lt1568 Linear Technology Corporation, lt1568 Datasheet - Page 13

• Manufacturer Part Number: lt1568
• Description: Very Low Noise, High Frequency Active Rc, Filter Building Block
• Manufacturer: Linear Technology Corporation

DUAL 2nd ORDER LOWPASS FILTER DESIG S
Amplitude Response 2nd Order Lowpass Chebyshev,
2nd Order Lowpass Bessel, f
0.25dB Passband Ripple, f
–20
–30
–50
–60
–70
–80
–90
–10
–40
–20
–30
–50
–70
–80
–90
–10
–40
–60
10
10
0
0
0.1
0.1
Amplitude Response
FREQUENCY (MHz)
FREQUENCY (MHz)
1
1
Table 2. Resistor Values in Ohms, Dual 2nd Order Lowpass
Chebyshev, 0.25dB Passband Ripple, Gain = 1, R11 = R12,
R21 = R22, R31 = R32
Table 3. Resistor Values in Ohms, Dual 2nd Order Lowpass
Bessel, Gain = 1
CUTOFF
CUTOFF
f
CUTOFF
10
1568 TA09
10
1568 TA11
f
CUTOFF
= 1MHz
20
20
1
2
3
4
5
6
7
(MHz)
= 1MHz
1
2
3
4
5
6
7
(MHz)
R11, R21
976
475
316
226
178
143
121
R11, R21
866
422
280
210
165
137
115
Transient Response 2nd Order Lowpass Chebyshev,
500mV/DIV
200mV/DIV
500mV/DIV
200mV/DIV
OUTPUT
OUTPUT
INPUT
INPUT
2nd Order Lowpass Bessel, f
U
0.25dB Passband Ripple, f
825
412
274
205
165
137
118
R31
1180
590
383
287
232
191
162
R31
Transient Response
1 s/DIV
1 s/DIV
CUTOFF
CUTOFF
1568 TA12
1568 TA10
= 1MHz
= 1MHz
LT1568
13
1568f