LT1719 Linear Technology, LT1719 Datasheet - Page 11

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

APPLICATIONS
evaluated carefully. Note that there is some degradation of
noise margin due to the 5% resistor selections shown.
With 10KH/E, there is no temperature compensation of the
logic levels, whereas the LT1719 and the circuits shown
give levels that are stable with temperature. This will lower
the noise margin over temperature. In some configura-
tions it is possible to add compensation with diode or
transistor junctions in series with the resistors of these
networks.
For more information on ECL design, refer to the ECLiPS
data book (DL140), the 10KH system design handbook
(HB205) and PECL design (AN1406), all from Motorola.
(d) LT1719 OUTPUT TO STANDARD ECL TRANSLATOR
(a) STANDARD TTL TO PECL TRANSLATOR
(b) LT1719 OUTPUT TO PECL TRANSLATOR
(c) 3V LT1719 OUTPUT TO PECL TRANSLATOR
U
V
V
V
V
V
V
LT1719
LT1719
LT1719
CC
CC
CC
EE
EE
EE
INFORMATION
LSTTL
U
+V
3V
S
5V
180
270
820
R1
R4
R4
W
R1
+V
R1
S
V
R2
R3
ECL
5V
R2
R3
R2
10KH/E
R3
U
V
ECL
DO NOT USE FOR LT1719
LEVEL TRANSLATION. SEE TEXT
10KH/E
100K/E
10KH/E
100K/E
Figure 6
5V OR 5.2V
ECL FAMILY
5V OR 5.2V
Circuit Description
The block diagram of the LT1719 is shown in Figure 7. The
circuit topology consists of a differential input stage, a
gain stage with hysteresis and a complementary com-
mon-emitter output stage. All of the internal signal paths
utilize low voltage swings for high speed at low power.
The input stage topology maximizes the input dynamic
range available without requiring the power, complexity
and die area of two complete input stages such as are
found in rail-to-rail input comparators. With a single 2.7V
supply, the LT1719 still has a respectable 1.6V of input
4.5V
+ V
10KH/E
100K/E
S
V
4.5V
ECL
510
620
R1
– 5.2V
– 4.5V
300
330
V
R1
ECL
180
180
R2
180
180
R2
+ V
5V
3V
5V
3V
S
750
510
R3
1500
OMIT
560
270
680
330
R3
R1
1000
560
270
510
270
390
R4
R2
330
300
300
270
R3
1200
1500
330
430
R4
1719 F06
LT1719
11