LTC4309IGN#PBF

Signal Buffers, Repeaters, Splitters Overview

The LTC4309IGN#PBF is a hot swappable 2-wire bus buffer manufactured by Analog Devices Inc. It supports I2C, I2C Fast-Mode, and SMBus protocols with a maximum operating frequency of 600 kHz. The device operates within a supply voltage range of 2.3 V to 5.5 V on the VCC pin and 1.8 V to 5.5 V on the VCC2 pin. It features bidirectional buffering that isolates backplane and card capacitances, preventing data corruption during live insertion. Key electrical parameters include a typical input-output offset voltage of 60 mV, a propagation delay of 85 ns (high-to-low) and 10 ns (low-to-high), and a bus stuck low timeout of 30 ms. The component is housed in a 16-lead narrow plastic SSOP package and is rated for an industrial temperature range of -40°C to +85°C.

Signal Buffers, Repeaters, Splitters Feature Summary

• Provides bidirectional buffering to isolate input and output bus capacitances, enabling safe live board insertion into active backplanes without signal corruption.
• Includes automatic stuck bus recovery functionality that detects low conditions for 30 ms and can generate clock pulses and stop bits to free the bus when configured.
• Features optional rise-time accelerators controlled by the ACC pin to drive high-capacitively loaded busses and extend bus reach.
• Supports level shifting between 2.5 V, 3.3 V, and 5 V bus domains while maintaining compatibility with non-compliant VOL I2C devices.

Signal Buffers, Repeaters, Splitters Applications

• Servers requiring hot-swappable I/O card insertion
• RAID systems needing reliable bus isolation
• AdvancedTCA (ATCA) architectures
• Capacitance buffering and bus extension applications

Signal Buffers, Repeaters, Splitters Procurement Notes

Verify the specific ordering suffix IGN#PBF corresponds to the 16-lead SSOP package and the industrial temperature grade (-40°C to +85°C). Confirm lead-free finish status and RoHS compliance through official manufacturer documentation or authorized distributor catalogs before finalizing procurement orders.

Signal Buffers, Repeaters, Splitters Selection Notes

Select this component when designing systems that require isolation between backplane and card-side I2C or SMBus lines. Ensure the application benefits from the 60 mV offset tolerance and the ability to cascade multiple buffers. Verify that the required bus capacitance and pull-up resistor values align with the rise-time accelerator specifications for optimal performance.

Signal Buffers, Repeaters, Splitters Part Context

This part belongs to the LTC4309 family of hot swappable bus buffers. It is distinct from similar models like the LTC4301 or LTC4304 by its specific combination of level shifting capabilities, stuck bus recovery logic, and dual-supply architecture for independent input/output acceleration control.

Signal Buffers, Repeaters, Splitters Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material. Consult Analog Devices technical support for cross-reference information regarding alternative components with compatible pinouts and electrical characteristics.

Signal Buffers, Repeaters, Splitters FAQ

How does the LTC4309 prevent bus corruption during live insertion?

It precharges the SDA and SCL lines to 1 V via internal resistors before connection, minimizing voltage differentials. Additionally, the ENABLE pin remains low during insertion to keep the input and output sides isolated until the system is ready.

What is the function of the DISCEN pin?

When tied high, the DISCEN pin enables the automatic disconnect feature. If a bus stuck low condition persists for 30 ms, the device breaks the connection and generates up to 16 clock pulses and a stop bit to attempt bus recovery.

How are the rise-time accelerators enabled?

Connect the ACC pin to GND to enable all four rise-time accelerators. Connecting ACC to VCC disables them, while connecting ACC to VCC2 enables only the output-side accelerators.