LT1573 - Low Dropout Regulator Driver


  • Low Cost Solution for High Current, Low Dropout Regulators
  • Fast Transient Response Needs Much Less Bulk Capacitance
  • Latching Overload Protection Minimizes Heat Sink Size
  • Precision Output Voltage (1%)
  • Single Supply Operation: VIN = 2.8V to 10V
  • Small Surface Mount Package
  • Capable of Very Low Dropout Voltage (<0.2V)
  • Fixed or Adjustable Outputs
  • Shutdown

Typical Application

LT1573 Typical Application
LT1573 Typical Application


The LT1573 is a regulator driver IC designed to provide a low cost solution for applications requiring high current, low dropout and fast transient response. When combined with an external PNP power transistor, this device provides load current up to 5A with dropout voltages as low as 0.35V. The LT1573 circuitry is designed for extremely fast transient response. This greatly reduces bulk storage capacitance when the regulator is used in applications with fast, high current load transients.

To keep cost and complexity low, the LT1573 uses a new time-delayed latching overcurrent protection technique that requires no external current sense resistor. Base drive is limited for instantaneous protection, and a time-delayed latch protects the regulator from continuous short circuits.

The LT1573 is available as an adjustable regulator with an output range of 1.27V to 6.8V and with fixed output voltages of 2.5V, 2.8V and 3.3V. Output accuracy is better than 1% to meet the critical regulation requirement of fast microprocessors. A special 8-pin, fused-lead surface mount package is used to minimize regulator footprint and provide adequate heat sinking.


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
LT1573CS8-2.5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573CS8-2.5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573CS8-2.8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573CS8-3.3#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1573IS8#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1573IS8#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes

LT1573 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
LT1573CS8-2.5#PBF SO-8 C $2.05 $1.75 Yes
LT1573CS8-2.5#TRPBF SO-8 C $1.81 Yes
LT1573CS8-2.8#PBF SO-8 C $2.05 $1.75 Yes
LT1573CS8-3.3#PBF SO-8 C $2.05 $1.75 Yes
LT1573CS8#PBF SO-8 C $2.05 $1.75 Yes
LT1573CS8#TRPBF SO-8 C $1.81 Yes
LT1573IS8#PBF SO-8 I $2.50 $2.10 Yes
LT1573IS8#TRPBF SO-8 I $2.16 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


  • 3.3V to 2.5V Regulator
  • Microprocessor Power Source
  • Post Regulator for Switching Supplies
  • High Efficiency Linear Regulators
  • Ultralow Dropout Regulators
  • Low Voltage Linear Regulators

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