LTC1562CN Datasheet, PDF (1/28 Pages) Linear Integrated Systems – Very Low Noise, Low Distortion Active RC Quad Universal Filter

LTC1562
Very Low Noise, Low Distortion
Active RC Quad Universal Filter
FEATURES
DESCRIPTIO
s _{Continuous Time—No Clock}
s _{Four 2nd Order Filter Sections, 10kHz to 150kHz}
Center Frequency
s _{±0.5% Typical Center Frequency Accuracy}
s _{±0.3% Typical Center Frequency Accuracy (A Grade)}
s _{Wide Variety of Response Shapes}
s _{Lowpass, Bandpass and Highpass Responses}
s _{103dB Typical S/N, ±5V Supply (Q = 1)}
s _{97dB Typical S/N, Single 5V Supply (Q = 1)}
s _{96dB Typical S/(N + THD) at ±5V Supply, 20kHz Input}
s _{Rail-to-Rail Input and Output Voltages}
s _{DC Accurate to 3mV (Typ)}
s _{“Zero-Power” Shutdown Mode}
s _{Single or Dual Supply, 5V to 10V Total}
U ^{s Resistor-Programmable fO, Q, Gain}
APPLICATIO S
s _{High Resolution Systems (14 Bits to 18 Bits)}
s _{Antialiasing/Reconstruction Filters}
s _{Data Communications, Equalizers}
s _{Dual or I-and-Q Channels (Two Matched 4th Order}
Filters in One Package)
s _{Linear Phase Filtering}
s _{Replacing LC Filter Modules}
The LTC^®1562 is a low noise, low distortion continuous-time
filter with rail-to-rail inputs and outputs, optimized for a
center frequency (f_O) of 10kHz to 150kHz. Unlike most
monolithic filters, no clock is needed. Four independent 2nd
order filter blocks can be cascaded in any combination, such
as one 8th order or two 4th order filters. Each block’s
response is programmed with three external resistors for
center frequency, Q and gain, using simple design formulas.
Each 2nd order block provides lowpass and bandpass out-
puts. Highpass response is available if an external capacitor
replaces one of the resistors. Allpass, notch and elliptic
responses can also be realized.
The LTC1562 is designed for applications where dynamic
range is important. For example, by cascading 2nd order
sections in pairs, the user can configure the IC as a dual 4th
order Butterworth lowpass filter with 94dB signal-to-noise
ratio from a single 5V power supply. Low level signals can
exploit the built-in gain capability of the LTC1562. Varying the
gain of a section can achieve a dynamic range as high as
118dB with a ±5V supply.
Other cutoff frequency ranges can be provided upon request.
Please contact LTC Marketing.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Dual 4th Order 100kHz Butterworth Lowpass Filter
R_IN1
10k
V_IN2
5V
0.1µF
R_IN3
10k
V_IN1
R_IN2, 10k
R_Q1, 5.62k
R21, 10k
R23, 10k
R_Q3, 5.62k
1
INV B
2
V1 B
3
V2 B
20
INV C
19 ^{RQ2, 13k}
V1 C
18 ^{R22, 10k}
V2 C
5 _{V+ LTC1562 V–} 16
6
SHDN
15
AGND
0.1µF
8
V2 A
9
V1 A
10
INV A
13
V2 D
12
V1 D
11
INV D
R24, 10k
R_Q4, 13k
1562 TA01
V_OUT2
–5V
SCHEMATIC INCLUDES PIN
NUMBERS FOR 20-PIN PACKAGE.
PINS 4, 7, 14, 17 (NOT SHOWN)
ALSO CONNECT TO V ^–
V_OUT1
SEE TYPICAL APPLICATIONS
FOR OTHER CUTOFF FREQUENCIES
DC ACCURATE, NONINVERTING,
UNITY-GAIN, RAIL-TO-RAIL
INPUT AND OUTPUTS. PEAK
SNR ≈ 100dB WITH ±5V SUPPLIES
R_IN4, 10k
10
0
–10
–20
–30
–40
–50
–60
–70
–80
10k
Amplitude Response
100k
FREQUENCY (Hz)
1M
1562 TA03b
1562fa
1