LTC4300A-3CDD#PBF

Overview

The LTC4300A-3CDD#PBF is a hot swappable 2-wire bus buffer manufactured by Analog Devices Inc. It supports I2C, SMBus, and I2C Fast Mode standards with operation up to 400 kHz. The device operates on supply voltages ranging from 2.7 V to 5.5 V for both the backplane (VCC) and card side (VCC2). It features bidirectional buffering, level translation between 3.3 V and 5 V, and rise time accelerators that provide a typical transient boosted pull-up current of 2 mA. The component includes a CMOS threshold ENABLE pin for low current shutdown mode and precharges SDA/SCL lines to 1 V during insertion. It is housed in an 8-lead (3mm × 3mm) plastic DFN package.

Feature Summary

• Provides bidirectional buffering and capacitance isolation between backplane and I/O card buses
• Features rise time accelerator circuitry allowing weaker DC pull-up currents while meeting timing requirements
• Incorporates a 1 V precharge mechanism on SDA and SCL lines to minimize bus disturbances during live insertion
• Includes a CMOS threshold ENABLE input to force low current mode and isolate the card from the backplane

Applications

• Bidirectional buffering for SDA and SCL lines to increase fanout
• Servers and desktop computers requiring hot board insertion capabilities
• Capacitance buffering and bus extending applications

Procurement Notes

Verify the specific ordering suffix #PBF indicates lead-free finish and RoHS compliance as per manufacturer documentation. Confirm the temperature grade 'C' corresponds to the commercial range of 0°C to 70°C. Ensure the DFN package variant matches the required footprint dimensions. Cross-reference the datasheet revision history for any updates to electrical characteristics or application notes before finalizing procurement specifications.

Selection Notes

Select this component when designing systems requiring hot swap functionality for 2-wire buses without data corruption. It is suitable for environments where the backplane and card operate at different voltage levels within the 2.7 V to 5.5 V range. Consider the 8-lead DFN package for space-constrained PCB layouts. Ensure pull-up resistor values are calculated to maintain a positive slew rate of at least 1.25 V/µs to activate the rise time accelerators effectively.

Part Context

This part belongs to the LTC4300A family of hot swappable 2-wire bus buffers. It shares functional similarities with the LTC4300A-1 and LTC4300A-2 but includes specific level shifting capabilities between 3.3 V and 5 V supplies. The CDD suffix denotes the commercial temperature grade and the 8-lead DFN package format, distinguishing it from the MSOP variants or industrial temperature grade parts.

Replacement Considerations

LTC4300A-1CDD#PBF: Similar hot swappable buffer but lacks the specific 5V to 3.3V level translation feature found in the -3 variant.