LT1721IGN#PBF

Overview

The LT1721IGN#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 and an input common-mode range extending from 100mV below ground to 1.2V below the positive supply. The device includes internal hysteresis, typically 3.5mV, to ensure stable switching with slow-moving signals. Propagation delay is specified at 4.5ns with 20mV overdrive and 7ns with 5mV overdrive. Quiescent current consumption is 4mA per comparator at 5V. The component operates within an industrial temperature range of -40°C to 85°C.

Feature Summary

• Ultrafast propagation delay of 4.5ns at 20mV overdrive
• Rail-to-rail output capability compatible with TTL and CMOS logic levels
• Internal hysteresis eliminates oscillation issues with slow input signals
• Input common-mode range extends 100mV below the negative supply rail

Applications

• Crystal oscillator circuits
• High-speed differential line receivers
• Window comparators and threshold detectors
• Zero-crossing detectors
• High-speed sampling circuits

Procurement Notes

Verify that the ordering suffix IGN#PBF corresponds to the 16-lead narrow plastic SSOP package and the industrial temperature grade (-40°C to 85°C). Confirm lead-free finish compliance via the PBF designation. Ensure the source documentation explicitly supports these specific attributes for this part number before procurement.

Selection Notes

Select this component when four independent high-speed comparators are required in a compact surface-mount form factor. It is suitable for applications demanding low power consumption alongside fast response times. The wide input common-mode range allows for direct interfacing with signals near ground potential without external level shifting.

Part Context

This part belongs to the LT1720/LT1721 family of UltraFast comparators. While the LT1720 provides dual channels, the LT1721 integrates four comparators on a single chip. Both share identical electrical characteristics and pinout optimizations designed to minimize parasitic effects by shielding sensitive inputs between power rails.

Replacement Considerations

LT1721CGN#PBF (Commercial Grade)

FAQ

How does the internal hysteresis affect the trip points?

The internal hysteresis creates two distinct trip points: VTRIP+ and VTRIP-. The offset voltage is defined as the average of these two points, while the hysteresis voltage is the difference between them.

What is the maximum toggle frequency of the LT1721?

The maximum toggle frequency is 62.5MHz at 5V supply with 50mV overdrive, and 70.0MHz at 3V supply with 50mV overdrive.