Datasheet

LT1011/LT1011A
11
1011afe
For more information www.linear.com/LT1011
applicaTions inForMaTion
In the “off” state, I
1
is switched off and both Q1 and Q2
turn off. The collector of Q2 can be now held at any voltage
above V
–
without conducting current, including voltages
above the positive supply level. Maximum voltage above
V
–
is 50V for the LT1011M and 40V for the LT1011C/I.
The emitter can be held at any voltage between V
+
and
V
–
as long as it is negative with respect to the collector.
In the “on” state, I
1
is connected, turning on Q1 and Q2.
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 provides turn-
off drive. Either the collector or emitter pin can be held at
a voltage between V
+
and V
–
. This allows the remaining
pin to drive the load. In typical applications, the emitter is
connected to V
–
or ground and the collector drives a load
tied to V
+
or a separate positive supply.
When the emitter is used as the output, the collector is
typically tied to V
+
and the load is connected to ground
or V
–
. Note that the emitter output is phase reversed with
respect to the collector output so that the “+” and “–”
input designations must be reversed. When the collector
Typical applicaTions
Offset Balancing Driving Load Referenced
to Positive Supply
Driving Load Referenced
to Negative Supply
is tied to V
+
, the voltage at the emitter in the “on” state is
about 2V below V
+
(see curves).
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 Characteristics). 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 temperatures
below 25°C, the output becomes undefined.
–
+
LT1011
5
R2
3k
R1
20k
6
7
8
2
3
1011 TA03
V
+
–
+
LT1011INPUTS*
2
7
R
LOAD
4
1
8
*INPUT POLARITY IS REVERSED
WHEN USING PIN 1 AS OUTPUT
V
V
V
+
3
1011 TA06
–
+
LT1011
3
7
R
LOAD
4
1
8
V
++
CAN BE GREATER OR LESS THAN V
+
V
V
+
V
++
V
OR
GROUND
2
1011 TA05
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