LT3669/LT3669-2 - IO-Link Transceiver with Integrated Step-Down Regulator and LDO

The LT®3669 is an industrial transceiver that includes a step-down switching regulator and a low dropout linear regulator. Wake-up detect functionality, as well as a programmable power-on reset timer are also included. The current limit and slew rate of the transmitters are externally adjustable for optimum EMC performance.

The line drivers can source/sink up to 250mA of current each or 500mA when connected together, with a minimal residual voltage of less than 2.1V. An internal adaptive pulsing scheme allows the drivers to safely switch heavy capacitive loads and incandescent bulbs. Thermal shutdown provides additional protection. Line protection of ±60V in the line interface pins allows the use of standard TVS diodes with L+ operating voltages up to 40V.

The switching regulator integrates the catch diode in LT3669 (up to 100mA load current) and requires an external catch diode in LT3669-2 (up to 300mA load current).

The LT3669 implements an IO-Link device PHY. For IO-Link master designs, see the LTC2874.

  • IO-Link® PHY Compatible (COM1/COM2/COM3)
  • Cable Interface Protected to ±60V
  • Operation from 7.5V to 40V
  • Integrated Step-Down Switching Regulator
  • Max Load Current: 100mA (LT3669)/300mA (LT3669-2)
  • Synchronizable and Adjustable Switching Frequency: 250kHz to 2.2MHz
  • Output Voltage: 0.8V to 16V
  • Integrated 150mA LDO Linear Regulator
  • Rugged Line Drivers with Adjustable Slew Rate and Current Limit
  • Adaptive Line Driver Pulsing Scheme to Switch Heavy Loads Safely
  • Drivers Configurable as Push-Pull, Pull-Up or Pull-Down
  • Adjustable Power-On Reset Timer
  • Small 28-Pin Thermally Enhanced 4mm × 5mm QFN Package
Typical Application
LT3669 Typical Application
LT3669 Typical Application
  • Industrial Sensors and Actuators
LT3669 Package Drawing
LT3669 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT3669EUFD-2#PBF4x5 QFN-28E$5.07$3.55
LT3669EUFD-2#TRPBF4x5 QFN-28E$3.61
LT3669EUFD#PBF4x5 QFN-28E$5.07$3.55
LT3669EUFD#TRPBF4x5 QFN-28E$3.61
LT3669HUFD-2#PBF4x5 QFN-28H$6.19$4.33
LT3669HUFD-2#TRPBF4x5 QFN-28H$4.39
LT3669HUFD#PBF4x5 QFN-28H$6.19$4.33
LT3669HUFD#TRPBF4x5 QFN-28H$4.39
LT3669IUFD-2#PBF4x5 QFN-28I$5.83$4.08
LT3669IUFD-2#TRPBF4x5 QFN-28I$4.14
LT3669IUFD#PBF4x5 QFN-28I$5.83$4.08
LT3669IUFD#TRPBF4x5 QFN-28I$4.14
Demo Boards
Part NumberDescriptionPrice
DC1733A-ALT3669-1 Demo Board | 7.5V to 40V input with Vout 1 being 5V at 100mA and Vout 2 (LDO) being 3.3V at 100mA$125.00
DC1733A-BLT3669-2 Demo Board | 7.5V to 40V input with Vout 1 being 5V at 300mA and Vout 2 (LDO) being 3.3V at 150mAContact Factory
DC2227ALT3669-2 Demo Board | I/O Link with 18V to 36V Input to 4V at 300mA and 3.3V at 150mA$299.00
Companion Boards
Part NumberDescriptionPrice
DC2228A8-Port IO-Link Master Reference Design. Includes LTC2874, LT4275A, IO-Link v1.1 Protocol Stack and Control Tool. Optionally powered by DC1814A-D PoE supply.$599.00
Product Selector Card
LT Journal
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LT3669 Footprints and Symbols
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