LT1721IS#PBF

Overview

The LT1721IS#PBF is a quad ultrafast comparator optimized for single-supply operation with a supply voltage range of 2.7V to 6V. It features rail-to-rail outputs that directly interface to TTL and CMOS logic. The input voltage range extends from 100mV below ground to 1.2V below the supply voltage. Propagation delay is specified at 4.5ns with 20mV overdrive and 7ns with 5mV overdrive. Quiescent supply current is 4mA per comparator at 5V. The device includes internal hysteresis with specified limits to handle slow-moving signals. It operates within a commercial temperature range of 0°C to 70°C.

Feature Summary

• Ultrafast propagation delay of 4.5ns at 20mV overdrive
• Rail-to-rail outputs compatible with TTL and CMOS logic levels
• Input common-mode range extends 100mV below the negative rail
• Integrated internal hysteresis for stable switching with slow signals

Applications

• Crystal oscillator circuits
• Window comparators
• Threshold detectors and discriminators
• High-speed sampling circuits
• Zero-crossing detectors

Procurement Notes

Verify the specific suffix IS#PBF corresponds to the industrial temperature grade (-40°C to 85°C) as indicated in ordering information, while ensuring the package matches the S (16-lead Plastic SO) description. Confirm lead-free finish compliance and tape and reel specifications if applicable. Cross-reference the manufacturer's official ordering guide to ensure the part marking and shipping container label align with the requested temperature and package variant.

Selection Notes

Select this component when high speed and low power are critical in single-supply systems. The quad configuration allows multiple comparisons in a compact footprint. Ensure the application benefits from the rail-to-rail output swing for direct logic interfacing without additional level shifting. Consider the internal hysteresis for noise immunity on slowly varying inputs. Verify that the source impedance remains low to prevent RC delays affecting propagation timing.

Part Context

The LT1721 is the quad-channel version of the LT1720 dual comparator family. Both devices share identical electrical characteristics and pinout optimizations designed to minimize parasitic effects by shielding sensitive inputs with power rails. The LT1721 utilizes a 16-pin SSOP or SO package, providing four independent comparators. This family is designed for applications requiring small size and fast response times under single-supply conditions.

Replacement Considerations

LT1721IGN#PBF serves as a verified substitute offering the same quad comparator functionality but rated for an extended industrial temperature range of -40°C to 85°C compared to the commercial grade of the LT1721IS#PBF.