LT1720IMS8#TRPBF Linear Technology, LT1720IMS8#TRPBF Datasheet - Page 16

• Manufacturer Part Number: LT1720IMS8#TRPBF
• Description: IC COMPARATOR DUAL HS 3/5V 8MSOP
• Manufacturer: Linear Technology
• Series: UltraFast™r
• Type: General Purposer

Specifications of LT1720IMS8#TRPBF

• Number Of Elements: 2
• Output Type: CMOS, Rail-to-Rail, TTL
• Voltage - Supply: 2.7 V ~ 6 V
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
LT1720/LT1721
The circuit in Figure 9 shows a crystal oscillator circuit
that generates two nonoverlapping clocks by making full
use of the two independent comparators of the LT1720.
C1 oscillates as before, but with a lower reference level,
C2’s output will toggle at different times. The resistors set
the degree of separation between the output’s high pulses.
With the values shown, each output has a 44% high and
56% low duty cycle, sufficient to allow 2ns between the
high pulses. Figure 10 shows the two outputs.
16
1000
Figure 8. Timing Skew of Figure 7’s Circuit
800
600
400
200
0
2.5
3.0
2.7V TO 6V
V
CC
3.5
SUPPLY VOLTAGE (V)
620Ω
2k
4.0
220Ω
4.5
1.3k
Figure 9. Crystal-Based Nonoverlapping 10MHz Clock Generator
2.2k
5.0
1/2 LT1720
CRYSTAL (AT-CUT)
+
–
+
1/2 LT1720
–
C2
5.5
C1
1720/21 F08
10MHz
0.1μF
GROUND
CASE
6.0
2k
OPTIONAL—
SEE TEXT
1k
0.1μF
The optional A1 feedback network shown can be used to
force identical output duty cycles. The steady state duty
cycles of both outputs will be 44%. Note, though, that
the addition of this network only adjusts the percentage
of time each output is high to be the same, which can be
important in switching circuits requiring identical settling
times. It cannot adjust the relative phases between the two
outputs to be exactly 180° apart, because the signal at the
input node driven by the crystal is not a pure sinusoid.
LT1636
A1
Figure 10. Nonoverlapping Outputs of Figure 9’s Circuit
+
–
2V/DIV
2V/DIV
Q0
Q1
100k
100k
0.1μF
OUTPUT 1
OUTPUT 0
20ns/DIV
17201 F09
17201 F10
17201fc