Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsLinear ICsLinear IC - Comparator + lock CMOS, Complementary, TTL PDIP 8

LT1016

1016fc

Typical applicaTion

FeaTures DescripTion

UltraFast Precision

10ns Comparator

The LT

1016 is an UltraFast 10ns comparator that interfaces

directly to TTL/CMOS logic while operating off either ±5V

or single 5V supplies. Tight offset voltage specifications

and high gain allow the LT1016 to be used in precision

applications. Matched complementary outputs further

extend the versatility of this comparator.

A unique output stage provides active drive in both direc

tions for maximum speed into TT

L/CMOS logic or passive

loads, yet does not exhibit the large current spikes found

in conventional output stages. This allows the LT1016 to

remain stable with the outputs in the active region which,

greatly reduces the problem of output “glitching” when

the input signal is slow moving or islow level.

The LT1016 has a LATCH pin which will retain input data

at the outputs, when held high. Quiescent negative power

supply current is only 3mA. This allows the negative supply

pin to be driven from virtually any supply voltage with a

simple resistivedivider. Device performance is not affected

by variations in negative supply voltage.

Linear Technology offers a wide range of comparators

in addition to the LT1016 that address different applica

tions. See

the Related Parts section on the back page of

the data sheet.

10MHz to 25MHz Crystal Oscillator

applicaTions

UltraFast™ (10ns typ)

Operates Off Single 5V Supply or ±5V

Complementary Output to TTL

Low Offset Voltage

No Minimum Input Slew Rate Requirement

No Power Supply Current Spiking

Output Latch Capability

High Speed A/D Converters

■

High Speed Sampling Circuits

■

Line Receivers

■

Extended Range V-to-F Converters

■

Fast Pulse Height/Width Discriminators

■

Zero-Crossing Detectors

■

Current Sense for Switching Regulators

■

High Speed Triggers

■

Crystal Oscillators

L, LT , LT C , LT M , Linear Technology and the Linear logo are registered trademarks and

UltraFast is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners.

Response Time

–

LT1016

10MHz TO 25MHz

(AT CUT)

22Ω

820pF

200pF

–

LATCH

GND

OUTPUT

1016 TA1a

TIME (ns)

1016 TA2b

THRESHOLD

100mV STEP

5mV OVERDRIVE

OUT

1V/DIV

Summary of content (20 pages)

