Dual Wire Bus Buffer allows connection on demand.
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Press Release Summary:
Available in 10-pin MSOP, addressable LTC4302-1/LTC4302-2 is I2 C and SMBus compatible and provides capacitive buffering, rise time acceleration, and input to output connection control. It maintains electrical isolation between backplane and peripheral board until Vcc supplies are valid and IC receives command to initiate connection. Users can select one of 32 possible I2 C addresses using external resistive divider. They work with supply voltages from 2.7-5.5 V.
Original Press Release:
Addressable 2-Wire Bus Buffer Allows Card & Backplane Bus Connection upon Command
MILPITAS, CA - November 17, 2003 - Linear Technology introduces the LTC4302-1/LTC4302-2, addressable I2 C and SMBus compatible bus buffers that provide capacitive buffering, rise time acceleration, and input to output connection control using 2-wire bus commands. The LTC4302 maintains electrical isolation between the backplane and peripheral board until the Vcc supplies are valid and the IC receives the 2-wire bus command to initiate a connection. One of 32 possible I2 C addresses can be selected using a single external resistive divider connected to the ADDRESS pin. The ICs work with supply voltages ranging from 2.7V to 5.5V. The LTC4302 is ideal for network servers, embedded control or telecom equipment due to the simplified 2-wire bus used to manage a large number of cards.
When I2 C is distributed over a backplane, each individual card contributes to the whole system bus capacitance, making rise and fall time requirements difficult to meet. The LTC4302 addresses this problem by providing capacitive buffering for I2 C busses connected across the backplane. As a result, the backplane bus sees only the capacitance of the LTC4302s, about 10pF each, instead of seeing the entire cards' bus capacitance. This dramatically increases the number of nodes that can be supported in a given system and eliminates most signal integrity problems.
The LTC4302-1 features two general-purpose input/output (GPIO) pins that can be configured as inputs, open-drain outputs, or push-pull outputs. The LTC4302-2 option replaces one GPIO pin with a second supply voltage pin, providing level shifting between different supply voltages.
The LTC4302-1 and LTC4302-2 are available in a 10-pin MSOP and specified over the commercial and industrial temperature ranges. Pricing starts at $2.50 each for 1,000 piece quantities.
Summary of Features: LTC4302
Compatible with I2 C Standard Mode, I2 C Fast Mode and SMBus Standards
Bi-Directional Buffer for SDA and SCL Lines Increases Fanout
Prevents SDA and SCL Corruption During Live Card Insertion and Removal from Backplane
Connect SDA and SCL Lines with 2-Wire Bus Commands
Rise Time Accelerators on SDA and SCL Lines
1V Pre-Charge on all SDA and SCL Lines
32 Unique Addresses from a Single ADDRESS Pin
Two General Purpose I/Os (LTC4302-1)
Translates Between 5V and 3.3V Systems (LTC4302-2)
Small 10-Pin MSOP Package
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.
Note: LT, AND LTC are registered trademarks of Linear Technology Corp.
