Datasheet

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LT1011/LT1011A

1011afc

OVERDRIVE (mV)

0.1

200

RESPONSE TIME (ns)

250

300

350

400

1 10 100

1011 TA02

150

100

450

500

FALLING

OUTPUT

RISING

OUTPUT

10μs 12-Bit A/D Converter

Response Time vs Overdrive

TYPICAL APPLICATION

DESCRIPTION

Voltage Comparator

The LT

1011 is a general purpose comparator with sig-

niﬁ cantly better input characteristics than the LM111.

Although pin compatible with the LM111, it offers four

times lower bias current, six times lower offset voltage

and ﬁ ve times higher voltage gain. Offset voltage drift,

a previously unspeciﬁ ed 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 speciﬁ ed 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 without trimming. In a

12-bit A/D application, for instance, 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 ﬂ oat-

ing transistor output with 50mA source/sink capability. It

can drive loads referenced to ground, negative supply or

positive supply, and is speciﬁ ed up to 50V between V

–

and

the collector output. 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.

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other

trademarks are the property of their respective owners.

FEATURES

APPLICATIONS

Pin Compatible with LM111 Series Devices

Guaranteed Max 0.5mV Input Offset Voltage

Guaranteed Max 25nA Input Bias Current

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 Speciﬁ ed for Single 5V Operation

Available in 8-Lead PDIP and SO Packages

SAR A/D Converters

Voltage-to-Frequency Converters

Precision RC Oscillator

Peak Detector

Motor Speed Control

Pulse Generator

Relay/Lamp Driver

6012

12-BIT

D/A CONVERTER

PARALLEL

OUTPUTS

PARALLEL

OUTPUTS

*R2 AND R4

SHOULD TC TRACK

820Ω

6.98k

R2*

6.49k

FULL-SCALE

TRIM

LM329

R4*

2.49k

0.001μF

–15V

3.9k

15V

SERIAL OUTPUT

INPUT

0V TO 10V 5V

7475

LATCH

AM2504

SAR REGISTER

START CLOCK f = 1.4MHz

1011 TA01

S CP

–

LT1011A

Summary of content (16 pages)

