LTC1520 Linear Technology, LTC1520 Datasheet - Page 7

• Manufacturer Part Number: LTC1520
• Description: 50Mbps Precision Quad Line Receiver
• Manufacturer: Linear Technology

Alternate Uses
The tightly controlled propagation delay of the LTC1520
allows the part to serve as a fixed delay element. Figure 9
shows the LTC1520 used as a tapped delay line with 18ns
to form longer delay lines. Each tap in the delay line is
accurate to within 17% over temperature.
As shown in Figure 10, the LTC1520 can be used to create
a temperature stable ring oscillator with period increments
APPLICATIONS
3ns steps. Several LTC1520s may be connected in series
U
0.01 F
INFORMATION
INPUT
5V
U
0.01 F
3.3k
3.3k
0.01 F
1/4 LTC1520
+
–
0ns DELAY
1/4 LTC1520
+
–
W
5V
Figure 10. Temperature Stable Ring Oscillators
3.3k
3.3k
Figure 9. Tapped Delay Line with 18ns Steps
1/4 LTC1520
–
+
1/4 LTC1520
+
–
1/4 LTC1520
U
1/4 LTC1520
18ns DELAY
+
1/4 LTC1520
–
+
–
+
–
of 36ns. Low skew and good channel-to-channel match-
ing enable this oscillator to achieve better than a 45/55
duty cycle (the duty cycle approaches 50/50 as more
LTC1520s are used for lower frequencies). Note that the
fixed voltage bias may either be created externally with a
resistor divider or generated internally using a bypass
capacitor and the internal open circuit bias point (approxi-
mately 3.3V). The use of the internal bias point will result
in a 1% to 2% distortion of the duty cycle.
1/4 LTC1520
+
–
1/4 LTC1520
+
–
36ns DELAY
1/4 LTC1520
+
–
1520 F10
9.3MHz OSCILLATOR
WITH BETTER THAN
45/55 DUTY CYCLE
TYPICAL STABILITY
5% OVER TEMPERATURE
54ns DELAY
6.9MHz
OSCILLATOR OUTPUT
+
1/4 LTC1520
–
72ns DELAY
1520 F09
LTC1520
7