LTC1064_15 Datasheet, PDF (1/20 Pages) Linear Technology – Low Noise, Fast, Quad Universal Filter Building Block

LTC1064
Low Noise, Fast, Quad
Universal Filter Building Block
FEATURES
DESCRIPTIO
■ _{Four Filters in a 0.3 Inch Wide Package}
■ _{Maximum Center Frequency: 140kHz}
■ _{Customized Version with Internal Resistors}
Available
■ _{One Half the Noise of the LTC1059/LTC1060/}
LTC1061 Devices
■ _{Maximum Clock Frequency: 7MHz}
■ _{Clock-to-Center Frequency Ratio of 50:1 and 100:1}
Simultaneously Available
■ _{Power Supplies: ±2.375V to ±8V}
■ _{Low Offsets}
■ _{Low Harmonic Distortion}
■ _{Available in 24-Pin DIP and SO Wide Packages}
U
APPLICATIO S
■ _{Anti-Aliasing Filters}
■ _{Wide Frequency Range Tracking Filters}
■ _{Spectral Analysis}
■ _{Loop Filters}
The LTC^®1064 consists of four high speed, low noise
switched-capacitor filter building blocks. Each filter build-
ing block, together with an external clock and three to five
resistors can provide various 2nd order functions like
lowpass, highpass, bandpass and notch. The center fre-
quency of each 2nd order function can be tuned with an
external clock, or a clock and resistor ratio. For Q ≤ 5, the
center frequency range is from 0.1Hz to 100kHz. For Q ≤
3, the center frequency range can be extended to 140kHz.
Up to 8th order filters can be realized by cascading all four
2nd order sections. Any classical filter realization (such as
Butterworth, Cauer, Bessel and Chebyshev) can be formed.
A customized monolithic version of the LTC1064 includ-
ing internal thin film resistors can be obtained for high
volume applications. Consult LTC Marketing for details.
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
Clock-Tunable 8th Order Cauer Lowpass Filter with f_CUTOFF up to 100kHz
13k
22.1k
V_IN
10k
18.25k
10.7k
8V
(FROM
R_H2, R_L2)
0.1µF
10k
49.9K
11.5K
66.5k
1 _{INV B}
INV C ²⁴
2 _{HPB/NB HPC/NC} 23
3 _BPB
BPC ²²
4 _LPB
LPC ²¹
5 _SB
SC ²⁰
6 _AGND
V^{– 19}
7 _V+ ^LTC1064 _CLK 18
8 _SA
50/100 ¹⁷
9 _LPA
LPD ¹⁶
10 _BPA
BPD ¹⁵
11 _HPA/NA
HPD ¹⁴
12 _{INV A}
INV D ¹³
10k
12.1k
17.4k
5MHz
8V
41.2k
12.7k
14k
121k
R_H2
102k
R_L2
26.7k
0.1µF
PIN 12
– 8V
V_OUT
10k
FOR f_CLK = 5MHz, ADD C1 = 10pF BETWEEN PINS 4, 1
C2 = 10pF BETWEEN PINS 21, 24
C3 = 27pF BETWEEN PINS 9, 12
WIDEBAND NOISE ≅ 140µV_RMS
1064 TA01
Gain vs Frequency
0
–15
–30
–45
f_CLK = 5MHz
–60 ^{RIPPLE = ±0.1dB}
–75
–90
–105
f_CLK = 1MHz
RIPPLE = ±0.05dB
–120
–135
1k
10k
100k
INPUT FREQUENCY (Hz)
1M
1064 TA02
1064fb
1