LT1533 - Ultralow Noise 1A Switching Regulator


  • Greatly Reduced Conducted and Radiated EMI (<100µVP-P in Typical Application)
  • Low Switching Harmonic Content
  • Independent Control of Switch Voltage and Current Slew Rates
  • Two 1A Current Limited Power Switches
  • Regulates Positive and Negative Voltages
  • 20kHz to 250kHz Oscillator Frequency
  • Easily Synchronized to External Clock
  • Wide Input Voltage Range: 2.7V to 23V
  • Low Shutdown Current: 12µA Typical
  • Easier Layout than with Conventional Switchers
  • Outputs Can Be Forced to 50% Duty Cycle for Unregulated Applications

Typical Application

LT1533 Typical Application
LT1533 Typical Application


The LT1533 is a new class of switching regulator designed to reduce conducted and radiated electromagnetic interference (EMI). Ultralow noise and EMI are achieved by providing user control of the output switch slew rates. Voltage and current slew rates can be independently programmed to optimize switcher harmonic content versus efficiency. The LT1533 can reduce high frequency harmonic power by as much as 40dB with only minor losses in efficiency. The LT1533 utilizes a dual output switch current mode architecture optimized for low noise topologies. The IC includes two 1A power switches along with all necessary oscillator, control and protection circuitry. Unique error amp circuitry can regulate both positive and negative voltages. The internal oscillator may be synchronized to an external clock for more accurate placement of switching harmonics. Protection features include cycle by cycle current limit protection, undervoltage lockout and thermal shutdown. Low minimum supply voltage and low supply current during shutdown make the LT1533 well suited for portable applications. The part may also be forced into a 50% duty cycle mode for unregulated applications. The LT1533 is available in the 16-pin narrow SO 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
LT1533CS#PBF SO-16 S C 05-08-1610 (S16) Yes
LT1533CS#TRPBF SO-16 S C 05-08-1610 (S16) Yes
LT1533IS#PBF SO-16 S I 05-08-1610 (S16) Yes
LT1533IS#TRPBF SO-16 S I 05-08-1610 (S16) Yes

LT1533 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
LT1533CS#PBF SO-16 C $5.50 $4.65 Yes
LT1533CS#TRPBF SO-16 C $4.71 Yes
LT1533IS#PBF SO-16 I $7.65 $6.15 Yes
LT1533IS#TRPBF SO-16 I $6.21 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.

Part Number Description Price Documentation
DC230A-A LT1533CS | Ultra Low Noise Bipolar Output DC/DC Converter, 5Vin to +/-12Vout @ 150mA, Vin min.=4.5V, 1.8W Output $125.00
DC230A-B LT1533CS | Ultra Low Noise Bipolar Output DC/DC Converter, 12Vin to +/-5Vout @ 700mA, Vin min.=10.8V, 3.5W Output $125.00
DC230A-C LT1533CS | Ultra Low Noise Bipolar Output DC/DC Converter, 5Vin to +/-15Vout @ 120mA, Vin min.=4.5V, 1.8W Output $125.00
DC230A-D LT1533CS | Ultra Low Noise Bipolar Output DC/DC Converter, 5Vin to +/-5Vout @ 350mA, Vin min.=4.5V, 1.8W Output $125.00
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Click here to view our complete list of demo boards


  • Precision Instrumentation Systems
  • Isolated Supplies for Industrial Automation
  • Medical Instruments
  • Wireless Communications
  • Single Board Data Acquisition Systems

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