REV. A

AD7724

–9–

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100

–110

–120

–130

0

0

6.5

FREQUENCY – MHz

Figure 15. Modulator Output (0 Hz to MCLK/2)

0

–154

–20

–80

–100

–120

–140

–40

–60

0E+0

10E+3 20E+3 30E+3 40E+3 50E+3 60E+3

70E+3 80E+3

98E+3

CLKIN = 13MHz

SNR = 90.1dB

S/(N+D) = 89.2dB

SFDR = –99.5dB

THD = –96.6dB

2ND = –100.9dB

3RD = –106.0dB

4TH = –99.5dB

90E+3

Figure 16. 16K Point FFT

0

–154

–20

–80

–100

–120

–140

–40

–60

0E+0

10E+3 20E+3 30E+3 40E+3

50E+3 60E+3 70E+3 80E+3

96E+3

90E+3

XTAL = 12.288MHz

SNR = 89.0dB

S/(N+D) = 87.8dB

SFDR = –94.3dB

THD = –93.8dB

2ND = –94.3dB

3RD = –108.5dB

4TH = –105.7dB

Figure 17. 16K Point FFT

CODE

1.0

0.8

–1.0

0

20000

65535

40000

–0.4

–0.8

–0.6

0

–0.2

0.6

0.2

0.4

Figure 14. Integral Nonlinearity Error

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100

–110

–120

–130

0

0

409.0268

FREQUENCY – kHz

Figure 18. Modulator Output (0 to 409.0268 kHz)

Figure 19. 16K Point FFT

Figure 20. 16K Point FFT

0

–154

–20

–80

–100

–120

–140

–40

–60

0E+0

10E+3 20E+3 30E+3 40E+3 50E+3 60E+3

70E+3 80E+3

98E+3

AIN = 90kHz

CLKIN = 13MHz

SNR = 89.6dB

S/(N+D) = 89.6dB

SFDR = –108.0dB

90E+3

0

–154

–20

–80

–100

–120

–140

–40

–60

0E+0

10E+3 20E+3 30E+3 40E+3 50E+3 60E+3 70E+3 80E+3

96E+3

AIN = 90kHz

XTAL = 12.288MHz

SNR = 88.1dB

S/(N+D) = 88.1dB

SFDR = –103.7dB

90E+3