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


  • 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


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.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LT1721CGN#PBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LT1721CGN#TRPBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LT1721CS#PBF SO-16 S C 05-08-1610 (S16) Yes
LT1721CS#TRPBF SO-16 S C 05-08-1610 (S16) Yes
LT1721IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1721IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1721IS#PBF SO-16 S I 05-08-1610 (S16) Yes
LT1721IS#TRPBF SO-16 S I 05-08-1610 (S16) Yes

LT1721 Package Drawing
LT1721 Package Drawing
LT1721 Package Drawing
LT1721 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LT1721CGN#PBF SSOP-16 C $5.60 $4.70 Yes
LT1721CGN#TRPBF SSOP-16 C $4.76 Yes
LT1721CS#PBF SO-16 C $5.40 $4.50 Yes
LT1721CS#TRPBF SO-16 C $4.56 Yes
LT1721IGN#PBF SSOP-16 I $5.80 $4.90 Yes
LT1721IGN#TRPBF SSOP-16 I $4.96 Yes
LT1721IS#PBF SO-16 I $5.60 $4.70 Yes
LT1721IS#TRPBF SO-16 I $4.76 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards


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