LTC1565-31IS8#PBF [Linear]

LTC1565-31 - 650kHz Continuous Time, Linear Phase Lowpass Filter; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C;
LTC1565-31IS8#PBF
型号: LTC1565-31IS8#PBF
厂家: Linear    Linear
描述:

LTC1565-31 - 650kHz Continuous Time, Linear Phase Lowpass Filter; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C

有源滤波器 过滤器 光电二极管 LTE
文件: 总12页 (文件大小:193K)
中文:  中文翻译
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LTC1565-31  
650kHz Continuous Time,  
Linear Phase Lowpass Filter  
U
FEATURES  
DESCRIPTIO  
The LTC®1565-31 is a 7th order, continuous time, linear  
phase lowpass filter. The selectivity of the LTC1565-31,  
combined with its linear phase and dynamic range, make it  
suitable for filtering in data communications or data acqui-  
sition systems. The filter attenuation is 36dB at 2× fCUTOFF  
and at least 72dB for frequencies above 3× fCUTOFF. Unlike  
comparable LC filters, the LTC1565-31 achieves this selec-  
tivity with a linear phase response in the passband.  
7th Order, 650kHz Linear Phase Filter in an SO-8  
Differential Inputs and Outputs  
Operates on a Single 5V or a ±5V Supply  
Low Offset: 5mV Typical  
75dB THD and SNR  
78dB SNR  
Shutdown Mode  
Requires No External Components  
Requires No External Clock Signal  
With 5% accuracy of the cutoff frequency, the LTC1565-31  
canbeusedinapplicationsrequiringpairsofmatchedfilters,  
such as transceiver I and Q channels. Furthermore, the  
differential inputs and outputs provide a simple interface for  
these wireless systems.  
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APPLICATIO S  
CDMA Base Stations  
Data Communications  
With a single 5V supply and a 2VP-P input, the LTC1565-31  
featuresanimpressivespuriousfreedynamicrangeof75dB.  
Themaximumsignal-to-noiseratiois78dBanditisachieved  
with a 2.5VP-P input signal.  
Antialiasing Filters  
Smoothing or Reconstruction Filters  
Matched Filter Pairs  
Replacement for LC Filters  
The LTC1565-31 features a shutdown mode where power  
supply current is typically less than 10µA.  
For W-CDMA, 3G, CDMA 2000 and other cellular and  
noncellular cutoff frequencies or single-ended I/O, please  
contact LTC Marketing for additional information.  
, LTC and LT are registered trademarks of Linear Technology Corporation.  
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TYPICAL APPLICATIO  
Frequency Response  
10  
0
2.0  
1.9  
1.8  
1.7  
1.6  
1.5  
1.4  
1.3  
1.2  
1.1  
1.0  
0.9  
GAIN  
Single 5V Supply, Differential 650kHz Lowpass Filter  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
1
2
8
7
+
+
V
V
V
V
+IN  
–IN  
+OUT  
–OUT  
IN  
IN  
OUT  
OUT  
DELAY  
LTC1565-31  
5V  
5V  
3
4
6
5
0.1µF  
+
GND  
V
0.1µF  
V
SHDN  
15645-31 TA01  
4
5
6
7
10  
10  
10  
10  
FREQUENCY (Hz)  
1565 G01  
1
LTC1565-31  
W W U W  
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W U  
ABSOLUTE MAXIMUM RATINGS  
PACKAGE/ORDER INFORMATION  
(Note 1)  
ORDER PART  
Total Supply Voltage............................................... 11V  
Power Dissipation............................................. 500mW  
Operating Temperature Range  
LTC1565-31CS8 ..................................... 0°C to 70°C  
LTC1565-31IS8 ................................. 40°C to 85°C  
Storage Temperature Range ................ 65°C to 150°C  
Lead Temperature (Soldering, 10 sec)................. 300°C  
TOP VIEW  
NUMBER  
+IN  
–IN  
1
2
3
4
8
7
6
5
+OUT  
–OUT  
LTC1565-31CS8  
LTC1565-31IS8  
+
GND  
V
V
SHDN  
S8 PART MARKING  
S8 PACKAGE  
8-LEAD PLASTIC SO  
156531  
56531I  
TJMAX = 150°C, θJA = 80°C/ W (NOTE 4)  
Consult factory for Military grade parts.  
