LT1185 - Low Dropout Regulator


  • Low Resistance Pass Transistor: 0.25Ω
  • Dropout Voltage: 0.75V at 3A
  • ±1% Reference Voltage
  • Accurate Programmable Current Limit
  • Shutdown Capability
  • Internal Reference Available
  • Full Remote Sense
  • Low Quiescent Current: 2.5mA
  • Good High Frequency Ripple Rejection
  • Available in 5-Lead TO-220 and DD Packages

Typical Application

LT1185 Typical Application
LT1185 Typical Application


The LT1185 is a 3A low dropout regulator with adjustable current limit and remote sense capability. It can be used as a positive output regulator with floating input or as a standard negative regulator with grounded input. The output voltage range is 2.5V to 25V, with ±1% accuracy on the internal reference voltage.

The LT1185 uses a saturation-limited NPN transistor as the pass element. This device gives the linear dropout characteristics of a FET pass element with significantly less die area. High efficiency is maintained by using special anti-saturation circuitry that adjusts base drive to track load current. The “on resistance” is typically 0.25Ω. Accurate current limit is programmed with a single 1/8W external resistor, with a range of zero to three amperes. A second, fixed internal limit circuit prevents destructive currents if the programming current is accidentally overranged. Shutdown of the regulator output is guaranteed when the program current is less than 1µA, allowing external logic control of output voltage.

The LT1185 has all the protection features of previous LTC regulators, including power limiting and thermal shutdown.


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
LT1185CQ#PBF DDPAK-5 Q C 05-08-1461 Yes
LT1185CQ#TRPBF DDPAK-5 Q C 05-08-1461 Yes
LT1185CT#06PBF TO-220 T C 05-08-1421 (Flow 06) Yes
LT1185CT#30PBF TO-220 T C 05-08-1421 (Std) Yes
LT1185CT#33PBF TO-220 T C 05-08-1421 (Std) Yes
LT1185CT#PBF TO-220 T C 05-08-1421 (Std) Yes
LT1185IQ#PBF DDPAK-5 Q I 05-08-1461 Yes
LT1185IQ#TRPBF DDPAK-5 Q I 05-08-1461 Yes
LT1185IT#06PBF TO-220 T I 05-08-1421 (Flow 06) Yes
LT1185IT#30PBF TO-220 T I 05-08-1421 (Std) Yes
LT1185IT#31PBF TO-220 T I 05-08-1421 (Std) Yes
LT1185IT#PBF TO-220 T I 05-08-1421 (Std) Yes

LT1185 Package Drawing
LT1185 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
LT1185CQ#PBF DDPAK-5 C $4.50 $3.80 Yes
LT1185CQ#TRPBF DDPAK-5 C $3.92 Yes
LT1185CT#06PBF TO-220 C $4.33 $3.55 Yes
LT1185CT#30PBF TO-220 C $4.78 $4.00 Yes
LT1185CT#33PBF TO-220 C $4.78 $4.00 Yes
LT1185CT#PBF TO-220 C $4.33 $3.55 Yes
LT1185IQ#PBF DDPAK-5 I $5.83 $4.75 Yes
LT1185IQ#TRPBF DDPAK-5 I $4.87 Yes
LT1185IT#06PBF TO-220 I $5.83 $4.75 Yes
LT1185IT#30PBF TO-220 I $6.28 $5.20 Yes
LT1185IT#31PBF TO-220 I $6.28 $5.20 Yes
LT1185IT#PBF TO-220 I $5.83 $4.75 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.

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