The LT3690 is a 36V input capable, synchronous step-down switching regulator that can deliver up to 4A of continuous output current at efficiencies as high as 93%. This device operates within a VIN range of 3.9V to 36V, and offers transient protection to 60V, making it well suited for load dump and cold-crank conditions found in automotive applications.
The LT3690’s Burst Mode operation requires only 70uA of quiescent current, ideal for applications such as automotive or telecom systems, which demand always-on operation and optimum battery life.
Switching frequency is user-programmable from 170kHz to 1.5MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 4mm x 6mm QFN-26 package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.
The LT3690 from Linear Technology utilizes a high efficiency 5.5A, 90mOhm high-side switch with the necessary boost diode, oscillator, control and logic circuitry integrated into a single chip. The 30mOhm internal synchronous power switch increases efficiency and eliminates the need for an external Schottky catch diode.
Low ripple Burst Mode operation maintains high efficiency at low output current while keeping output ripple below 15m VPK-PK. Special design techniques enable high efficiency over a wide input voltage range and the device’s current mode topology enables fast transient response and excellent loop stability. Other features include external synchronization (from 170kHz to 1.5MHz), a power good flag and robust short-circuit protection.
The LT3690EUFE is priced at $4.95 each for 1,000-piece quantities. The LT3690IUFE is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature and is priced at $5.45 each in 1,000-piece quantities. All versions are available from stock.
The LT3690 is also available in high temperature (H-grade) and High Reliability (MP-grade) versions. The H-grade version operates from -40°C to a junction temperature of 150°C, and is guaranteed and tested throughout this temperature range. Similarly, the MP-grade version operates from -55°C to a junction temperature of 150°C, and is guaranteed and tested throughout this temperature range. Electrical specifications for the H-grade and the MP-grade are identical to the E and I grades. They are ideal for automotive, industrial and military applications, which are subject to high ambient temperatures.
Both the LT3690HUFE and the LT3690MPUFE are available in 26-lead 4mm x 6mm QFN packages. Pricing starts at $5.70 and $14.70 each, respectively, for 1,000-piece quantities and are available from stock.
For more information on the LT3690, visit www.linear.com/product/LT3690.
Summary of Features of the LT3690:
- Wide Input Range: Operation from 3.9V to 36V, Overvoltage Lockout Protects Circuits Through 60V Transients
- 4A Maximum Output Current
- Integrated 30mOhm N-Channel Synchronous Switch
- 70µA IQ at 12VIN to 3.3VOUT
- Low Ripple Burst Mode Operation Allows Output Ripple <15mVP-P
- Programmable Input Undervoltage Lockout
- 0.8V Feedback Reference Voltage
- Output Voltage 0.8V to 20V
- Programmable & Synchronizable Oscillator (170kHz to 1.5MHz)
- Soft-Startup & Output Voltage Tracking
- Short-Circuit Robust
- Power Good Flag
- Small Thermally Enhanced 4mm x 6mm QFN Package
Typical Application
Applications
- Automotive Systems
- Industrial Supplies
- Distributed Supply Regulation
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, µModule products, and many other analog functions. Applications for Linear Technology’s high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
Linear Technology (UK) Limited
Tel: +44 (0)1628 477066
E-mail: uksales@linear.com
Web site: www.linear.com
Website for product information: http://www.linear.com/product/LT3690