ELECTRICAL CHARACTERISTICS  
The denotes the specifications which apply over the full operating  
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open  
unless otherwise specified.  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Operating Supply Voltage  
Filter Gain  
4.75  
11  
V
V
= 1V , f = 25kHz  
0.3  
0.2  
0.7  
2.2  
–4  
0
0
0.3  
0.1  
0.1  
0.95  
–2  
–7  
31  
dB  
dB  
dB  
dB  
dB  
dB  
dB  
dB  
IN  
P-P IN  
f
f
f
f
f
f
f
= 200kHz (Gain Relative to 25kHz)  
= 300kHz (Gain Relative to 25kHz)  
= 500kHz (Gain Relative to 25kHz)  
= 650kHz (Gain Relative to 25kHz)  
= 900kHz (Gain Relative to 25kHz)  
= 1.3MHz (Gain Relative to 25kHz)  
= 2.3MHz (Gain Relative to 25kHz)  
IN  
IN  
IN  
IN  
IN  
IN  
IN  
–0.4  
–1.6  
–3  
–11  
–36  
–72  
Filter Phase  
V
= 1V , f = 25kHz  
–13  
–101  
–150  
113  
60  
36  
92  
Deg  
Deg  
Deg  
Deg  
Deg  
Deg  
Deg  
IN  
P-P IN  
f
f
f
f
f
f
= 200kHz  
= 300kHz  
= 500kHz  
= 600kHz  
= 650kHz  
= 900kHz  
IN  
IN  
IN  
IN  
IN  
IN  
162  
34  
138  
85  
Phase Linearity  
Wideband Noise  
THD  
Ratio of 600kHz Phase/300kHz Phase  
Noise BW = DC to 2 • f  
1.95  
2
2.03  
118  
86  
µV  
RMS  
CUTOFF  
f
= 100kHz, 1V (Note 2)  
dB  
IN  
P-P  
Filter Differential DC Swing  
Maximum Difference Between Pins 7 and 8  
V = 5V  
V = ±5V  
S
±1.4  
±2.2  
±1.7  
±2.3  
±1.9  
±2.5  
V
V
S
P
P
Input Bias Current  
Input Offset Current  
Input Resistance  
0.1  
0.3  
0.6  
µA  
±10  
nA  
Common Mode, V = 2.5V  
Differential  
75  
145  
MΩ  
MΩ  
IN  
Input Capacitance  
3
pF  
Output DC Offset (Note 3)  
V = 5V  
V = ±5V (Note 5)  
S
±5  
±5  
±12  
±12  
mV  
mV  
S
2
LTC1565-31  
ELECTRICAL CHARACTERISTICS  
unless otherwise specified.  
The denotes the specifications which apply over the full operating  
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RLOAD = 10k from each output to AC ground, and Pin 5 open  
PARAMETER  
CONDITIONS  
V = 5V  
V = ±5V  
S
MIN  
TYP  
MAX  
UNITS  
Output DC Offset Drift  
400  
400  
µV/°C  
µV/°C  
S
Ground Voltage (Pin 3) in  
Single Supply Applications  
V = 5V  
2.49  
2.51  
2.52  
4.2  
V
S
SHDN Pin Logic Thresholds  
V = 5V, Minimum Logical “1”  
V
V
S
V = 5V, Maximum Logical “0”  
S
3.3  
2.4  
V = ±5V, Minimum Logical “1”  
2.9  
V
V
S
V = ±5V, Maximum Logical “0”  
S
SHDN Pin Pull-Up Current  
V = 5V  
V = ±5V  
S
5
9
µA  
µA  
S
Power Supply Current  
V = 5V  
V = ±5V  
S
24  
25  
31  
33  
mA  
mA  
S
Power Supply Current in Shutdown Mode  
Shutdown. Includes SHDN Pull-Up Current  
V = 5V  
8
20  
16  
40  
µA  
µA  
S
V = ±5V  
S
Note 1: Absolute Maximum Ratings are those values beyond which the life  
of a device may be impaired.  
