LT1719IS8 Linear Technology, LT1719IS8 Datasheet - Page 22

• Manufacturer Part Number: LT1719IS8
• Description: IC COMP R-R SINGLE 4.5NS 8SOIC
• Manufacturer: Linear Technology
• Series: UltraFast™r
• Type: General Purposer

Specifications of LT1719IS8

• Number Of Elements: 1
• Output Type: CMOS, Rail-to-Rail, TTL
• Voltage - Supply: 2.7 V ~ 10.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LT1719
TYPICAL APPLICATION
High Performance Sine Wave
to Square Wave Converter
Propagation delay of comparators is typically specifi ed for
a 100mV step with some fraction of that for overdrive. But
in many signal processing applications, such as in com-
munications, the goal is to convert a sine wave, such as
a carrier, to a square wave for use as a timing clock. The
desired behavior is for the output timing to be dependent
on the input timing only. No phase shift should occur as
a function of the input amplitude, which would result in
AM to FM conversion.
The circuit of Figure 9a is a simple LT1719S8-based sine
wave to square wave converter. The ± 5V supplies on the
input allow very large swing inputs, while the 3V logic
supply keeps the output swing small to minimize cross
talk. Figure 9b shows the time delay vs input amplitude
with a 10MHz sine wave. The LT1719 delay changes just
0.65ns over the 26dB amplitude range; 2.33° at 10MHz.
The delay is particularly fl at yielding excellent AM rejection
RELATED PARTS
PART NUMBER
LT1016
LT1116
LT1394
LT1671
LT1713/LT1714
LT1720/LT1721
22
Figure 9a. LT1719-Based Sine Wave to Square Wave Converter
SINE WAVE
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone]
INPUT
50Ω
●
DESCRIPTION
UltraFast Precision Comparator
12ns Single Supply Ground-Sensing Comparator
7ns, UltraFast, Single Supply Comparator
60ns, Low Power, Single Supply Comparator
Single/Dual 7ns, Rail-to-Rail Comparator
Dual/Quad 4.5ns, Single Supply 3V/5V Comparator
FAX: [phone]
+
–
–5V
LT1719S8
5V
3V
●
SQUARE WAVE
www.linear.com
OUTPUT
1719 F09a
from 0dBm to 15dBm. If a 2:1 transformer is used to drive
the input differentially, this exceptionally fl at zone spans
–5dBm to 10dBm, a common range for RF signal levels.
Similar delay performance is achieved with input frequen-
cies as high as 50MHz. There is, however, some additional
encroachment into the central fl at zone by both the small
amplitude and large amplitude variations.
With small input signals, the hysteresis and dispersion
make the LT1719 act like a comparator with a 12mV
hysteresis span. In other words, a 12mV
10MHz will barely toggle the LT1719, with 90° of phase
lag or 25ns additional delay.
Above 5V
due to internal capacitive feed-forward in the input stage.
Unlike some comparators, the LT1719 will not falsely an-
ticipate a change in input polarity, but the feed-forward is
enough to make a transition propagate through the LT1719
faster once the input polarity does change.
Figure 9b. Time Delay vs Sine Wave Input Amplitude
COMMENTS
Industry Standard 10ns Comparator
Single Supply Version of LT1016
6mA Single Supply Comparator
450μA Single Supply Comparator
Rail-to-Rail Inputs and Outputs
Dual/Quad Comparator Similar to the LT1719
P-P
5
1
0
4
3
2
at 10MHz, the LT1719 delay starts to decrease
–5
25°C
V
V
+V
10MHz
632mV
CC
EE
S
= –5V
= 5V
= 3V
0
P-P
INPUT AMPLITUDE (dBm)
5
2V
© LINEAR TECHNOLOGY CORPORATION 2000
10
P-P
15
6.32V
LT 0809 REV A • PRINTED IN USA
20
P-P
1719 F09b
P-P
25
sine wave at
1719fa