LTC1728 - Micropower Precision Triple Supply Monitors in 8-Lead MSOP and 5-Lead SOT-23 Packages


  • Monitors Three Inputs Simultaneously
    LTC1727-5: 5V, 3.3V and ADJ
    LTC1727-2.5: 2.5V, 3.3V and ADJ
    LTC1728-5: 5V, 3.3V and ADJ
    LTC1728-2.5: 2.5V, 3.3V and ADJ
    LTC1728-1.8: 3V, 1.8V and ADJ
    LTC1728-3.3: 3.3V, 1.8V and ADJ
  • ±1.5% Threshold Accuracy Over Temperature
  • Very Low Supply Current: 10µA Typ
  • 200ms Reset Time Delay
  • Active Low RESET Output
  • Power Supply Glitch Immunity
  • Guaranteed RESET for VCC3 ≥ 1V
  • or VCC5/VCC25/VCC18 ≥ 1V
  • LTC1727 Includes Monitor Output for Each Supply
  • LTC1727: 8-Lead MSOP and SO Packages
  • LTC1728: 5-Lead SOT-23 Package

Typical Application

LTC1728 Typical Application
LTC1728 Typical Application


The LTC1727 is a triple supply monitor intended for systems with multiple supply voltages. Each supply monitor has its own open-drain output for individual supply monitoring. A common open-drain reset output remains low until all three supplies have been in compliance for 200ms. Tight 1.5% accuracy specifications and glitch immunity ensure reliable reset operation without false triggering.

The LTC1728 is functionally identical to the LTC1727 without the individual monitor outputs.

The RST output is guaranteed to be in the correct state for VCC5/VCC25/VCC18 or VCC3 down to 1V. The LTC1727/LTC1728 may also be configured to monitor any one or two VCC inputs instead of three, depending on system requirements.

Very low (10µA typical) supply current makes the LTC1727/LTC1728 ideal for power conscious systems.

The LTC1727 is available in an 8-lead MSOP or SO package and the LTC1728 is available in a 5-lead SOT-23 package.


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
LTC1728ES5-1.8#PBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-1.8#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-1.8#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-2.5#PBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-2.5#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-2.5#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-3.3#PBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-3.3#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-3.3#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-5#PBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-5#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728ES5-5#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC1728HS5-5#PBF SOT-23 S5 H 05-08-1635 Yes
LTC1728HS5-5#TRMPBF SOT-23 S5 H 05-08-1635 Yes
LTC1728HS5-5#TRPBF SOT-23 S5 H 05-08-1635 Yes

LTC1728 Package Drawing
LTC1728 Package Drawing
LTC1728 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
LTC1728ES5-1.8#PBF SOT-23 E $1.66 Yes
LTC1728ES5-1.8#TRMPBF SOT-23 E $1.66 $1.45 Yes
LTC1728ES5-1.8#TRPBF SOT-23 E $1.66 $1.40 Yes
LTC1728ES5-2.5#PBF SOT-23 E $1.66 Yes
LTC1728ES5-2.5#TRMPBF SOT-23 E $1.66 $1.45 Yes
LTC1728ES5-2.5#TRPBF SOT-23 E $1.66 $1.40 Yes
LTC1728ES5-3.3#PBF SOT-23 E $1.66 Yes
LTC1728ES5-3.3#TRMPBF SOT-23 E $1.66 $1.45 Yes
LTC1728ES5-3.3#TRPBF SOT-23 E $1.66 $1.40 Yes
LTC1728ES5-5#PBF SOT-23 E $1.66 Yes
LTC1728ES5-5#TRMPBF SOT-23 E $1.66 $1.45 Yes
LTC1728ES5-5#TRPBF SOT-23 E $1.66 $1.40 Yes
LTC1728HS5-5#PBF SOT-23 H $2.42 Yes
LTC1728HS5-5#TRMPBF SOT-23 H $2.42 $1.75 Yes
LTC1728HS5-5#TRPBF SOT-23 H $2.48 $1.70 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.

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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.

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