Note 4: Thermal resistance varies depending upon the amount of PC board  
metal attached to the device. θ is specified for a 3.8 square inch test  
JA  
board covered with 2 oz copper on both sides.  
Note 2: Input and output voltages expressed as peak-to-peak numbers are  
assumed to be fully differential.  
Note 5: Output DC offset measurements are performed by automatic test  
equipment approximately 0.5 seconds after application of power.  
Note 3: Output DC offset is measured between Pin 8 and Pin 7 with Pin 1  
and Pin 2 connected to Pin 3.  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
Passband Gain and Delay  
vs Frequency  
Frequency Response  
10  
0
2.0  
1.9  
1.8  
1.7  
1.6  
1.5  
1.4  
1.3  
1.2  
1.1  
1.0  
0.9  
0.5  
0
2.0  
1.9  
1.8  
1.7  
1.6  
1.5  
1.4  
1.3  
1.2  
1.1  
1.0  
GAIN  
GAIN  
5V  
±5V  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
–0.5  
–1.0  
–1.5  
–2.0  
–2.5  
–3.0  
–3.5  
–4.0  
–4.5  
DELAY  
DELAY  
T
A
= 25°C  
4
5
6
7
25k  
100k  
FREQUENCY (Hz)  
1M  
10  
10  
10  
10  
FREQUENCY (Hz)  
1565 G02  
1565 G01  
3
LTC1565-31  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
Stopband Gain vs Frequency  
Over Temperature  
Passband Gain vs Frequency  
Over Temperature  
Stopband Gain vs Frequency  
–40  
–50  
–60  
–70  
–80  
–90  
–40  
–50  
–60  
–70  
–80  
–90  
0.5  
0.4  
V
= 5V  
V
= 5V  
S
S
0.3  
0.2  
–40°C  
25°C  
–40°C  
25°C  
0.1  
85°C  
0
85°C  
V
= 5V  
S
–0.1  
–0.2  
–0.3  
–0.4  
–0.5  
V
= ±5V  
S
25k  
100k  
FREQUENCY (Hz)  
400k  
1.5  
1.8  
2.7  
3.0  
1.5  
1.8  
2.7  
3.0  
2.1  
2.4  
FREQUENCY (MHz)  
2.1  
2.4  
FREQUENCY (MHz)  
1565 G03  
1565 G04  
1565 G04  
Common Mode Rejection Ratio  
Power Supply Rejection Ratio  
Supply Current vs Temperature  
110  
80  
70  
60  
50  
40  
30  
26  
25  
V
V
T
= 1V  
= 5V  
V
V
T
= 200mV  
= 5V  
IN  
S
A
P-P  
IN  
S
A
P-P  
= 25°C  
= 25°C  
100  
90  
V
S
= ±5V  
80  
70  
V
S
= 5V  
24  
23  
60  
50  
3
4
5
6
7
3
4
5
6
7
10  
10  
10  
10  
10  
10  
10  
10  
FREQUENCY (Hz)  
10  
10  
30  
TEMPERATURE (°C)  
70  
90  
–50 –30 –10 10  
50  
FREQUENCY (Hz)  
1565 G06  
1565 G07  
1565 G08  
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PIN FUNCTIONS  
+IN, –IN (Pins 1, 2): Input Pins. Signals can be applied to  
either or both input pins. The typical DC gain from differ-  
ential inputs (Pin 1 to Pin 2) to the differential outputs (Pin  
8 to Pin 7) is 1.0V/V. The input range is described in the  
Applications Information section.  
ceramic capacitor to Pin 4. For dual supply operation,  
connect Pin 3 to a high quality DC ground. A ground plane  
should be used. A poor ground will increase noise and  
distortion.  
