LT3599 - 4-String 120mA LED Driver with ±1.5% Current Matching


  • True Color PWM Dimming Ratio Up to 3000:1
  • Drives Four Strings of LEDs at Up to 120mA
  • ±1.5% Accurate LED Current Matching
  • Wide Input Voltage Range: 3.1V to 30V
  • Output Voltage Up to 44V
  • Regulates LED Current Even When VIN > VOUT
  • Disconnects LEDs in Shutdown
  • Programmable Maximum VOUT (Regulated)
  • Open/Short LED Protection and Fault Flags
  • Programmable LED Current Derating
  • Adjustable Frequency: 200kHz to 2.1MHz
  • Synchronizable to an External Clock
  • Analog Dimming Up to 20:1
  • Programmable Input UVLO with Hysteresis
  • Thermally Enhanced 32-Pin (5mm × 5mm) QFN and 28-Pin TSSOP Packages

Typical Application

LT3599 Typical Application
LT3599 Typical Application


The LT3599 is a fixed frequency 2A step-up DC/DC converter designed to drive four strings of 120mA LEDs up to a 44V output voltage. The switching frequency is programmable from 200kHz to 2.1MHz through an external resistor.

LED dimming can be achieved with analog dimming on the CTRL pin, and with pulse width modulation dimming on the PWM pin. The LT3599 accurately regulates LED current even when the input voltage is higher than the LED output voltage.

Additional features include programmable LED current derating, switching frequency synchronization to an external clock, LED string disable control, OPENLED alert pin, SHORTLED alert pins and programmable maximum output voltage when all LED strings are disconnected. The LT3599 is available in the thermally enhanced 32-pin (5mm × 5mm) QFN and 28-pin TSSOP packages.


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

Part Number Package Code Temp Package
LT3599EFE#PBF TSSOP-28 FE E 05-08-1663 (EB) RoHS
LT3599EFE#TRPBF TSSOP-28 FE E 05-08-1663 (EB) RoHS
LT3599EUH#PBF 5x5 QFN-32 UH E 05-08-1693 RoHS
LT3599EUH#TRPBF 5x5 QFN-32 UH E 05-08-1693 RoHS
LT3599HFE#PBF TSSOP-28 FE H 05-08-1663 (EB) RoHS
LT3599HFE#TRPBF TSSOP-28 FE H 05-08-1663 (EB) RoHS
LT3599IFE#PBF TSSOP-28 FE I 05-08-1663 (EB) RoHS
LT3599IFE#TRPBF TSSOP-28 FE I 05-08-1663 (EB) RoHS
LT3599IUH#PBF 5x5 QFN-32 UH I 05-08-1693 RoHS
LT3599IUH#TRPBF 5x5 QFN-32 UH I 05-08-1693 RoHS

LT3599 Package Drawing
LT3599 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
LT3599EFE#PBF TSSOP-28 E $4.79 $3.35 Yes
LT3599EFE#TRPBF TSSOP-28 E $3.41 Yes
LT3599EUH#PBF 5x5 QFN-32 E $4.64 $3.25 Yes
LT3599EUH#TRPBF 5x5 QFN-32 E $3.31 Yes
LT3599HFE#PBF TSSOP-28 H $5.99 $4.19 Yes
LT3599HFE#TRPBF TSSOP-28 H $4.25 Yes
LT3599IFE#PBF TSSOP-28 I $5.63 $3.94 Yes
LT3599IFE#TRPBF TSSOP-28 I $4.00 Yes
LT3599IUH#PBF 5x5 QFN-32 I $5.46 $3.82 Yes
LT3599IUH#TRPBF 5x5 QFN-32 I $3.88 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
DC1327B LT3599EFE Demo Board | 4-Channel Boost LED Driver, 8V ≤ PVIN ≤ 16V, VLED up to 44V @ 80mA $175.00
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