MAX2108 Maxim, MAX2108 Datasheet - Page 7

• Manufacturer Part Number: MAX2108
• Description: Direct-Conversion Tuner IC
• Manufacturer: Maxim

The MAX2108 has several +5V supply pins. Configure
the supply layout in a star format, with a bypass capac-
itor that dominates the rise time of the supply at the
center of the star to ensure that all pins see approxi-
mately the same voltage during power-up.
Table 1. Suggested Component Values for Discrete Lowpass Filters
SAMPLING
(Msps)
RATE
ADC
40
60
90
_______________________________________________________________________________________
0.1dB Chebyshev,
0.1dB Chebyshev,
0.1dB Chebyshev,
0.1dB Chebyshev,
FILTER TYPE
Power-Supply Sequencing
f
f
f
f
C
C
C
C
= 20MHz
= 30MHz
= 20MHz
= 45MHz
(Ω)
R
50
50
50
50
S
(pF)
C1
20
11
15
Direct-Conversion Tuner IC
9
(nH)
910
620
680
390
L1
Typically, a 5th- or 7th-order L-C lowpass filter is used
for anti-aliasing the ADCs following the MAX2108.
Table 1 offers suggested component values for these
lowpass filters. Figures 1 and 2 describe typical filtering
requirements.
(pF)
C2
60
41
39
28
Filters in Direct-Conversion Tuners
1500
(nH)
910
820
620
L2
(pF)
C3
75
50
33
34
1500
1000
Short
(nH)
680
L3
Open
(pF)
C4
60
41
28
(kΩ)
R
20
20
20
20
L
7