The impedance seen at Pin 3 is 2.5kin normal mode. In  
shutdown, the pin is internally biased to the same levels  
as normal mode. The impedance in shutdown mode is  
typically 500kbut varies with supply voltage and  
temperature.  
GND (Pin 3): Ground. The ground pin is the reference  
voltage for the filter and is internally biased to one-half the  
total power supply voltage of the filter, maximizing the  
dynamic range of the filter. For single supply operation,  
the ground pin should be bypassed with a quality 0.1µF  
4
LTC1565-31  
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PIN FUNCTIONS  
V, V+ (Pins 4, 6): Power Supply Pins. For a single 5V  
supply (Pin 4 grounded), a quality 0.1µF ceramic bypass  
capacitor is required from the positive supply pin (Pin 6)  
to the negative supply pin (Pin 4). The bypass should be  
as close as possible to the IC. For dual supply applications  
(Pin 3 is grounded), bypass Pin 6 to Pin 3 and Pin 4 to Pin  
3 with a quality 0.1µF ceramic capacitor.  
SHDN (Pin 5): Shutdown. When the Pin 5 voltage is low,  
the LTC1565-31 goes into the current saving shutdown  
mode. Pin 5 has a 4µA pull-up current. Leaving Pin 5 open  
will place the LTC1565-31 in its normal operating mode.  
OUT, +OUT(Pins7, 8):OutputPins. Pins7and8arethe  
filter differential output. Each pin can drive 1kor 300pF  
loads. The common mode voltage at the output pins is the  
same as the voltage at Pin 3.  
The maximum voltage difference between the ground pin  
(Pin 3) and the positive supply pin (Pin 6) should not  
exceed 5.5V.  
W
BLOCK DIAGRA  
+IN  
1
+
+OUT  
8
7
R
R
OUTPUT  
BUFFER  
7th ORDER  
LINEAR  
+
PHASE  
FILTER  
NETWORK  
OUTPUT  
BUFFER  
+
+
–OUT  
INPUT BUFFERS  
WITH COMMON MODE  
TRANSLATION CIRCUIT  
–IN  
2
3
4
V
SHUTDOWN  
SWITCH  
~1M  
5k  
+
GND  
6
V
5k  
SHUTDOWN  
SWITCH  
~1M  
+
V
V
4µA  
V
SHUTDOWN  
5
SHDN  
1565-31 BD  
5
LTC1565-31  
U
W U U  
APPLICATIONS INFORMATION  
Interfacing to the LTC1565-31  
Input Common Mode and Differential Voltage Range  
The difference between the voltages at Pin 1 and Pin 2 is  
thedifferentialinputvoltage.Theaverageofthevoltages  
at Pin 1 and Pin 2 is the “common mode input voltage.”  
The difference between the voltages at Pin 7 and Pin 8 is  
the “differential output voltage.” The average of the volt-  
ages at Pin 7 and Pin 8 is the “common mode output  
voltage.” The input and output common mode voltages  
are independent. The input common mode voltage is set  
by the signal source, if DC coupled, or by the biasing  
network if AC coupled (Figures 1 and 2). The output  
common mode voltage is equal to the voltage of Pin 3, the  
GND pin. The GND pin is biased to one-half of the supply  
voltage by an internal resistive divider (see Block Dia-  
gram). To alter the common mode output voltage, Pin 3  
can be driven with an external voltage source or resistor  
network. If external resistors are used, it is important to  
note that the internal 5k resistors can vary ±20% (their  
ratioonlyvaries±1%). TheoutputcanalsobeACcoupled.  
The range of voltage each input can support while operat-  
ing in its linear region is typically 0.8V to 3.7V for a single  
5V supply and 4.2V to 3.2V for a ±5V supply. Therefore,  
the filter can accept a variety of common mode input  
voltages. Figures 3 and 4 show the THD of the filter versus  
commonmodeinputvoltagewitha2VP-P differentialinput  
signal.  