PAGE 1
LT1011/LT1011A Voltage Comparator FEATURES DESCRIPTION n The LT®1011 is a general purpose comparator with signiﬁcantly better input characteristics than the LM111. Although pin compatible with the LM111, it offers four times lower bias current, six times lower offset voltage and 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.
PAGE 2
LT1011/LT1011A ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage (Pin 8 to Pin 4) .................................36V Output to Negative Supply (Pin 7 to Pin 4) LT1011AC, LT1011C ..............................................40V LT1011AI, LT1011I ................................................40V LT1011AM, LT1011M (OBSOLETE) .......................50V Ground to Negative Supply (Pin 1 to Pin 4) ..............30V Differential Input Voltage.........................................
PAGE 3
LT1011/LT1011A ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VS = ±15V, VCM = 0V, RS = 0Ω, VGND = –15V, output at pin 7 unless otherwise noted. LT1011AC/AI/AM SYMBOL PARAMETER CONDITIONS MIN (Note 5) TYP MAX 0.2 3 5 LT1011C/I/M MIN TYP MAX 0.
PAGE 4
LT1011/LT1011A TYPICAL PERFORMANCE CHARACTERISTICS Input Bias Current Input Offset Current 0.8 35 0.7 30 0.6 25 20 0.5 0.4 15 0.3 10 0.2 5 0.1 0 –50 –25 0 EQUIVALENT OFFSET VOLTAGE (mV) IB FLOWS OUT 40 OF INPUTS CURRENT (nA) 0 –50 –25 25 50 75 100 125 150 TEMPERATURE (°C) 0 Input Characteristics* Transfer Function (Gain) 50 –20 –25 –30 –35 POSITIVE LIMIT –1.0 TA = 25°C REFERRED TO SUPPLIES 0.4 0.3 NEGATIVE LIMIT 0.2 COLLECTOR OUTPUT RL = 1k 40 –1.5 –2.
PAGE 5
LT1011/LT1011A TYPICAL PERFORMANCE CHARACTERISTICS Response Time Using GND Pin as Output V+ 20mV 10 5mV 2mV V+ 5 VIN 0 –5 VOUT –10 2k –15 V– 0 –50 VS = ±15V TA = 25°C –100 0 4 3 2 TIME (μs) 1 INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 15 VIN 10 5 VOUT 0 2k –5 V– –10 5mV 20mV –15 2mV 0 VS = ±15V TA = 25°C –50 –100 0 1 2 TIME (μs) 1011 G10 Supply Current vs Supply Voltage 0.4 60 0.3 SHORT-CIRCUIT CURRENT 40 0.2 20 0.
PAGE 6
LT1011/LT1011A TYPICAL PERFORMANCE CHARACTERISTICS 2.5 INPUT OFFSET VOLTAGE (mV) 2.0 CHANGE IN VOS (mV/μA) Input Offset Voltage vs Common Mode Voltage TJ = 25°C 1.5 1.0 0.5 UPPER COMMON MODE + – (1.5V) LIMIT = V 0 Offset Pin Characteristics 0.8 0.6 0.4 0.2 0 –0.5 –150mV –1.0 –1.5 –2.0 –2.5 V– (OR GND WITH SINGLE SUPPLY) V– 0.1 0.2 0.3 0.4 0.5 0.6 0.
PAGE 7
LT1011/LT1011A APPLICATIONS INFORMATION 15V 2μF TANT + 3 INPUTS 2 – + C1 0.003μF 8 6 LT1011 5 7 R2 15M 8 C8 TO C6 = 0.003μF 7 INPUT OFFSET VOLTAGE (mV) of the compara tor, but require a minimum input signal slew rate to be effective. DC hysteresis works for all input slew rates, but creates a shift in offset voltage dependent on the previous condition of the input signal. The circuit shown in Figure 1 is an excellent compromise between AC and DC hysteresis.
PAGE 8
LT1011/LT1011A APPLICATIONS INFORMATION The input resistors should limit fault current to a reasonable value (0.1mA to 20mA). Power dissipation in the resistors must be considered for continuous faults, especially when the LT1011 supplies are off. One ﬁnal caution: lightly loaded supplies may be forced to higher voltages by large fault currents ﬂowing through D1-D4. 15V The response time of a comparator is typically measured with a 100mV step and a 5mV to 10mV overdrive.
