LTC1068 Linear Technology, LTC1068 Datasheet - Page 16

• Manufacturer Part Number: LTC1068
• Description: Clock-Tunable/ Quad Second Order/ Filter Building Blocks
• Manufacturer: Linear Technology

APPLICATIONS
LTC1068 Series
A Surface Mount Printed Circuit Layout
A very compact surface mount printed circuit layout can
be designed with 0603 size surface mount resistors,
capacitors and a 28-pin SSOP of the LTC1068 product
family. An example of a printed circuit layout is shown in
16
FilterCAD Custom Inputs for f
2nd ORDER SECTION
D
B
C
A
U
70kHz Elliptic Bandpass Filter, f
5V
V
IN
67.7624
67.0851
73.9324
73.3547
f
O
INFORMATION
(kHz)
R11 29.4k
C
U
= 70kHz
R61 11.3k
20.5500
15.1339
16.3491
5.7236
R43 43.2k
R23 4.99k
R21 4.99k
R31 24.9k
R41 20.5k
Q
R33 59k
W
0.1 F
45.3K
4.99k
C1
R51
R
L3
f
58.3011
81.6810
81.0295
N
(kHz)
U
10
11
12
13
14
1
2
3
4
5
6
7
8
9
CENTER
INV B
HPB/NB
BPB
LPB
NC
NC
SA
LPA
BPA
HPA/NA
INV A
SB
AGND
V
+
TYPE
HPN
LPN
LPN
BP
LTC1068-25
R
R
= f
H1
H3
U1
CLK
15.4k
28k
HPD/ND
HPC/NC
/25 (Maximum f
INV C
INV D
the folowing figures for an 8th order elliptic bandpass
filter. The total board area of this 8th order filter is 1" by
0.8". No attempt was made to design the smallest possible
printed circuit layout.
BPC
CLK
LPD
BPD
LPC
MODE
SC
V
NC
NC
SD
1bn
–
2b
2n
2b
28
27
26
25
24
23
22
21
20
19
18
17
16
15
R52
4.99k
R54
4.99k
R34 63.4k
C2
0.1 F
R44 17.4k
R64 10k
CENTER
R24 7.5k
R22 4.99k
R
R
R32 107k
L2
H2
R62 56.2k
23.2k
11.3k
–10
–20
–30
–40
–50
–60
–70
–80
–90
is 80kHz, V
10
0
20
30
1068 TA07a
Gain vs Frequency
S
40
V
1.75MHz
–5V
OUT
= 5V)
FREQUENCY (kHz)
50
60
70
80
90
1068 TA07b
100