LTC1164-8
Ultraselective, Low Power
8th Order Elliptic Bandpass Filter
with Adjustable Gain
FEATURES
s
s
s
s
s
s
DESCRIPTION
The LTC
®
1164-8 is a monolithic ultraselective, 8th order,
elliptic bandpass filter. The passband of the LTC1164-8 is
tuned with an external clock and the clock-to-center fre-
quency ratio is 100:1. The – 3dB pass bandwidth is typi-
cally 1% of the filter center frequency. The stopband
attenuation of the LTC1164-8 is greater than 50dB. The
lower and upper stopband frequencies are less than
0.96 • center frequency and greater than 1.04 • center
frequency, respectively.
The LTC1164-8 requires an external op amp and two
external resistors (see the circuit below). The filter’s gain
at center frequency is set by the ratio R
IN
/R
F
. For a gain
equal to one and an optimum dynamic range, R
F
should be
set to 61.9k and R
IN
should be 340k. For gains other than
one, R
IN
= 340k/Gain. Gains up to 1000 are obtainable.
Setting the filter’s gain with input resistor R
IN
does not
increase the filter’s wideband noise. The 270µV
RMS
wideband noise of the LTC1164-8 is independent of the
filter’s center frequency.
The LTC1164-8 is available in a 14-pin PDIP or a 16-pin
surface mount SO Wide package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
Ultraselectivity
(50dB Attenuation at
±4%
of Center Frequency)
Adjustable Passband Gain
Noise Independent of Gain
Filter Noise: 270µV
RMS
, V
S
= Single 5V Supply
Clock-Tunable (Center Frequency = f
CLK
/100)
Center Frequencies up to 5kHz, V
S
=
±5V
(Typical I
SUPPLY
= 3.2mA)
Center Frequencies up to 4kHz, V
S
= Single 5V Supply
(Typical I
SUPPLY
= 2.3mA)
APPLICATIONS
s
s
s
s
Asynchronous Narrowband Signal Detectors
Low Frequency Asynchronous Demodulators
Handheld Spectrum Analyzers
In-Band Tone Signaling Detectors
TYPICAL APPLICATION
Ultranarrow 1kHz Bandpass Filter with Gain = 10
Gain = 340k/R
IN
, 1/(2π • R
F
• C
F
)
≥
10 • Center Frequency
R
IN
34k
V
IN
5V
1
2
3
4
5
6
7
LTC1164-8
14
13
11
10
9
8
3
SHORT CONNECTION UNDER IC AND
SHIELDED BY A GROUND PLANE
2
GAIN (dB)
30
20
10
0
C
F
200pF
R
F
61.9k
5V
12
–5V
100kHz
–10
–20
–30
–40
–
®
7
6
V
OUT
LT 1006
–50
–60
+
4
–5V
LTC1164-8 • TA01
–70
0.90
U
U
U
Frequency Response
50dB
0.95
1.05
1.00
FREQUENCY (kHz)
1.10
1.15
1164-8 TA02
1
LTC1164-8
ABSOLUTE
MAXIMUM
RATINGS
Total Supply Voltage (V
+
to V
–
)........................... 16.5V
Power Dissipation............................................. 700mW
Burn-In Voltage ................................................... 16.5V
Voltage at Any Input .... (V
–
– 0.3V)
≤
V
IN
≤
(V
+
+ 0.3V)
Operating Temperature Range* .................. 0°C to 70°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
Maximum Clock Frequency
V
S
=
±7.5V
.................................................... 720kHz
V
S
=
±5V
....................................................... 540kHz
V
S
= Single 5V ............................................... 430kHz
*For an extended operating temperature range contact LTC Marketing for
details.
PACKAGE/ORDER INFORMATION
TOP VIEW
NC
INVB
AGND
V
+
AGND
NC
INVA
1
2
3
4
5
6
7
N PACKAGE
14-LEAD PDIP
T
JMAX
= 110°C,
θ
JA
= 65°C/ W
ORDER PART
NUMBER
14 R(h, l)
13 NC
12
V
–
LTC1164-8CN
11 f
CLK
10 NC
9
8
I
OUT
NC
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
PARAMETER
Gain at Center Frequency
V
S
=
±2.375V
V
S
=
±5V
Gain at 0.995 • Center Frequency and
1.005 • Center Frequency
(Referenced to Gain at Center Frequency)
Lower Stopband Attenuation
(Referenced to Gain at Center Frequency)
V
S
=
±2.375V
V
S
=
±5V
V
S
=
±2.375V
(See Test Circuit)
T
A
= 25°C, Center Frequency = f
CLK
/100, f
CLK
= 100kHz (the clock signal is a TTL or CMOS square wave, clock rise or fall time
≤
1µs),
the AC test signal level is 1V
RMS
for V
S
=
±5V
or 0.5V
RMS
for V
S
=
±2.375V,
unless otherwise specified.