PAGE 1
LT1016 UltraFast Precision 10ns Comparator Features n n n n n n n Description UltraFast™ (10ns typ) Operates Off Single 5V Supply or ±5V Complementary Output to TTL Low Offset Voltage No Minimum Input Slew Rate Requirement No Power Supply Current Spiking Output Latch Capability Applications n ■ ■ ■ ■ ■ ■ ■ ■ High Speed A/D Converters High Speed Sampling Circuits Line Receivers Extended Range V-to-F Converters Fast Pulse Height/Width Discriminators Zero-Crossing Detectors Current Sense for Switching Regu
PAGE 2
LT1016 Absolute Maximum Ratings (Note 1) Positive Supply Voltage (Note 5).................................7V Negative Supply Voltage..............................................7V Differential Input Voltage (Note 7)............................ ±5V +IN, –IN and LATCH ENABLE Current (Note 7)..... ±10mA Output Current (Continuous) (Note 7).................. ±20mA Operating Temperature Range LT1016I.................................................–40°C to 85°C LT1016C........................................
PAGE 3
LT1016 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 5V, V– = 5V, VOUT (Q) = 1.4V, VLATCH = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS VOS Input Offset Voltage RS ≤ 100Ω (Note 2) ∆VOS /∆T Input Offset Voltage Drift IOS Input Offset Current IB Input Bias Current MIN LT1016C/I TYP 1.0 ● ±3 3.5 UNITS mV mV ● 4 ● 0.3 0.3 1.0 1.3 µA µA 5 10 13 µA µA 3.5 3.
PAGE 4
LT1016 Typical Performance Characteristics Propagation Delay vs Input Overdrive Gain Characteristics 5.0 4.5 TJ = 125°C 25 VS = ±5V TJ = 25°C =0 I 20 VOUT = 100mV STEP OVERDRIVE = 5mV VS = ±5V TJ = 25°C VSTEP = 100mV CLOAD = 10pF 20 3.5 TJ = 25°C 2.5 2.0 15 TIME (ns) 3.0 TIME (ns) OUTPUT VOLTAGE (V) 4.0 25 VS = ±5V IOUT = 0 Propagation Delay vs Load Capacitance 10 15 tPDHL 10 tPDLH 1.5 5 TJ = – 55°C 1.0 5 0.5 – 0.5 –1.5 0.5 1.5 DIFFERENTIAL INPUT VOLTAGE (mV) 0 2.
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LT1016 Typical Performance Characteristics Negative Supply Current vs Temperature 40 V – = 0V VIN = 60mV IOUT = 0 45 40 3 2 30 30 25 20 15 TJ = 125°C 10 1 5 0 50 100 –50 –25 25 75 0 JUNCTION TEMPERATURE (°C) 0 125 TJ = 25°C 1 2 7 6 4 3 5 SUPPLY VOLTAGE (V) 70 10M 100 VS = SINGLE 5V SUPPLY 1 3 2 1 50 *SEE APPLICATION INFORMATION FOR COMMON MODE LIMIT WITH VARYING SUPPLY VOLTAGE. 0 –1 *SEE APPLICATION INFORMATION FOR COMMON MODE LIMIT WITH VARYING SUPPLY VOLTAGE.
PAGE 6
LT1016 Applications Information Common Mode Considerations The LT1016 is specified for a common mode range of –3.75V to 3.5V with supply voltages of ±5V. A more general consideration is that the common mode range is 1.25V above the negative supply and 1.5V below the positive supply, independent of the actual supply voltage. The criteria for common mode limit is that the output still responds correctly to a small differential input signal.
PAGE 7
LT1016 Applications Information The circuit shown in Figure 1 is the best electronic means of generating a known fast, clean step to test comparators. It uses a very fast transistor in a common base configuration. The transistor is switched “off” with a fast edge from the generator and the collector voltage settles to exactly 0V in just a few nanoseconds. The most important feature of this circuit is the lack of feedthrough from the generator to the comparator input.
PAGE 8
LT1016 Applications Information Other common problems include different measurement results using various pieces of test equipment, inability to make measurement connections to the circuit without inducing spurious responses and dissimilar operation between two “identical” circuits. If the components used in the circuit are good and the design is sound, all of the above problems can usually be traced to failure to provide a proper circuit “environment.
PAGE 9
LT1016 Applications Information In Figure 4 the LT1016’s supplies are bypassed, but it still oscillates. In this case, the bypass units are either too far from the device or are lossy capacitors. Use capacitors with good high frequency characteristics and mount them as close as possible to the LT1016. An inch of wire between the capacitor and the LT1016 can cause problems. If operation in the linear region is desired, the LT1016 must be over a ground plate with good RF bypass capacitors (≥0.
PAGE 10
