIC World Wide Web Site: http://www.analog.com © Analog Devices, Inc., 1997 REF2 DATA ...
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... AD7720–SPECIFICATIONS Parameter STATIC PERFORMANCE Resolution Differential Nonlinearity Integral Nonlinearity Precalibration Offset Error 2 Precalibration Gain Error 3 Postcalibration Offset Error 2, 3 Postcalibration Gain Error Offset Error Drift Gain Error Drift Unipolar Mode Bipolar Mode ANALOG INPUTS Signal Input Span (VIN(+) – VIN(–)) ...
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... V min/V max 4.75/5.25 V min/V max Digital Inputs Equal DVDD 43 mA max 25 A max 90.625kHz DECIMATE BY 32 120dB 292.969kHz FILTER 2 BANDWIDTH = 90.625 kHz TRANSITION = 104.687kHz ATTENUATION = 90dB COEFFICIENTS = 151 –3– | 200 A OUT | 1.6 mA OUT DECIMATE 16-BIT BY 2 OUTPUT 90dB 104.687kHz AD7720 ...
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... AD7720 TIMING CHARACTERISTICS Limit at T MIN Parameter (B Version) f 100 MCLK 0. MCLK t 0. MCLK MCLK NOTE Guaranteed by design. Figure 2. Load Circuit for Access Time and Bus Relinquish Time SCLK (O) DATA (O) NOTE: O SIGNIFIES AN OUTPUT ...
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... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD7720 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...
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... When STBY is low, the device is powered up. Data Valid Logic Output. A logic high on DVAL indicates that the data bit stream from the AD7720 is an accurate digital representation of the analog voltage at the input to the sigma-delta modulator. The DVAL pin is set low for 20 MCLK cycles if the analog input is overranged ...
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... TERMINOLOGY (IDEAL FIR FILTER USED WITH AD7720 [FIGURE 1]) Integral Nonlinearity This is the maximum deviation of any code from a straight line passing through the endpoints of the transfer function. The endpoints of the transfer function are zero scale (not to be con- fused with bipolar zero), a point 0.5 LSB below the first code transition (100 ...
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... AD7720–Typical Characteristics (AVDD = DVDD = 5 +25 C; CLKIN = 12.5 MHz, AIN = 20 kHz, Bipolar Mode noted) 110 100 90 SFDR 80 S/ (N+ –40 –30 –20 –10 0 INPUT LEVEL – dB Figure 5. S/(N+D) and SFDR vs. Analog Input Level –85 –90 SNR V (+) = V (–) = 1.25Vpk– – ...
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... AD7720 65535 FREQUENCY – kHz 70E+3 80E+3 Figure 19. 16K Point FFT 70E+3 80E+3 Figure 20. 16K Point FFT 393.295 kHz 90E+3 98E+3 90E+3 96E+3 ...
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... To remedy the situation, a low pass MCLK RC filter can be connected between the amplifier and the input to the AD7720 as shown in Figure 23. The external capacitor at each input aids in supplying the current spikes created during the sampling process. The resistor in this diagram, as well as creating the pole for the antialiasing, isolates the op amp from the transient nature of the load ...
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... VIN(+) pin to form a differential signal around an initial bias voltage of 1.25 V. For single-ended applications, best THD performance is obtained with VIN(–) set to 1.25 V rather than 2.5 V. The input to the AD7720 can also be driven differen- tially with a complementary input as shown in Figure 29. SWITCHED-CAP DAC REF In this case, the input common-mode voltage is set to 2 ...
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... REF1 multipurpose system clock that is generated on the digital ground plane. If the clock signal is passed between its origin on a digital plane to the AD7720 on the analog ground plane, the REF2 ground noise between the two planes adds directly to the clock and will produce excess jitter. The jitter can cause unwanted degradation in the signal-to-noise ratio and also produce un- wanted harmonics ...
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... Digital and analog ground planes should only be joined in one place. If the AD7720 is the only device requir- ing an AGND-to-DGND connection, the ground planes should be connected at the AGND and DGND pins of the AD7720. ...
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... AD7720 0.006 (0.15) 0.002 (0.05) SEATING PLANE OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 28-Lead Thin Shrink Small Outline (RU-28) 0.386 (9.80) 0.378 (9.60 PIN 1 0.0433 (1.10) MAX 0.0118 (0.30) 0.0256 (0.65) 0.0079 (0.20) BSC 0.0075 (0.19) 0.0035 (0.090) –14– 0.028 (0.70 0.020 (0.50) REV. 0 ...
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