–30  
–40  
V
= ±5V  
S
–50  
–60  
–70  
–80  
–90  
V
= 2V  
P-P  
IN  
= 100kHz  
f
IN  
–5 –4 –3 –2 –1  
INPUT COMMON MODE VOLTAGE (V)  
0
1
2
3
4
5
1
2
8
7
+
V
V
+IN  
–IN  
+OUT  
–OUT  
OUT  
OUT  
1565-31 F03  
Figure 3. THD vs Common Mode Input Voltage  
+
+
+
V
V
IN  
IN  
5V  
LTC1565-31  
3
4
6
5
–30  
+
GND  
V
0.1µF  
0.1µF  
V
SHDN  
V
S
= 5V  
–40  
–50  
15645-31 F01  
DC COUPLED INPUT  
+
V
+ V  
IN  
IN  
V
V
(COMMON MODE) =  
IN  
2
+
+
V
+ V  
2
V
OUT  
OUT  
–60  
(COMMON MODE) =  
=
OUT  
2
Figure 1  
–70  
–80  
V
IN  
= 2V  
P-P  
= 100kHz  
IN  
f
0.1µF  
0.5  
1.0  
2.0  
2.5  
3.0  
3.5  
1.5  
1
2
8
7
+
V
V
+IN  
–IN  
+OUT  
–OUT  
OUT  
INPUT COMMON MODE VOLTAGE (V)  
1565-31 F04  
OUT  
+
+
+
V
IN  
V
IN  
0.1µF  
100k  
100k  
5V  
LTC1565-31  
Figure 4. THD vs Common Mode Input Voltage  
3
4
6
5
+
GND  
V
1µF  
0.1µF  
Figure 5 shows the THD and S/N ratio versus differential  
input voltage level for both a single 5V supply and a ±5V  
supply. The common mode voltage of the input signal is  
one-half the total power supply voltage of the filter. The  
spurious free dynamic range, where the THD and S/N ratio  
are equal, is 75dB to 76dB when the differential input  
voltage level is 2VP-P; that is, for a single 5V supply, the  
V
SHDN  
15645-31 F02  
AC COUPLED INPUT  
(COMMON MODE) = V  
V
IN  
(COMMON MODE)  
OUT  
+
V
=
2
Figure 2  
6
LTC1565-31  
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APPLICATIONS INFORMATION  
–30  
Output Common Mode and Differential Voltage Range  
THD: V = 5V, V = 2.5V  
S
CM  
THD: V = ±5V, V = 0V  
S
CM  
–40  
–50  
–60  
–70  
–80  
–90  
SNR  
Theoutputisafullydifferentialsignalwithacommonmode  
level equal to the voltage at Pin 3. The specifications in the  
ElectricalCharacteristicstableassumetheinputsaredriven  
differentially and the output is observed differentially.  
However, Pin 8 can be used as a single-ended output by  
simply floating Pin 7. Pin 7 can be used as an inverting  
single-ended output by floating Pin 8. Using Pins 7 or 8 as  
single-ended outputs will decrease the performance.  
f
= 100kHz  
IN  
0.5  
1.5  
2.0  
2.5  
3.0  
3.5  
1.0  
The common mode output voltage can be adjusted by  
overdriving the voltage present on Pin 3. The best perfor-  
mance is achieved using a common mode output voltage  
that is equal to mid supply (the default Pin 3 voltage). Fig-  
ures7and8illustratetheTHDversusoutputcommonmode  
voltagefora2VP-P differentialinputvoltageandacommon  
mode input voltage that is 0.5V below mid supply.  
DIFFERENTIAL INPUT (  
)
P-P  
1565-31 F05  
Figure 5. Dynamic Range Diff-In, Diff-Out  
input voltages are Pin 1 = 2.5V DC ±0.5V and Pin 2 = 2.5V  
DC ±0.5V. Also note Figure 5 shows a 78dB SNR ratio for  
higher THD levels.  
