Features and Benefits
- Dual Buck Plus Single Boost Synchronous Controllers
- Wide Bias Input Voltage Range: 4.5V to 60V
- Outputs Remain in Regulation Through Cold Crank Down to a 2.2V Input Supply Voltage
- Buck and Boost Output Voltages Up to 60V
- Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
- No External Bootstrap Diodes Required
- Low Operating IQ: 29μA (One Channel On)
- 100% Duty Cycle for Boost Synchronous MOSFET
- Phase-Lockable Frequency (75kHz to 850kHz)
- Programmable Fixed Frequency (50kHz to 900kHz)
- Very Low Dropout Operation: 99% Duty Cycle (Bucks)
- Low Shutdown IQ: 3.6μA
- Fixed or Adjustable Boost Output Voltage Saves IQ
- Small 38-Lead 5mm × 7mm QFN and TSSOP Packages
The LTC3899 is a high performance triple output (buck/ buck/boost) DC/DC switching regulator controller that drives all N-channel synchronous power MOSFET stages. The constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. The LTC3899 operates from a wide 4.5V to 60V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC3899 can operate from an input supply as low as 2.2V after start-up.
The gate drive for the LTC3899 can be programmed from 5V to 10V to allow the use of logic-level or standard-level FETs and to maximize efficiency. Internal switches in the top gate drivers eliminate the need for external bootstrap diodes. The 29μA no-load quiescent current extends operating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.
- Automotive Always-On and Start-Stop Systems
- Distributed DC Power Systems
- Multioutput Buck-Boost Applications
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 1898A is a triple output synchronous step-up/dual step-down supply featuring the LTC3899EFE. The circuit is using a drop-in layout: the main buck circuit components fit in an area of ¾˝ × 1½˝, while the main boost circuit area is ¾˝ × 1¾˝. The package style for the LTC3899EFE is a 38-pin exposed pad TSSOP package.
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:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
LTC3899 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.