Features and Benefits
- Dual Low Dropout Linear Tracking Regulators
- 200mA Outputs with Programmable Current Limits
- 1.6V to 45V Input Range
- Fault Protected to ±45V
- Triple Output Supply from a Single Input Requires Only One Inductor
- IQ = 50μA at 12VIN to 6V and 5V with No Load
- Buck Regulator:
- Low Ripple (<15mVP-P) Burst Mode® Operation
- 400mA Output with Internal Power Switch
- 4.3V to 40V Input Operation Range (60V Max)
- Adjustable 250kHz to 2.2MHz Switching Frequency
- Power Good Indicator
- Available in a Thermally-Enhanced 16-Lead MSOP Package
The LT3668 is a monolithic triple power supply composed of a 400mA buck switching regulator and two 200mA low dropout linear tracking regulators (LDOs).This provides a complete and robust power solution for applications that require the power supply of a sensor to tightly track the power supply of a measurement ASIC.
Each tracking LDO supplies 200mA of output current with a typical dropout voltage of 340mV, and each LDO has an accurate resistor programmable current limit.
Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection.
The buck regulator includes a high efficiency switch, a boost diode, and the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application.
The LT3668 is available in a thermally-enhanced 16-lead MSOP package with exposed pad for low thermal resistance.
- Fault-Protected Sensor Supply
- Automotive and Industrial Supplies
- Power for Portable Instrumentation
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 2243A is a triple power supply that includes one 400mA step-down regulator and two 200mA low dropout (LDO) linear tracking regulators featuring the LT3668. The demo circuit is designed for one 6V and dual 5V outputs from a 7V to 40V input. Two LDO outputs are configured as post-regulators of the switching regulator output. The total current capability of three output channels is up to 400mA, while the two LDO regulators are capable of 200mA each.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
LT3668 Companion Parts
Recommended Related Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.