LT1721 - Quad, 4.5ns, Single Supply 3V/5V Comparators with Rail-to-Rail Outputs

The LT1720/LT1721 are UltraFast dual/quad comparators optimized for single supply operation, with a supply voltage range of 2.7V to 6V. The input voltage range extends from 100mV below ground to 1.2V below the supply voltage. Internal hysteresis makes the LT1720/LT1721 easy to use even with slow moving input signals. The rail-to-rail outputs directly interface to TTL and CMOS. Alternatively, the symmetric output drive can be harnessed for analog applications or for easy translation to other single supply logic levels.

The LT1720 is available in three 8-pin packages; three pins per comparator plus power and ground. In addition to SO and MSOP packages, a 3mm x 3mm low profile (0.8mm) dual fine pitch leadless package (DFN) is available for space limited applications. The LT1721 is available in the 16-pin SSOP and S packages.

The pinouts of the LT1720/LT1721 minimize parasitic effects by placing the most sensitive inputs (inverting) away from the outputs, shielded by the power rails. The LT1720/LT1721 are ideal for systems where small size and low power are paramount.

  • UltraFast: 4.5ns at 20mV Overdrive 7ns at 5mV Overdrive
  • Low Power: 4mA per Comparator
  • Optimized for 3V and 5V Operation
  • Pinout Optimized for High Speed Ease of Use
  • Input Voltage Range Extends 100mV Below Negative Rail
  • TTL/CMOS Compatible Rail-to-Rail Outputs
  • Internal Hysteresis with Specified Limits
  • Low Dynamic Current Drain; 15µA/(V-MHz), Dominated by Load In Most Circuits
  • Tiny 3mm x 3mm x 0.8mm DFN Package (LT1720)
Typical Application
LT1721 Typical Application
LT1721 Typical Application
  • High Speed Differential Line Receiver
  • Crystal Oscillator Circuits
  • Window Comparators
  • Threshold Detectors/Discriminators
  • Pulse Stretchers
  • Zero-Crossing Detectors
  • High Speed Sampling Circuits
LT1721 Package Drawing
LT1721 Package Drawing
LT1721 Package Drawing
LT1721 Package Drawing
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Application Note
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R377 Reliability Data
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LT1721 Footprints and Symbols
LT1721 Demo Circuit - 0ns to 10ns Pulse Width Generator