LTC6957-1/LTC6957-2/
LTC6957-3/LTC6957-4
Low Phase Noise, Dual
Output Buffer/Driver/
Logic Converter
FEATURES DESCRIPTION
n
Low Phase Noise Buffer/Driver The LTC 6957-1/LTC6957-2/LTC6957-3/LTC6957-4 is a
n
family of very low phase noise, dual output AC signal
Optimized Conversion of Sine Wave Signals to
buffer/driver/logic level translators. The input signal can
Logic Levels
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be a sine wave or any logic level (2V ). There are four
Three Logic Output Types Available
P-P
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members of the family that differ in their output logic
LVPECL
n signal type as follows:
LVDS
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CMOS
LTC6957-1: LVPECL Logic Outputs
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Additive Jitter 45fs (LTC6957-1)
RMS
LTC6957-2: LVDS Logic Outputs
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Frequency Range Up to 300MHz
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3.15V to 3.45V Supply Operation
LTC6957-3: CMOS Logic, In-Phase Outputs
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Low Skew 3ps Typical
LTC6957-4: CMOS Logic, Complementary Outputs
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Fully Specified from 40C to 125C
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The LTC6957 will buffer and distribute any logic signal
12-Lead MSOP and 3mm 3mm DFN Packages
with minimal additive noise, however, the part really
APPLICATIONS
excels at translating sine wave signals to logic levels. The
early amplifier stages have selectable lowpass filtering
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System Reference Frequency Distribution
to minimize the noise while still amplifying the signal to
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High Speed ADC, DAC, DDS Clock Driver
increase its slew rate. This input stage filtering/noise limit-
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Military and Secure Radio
ing is especially helpful in delivering the lowest possible
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Low Noise Timing Trigger
phase noise signal with slow slewing input signals such
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Broadband Wireless Transceiver
as a typical 10MHz sine wave system reference.
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High Speed Data Acquisition
All registered trademarks and trademarks are the property of their respective owners. Protected
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Medical Imaging
by U.S. Patents 7969189 and 8319551.
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Test and Measurement
TYPICAL APPLICATION
3.3V
Additive Phase Noise at 100MHz
0.1F
140
SINGLE-ENDED SINE WAVE INPUT
AT +7dBm (500mV )
RMS
FILTA = FILTB = GND
+
V SD1 145
FILTA
FILTB
TO PLL CHIPS LTC6957-2 (LVDS)
100MHz OUT1
150
OR SYSTEM
+7dBm
10nF
SAMPLING CLOCKS
LTC6957-4 (CMOS)
SINE WAVE +
IN
OCXO
155
IN
50
10nF
OUT2
LTC6957-3
160
(CMOS)
LTC6957-1 (LVPECL)
GND SD2
165
6957 TA01a 100 1k 10k 100k 1M
OFFSET FREQUENCY (Hz)
69571234 TA01b
6957fb
1
For more information www.linear.com/LTC6957-1
PHASE NOISE (dBc/Hz)LTC6957-1/LTC6957-2/
LTC6957-3/LTC6957-4
ABSOLUTE MAXIMUM RATINGS (Note 1)
+
Supply Voltage (V or V ) to GND ..........................3.6V Specified Temperature Range
DD
+
Input Current (IN , IN , FILTA, FILTB, SD1, SD2) LTC6957I .............................................40C to 85C
(Note 2) .......................................................... 10mA LTC6957H .......................................... 40C to 125C
LTC6957-1 Output Current ........................ 1mA, 30mA Junction Temperature .......................................... 150C
LTC6957-2 Output Current ................................. 10mA Storage Temperature Range ................. 65C to 150C
LTC6957-3, LTC6957-4 Output Current (Note 3) .. 30mA Lead Temperature (for MSOP Soldering, 10sec) ...300C
PIN CONFIGURATION
LTC6957-1, LTC6957-2 LTC6957-3, LTC6957-4
TOP VIEW TOP VIEW
1 SD1 1 SD1
FILTA 12 FILTA 12
+ + +
V 2 11 OUT1 V 2 11 V
DD
+ +
3 3
IN 10 OUT1 IN 10 OUT1
13 13
GND GND
4 4
9 OUT2 9 OUT2
IN IN
+
5 8 5 8
GND OUT2 GND GNDOUT
6 7 6 7
FILTB SD2 FILTB SD2
DD PACKAGE DD PACKAGE
12-LEAD (3mm 3mm) PLASTIC DFN 12-LEAD (3mm 3mm) PLASTIC DFN
T = 150C, = 58C/W, = 10C/W T = 150C, = 58C/W, = 10C/W
JMAX JA JC JMAX JA JC
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
LTC6957-1, LTC6957-2 LTC6957-3, LTC6957-4
TOP VIEW TOP VIEW
FILTA 1 12 SD1 FILTA 1 12 SD1
+ + +
V 2 11 OUT1 V 2 11 V
DD
+ +
IN 3 10 OUT1 IN 3 10 OUT1
IN 4 9 OUT2 IN 4 9 OUT2
+
GND 5 8 OUT2 GND 5 8 GNDOUT
FILTB 6 7 SD2 FILTB 6 7 SD2
MS PACKAGE MS PACKAGE
12-LEAD PLASTIC MSOP 12-LEAD PLASTIC MSOP
T = 150C, = 145C/W T = 150C, = 145C/W
JMAX JA JMAX JA
6957fb
2
For more information www.linear.com/LTC6957-1