0
V
V
V
= 2V 100kHz  
P-P  
IN  
S
As seen in Figures 3 and 4, the spurious free dynamic  
rangecanbeoptimizedbysettingtheinputcommonmode  
voltage slightly below one-half of the power supply volt-  
age, i.e., 2V for a single 5V supply and 0.5V for a ±5V  
supply. Figure 6 shows the THD and SNR ratio versus  
differential input voltage level for both a single 5V supply  
and a ±5V supply when the common mode input voltage  
is 2V and 0.5V respectively.  
= 5V  
–10  
–20  
–30  
= 2V  
IN(CM)  
–40  
–50  
–60  
–70  
–80  
For best performance, the inputs should be driven differ-  
entially. For single-ended signals, connect the unused  
input to Pin 3 or a common mode reference.  
2.0  
2.5  
3.5  
1.0  
1.5  
4.0  
3.0  
COMMON MODE OUTPUT VOLTAGE (V)  
1565-31 F07  
Figure 7. THD vs Common Mode Output Voltage  
–30  
THD: V = 5V, V = 2V  
S
CM  
THD: V = ±5V, V = –0.5V  
S
CM  
0
–40  
–50  
–60  
–70  
–80  
–90  
SNR  
= 100kHz  
V
V
V
= 2V 100kHz  
P-P  
IN  
S
f
= ±5V  
IN  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
= –0.5V  
IN(CM)  
0.5  
1.5  
2.0  
2.5  
3.0  
3.5  
1.0  
DIFFERENTIAL INPUT VOLTAGE (V  
)
P-P  
–4 –3 –2 –1  
0
1
2
3
4
1565-31 F06  
COMMON MODE OUTPUT VOLTAGE (V)  
1565-31 F08  
Figure 6. THD vs VIN for a Common Mode  
Input Voltage 0.5V Below Mid Supply  
Figure 8. THD vs Common Mode Output Voltage  
7
LTC1565-31  
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APPLICATIONS INFORMATION  
Output Drive  
concentratedinthefilterpassbandandcannotberemoved  
withpostfiltering(Table1). Table2liststhetypicalchange  
in wideband noise with supply voltage.  
Pin 7 and Pin 8 can drive a 1kor 300pF load connected  
to AC ground with a ±0.5V signal (corresponding to a  
2VP-P differential signal). For differential loads (loads  
connected from Pin 7 to Pin 8) the outputs can produce  
a 2VP-P differential signal across 2kor 150pF. For  
smaller signal amplitudes the outputs can drive corre-  
spondingly larger loads.  
Table 1. Wideband Noise vs Bandwidth, Single 5V Supply  
BANDWIDTH  
TOTAL INTEGRATED NOISE  
DC to f  
104µV  
CUTOFF  
RMS  
DC to 2 • f  
118µV  
RMS  
CUTOFF  
Table 2. Wideband Noise vs Supply Voltage, fCUTOFF = 650kHz  
TOTAL INTEGRATED NOISE  
Noise  
POWER SUPPLY  
DC TO 2 • f  
CUTOFF  
The wideband noise of the filter is the RMS value of the  
device’s output noise spectral density. The wideband  
noise data is used to determine the operating signal-to-  
noise at a given distortion level. Most of the noise is  
5V  
118µV  
120µV  
RMS  
RMS  
±5V  
U
TYPICAL APPLICATIO S  
Test Circuit for Single 5V Supply Operation  
4.99k  
AMPLIFIERS A1, A2 AND A3 ALLOW THE USE OF A GROUND-  
5V  
REFERENCED SINGLE-ENDED AC SOURCE AS THE INPUT  
