LTC4300A-1CMS8#PBF

Overview

The LTC4300A-1CMS8#PBF is a hot swappable 2-wire bus buffer designed for I/O card insertion into live backplanes without data corruption. It provides bidirectional buffering between SDA and SCL lines, isolating backplane and card capacitances. The device features rise-time accelerator circuitry to maintain signal integrity with weaker pull-ups and precharges lines to 1V during insertion. Operating on a single supply voltage (VCC) ranging from 2.7V to 5.5V, it includes an ENABLE pin for low current shutdown (<1μA) and an open-drain READY output indicating connection status. It supports I2C, Fast Mode, and SMBus standards up to 400kHz in an 8-lead MSOP package.

Feature Summary

• Hot swap protection prevents bus corruption during live board insertion
• Rise-time accelerators allow use of weaker DC pull-up currents
• Bidirectional buffering isolates input and output capacitances
• Low current disable mode reduces power consumption significantly

Applications

• Servers and desktop computer backplanes
• CompactPCI and PCI peripheral cards
• I2C bus extenders and repeaters

Procurement Notes

Verify the specific suffix CMS8 corresponds to the commercial temperature range and plastic MSOP package. Confirm lead-free finish compliance with RoHS directives before finalizing procurement orders. Ensure the ordering part number matches the required tape or tube packaging format for your assembly line.

Selection Notes

Select this component when a single-supply interface is required between backplane and card sides. Use the ENABLE pin for system-level power management control. Verify that the system pull-up resistors meet the slew rate requirements to activate the boost currents properly during signal transitions.

Part Context

This part belongs to the LTC4300A series of 2-wire bus buffers. The -1 variant utilizes an ENABLE pin for control, whereas the -2 variant uses a separate VCC2 supply for level shifting. Both share similar hot swap and buffering capabilities but differ in pin configuration and multi-voltage support options.

Replacement Considerations

LTC4300A-1IMS8#PBF offers the same functionality with an extended industrial temperature range (-40°C to 85°C).

FAQ

How does the device handle live insertion?

It precharges SDA and SCL lines to 1V and keeps backplane and card capacitances isolated until the start-up sequence completes.

What is the function of the READY pin?

The READY pin is an open-drain output that goes high when the ENABLE pin is high and the start-up sequence is complete, indicating the busses are connected.

Can this buffer be used as a repeater?

Yes, two LTC4300A-1 devices can be connected back-to-back to extend the distance between two 2-wire systems.