LTC1563-2 LINER [Linear Technology], LTC1563-2 Datasheet - Page 14

• Manufacturer Part Number: LTC1563-2
• Description: Active RC, 4th Order Lowpass Filter Family
• Manufacturer: LINER [Linear Technology]

LTC1563-2/LTC1563-3
APPLICATIONS
4th Order Filter Responses Using the LTC1563-3
14
Figure 6. 4th Order Filter Connections (Power Supply, Ground,
EN and LP Connections Not Shown for Clarity). Table 2 Shows
Resistor Values
V
IN
R11
1.2
1.0
0.8
0.6
0.4
0.2
R31
R21
0
0
Table 2. Resistor Values, Normalized to 256kHz Cutoff Frequency (f
Gain, of the 4th Order LTC1563-3 Lowpass Filter, Is Set to Unity. (Note 1)
Note 1: The resistor values listed in this table provide good approximations of the listed transfer functions. For the
optimal resistor values, higher gain or other transfer functions, use FilterCAD Version 3.0 (or newer) or contact the
Linear Technology Filter Applications group for assistance.
Figure 6b. Step Response
0.5
U
1
2
3
4
5
6
7
8
LP Mode Max f
HS Mode Max f
R11 = R21 =
R31 =
R12 = R22 =
R32 =
LP
SA
NC
INVA
NC
LPA
AGND
V
–
LTC1563-3
1.0
INFORMATION
U
TIME (s)
NORMALIZED TO f
1.5
INVB
LPB
NC
NC
SB
NC
EN
V
BESSEL
TRANSITIONAL
GAUSSIAN TO 12dB
TRANSITIONAL
GAUSSIAN TO 6dB
+
C
C
16
15
14
13
12
11
10
9
2.0
W
2.5
C
R22
R32
= 1Hz
10k(256kHz/f
10k(256kHz/f
10k(256kHz/f
10k(256kHz/f
1563 F06b
BESSEL
25.6kHz
256kHz
3.0
1563 F06
R12
U
V
OUT
C
C
C
C
)
)
)
)
GAUSSIAN TO 6dB
17.4k(256kHz/f
13.3k(256kHz/f
14.3k(256kHz/f
6.04k(256kHz/f
TRANSITIONAL
175kHz
20kHz
1.05
1.00
0.95
–20
–40
–60
–80
–90
10
0
0.1
C
C
C
C
0
Figure 6c. Step Response—Settling
)
)
)
)
NORMALIZED TO f
Figure 6a. Frequency Response
C
), Figure 6. The Passband
BESSEL
TRANSITIONAL
GAUSSIAN TO 12dB
TRANSITIONAL
GAUSSIAN TO 6dB
BESSEL
TRANSITIONAL
GAUSSIAN TO 12dB
TRANSITIONAL
GAUSSIAN TO 6dB
0.5
FREQUENCY (Hz)
GAUSSIAN TO 12dB
11.8k(256kHz/f
10.5k(256kHz/f
6.19k(256kHz/f
TRANSITIONAL
15k(256kHz/f
NORMALIZED TO f
TIME (s)
C
= 1Hz
1.0
185kHz
1
21kHz
C
1.5
C
C
C
)
)
)
)
C
= 1Hz
1563 F06a
1563 F06c
2.0
10
156323fa