Datasheet

AD9761
–4–
AD9761
–5–
DIGITAL FILTER SPECIFICATIONS
(T
MIN
to T
MAX
, AVDD = 2.7 V to 5.5 V, DVDD = 2.7 V to 5.5 V, I
OUTFS
= 10 mA, unless
otherwise noted.)
Parameter Min Typ Max Unit
MAXIMUM INPUT CLOCK RATE (f
CLOCK
) 40 MSPS
DIGITAL FILTER CHARACTERISTICS
Pass Bandwidth
1
: 0.005 dB 0.2010 f
OUT
/f
CLOCK
Pass Bandwidth: 0.01 dB 0.2025 f
OUT
/f
CLOCK
Pass Bandwidth: 0.1 dB 0.2105 f
OUT
/f
CLOCK
Pass Bandwidth: –3 dB 0.239 f
OUT
/f
CLOCK
Linear Phase (FIR Implementation)
Stop-Band Rejection: 0.3 f
CLOCK
to 0.7 f
CLOCK
–62.5 dB
Group Delay
2
32 Input Clock Cycles
Impulse Response Duration
3
–40 dB 28 Input Clock Cycles
–60 dB 40 Input Clock Cycles
NOTES
1
Excludes SINx/x characteristic of DAC.
2
Dened as the number of data clock cycles between impulse input and peak of output response.
3
55 input clock periods from input to I DAC, 56 to Q DAC. Propagation delay is delay from data input to DAC update.
Specications subject to change without notice.
FREQUENCY RESPONSE (DC to f
CLOCK
/2)
OUTPUT (dBFS)
0
–20
–120
0 0.50.1 0.2 0.3 0.4
–40
–60
–80
–100
Figure 2a. FIR Filter Frequency Response
TIME (Samples)
1
0
0 405 10 15 20 25 30 35
0.9
0.6
0.4
0.2
0.1
0.8
0.7
0.5
0.3
–0.1
–0.2
–0.3
NORMALIZED OUTPUT
Figure 2b. FIR Filter Impulse Response
Table I. Integer Filter Coefcients for 43-Tap Half-Band
FIR Filter
Lower Coefcient Upper Coefcient Integer Value
H(1) H(43) 1
H(2) H(42) 0
H(3) H(41) –3
H(4) H(40) 0
H(5) H(39) 8
H(6) H(38) 0
H(7) H(37) –16
H(8) H(36) 0
H(9) H(35) 29
H(10) H(34) 0
H(11) H(33) –50
H(12) H(32) 0
H(13) H(31) 81
H(14) H(30) 0
H(15) H(29) –131
H(16) H(28) 0
H(17) H(27) 216
H(18) H(26) 0
H(19) H(25) –400
H(20) H(24) 0
H(21) H(23) 1264
H(22) 1998
REV. C
REV. C