LTC1064-1_15 Datasheet, PDF (4/8 Pages) Linear Technology – Low Noise, 8th Order, Clock Sweepable Elliptic Lowpass Filter

LTC1064-1
TYPICAL PERFOR A CE CHARACTERISTICS
Gain vs Frequency
15
0
–15
f_CLK = 2MHz, f_C = 20kHz
COMP1 NOT USED,
–30
COMP2 = 20pF
–45
f_CLK = 3MHz, f_C = 30kHz
COMP1 = 24pF
–60
COMP2 = 36pF
f_CLK = 4MHz, f_C = 40kHz
–75
COMP1 = 36pF
COMP2 = 47pF
–90 _{VS = ±5V}
–105 ^{TA = 25°C}
1
10
FREQUENCY (kHz)
100
1064 G04
Typical Wideband Noise
(151µV_RMS) V_S = ± 5V, T_A = 25°C
f_CLK = 1MHz, f_C = 10kHz Input
Grounded
Gain vs Frequency
15
0
–15
f_CLK = 3MHz, f_C = 30kHz
COMP1 = 10pF
–30
COMP2 = 15pF
–45
f_CLK = 4MHz, f_C = 40kHz
COMP1 = 20pF
COMP2 = 30pF
–60
f_CLK = 5MHz, f_C = 50kHz
–75
COMP1 = 30pF
COMP2 = 47pF
–90 _{VS = ±7.5V}
–105 ^{TA = 25°C}
1
10
FREQUENCY (kHz)
100
1064 G05
Total Harmonic Distortion
(0.025%) V_S = ± 7.5V, T_A = 25°C
f_CLK = 1MHz, f_C = 10kHz
Input = 1kHz at 3V_RMS
Gain vs Frequency
5
0
25°C GAIN PEAK =
–5
0.4dB AT 30kHz
–10
–15
–20
–25
–30
V_S = ±7.5V
f_CLK = 5MHz
f_C = 50kHz
125°C GAIN PEAK =
1dB AT 35kHz
COMP1 = 33pF
–35 ^{COMP2 = 56pF}
1
10
FREQUENCY (kHz)
100
1064 G06
Power Supply Current vs Power
Supply Voltage
48
44 ^{fCLK = 1MHz}
40
36
32
28
24
T_A = –55°C
20
T_A = 25°C
16
T_A = 125°C
12
8
4
0
0 2 4 6 8 10 12 14 16 18 20 22 24
TOTAL POWER SUPPLY VOLTAGE (V)
1064 G09
PI FU CTIO S (Pin Numbers Refer to the 14-Pin Package)
COMP1, INV A, COMP2, INV C (Pins 1,6,7, and 13): For
filter cutoff frequencies higher than 20kHz, in order to
minimize the passband ripple, compensation capacitors
should be added between Pin 6 and Pin 7 (COMP1) and
Pin 1 and Pin 13 (COMP2). For COMP1 (COMP2), add 1pF
(1.5pF) mica capacitor for each kHz increase in cutoff
frequency above 20kHz. For more detail refer to Gain vs
Frequency graphs.
V_IN, V_OUT (Pins 2, 9): The input Pin 2 is connected to an
18k resistor tied to the inverting input of an op amp. Pin 2
is protected against static discharge. The device’s output,
Pin 9, is the output of an op amp which can typically source/
sink 3mA/1mA. Although the internal op amps are unity
gain stable, driving long coax cables is not recommended.
When testing the device for noise and distortion, the
output, Pin 9, should be buffered (Figure 4). The op amp
power supply wire (or trace) should be connected
directly to the power source.
AGND (Pins 3, 5): For dual supply operation these pins
should be connected to a ground plane. For single supply
10641fa
4