SIGNAL AND A SEPARATE GROUND-REFERENCED DC SOURCE  
TO PROVIDE THE INPUT DC COMMON MODE VOLTAGE  
0.1µF  
4.99k  
2
3
7
AMPLIFIERS A4 AND A5 ALLOW MONITORING/MEASURING  
THE DIFFERENTIAL OUTPUT WITH A SINGLE-ENDED, GROUND-  
REFERENCED INSTRUMENT  
6
A1  
LT®1809  
2.49k  
+
4
10µF  
2.49k  
4.99k  
5V  
5V  
0.1µF  
4.99k  
2.49k  
0.1µF  
V
4.99k  
+
2
3
+V /2 + V  
IN  
IN  
1
2
3
4
8
7
6
5
+
7
2
3
CM  
CM  
7
+IN  
+OUT  
–OUT  
6
A2  
LT1809  
6
A4  
LT1809  
V
OUT  
(SINGLE ENDED)  
V
2.49k  
–V /2 + V  
IN  
CM  
–IN  
GND  
4
4
+
4.99k 10µF  
2.49k  
5V  
LTC1565-31  
+
V
1k  
0.1µF  
0.1µF  
4.99k  
5V  
V
SHDN  
19k  
0.01µF  
0.1µF  
5V  
+
2
3
7
0.1µF  
4.99k  
2.49k  
20Ω  
+
6
2
3
A5  
LT1812  
7
+
1k  
V /2  
6
A3  
LT1809  
2.2µF  
4
0.1µF  
1565-31 TA08  
4
8
LTC1565-31  
U
TYPICAL APPLICATIO S  
Single-Ended Input/Output Dual Supply Filter  
4.99k  
5V  
0.1µF  
0.1µF  
4.99k  
2
3
1
2
3
4
8
7
6
5
7
V
+IN  
–IN  
GND  
+OUT  
–OUT  
IN  
6
V
LT1809  
OUT  
2.49k  
+
4
LTC1565-31  
+
–5V  
V
5V  
R2  
0.1µF  
0.1µF  
2.49k  
1565-31 TA09  
–5V  
V
SHDN  
0.1µF  
NOTE: FOR SINGLE 5V SUPPLY CONNECTION, PIN 4 (LTC1565-31)  
AND PIN 4 (LT1809) SHOULD BE GROUNDED AND RESISTOR  
R2 SHOULD BE DC BIASED AT APPROXIMATELY 2.5V  
(SEE TEST CIRCUIT FOR SINGLE SUPPLY OPERATION)  
A Fully Differential Filter with Adjustable Output Common Mode Voltage  
+
1
2
3
4
8
7
6
5
(V – V )R2  
R1 + R2  
+
+
V
V
*
V
V
V
= V  
+
+IN  
–IN  
GND  
+OUT  
–OUT  
IN  
OUT  
OUT(CM)  
*
IN  
OUT  
LTC1565-31  
+
V
5V  
0.1µF  
–5V  
V
SHDN  
0.1µF  
–3V V  
OUT(CM)  
3V  
2.5V  
5V  
*–3.4V V  
IN(CM)  
DIFFERENT FROM V  
OUT(CM)  
IN(CM)  
+
V
CAN BE EQUAL OR  
V
0.1µF  
0.1µF  
2
7
6
NOTE: FOR SINGLE 5V SUPPLY OPERATION,  
PIN 4 (LTC1565-31), PIN 4 (LT1812) AND  
RESISTOR R2 SHOULD BE GROUNDED  
R1  
R2  
3 +LT1812  
4
100pF  
0.1µF  
–5V  
1565-31 TA10  
V
9
LTC1565-31  
TYPICAL APPLICATIO S  
U
Simple Pulse Shaping Circuit for Single 5V Operation, 1.25Mbps 2 Level Data  
5V  
4.99k  
4.99k  
1
2
8
7
+
4.99k  
V
V
+IN  
–IN  
+OUT  
–OUT  
OUT  
OUT  
1.25Mbps  
DATA  
LTC1565-31  
3
4
6
5
+
GND  
V
5V  
0.1µF  
0.1µF  
V
SHDN  
15645-31 TA04  
250ns/DIV  
1565-31 TA05  
Simple Pulse Shaping Circuit for Single 5V Operation, 2Mbps (1Msps) 4 Level Data  
5V  
4.99k  
4.99k  
10k  
D1  
1Msps  
DATA  
1
2
8
7
+
V
V
+IN  
–IN  
+OUT  
–OUT  
OUT  
D0  
OUT  
4.99k  
LTC1565-31  
3
4
6
5
+
GND  
V
5V  
0.1µF  
0.1µF  
V
SHDN  
15645-31 TA06  
200ns/DIV  
1565-31 TA07  
10  
LTC1565-31  
U
TYPICAL APPLICATIO S  
Narrowband Cellular Base Station Receiver  
LTC1565-31  
LPF  
ADC  
ADC  
0°  
I
RF/IF  
SECTION  
90°  
DSP  
LO  
Q
90°  
LTC1565-31  
LPF  
1565-31 TA03  
U
PACKAGE DESCRIPTION  
Dimensions in inches (millimeters) unless otherwise noted.  
