LTC4309CDE#TRPBF

Signal Buffers, Repeaters, Splitters Overview

The LTC4309CDE#TRPBF is a hot swappable 2-wire bus buffer manufactured by Analog Devices Inc. It supports I2C, I2C Fast-Mode, and SMBus protocols within an operating temperature range of 0°C to 70°C. The device operates with supply voltages (VCC) from 2.3V to 5.5V and input side accelerator supplies (VCC2) from 1.8V to 5.5V. Key electrical parameters include a typical propagation delay of 85ns (high-to-low) and 10ns (low-to-high), a maximum operating frequency of 600kHz, and a bus stuck low timeout of 30ms. It features a 60mV typical input-output offset voltage and ±6kV human body model ESD ruggedness. The component is housed in a 12-lead DFN package measuring 4mm x 3mm.

Signal Buffers, Repeaters, Splitters Feature Summary

• Provides bidirectional buffering that isolates backplane capacitance from card capacitance during live board insertion.
• Includes automatic stuck bus recovery functionality that generates clock pulses and stop bits when the bus remains low for 30ms.
• Features rise time accelerators to support high capacitively loaded busses and level shifting between 2.5V, 3.3V, and 5V buses.

Signal Buffers, Repeaters, Splitters Applications

• Servers
• RAID Systems
• ATCA

Signal Buffers, Repeaters, Splitters Procurement Notes

Verify the specific ordering suffix #TRPBF indicates tape and reel packaging rather than tube packaging. Confirm the DE suffix corresponds to the 12-lead DFN package variant. Ensure the C grade matches the required 0°C to 70°C operating temperature range for your application environment.

Signal Buffers, Repeaters, Splitters Selection Notes

Select this part for applications requiring isolation between backplane and card I2C lines. Consider the VCC2 pin requirements if utilizing input rise time accelerators. Verify that the 60mV offset voltage is acceptable for the lowest logic levels in your system. Check compatibility with non-compliant VOL I2C devices if necessary.

Signal Buffers, Repeaters, Splitters Part Context

This component belongs to the LTC4304/LTC4309 family of hot swappable bus buffers. It shares functional similarities with parts like the LTC4304 but offers specific level shifting and stuck bus recovery capabilities. It is designed to prevent data corruption during the insertion or removal of I/O cards into live backplanes.

Signal Buffers, Repeaters, Splitters Replacement Considerations

LTC4309CDE#PBF

Signal Buffers, Repeaters, Splitters FAQ

How does the device handle live board insertion?

During insertion, the SDA and SCL lines are precharged to 1V to minimize bus disturbances. The ENABLE input prevents connection until a stop bit or bus idle condition is detected.

What happens if the bus gets stuck low?

If SDAOUT or SCLOUT remain low for 30ms, the FAULT pin pulls low. If DISCEN is tied high, the device disconnects the bus and generates up to 16 clock pulses and a stop bit to attempt recovery.

Can the LTC4309 be used as a repeater?

Yes, two LTC4309s can be connected back-to-back to extend the distance between two 2-wire systems or to isolate ground potential differences.