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DEMO MANUAL DC2767A
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DESCRIPTION
LTC6754
High Speed Comparator with LVDS
Demonstration circuit 2767A features the LT C
®
6754 high-
speed rail-to-rail comparator in a QFN package with LVDS
compatible outputs. The DC2767 input is AC-coupled for
single-ended signal greater than 5MHz and up to 445MHz.
The DC2767 outputs are AC-coupled 50Ω source imped-
ance for driving directly the 50Ω inputs of a 1GHz or
higher oscilloscope. The DC2767 has a supply connection
for the LTC6754 rail-to-rail inputs and a separate supply
connection for the QFN LTC6754 LVDS outputs.
The LTC6754 includes 4.5mV of hysteresis to minimize
instability. For the QFN package, a separate pin is available
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
to set the hysteresis from 0mV (off) up to 40mV. The
QFN version also features output latching to provide the
ability to capture the state of the comparator. The DC2767
provides a connection to set the hysteresis or for output
latching.
LTC6754 is ideally suited for high frequency line driver
and clock recovery circuits.
Design files for this circuit board are available.
Specifications are at TA = 25°C. Differential RL = 100Ω, VOVERDRIVE = 50mV,
LE/HYST and SHDN Pins Floating.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Supply 2.4 5.25 V
Output Supply 2.4 5.25 V
Input Voltage Range VEE–0.2 VCC+0.1 V
Input Offset Voltage –4 ±0.75 4 mV
Input Hysteresis Voltage HYST Pin Floating 4.5 mV
Input Bias Current VCM = VEE + 0.3V –3.8 –1.8 µA
Input Bias Current VCM = VCC – 0.3V 0.6 1.5 µA
Output Common Mode Voltage 1.18 1.26 1.31 V
Differential Output Voltage 260 362 420 mV
Input Supply Current 2.4 2.9 mA
Output Supply Current 11 11.8 mA
Propagation Delay VOVERDRIVE = 50mV 1.8 2.8 ns
Toggle Rate VIN = 200mVP-P, Sine Wave 445 MHz
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DEMO MANUAL DC2767A
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QUICK TEST SETUP
Test Equipment: Dual Supply 3V-5V, 50MHz Square Wave Generator Oscilloscope 1GHz or Higher
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DEMO MANUAL DC2767A
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TEST PROCEDURE
DC2767 RJ45 RECEIVER CONFIGURATION
1. Connect a 3V supply to the input (VCCI) and output
(VCCO) turrets.
2. Connect a 50 MHz, 100mVP-P square wave to the IN+
SMA connector.
3. Connect the OUT+ and OUT– SMAs to two channels of
a 1GHz or higher oscilloscope
(the oscilloscope’s channel impedance must be 50Ω).
4. Turn on the dual supply and the oscilloscope shows a
175mV, ±50mV.
Note: The DC2767 differential output is an AC-coupled
100Ω differential voltage source (two 50Ω singled-ended
outputs divided by two into a 50Ω load).
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DEMO MANUAL DC2767A
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DC2767 RJ45 TRANSMITTER CONFIGURATION
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DEMO MANUAL DC2767A
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Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications
subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
DC2767 INPUT CONFIGURATION FOR A CMOS LOGIC DATA SOURCE
TYPICAL APPLICATION
–
+
LTC6754
RJ45
RJ45
CAT 6 CABLE
V
CCI
V
V
EE
–IN
+IN
–IN
+IN
CABLE RECEIVER
2.4V to 5.25V
CABLE DRIVER
2.4V to 5.25V
1.8V to 5V
V
+
V
+
100Ω
100Ω
DC2767
Q
Q
–
+
LTC6754
V
CCI
V
V
EE
Q
Q
750Ω
DATA
SOURCE
249Ω
0.1µF
750Ω
750Ω
LVDS Data Transmitter and Receiver
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DEMO MANUAL DC2767A
Rev. 0
ANALOG DEVICES, INC. 2018
12/18
www.analog.com
ESD Caution
ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection
circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
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