LTC4318CUF#PBF

Specialized Overview

The LTC4318CUF#PBF is a dual-channel I2C/SMBus address translator manufactured by Analog Devices Inc. It enables the translation of hardwired addresses for slave devices, allowing multiple units with identical addresses to coexist on the same bus segment. The device operates within a supply voltage range of 2.25V to 5.5V and supports clock frequencies up to 400 kHz. It features two independent channels, each capable of translating addresses using external resistor-configured XOR bytes. Key electrical parameters include an input supply current of 0.8 mA (typical) at VCC = 3.3V, a pass switch on-resistance of 2.2 Ω at VCC = 3.3V, and a stuck bus timeout of 30 ms. The component is housed in a 20-lead QFN package measuring 4 mm × 4 mm and is rated for operation from 0°C to 70°C.

Specialized Feature Summary

• Dual-channel architecture allows simultaneous address translation for two independent I2C or SMBus segments.
• Resistor-configurable address translation eliminates the need for software programming to modify slave device addresses.
• Integrated hot swap logic with precharge circuitry prevents SDA and SCL corruption during live board insertion and removal.
• Automatic recovery mechanisms handle abnormal bus conditions such as stuck low/high lines and premature STOP bits.

Specialized Applications

• Servers requiring expansion of I2C or SMBus address space
• Telecommunications equipment utilizing multiple identical peripheral devices
• Hot swap applications involving plug-in cards on motherboards

Specialized Procurement Notes

Verify the specific ordering suffix #PBF indicates lead-free finish and tube packaging when sourcing. Confirm the temperature grade 'C' corresponds to the commercial range of 0°C to 70°C. Ensure compatibility with the target I2C/SMBus voltage levels, noting that VCC must connect to the lower bus supply if level shifting between different voltages is required.

Specialized Selection Notes

Select the LTC4318IUF#PBF variant if the application requires an extended industrial temperature range of –40°C to 85°C. Consider the number of channels needed; this model provides two independent translators. Verify that the required address translation byte can be accurately set using standard 1% tolerance resistive dividers connected to the XORH and XORL pins.

Specialized Part Context

The LTC4318 belongs to the LTC431x family of 2-Wire Bus Buffers and Translators from Analog Devices. It complements other interface ICs like the LTC4312 and LTC4313 by offering hardware-based address manipulation rather than simple buffering or acceleration. This family targets complex bus topologies where address conflicts are prevalent.

Specialized Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. The related parts list includes the LTC4316 and LTC4317, which offer single-channel configurations instead of dual-channel functionality.

Specialized FAQ

How is the address translation byte configured?

The translation byte is configured using external resistive dividers connected to the XORH and XORL pins. The XORH pin sets the upper 3 bits and the XORL pin sets the lower 4 bits of the translation value relative to VCC.

What happens if the ENABLE pin is driven low?

Driving the ENABLE pin low disables address translation, disconnects the input bus from the output bus via internal switches N1 and N2, pulls the READY pin low, and reduces the quiescent current to approximately 350 µA.

Does the device support general call addressing?

Yes, the LTC4318 supports general call addressing through a pass-through mode. Pulling the XORH pin high disables address translation, allowing general calls to pass through unmodified.