lt1671cs8-trpbf Linear Technology Corporation, lt1671cs8-trpbf Datasheet - Page 10

• Manufacturer Part Number: lt1671cs8-trpbf
• Description: 60ns, Low Power,single Supply, Ground-sensing Comparator
• Manufacturer: Linear Technology Corporation

LT1671
APPLICATIONS
Crystal Oscillators
Figure 7 shows a crystal oscillator circuit. In the circuit, the
resistors at the LT1671’s positive input set a DC bias point.
The 2k-0.068 F path sets up phase shifted feedback and
the circuit looks like a wideband unity-gain follower at DC.
The crystal’s path provides resonant positive feedback
and stable oscillation occurs.
10
Figure 7. 1MHz to 10MHz Crystal Oscillator
5V
2k
2k
U
CRYSTAL (AT-CUT)
1MHz TO 10MHz
0.068 F
+
–
INFORMATION
LT1671
U
2k
W
OUTPUT
1671 F07
U
Switchable Output Crystal Oscillator
Figure 8 permits crystals to be electronically switched by
logic commands. This circuit is similar to the previous
examples, except that oscillation is only possible when
one of the logic inputs is biased high.
5V
Figure 8. Switchable Output Crystal Oscillator. Biasing A or B
High Places Associated Crystal in Feedback Path. Additional
Crystal Branches Are Permissible
1k
1k
75pF
–
+
LT1671
XTAL X
XTAL B
XTAL A
GROUND XTAL CASES
= 1N4148
2k
D1
D2
D
X
1k
1k
R
X
B
A
OUTPUT
LOGIC INPUTS
AS MANY STAGES
AS DESIRED
1671 F08