PAGE 9
LT1011/LT1011A APPLICATIONS INFORMATION is tied to V+, the voltage at the emitter in the “on” state is about 2V below V+ (see curves). In the “off” state, I1 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.
PAGE 10
LT1011/LT1011A TYPICAL APPLICATIONS Strobing 2 Window Detector V++** V+ V+ + 7 LT1011 3 Driving Ground Referred Load – 2 6 INPUTS* TTL STROBE 4 1k V– L1 NOTE: DO NOT GROUND STROBE PIN – OUTPUT HIGH INSIDE “WINDOW” AND LOW ABOVE HIGH LIMIT OR BELOW LOW LIMIT 1 VIN 2 1011 TA07 *INPUT POLARITY IS REVERSED WHEN USING PIN 1 AS OUTPUT **V++ MAY BE ANY VOLTAGE ABOVE V–.
PAGE 11
LT1011/LT1011A TYPICAL APPLICATIONS Combining Offset Adjust and Strobe Combining Offset Adjustment and Hystersis V+ 10k 2RH** 20k 5 – RH* – TTL OR CMOS 5V LT1011 5 + 1k *HYSTERESIS IS ≈0.45mV/μA OF CURRENT CHANGE IN RH RL **THIS RESISTOR CAUSES HYSTERESIS TO BE CENTERED AROUND VOS 20k 6 6 + V+ 5k 7 LT1011 1011 TA15 1 1011 TA13 Direct Strobe Drive When CMOS* Logic Uses Same V + Supply as LT1011 Low Drift R/C Oscillator † V+ ** 8 – 2 6 + 15V LT1011 C1 0.
PAGE 12
LT1011/LT1011A TYPICAL APPLICATIONS 4-Digit (10,000 Count) A/D Converter 15V ZERO TRIM R1 1k 1 3 R2 18k INPUT 0V TO 10V C4 0.01μF 7 R3 3.9k 8 4 8 6 LT1011 D1 D2 C1* 0.1μF C2** 15pF R7 22Ω 5V C5 0.01μF + 3 6 5V R5 4.7k 2 2 5 LF398 15V R6 4.7K 7 1 – OUTPUT = 1 COUNT PER mV, f = 1MHz CLOCK 1MHz 4 –15V 15V –15V R4 5.6k R8 3k D3 15V D4 C3 0.1μF R11 6.8K R10 1k R9 FULL-SCALE 3.65k TRIM R12 6.
PAGE 13
LT1011/LT1011A TYPICAL APPLICATIONS Fast Settling* Filter 100pF 1M 15V 2 7 1M OUTPUT 8 3 VIN 1 4 4.7k –15V 15V 0.1μF 6 LT1008C 4.7k 1μF OFM-1A** –15V 100k 100pF 4 2 8 – 3 1.5k 7 1 LT1011 5 + 6 15V 15V 5k THRESHOLD 5k 6 + 5 1 LT1011 7 – 8 4 10k –15V 15V 1011 TA21 100kHz Precision Rectiﬁer 0.
PAGE 14
LT1011/LT1011A SCHEMATIC DIAGRAM OFFSET OFFSET/STROBE V+ 5 6 8 R8 800Ω Q6 R27 3k R4 300Ω R5 160Ω R1 1.3k R2 1.3k Q10 R3 300Ω R23 4k Q11 Q5 Q31 Q12 R6 3.2k D1 D2 Q30 INPUT (+) R7 3.2k Q13 Q8 D4 D6 Q29 2 R9 800Ω R11 170Ω Q7 D5 R12 470Ω Q4 Q27 R16 Q24 800Ω Q2 Q23 Q26 Q25 Q15 Q9 Q19 Q28 3 7 Q20 R22 200Ω Q1 D7 OUTPUT Q14 Q3 INPUT (–) R10 4k Q16 R17 200Ω Q21 R24 400Ω R20 940Ω R13 4Ω R15 700Ω Q22 1 Q18 GND R25 1.6k R26 1.
PAGE 15
LT1011/LT1011A PACKAGE DESCRIPTION J8 Package 8-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) CORNER LEADS OPTION (4 PLCS) 0.005 (0.127) MIN 0.023 – 0.045 (0.584 – 1.143) HALF LEAD OPTION 0.045 – 0.068 (1.143 – 1.727) FULL LEAD OPTION 0.405 (10.287) MAX 8 7 6 5 0.025 (0.635) RAD TYP 0.220 – 0.310 (5.588 – 7.874) 1 2 0.300 BSC (0.762 BSC) 3 4 0.200 (5.080) MAX 0.015 – 0.060 (0.381 – 1.524) 0.008 – 0.018 (0.203 – 0.
PAGE 16
LT1011/LT1011A TYPICAL APPLICATION 10Hz to 100kHz Voltage to Frequency Converter R7 4.7k R4 1M 15V 15V C1 0.002μF POLYSTYRENE R1 4.7k LT1009 2.5V 15V INPUT 0V TO 10V R2 5k FULL-SCALE R3 TRIM 8.06k 3 C2 0.68μF 15V R16 50k 10Hz TRIM R5 2k 15V LINEARITY ≈0.01% 8 – 1 + R17† 22M R8 4.7k 7 LT1011 2 R6 2k –15V 4 1.5μs 6 4.4V –15V 0.