LT1011/LT1011A
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APPLICATIONS INFORMATION
Inthe“off”state,I1 isswitchedoffandbothQ1andQ2turn
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– is50VfortheLT1011Mand40VfortheLT1011C/I. The
emitter can be held at any voltage between V+ and V– as
long as it is negative with respect to the collector.
designations must be reversed. When the collector 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 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;itwillremainunconditionallyhigh(collectoroutput)
except at –40°C where it is undefined.
In the “on” state, I1 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 pro-
vides 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
respecttothecollectoroutputsothatthe“+”and“–”input
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TYPICAL APPLICATIONS
Offset Balancing
Driving Load Referenced
to Positive Supply
Driving Load Referenced
to Negative Supply
R2
3k
+
+
++
V
V
V
V
R1
3
2
2
3
8
8
+
R
–
+
LOAD
–
+
20k
V
7
5
7
LT1011
INPUTS*
LT1011
2
3
6
1
1
+
–
8
4
7
R
LT1011
LOAD
4
V
V
OR
GROUND
1011 TA03
V
1011 TA06
++
+
V
CAN BE GREATER OR LESS THAN V
*INPUT POLARITY IS REVERSED
WHEN USING PIN 1 AS OUTPUT
1011 TA05
9
Linear [ Linear ]
