LTC1164-8_09 Datasheet, PDF (12/12 Pages) Linear Technology – Ultraselective, Low Power 8th Order Elliptic Bandpass Filter with Adjustable Gain

LTC1164-8
TYPICAL APPLICATION
Tone Detector — Detecting a Low Level Signal Buried in Wideband Noise
f_CLK
1
14
R_IN
V_IN
2
13
3
12
5V
0.1μ₊F
1μF
4 _LTC1164-8 11
5
10
6
9
7
8
5V
30.1k
AGND (2V)
C_F
R_F
61.9k
–
1/2 LT1413
+
4
C1 ^R1
10k
5V
R2
10k
5V
0.1μF
–⁸
1/2 LT1413
+
REF1
1.9V
18
1
STROBE
LTC1040
5+
6^–
7 ⁺ COMP1
8^–
0.1μF
4
0.1μF _1k
FOR OPTIMUM TONE DETECTION, THE SIGNAL’S FREQUENCY SHOULD BE IN THE
REF1 (1.9V) FILTER’S PASSBAND AND WITHIN ±0.1% FROM f_CENTER.
AT V_OUT, LOGIC HIGH = SIGNAL AT V_IN, LOGIC LOW = NO SIGNAL AT V_IN.
0.1μF _8.87k
THE MINIMUM DETECTABLE SIGNAL AT V_IN: V_IN(MIN) = 200mV_RMS/GAIN.
THE MAXIMUM NOISE SPECTRAL DENSITY AT V_IN: V_IN = 32mV_RMS/[GAIN • √(BW)_f] R3
REF2 (1V)
WHERE: (BW)_f = 0.01 • f_CENTER AND IS THE NOISE EQUIVALENT BANDWIDTH
10k
OF THE FILTER
0.1μF _10k
GAIN = 340k/R_IN AND IS THE FILTER GAIN AT f_CENTER
R_IN = 340k/GAIN; f_CENTER = f_CLK/100; 1/(2π • R_F • C_F) ≥ 10 • f_CENTER
1/(2π • R1 • C1) ≤ f_CENTER/10; 1/(2π • R3 • C2) ≤ f_CENTER/32
14
C2
REF2
1V
13
12
11
+
–
+ COMP2
–
15
V_OUT
LTC1164-8 • TA04
RELATED PARTS
PART NUMBER
LTC1064
DESCRIPTION
Universal Filter Building Block
LTC1164
Universal Filter Building Block
LTC1264
Universal Filter Building Block
See Table 4 for additional information
COMMENTS
This Part, with External Resistors, Allows Design of Bandpass Filters Similar to
LTC1164-8 (Up to 50kHz)
This Part, with External Resistors, Allows Design of Bandpass Filters Similar to
LTC1164-8 (Low Power Up to 20kHz)
This Part, with External Resistors, Allows Design of Bandpass Filters Similar to
LTC1164-8 (Up to 100kHz)
12 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417^● [phone]
FAX: [phone]^● TELEX: 499-3977 ^● www.linear-tech.com
11648fb
LT 10/09 REV B • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 1995