LTC1066-1 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC1066-1
Linear Technology
'LTC1066-1' PDF : 20 Pages View PDF
LTC1066-1
TYPICAL APPLICATIO
DC Accurate Lowpass Filter with Input Anti-Aliasing
(fCLK ≤ 250kHz)
2ND ORDER BUTTERWORTH ANTI-
ALIASING FILTER PROVIDES –68dB
ATTENUATION TO INPUTS AT 2fCLK
C2
R1
VIN
R2
C1
fCUTOFF
=
fCLK
50
,
1
2πRFCF
=
fCUTOFF
250
20Ω
–7.5V
f–3dB = 2•fCUTOFF (f–3dB IS THE –3dB FREQUENCY OF THE
2ND ORDER ANTI-ALIASING FILTER)
2π(R1
1
+
R2)C1
=
0.707
•f–
3dB,
R2
=
17.946•R1,
C2
=
10
•C1
0.1µF
7.5V
0.1µF
FOR CUTOFF FREQUENCIES 2kHz TO 5kHz, SET RF = 20k,
CF = 1µF AND R1 + R2 ≤ 2k
FOR CUTOFF FREQUENCIES <2kHz, SET R1 + R2 = RF
fCLK
FOR EXAMPLE:
IF THE CUTOFF FREQUENCY OF LTC1066-1 IS 500Hz, THEN
f–3dB = 1000Hz
1
2πRFCF
=
2Hz,
SET
RF
=
80.6k,
CF
=
1µF
AND
C1
=
0.0027µF
R1 + R2 = 80.6k, R1 = 4.22k AND R2 = 76.8k ROUNDED TO NEAREST 1% VALUE.
C2 = 0.027µF ROUNDED TO NEAREST STANDARD VALUE.
NOTE: RF SHOULD BE ≤100k TO MINIMIZE DC OFFSET TO ±5.5mV
RF
7.5V
CF
1 OUT A
V+ 18
2 –IN A
OUT B 17
3 +IN A
+IN B 16
4 V–
LTC1066-1 GND 15
5 V+
FILTERIN 14
6 CONNECT 1
COMP 2 13
7 FILTEROUT
8 50/100
CONNECT 2 12
COMP 1 11
9 CLK
V– 10
0.1µF
20Ω
VOUT
0.1µF
– 7.5V
1066-1 TA05
10661fa
16
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