Datasheet AD7720 (Analog Devices) - 10

AD7720 1.0 0.8 0.6 0.4 0.2 0 –0.2 INL ERROR – LSB –0.4 –0.6 –0.8 –1.0 0 20000 40000 65535 CODE
Figure 14. Integral Nonlinearity Error
0 0 –10 –10 –20 –20 –30 –30 –40 –40 –50 –50 –60 dB –60 dB –70 –70 –80 –80 –90 –90 –100 –100 –110 –110 –120 –120 –130 –130 0 6.25 0 393.295 kHz FREQUENCY – MHz FREQUENCY – kHz
Figure 15. Modulator Output (0 Hz to MCLK/2) Figure 18. Modulator Output (0 to 393.295 kHz)
0 0 –20 CLKIN = 12.5MHz –20 AIN = 90kHz SNR = 90.1dB CLKIN = 12.5 MHz –40 S/(N+D) = 89.2dB –40 SNR = 89.6dB SFDR = –99.5dB S/(N+D) = 89.6dB –60 THD = –96.6dB –60 SFDR = –108.0dB 2ND = –100.9dB dB –80 3RD = –106.0dB dB –80 4TH = –99.5dB –100 –100 –120 –120 –140 –140 –154 –154 0E+0 10E+3 20E+3 30E+3 40E+3 50E+3 60E+3 70E+3 80E+3 90E+3 98E+3 0E+0 10E+3 20E+3 30E+3 40E+3 50E+3 60E+3 70E+3 80E+3 90E+3 98E+3
Figure 16. 16K Point FFT Figure 19. 16K Point FFT
0 0 –20 XTAL = 12.288MHz –20 AIN = 90kHz SNR = 89.0dB XTAL = 12.288MHz –40 S/(N+D) = 87.8dB –40 SNR = 88.1dB SFDR = –94.3dB S/(N+D) = 88.1dB –60 THD = –93.8dB –60 SFDR = –103.7dB 2ND = –94.3dB dB –80 3RD = –108.5dB dB –80 4TH = –105.7dB –100 –100 –120 –120 –140 –140 –154 –154 0E+0 10E+3 20E+3 30E+3 40E+3 50E+3 60E+3 70E+3 80E+3 90E+3 96E+3 0E+0 10E+3 20E+3 30E+3 40E+3 50E+3 60E+3 70E+3 80E+3 90E+3 96E+3
Figure 17. 16K Point FFT Figure 20. 16K Point FFT REV. 0 –9–