LT1011 Linear Technology, LT1011 Datasheet - Page 9

• Manufacturer Part Number: LT1011
• Description: Voltage Comparator
• Manufacturer: Linear Technology

APPLICATIONS
In the “off” state, I
off. The collector of Q2 can be now held at any voltage
above V
above the positive supply level. Maximum voltage above
V
emitter can be held at any voltage between V
long as it is negative with respect to the collector.
In the “on” state, I
Diodes D1 and D2 prevent deep saturation of Q2 to
improve speed and also limit the drive current of Q1. The
R1/R2 divider sets the saturation voltage of Q2 and pro-
vides turn-off drive. Either the collector or emitter pin can
be held at a voltage between V
remaining pin to drive the load. In typical applications, the
emitter is connected to V
drives a load tied to V
When the emitter is used as the output, the collector is
typically tied to V
V
respect to the collector output so that the “+” and “–” input
designations must be reversed. When the collector is tied
TYPICAL APPLICATIONS
–
–
. Note that the emitter output is phase reversed with
is 50V for the LT1011M and 40V for the LT1011C/I. The
–
Offset Balancing
2
3
without conducting current, including voltages
+
–
5
LT1011
20k
R1
R2
3k
6
+
1
1
and the load is connected to ground or
is switched off and both Q1 and Q2 turn
8
U
is connected, turning on Q1 and Q2.
7
+
1011 TA03
or a separate positive supply.
V
INFORMATION
+
U
–
or ground and the collector
+
and V
U
W
–
. This allows the
V
++
+
Driving Load Referenced
CAN BE GREATER OR LESS THAN V
U
and V
3
2
to Positive Supply
–
+
LT1011
–
V
as
V
+
8
4
GROUND
OR
V
1
7
to V
2V below V
Input Signal Range
The common mode input voltage range of the LT1011 is
about 300mV above the negative supply and 1.5V below
the positive supply, independent of the actual supply
voltages (see curve in the Typical Performance Character-
istics). This is the voltage range over which the output will
respond correctly when the common mode voltage is
applied to one input and a higher or lower signal is applied
to the remaining input. If one input is inside the common
mode range and one is outside, the output will be correct.
If the inputs are outside the common mode range in
opposite directions, the output will still be correct. If both
inputs are outside the common mode range in the same
direction, the output will not respond to the differential
input; for temperatures of 25 C and above, the output will
remain unconditionally high (collector output), for tem-
peratures below 25 C, the output becomes undefined.
V
1011 TA05
+
++
, the voltage at the emitter in the “on” state is about
R
LOAD
+
+
(see curves).
LT1011/LT1011A
INPUTS*
Driving Load Referenced
*INPUT POLARITY IS REVERSED
to Negative Supply
WHEN USING PIN 1 AS OUTPUT
2
3
–
+
LT1011
4
V
+
8
V
1
R
7
LOAD
1011 TA06
V
9