Bus Buffer translates I²C bus levels to 1.xV processors.

Press Release Summary:




Model LTC4301L accepts input data and clock pull-up voltages as low as 1 V and level translates them to standard 3.3-5 V logic rails. It allows card insertion into live backplane without corruption of SDA and SCL lines, while providing capacitive isolation between lines even if respective supplies are at different levels. SDA and SCL pins withstand 10 kV ESD, protecting card from damage due to handling. Unit comes in 8-pin MSOP and DFN packages.



Original Press Release:



Buffer Translates I²C Bus Levels to 1.xV Processors



MILPITAS, CA - May 24, 2004 - Linear Technology Corporation introduces the LTC4301L, an I2C bus buffer designed for ultra low voltage processor applications. The IC accepts input data (SDA) and clock (SCL) pull-up voltages as low as 1V and level translates them to standard 3.3V and 5V logic rails. The LTC4301L allows card insertion into a live backplane without corruption of the SDA and SCL lines, while providing capacitive isolation between the lines even if the respective supplies are at different levels. Without compromising the I2C threshold levels, this supply-independent feature eliminates the need to dedicate a connector pin for the backplane supply voltage.

In addition to facilitating live card insertion or removal, the LTC4301L's SDA and SCL pins withstand 10kV ESD, thus protecting the card from damage due to handling. The device greatly simplifies the task of using a 2-wire bus to manage a large number of cards with different supply and bus voltage levels in network server, desktop PC or telecom environments.

When I2C 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 LTC4300 family addresses this problem, providing capacitive buffering for I2C busses connected across the backplane. As a result, the backplane bus sees only the capacitance of the buffer ICs, about 10pF each, instead of seeing the entire card's bus capacitance. The LTC4301L dramatically increases the number of nodes that a controller can support in a given system and eliminates most signal integrity problems.

During insertion, control circuitry prevents connection of the backplane to the card until a stop bit or a bus idle condition is present. The READY output pin indicates that the backplane and card sides are connected together.

The LTC4301L is offered in the commercial and industrial temperature ranges and pricing begins at $2.05 each for 1,000-piece quantities.

Summary of Features: LTC4301L
Level Translates 1V Signals to Standard 3.3V & 5V Logic Rails
Allows Bus Pull-Up Voltages as low as 1V on SDAIN & SCLIN
Bi-Directional Buffer for SDA & SCL Lines Increases Fanout
Prevents SDA & SCL Corruption During Live Board Insertion & Removal from Backplane
Isolates SDA & SCL Line from Output
10kV Human Body Model ESD Protection
Compatible with I2C, I2C Fast Mode and SMBus Standards (Up to 400kHz Operation)
Small 8-Pin MSOP & DFN (3mm x 3mm) Packages

Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. 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, 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.

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