of Microprocessors

DIGITAL-TO-ANALOG AND ANALOG-TO-DIGITAL CONVERSION 397
OUTPUT
(DRIVE FROM RI
A ZERO o---""~o-JVv'v1o---j
IMPEDANCE
SOURCE)
OUTPUT
Sample 3-dB R1 C1 C2 R2 C3 C4 R3 C5 C6
Rate" Cutoff (kill (pF) (pF) (kill (pF) (pF) (kil) (pF) (pF)
(kHz) (kHz)
8 2.67 15.2 17,380 7,500 14.9 24,200 1,250 15.4 64,190 250
10 3.33 15.2 13,900 6,000 14.9 19,360 1,000 15.4 51,353 200
12 4.0 15.2 11,590 5,000 14.9 16,133 833 12.8 51,353 200
15 5.0 12.2 11,590 5,000 14.9 12,910 667 10.3 51,353 200
20 6.67 9.14 "1,590 5,000 14.9 9,680 500 7.70 51,353 200
25 8.33 7.31 11,590 5,000 11.9 9,680 500 6.16 51,353 200
30 10.0 6.09 11,590 5,000 9.93 9,680 500 5.13 51,353 200
40 13.3 4.57 11,590 5,000 7.45 9,680 500 3.85 51,353 200
*Filter ftlspOnSe is down 40 dB at 1/2 sampling frequency
(Aj
INPUT
RI
Sample 3-dB Al Cl C2 A2 C3 C' A3 C5 C6 A' C7 C8 A5 C9 C10
Rate' CuloH (klll (pF) (pFl (kill IpF) (pF) (kIll (pF) (pFI (kill (pFJ (pF) (Kll) (pF) (pF;
(kHz) (kHz)
8 3.08 12,74 19.70D 12,500 159917,4002.5001561 22,450 937 13.5740,2504501584 100,000 109
10 3.85 12.74 15,760 10,000 15.9913,9182.000 1561 17,960 750 13.57 32,200 360 1382 91.680 100
12 4,62 12.74 13,130 8,330 15,99 11,600 1,667 1561 14.970 62~ 1357 26.836 300 11 52 91.680 100
15 5,77 1274 10,500 6.667 1599 9,280 1,333 156\ 11,975 500 10.85 26,836 300 9.21 91,680 100
20 7691274 7,880 5,000 1599 6,959 1.000 11 71 ".975 500 8 14 26,836 300 6.91 91,680 100
25 9,62 10,19 7,880 5.000 12,79 6,959 1.000 9.37 11,975 500 6.51 26.836 300 5.53 91,680 100
30 115 8,49 7,880 5,000 10,66 5.959 1,000 781 11.975 500 543 26.836 300 4.61 9\.680 100
40 15 , 6,37 7,B80 5,000 8.00 6,959 1,000 5.85 11,975 500 407 26.836 300 345 91.680 100
'Filler response IS down 50 dB at 1,2 sampling frequency
(8)
Fig. 12-24. Design data for active Chebyshev filters. (A) Three-section 1-d8
ripple. (8) Five-section O.25-d8 ripple.