LT1719 Linear Technology, LT1719 Datasheet - Page 6

• Manufacturer Part Number: LT1719
• Description: 4ns/ 150MHz Dual Comparator with Independent Input/Output Supplies
• Manufacturer: Linear Technology

APPLICATIONS
LT1719
Power Supply Configurations
The LT1719 has separate supply pins for the input and
output stages that allow flexible operation, accommodat-
ing separate voltage ranges for the analog input and the
output logic. Of course, a single 3V/5V supply may be used
by tying + V
The minimum voltage requirement can be simply stated as
both the output and the input stages need at least 2.7V and
the V
The following rules must be adhered to in any
configuration:
6
TEST CIRCUITS
2.7V (V
2.7V (+ V
(+ V
V
EE
EE
V
50
CM
50k
S
NOTES: LT1638, LT1112, LTC203s ARE POWERED FROM 15V.
pin must be equal to or less than ground.
– V
Ground
100k
1/2 LT1638
S
50
CC
EE
+
–
BANDWIDTH-LIMITED TRIANGLE WAVE
100k
200k PULL-DOWN PROTECTS LTC203 LOGIC INPUTS
WHEN DUT IS NOT POWERED
and V
S
) 10.5V
– V
– GND) 6V
+
–
LT1719
~
DUT
U
CC
EE
1kHz, V
100k
V
CC
) 10.5V
together as well as GND and V
0.1 F
CM
INFORMATION
1/2 LT1638
U
100k
7.5V
+
–
200k
0.15 F
W
2.4k
U
14
11
3
6
LTC203
LTC203
V
EE
TRIP
.
16
9
1
8
Test Circuit
Although the ground pin need not be tied to system
ground, most applications will use it that way. Figure 1
shows three common configurations. The final one is
uncommon, but it will work and may be useful as a level
translator; the input stage is run from – 5.2V and ground
while the output stage is run from 3V and ground. In this
case the common mode input voltage range does not
include ground, so it may be helpful to tie V
anyway. Conversely, V
as long as the above rules are not violated.
Input Voltage Considerations
The LT1719 is specified for a common mode range of
–100mV to 3.8V when used with a single 5V supply. A
more general consideration is that the common mode
range is 100mV below V
for this common mode limit is that the output still
15
10
2
7
10nF
10nF
14
11
3
6
16
1
8
9
15
10
2
7
CC
EE
1719 TC01
may also be tied below ground,
to 1.2V below V
1 F
1 F
–
–
+
+
1/2 LT1112
1/2 LT1112
CC
10k
10k
. The criterion
1000 V
1000 V
1000 V
1000 V
CC
to 3V
TRIP
HYST
TRIP
OS
+
–