LTC1562 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1562' PDF : 28 Pages View PDF
LTC1562
TYPICAL APPLICATIONS (Basic)
8th Order Bandpass Filter, Single 5V Supply,
Center Frequency
– 3dB Bandwidth =
10
CIN1
VIN
5V
0.1µF
RQ1
R21
R23
RQ3
CIN3
RIN2
1
INV B
20
INV C
2
V1 B
19
V1 C
3
V2 B
18
V2 C
5 V+ LTC1562 V– 16
6
SHDN
15
AGND
8
V2 A
13
V2 D
9
V1 A
12
V1 D
10
INV A
11
INV D
RIN4
RQ2
R22
1µF
R24
RQ4
VOUT
1562 TA07a
SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE.
PINS 4, 7, 14, 17 (NOT SHOWN) ALSO CONNECT TO V –
Amplitude Response
10
fCENTER = 80kHz
0
– 10
– 20
– 30
– 40
– 50
– 60
– 70
– 80
– 90
40 48 56 64 72 80 88 96 104 112 120
FREQUENCY (kHz)
1562 TA07b
Quick Design Formulas for Center Frequency fC (Recommended Range 40kHz to 140kHz):
R21
=
R23
=
10.6k
100kHz
ƒC
2
R22
=
R24
=
9.7k
100kHz
ƒC
2
CIN1
=
CIN3
=
159pF
10k
RQ1
RQ1
=
RQ3
=
164.6k
100kHz
ƒC
100kHz
ƒC + 319kHz
RQ2
=
RQ4
=
143.2k
100kHz
ƒC
100kHz
ƒC + 294kHz
RIN2
=
RIN4
=
R22RQ1CIN1
(10k)(10.6pF)
100kHz
ƒC + 286kHz
Notes: RQ1, R22 and CIN1 should be rounded to the nearest standard finite-tolerance value before using these
values in the later formulas.
Example: Center frequency fC of 80kHz. The formulas give R21 = R23 = 16.56k, nearest standard 1% value 16.5k.
RQ1 = RQ3 = 51.56k, nearest 1% value 51.1k. R22 = R24 = 15.15k, nearest 1% value 15k. RQ2 = RQ4 = 47.86k,
nearest 1% value 47.5k. CIN1 = CIN2 = 31.11pF using 51.1k for RQ1, nearest standard 5% capacitor value 33pF.
This and the 1% value R22 = 15k also go into the calculation for RIN2 = RIN4 = 65.20k, nearest 1% value 64.9k.
1562 TA07 TABLE
16
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