Isolated DC/DC Controller integrates opto drive.

Press Release Summary:




Model LT3804 is a 100 W, secondary side, DC/DC regulator for dual output isolated power supplies. Housed in 28-lead TSSOP package, it converts 36-72 V supplies to output voltages of 5, 3.3, 2.5, 1.5, and lower at up to 50 W per output. Differential Kelvin voltage sensing is used for each output feedback. Model LT3804 operates with switching frequencies from 200-800 kHz. It contains error amplifier and optocoupler driver to regulate main output.



Original Press Release:



Isolated Dual Output 100W DC/DC Controller Integrates Opto Drive



MILPITAS, CA - August 25, 2003 - Linear Technology Corporation introduces the LT3804, a secondary side DC/DC regulator with integrated optocoupler driver for dual output isolated power supplies. Unlike previous dual output isolated power supplies that require up to two DC/DC regulators and an external optocoupler driver, the LT3804 is a single controller solution housed in a small 28-lead TSSOP package. The LT3804 is ideal for converting 36V to 72V supplies to output voltages of 5V, 3.3V, 2.5V, 1.8V, 1.5V and lower at up to 50W per output. Differential Kelvin voltage sensing is used for each output feedback to achieve high regulation accuracy and design simplicity.

When combined with Linear Technology's primary side DC/DC regulators, the LT3804 offers a complete isolated dual output power supply priced up to 40% below comparable DC/DC modules. Applications include 48Vdistributed power, datacom/telecom, DSL/cable modems, servers and RAID systems as well as industrial and automotive instruments.

The LT3804 contains an error amplifier and an optocoupler driver to regulate the main output. For the second output regulation, the IC contains a complete PWM controller to drive dual synchronous N-channel MOSFETs. With leading edge modulation, it operates with either current or voltage mode control of the primary side. The device is synchronized to the falling edge of the transformer secondary winding and can be used in single ended or double-ended isolated power converter topologies. The LT3804 operates with switching frequencies ranging from 200kHz to 800kHz.

The LT3804 is rated for operation from -40°C to 125°C. The 1,000-piece price is $5.35 each.

Summary of Features: LT3804
Regulated Two Secondary Outputs
Optocoupler Feedback Driver and Second Output Synchronous Driver Controller
True Differential Remote Sensing Regulation
Programmable Current Limit
Automatic Frequency Synchronization

Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators, power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequency devices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.

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