CONDITIONS
f
IN
= 1000Hz
q
V
S
=
±5V
2
U
U
W
W W
U
W
TOP VIEW
NC
INVB
AGND
V
+
AGND
NC
NC
INVA
1
2
3
4
5
6
7
8
16 R(h, l)
15 NC
14 V
–
13 NC
12 f
CLK
11 NC
10 NC
9
I
OUT
ORDER PART
NUMBER
LTC1164-8CSW
SW PACKAGE
16-LEAD PLASTIC SO WIDE
T
JMAX
= 110°C,
θ
JA
= 85°C/ W
MIN
–3
–4
–3
–4
–9
–9
TYP
0
±
1.5
0
±
2.0
0
±
1.5
0
±
2.0
MAX
3
4
3
4
3
3
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
f
IN
= 1000Hz
q
f
IN
= 995Hz
f
IN
= 1005Hz
f
IN
= 995Hz
f
IN
= 1005Hz
f
IN
= 960Hz (Note 1)
f
IN
= 800Hz
f
IN
= 960Hz (Note 1)
f
IN
= 800Hz
q
q
q
– 48
– 50
– 48
– 48
– 3
±2
– 3
±2
– 52
– 52
– 52
– 52
– 58
– 60
LTC1164-8
ELECTRICAL CHARACTERISTICS
PARAMETER
Upper Stopband Attenuation
(Referenced to Gain at Center Frequency)
V
S
=
±2.375V
(See Test Circuit)
T
A
= 25°C, Center Frequency = f
CLK
/100, f
CLK
= 100kHz ( the clock signal is a TTL or CMOS square wave, clock rise or fall time
≤
1µs),
the AC test signal level is 1V
RMS
for V
S
=
±5V
or 0.5V
RMS
for V
S
=
±2.375V,
unless otherwise specified.
CONDITIONS
f
IN
= 1040Hz (Note 1)
f
IN
= 1200Hz
q
MIN
– 48
– 50
– 48
– 48
TYP
– 52
– 52
– 52
– 52
1.0
2.5
– 40
±50
– 50
±60
2.3
MAX
– 58
– 60
UNITS
dB
dB
dB
dB
dB
V
RMS
V
RMS
mV
mV
V
S
=
±5V
Maximum Output for < 0.25%
Total Harmonic Distortion
Output DC Offset
Power Supply Current (Note 2)
V
S
=
±2.5V
V
S
=
±5V
f
IN
= 1040Hz (Note 1)
f
IN
= 1200Hz
f
IN
= 1000Hz
f
IN
= 1000Hz
V
S
=
±2.5V
(At the Output of External Op Amp)
V
S
=
±5V
V
S
=
±2.375V
q
4.0
4.5
7.0
8.0
11.0
12.5
±8
mA
mA
mA
mA
mA
mA
V
V
S
=
±5V
q
3.2
4.5
q
V
S
=
±7.5V
Power Supply Range
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
The minimum stopband attenuation at 960Hz and 1040Hz is
guaranteed by design and test correlation.
±2.375
Note 2:
The maximum current over temperature is at 0°C. At 70°C the
maximum current is less than its maximum value at 25°C.
TYPICAL PERFORMANCE CHARACTERISTICS
Gain vs Frequency
T
A
= 25°C
0 V
S
=
±5V
= 100kHz
f
–10
CLK
–20
GAIN (dB)
10
GAIN (dB)
–6
–9
–12
–15
–18
990
V
S
=
±7.5V
GAIN (dB)
–30
–40
–50
–60
–70
–80
–90
760
880
1120
1000
FREQUENCY (Hz)
1240
LTC1164-8 • TPC01
U W
Passband Variations
vs Power Supply
f
CLK
= 100kHz
GAIN = 1
0 R = 340k
IN
R
F
= 61.9k
–3
3
Passband Gain and Phase
vs Frequency
6
V
S
=
±2.5V
3
0
–3
T
A
= 25°C
V
S
=
±5V
f
CLK
= 100kHz
180
120
60
0
V
S
=
±5V
PHASE (DEG)
–6
–9
–12
–15
–18
–21
–24
–60
–120
–180
–240
–300
–360
984
992
1008
1000
FREQUENCY (Hz)
1016
LTC1164-8 • TPC03
995
1000
FREQUENCY (Hz)
1005
1010
–420
LTC1164-8 • TPC02
3
LTC1164-8
TYPICAL PERFORMANCE CHARACTERISTICS
Passband Gain and Delay
vs Frequency
T
A
= 25°C
3 V
S
=
±5V
= 100kHz
f
0
CLK
–3
GAIN (dB)
6
20 LOG (THD + NOISE/V
IN
) (dB)
80
70
DELAY (ms)
–32
–38
–44
–50
–56
–62
–68
–74
–80
0.01
20 LOG (THD + NOISE/V
IN
) (dB)
–6
–9
–12
–15
–18
–21
–24
984
992
1008
1000
FREQUENCY (Hz)
1016
LTC1164-8 • TPC04
THD + Noise vs Input Voltage
T
A
= 25°C
V
S
= SINGLE 5V
f
IN
= 1kHz
–50 f
CLK
= 100kHz
FILTER GAIN AT f
CENTER
= 1
OUTPUT OP AMP IS LT1006
–60
–40
5.0
POWER SUPPLY CURRENT (mA)
20 LOG (THD + NOISE/V
IN
) (dB)
OUTPUT LEVEL (dBV)
AGND AT 2.5V
AGND AT 2V
–70
–80
0.5
1.0
1.5
2.0
2.5
INPUT VOLTAGE (V
P-P
)
3.0
3.5
4
