LT1011/LT1011A
Voltage Comparator
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FEATURES
DESCRIPTIO
The LT®1011 is a general purpose comparator with sig-
nificantly better input characteristics than the LM111.
Although pin compatible with the LM111, it offers four
timeslowerbiascurrent,sixtimesloweroffsetvoltageand
five times higher voltage gain. Offset voltage drift, a
previously unspecified parameter, is guaranteed at
15µV/°C. Additionally, the supply current is lower by a
factor of two with no loss in speed. The LT1011 is several
times faster than the LM111 when subjected to large
overdrive conditions. It is also fully specified for DC
parameters and response time when operating on a single
5V supply. These parametric improvements allow the
LT1011 to be used in high accuracy (≥12-bit) systems
withouttrimming. Ina12-bitA/Dapplication, forinstance,
using a 2mA DAC, the offset error introduced by the
LT1011 is less than 0.5LSB. The LT1011 retains all the
versatile features of the LM111, including single 3V to
±18V supply operation, and a floating transistor output
with 50mA source/sink capability. It can drive loads refer-
enced to ground, negative supply or positive supply, and
isspecifiedupto50VbetweenV– andthecollectoroutput.
A differential input voltage up to the full supply voltage is
allowed, even with ±18V supplies, enabling the inputs to
be clamped to the supplies with simple diode clamps.
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Pin Compatible with LM111 Series Devices
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Guaranteed Max 0.5mV Input Offset Voltage
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Guaranteed Max 25nA Input Bias Current
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Guaranteed Max 3nA Input Offset Current
Guaranteed Max 250ns Response Time
Guaranteed Min 200,000 Voltage Gain
50mA Output Current Source or Sink
±30V Differential Input Voltage
Fully Specified for Single 5V Operation
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APPLICATIO S
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SAR A/D Converters
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Voltage-to-Frequency Converters
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Precision RC Oscillator
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Peak Detector
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Motor Speed Control
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Pulse Generator
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Relay/Lamp Driver
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
10µs 12-Bit A/D Converter
3.9k
R1
1k
15V
LM329
7V
Response Time vs Overdrive
FULL-SCALE
TRIM
*R2 AND R4
SHOULD TC TRACK
500
450
400
350
–15V
R2*
6.49k
R3
6.98k
0.001µF
15V
20
14
15
16
17
INPUT
0V TO 10V
5V
19
6012
12-BIT
D/A CONVERTER
R4*
R5
1k
300
250
2.49k
FALLING
OUTPUT
2
3
13
18
+
7
R6
820Ω
200
150
100
50
LT1011A
RISING
OUTPUT
12 11 10
9
7
8
7
6
5
4
3
2
1
–
PARALLEL
OUTPUTS
PARALLEL
OUTPUTS
SERIAL OUTPUT
4
5
6
8
9
16 17 18 19 20 21
D
0
0.1
7475
LATCH
1
10
100
AM2504
24
OVERDRIVE (mV)
5V
SAR REGISTER
CC
S
1011 TA02
E
S
CP
12
START
CLOCK f = 1.4MHz
1011 TA01
1