LT1016 Applications Information In Figure 7 the probes are properly selected and applied but the LT1016’s output rings and distorts badly. In this case, the probe ground lead is too long. For general purpose work most probes come with ground leads about six inches long. At low frequencies this is fine. At high speed, the long ground lead looks inductive, causing the ringing shown. High quality probes are always supplied with some short ground straps to deal with this problem.
PAGE 11
LT1016 Applications Information “Fuzz” on the edges is the difficulty in Figure 10. This condition appears similar to Figure 10, but the oscillation is more stubborn and persists well after the output has gone low. This condition is due to stray capacitive feedback from the outputs to the inputs. A 3kΩ input source impedance and 3pF of stray feedback allowed this oscillation. The solution for this condition is not too difficult. Keep source impedances as low as possible, preferably 1k or less.
PAGE 12
LT1016 Applications Information Another output-caused fault is shown in Figure 13. The output transitions are initially correct but end in a ringing condition. The key to the solution here is the ringing. What is happening is caused by an output lead that is too long. The output lead looks like an unterminated transmission line at high frequencies and reflections occur. This accounts for the abrupt reversal of direction on the leading edge and the ringing.
PAGE 13
LT1016 Applications Information 1.8µs, 12-Bit A/D Converter The LT1016’s high speed is used to implement a very fast 12-bit A/D converter in Figure 15. The circuit is a modified form of the standard successive approximation approach and is faster than most commercial SAR 12-bit units. In this arrangement the 2504 successive approximation register (SAR), A1 and C1 test each bit, beginning with the MSB, and produce a digital word representing VIN’s value.
PAGE 14
LT1016 Typical Applications Voltage Controlled Pulse Width Generator Single Supply Precision RC 1MHz Oscillator 6.2k* 5V FULL-SCALE CALIBRATION 500Ω LM385 1.23V 2N3906 100pF 25Ω 2.7k 5V 1k 2N3906 1000pF Q LT1016 + + 2k LT1016 – VIN = 0V TO 2.5V – 100pF 5V START 5V –5V 1N914 CEXT 1k Q V– B 74121 A1 Q 5V 10k 1% 2N3906 470pF GND LATCH 5pF 10k 1% 0µs TO 2.5µs (MINIMUM WIDTH ≈ 0.05µs) Q 74HC04 10k 1% OUTPUTS * SELECT OR TRIM FOR f = 1.00MHz 1016 AI02 8.
PAGE 15
LT1016 Typical Applications 1MHz to 10MHz Crystal Oscillator 18ns Fuse with Voltage Programmable Trip Point 5V 2k 1MHz TO 10MHz CRYSTAL 330Ω V+ + V– – 5V A1 LT1193 Q LT1016 – 2.4k Q2 2N2369 5V 2k Q1 2N3866 28V Q GND LATCH 900Ω + – FB OUTPUT 33pF 300Ω 1k 2k A2 LT1016 L 0.068µF 1016 AI04 * = 1% FILM RESISTOR A1 AND A2 USE 5V SUPPLIES + – 1k* 9k* 9k* 10Ω CARBON 1k* 200Ω CALIBRATE TRIP SET 0mA TO 250mA = 0V TO 2.
PAGE 16
LT1016 Appendix A 15V 1k +V 2N2369 2N3866 + OUTPUT = 0V TO TYPICALLY 3V TO 4V LT1016 OUTPUT HP5082-2810 LT1016 OUTPUT – 1k NONINVERTING VOLTAGE GAIN tRISE = 4ns tFALL = 5ns 1016 FA01 1k 12pF 1016 fFA02 Figure A1 Figure A2 5V + INPUT LT1016 – 1N4148 4.7k 430Ω Q1 2N2907 HP5082-2810 1000pF 0.
PAGE 17
V– LATCH – INPUT + INPUT D2 D1 Q50 + Q16 D3 D4 15pF Q20 1.5k Q51 165Ω Q10 Q6 150Ω 375Ω Q19 1.1k D5 Q9 Q7 Q8 150Ω Q18 Q5 1.3k Q4 830Ω Q3 Q17 1.3k 75Ω Q2 65Ω Q1 15pF 800Ω 50Ω + 75Ω 800Ω 50Ω 3k Q49 955Ω 350Ω 1.3k Q11 165Ω Q21 15pF 1k 1k Q14 Q25 Q22 + 210Ω + 150Ω 565Ω 150Ω Q13 1.3k Q12 Q15 2k 300Ω 1.8k 100pF 3.5k 100Ω 1.5k Q23 1.8k Q28 3.5k 100Ω 1.5k Q24 1.
PAGE 18
LT1016 Package Description N8 Package 8-Lead PDIP (Narrow .300 Inch (Reference LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( + 0.035 0.325 – 0.015 8.255 + 0.889 – 0.381 ) 0.045 – 0.065 (1.143 – 1.651) 0.065 (1.651) TYP 0.100 (2.54) BSC 0.130 ± 0.005 (3.302 ± 0.127) 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.
PAGE 19
LT1016 Package Description S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 8 7 6 5 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) SO8 1298 1 0.010 – 0.020 ×45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0° – 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.014 – 0.019 (0.355 – 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.
PAGE 20
LT1016 Applications Information 1Hz to 10MHz V-to-F Converter the circuit’s output pulse generator, closing feedback loop around the integrating amplifier. To maintain the summing node at zero, the pulse generator runs at a frequency that permits enough charge pumping to offset the input signal. Thus, the output frequency is linearly related to the input voltage. The LT1016 and the LT1122 FET input amplifier combine to form a high speed V-to-F converter in Figure 16.