S8 Package  
8-Lead Plastic Small Outline (Narrow 0.150)  
(LTC DWG # 05-08-1610)  
0.189 – 0.197*  
(4.801 – 5.004)  
7
5
8
6
0.150 – 0.157**  
(3.810 – 3.988)  
0.228 – 0.244  
(5.791 – 6.197)  
1
3
4
2
0.010 – 0.020  
(0.254 – 0.508)  
× 45°  
0.053 – 0.069  
(1.346 – 1.752)  
0.004 – 0.010  
(0.101 – 0.254)  
0.008 – 0.010  
(0.203 – 0.254)  
0°– 8° TYP  
0.016 – 0.050  
(0.406 – 1.270)  
0.050  
(1.270)  
BSC  
0.014 – 0.019  
(0.355 – 0.483)  
TYP  
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH  
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE  
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD  
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE  
SO8 1298  
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.  
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-  
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.  
11  
LTC1565-31  
U
TYPICAL APPLICATIO  
Selective 620kHz CDMA Filter  
R5  
1k  
5V  
R4  
1.13k  
C6  
0.1µF  
R6  
1k  
C3  
18pF  
C4  
18pF  
1
2
3
4
8
7
6
5
1
2
8
7
V
V
R1  
R2  
R3  
1.24k  
+IN  
–IN  
+OUT  
–OUT  
OUT1  
OUT2  
C5  
180pF  
562Ω  
562Ω  
U1  
LT1813  
V
V
IN1  
U2  
LTC1565-31  
FGND  
C1  
150pF  
C2  
1000pF  
3
4
6
5
+
GND  
V
C8  
0.1µF  
C7  
0.1µF  
R7  
562Ω  
R8  
562Ω  
R9  
V
SHDN  
1.24k  
15645-31 TA11  
R11  
1k  
IN2  
5V  
R10  
1.13k  
R12  
1k  
Frequency Response  
0
–6  
–12  
–18  
–24  
–30  
–36  
–42  
–48  
100k  
1M  
FREQUENCY (Hz)  
1565 TA12  
RELATED PARTS  
PART NUMBER  
LTC1560-1  
DESCRIPTION  
COMMENTS  
1MHz/500kHz Continuous Time, Low Noise, Lowpass Elliptic Filter  
Universal 8th Order Active RC Filters  
f
= 500kHz or 1MHz  
CUTOFF  
LTC1562/LTC1562-2  
f
f
= 150kHz (LTC1562),  
= 300kHz (LTC1562-2)  
CUTOFF(MAX)  
CUTOFF(MAX)  
LTC1563-2/LTC1563-3 4th Order Active RC Lowpass Filters  
f
= 256kHz  
CUTOFF(MAX)  
LTC1569-6/LTC1569-7 Self Clocked, 10th Order Linear Phase Lowpass Filters  
f
f
/f  
= 64/1, f  
= 32/1, f  
= 75kHz (LTC1569-6)  
= 300kHz (LTC1569-7)  
CLK CUTOFF  
CUTOFF(MAX)  
CUTOFF(MAX)  
/f  
CLK CUTOFF  
156531f LT/LCG 1000 4K • PRINTED IN USA  
LINEAR TECHNOLOGY CORPORATION 2000  
12 LinearTechnology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7417  
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com  

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