U W
LTC1164-8 • TPC07
THD + Noise vs Input Voltage
100
90
–20
–26
T
A
= 25°C
V
S
=
±5V
f
IN
= 1kHz
f
CLK
= 100kHz
FILTER GAIN AT f
CENTER
= 1
OUTPUT OP AMP IS LT1006
–20
–26
–32
–38
–44
–50
–56
–62
–68
–74
0.1
1
INPUT VOLTAGE (V
RMS
)
5
THD + Noise vs Input Voltage
T
A
= 25°C
V
S
= SINGLE 5V
f
IN
= 1kHz
f
CLK
= 100kHz
FILTER GAIN AT f
CENTER
= 1
OUTPUT OP AMP IS LT1006
AGND = 2.5V
AGND = 2V
60
50
40
30
20
10
0
–80
0.01
0.1
INPUT VOLTAGE (V
RMS
)
1
2
LTC1164-8 • TPC05
LTC1164-8 • TPC06
Power Supply Current
vs Power Supply Voltage
10
25°C
4.0
70°C
3.0
Output vs Input
0
–10
–20
–30
–40
–50
V
S
= SINGLE 5V
(PINS 3, 5 AT 2V)
f
CLK
= 100kHz
f
CENTER
= 1kHz
f
IN
= 1kHz
2.0
1.0
V
S
=
±
5V
0
0
0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4 7.2 8.0
POWER SUPPLY VOLTAGE (V
+
OR V
–
)
LTC1164-8 • TPC08
–60
–60 –50
–40 –30 –20 –10
INPUT LEVEL (dBV)
0
10
LTC1164-8
• TPC09
LTC1164-8
PIN FUNCTIONS
V
+
, V
–
(Pins 4, 12):
Power Supply Pins. The V
+
(Pin 4)
and the V
–
(Pin 12) should be bypassed with a 0.1µF
capacitor to a reliable ground plane. The filter’s power
supplies should be isolated from other digital or high
voltage analog supplies. A low noise linear supply is
recommended. Using a switching power supply will
lower the signal-to-noise ratio of the filter. The power
supply during power-up should have a slew rate of less
than 1V/µs.
For dual supply operation if the V
+
supply is applied before
the V
–
supply or the V
–
supply is applied before the V
+
supply, a signal diode on each supply pin to ground will
prevent latchup. Figures 1 and 2 show typical connections
for dual and single supply operation.
f
CLK
(Pin 11):
Clock Input Pin. Any TTL or CMOS clock
source with a square wave output and 50% duty cycle
(±10%) is an adequate clock source for the device. The
V
IN
7
8
Figure 1. Dual Power Supply Operation (Gain = 1)
R
F
61.9k
5V
f
CLK
R
IN
340k
V
IN
1
2
3
14
13
12
LTC1164-8
11
10
5V
0.1µF
15k
4
5
6
7
+
1µF
10k
8
Figure 2. Single Power Supply Operation (Gain = 1)
+
3
–
9
2
+
*FOR SURFACE MOUNT CIRCUITS
USE MOTOROLA DIODE MBR0530
OR EQUIVALENT
3
–
5V
*1N4148
OR EQUIVALENT
U
U
U
(14-Lead PDIP)
power supply for the clock source should not be the filter’s
power supply. The analog ground for the filter should be
connected to the clock’s ground at a single point only.
Table 1 shows the clock’s low and high level threshold
values for dual or single supply operation. A pulse genera-
tor can be used as a clock source provided the high level
on-time is at least 1µs. Sine waves are not recommended
for clock input frequencies less than 100kHz. The clock’s
rise or fall time should be equal to or less than 1µs.
Table 1. Clock Source High and Low Threshold Levels
POWER SUPPLY
Single Supply = 5V
Single Supply = 12V
Dual Supply =
±2.5V
Dual Supply =
±5V
Dual Supply =
±7.5V
HIGH LEVEL
>1.45V
>7.80V
>0.73V
>1.45V
>2.18V
LOW LEVEL
<0.5V
<6.5V
<– 2.0V
<0.5V
<0.5V
R
IN
340k
1
2
3
4
LTC1164-8
14
13
12
11
10
9
f
CLK
0.1µF
–5V
1N4148*
OR EQUIVALENT
2
R
F
61.9k
5V
0.1µF
7
6
4
0.1µF
–5V
V
OUT
LTC1164-8 • F01
0.1µF
5
6
0.1µF
7
6
4
LTC1164-8 • F02
V
OUT
5
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