LTC2851 RS485 communication issue, possible contention

Hi,

The LTC2851 is a full-duplex RS485 transceiver without enable (DE and RE) pins. Driver and receiver are active whenever the part is powered. LTC2852, with DE and RE pins, provides impedance outputs when the driver is disabled. To disable LTC2851’s driver, you can power down the part, and the receiver will also be disabled. A full-duplex RS485 transceiver without enable pins is typically for point-to-point applications. For multi-drop applications, enable pins are required.

Best,

Jane

That's unfortunate, I'll have to devise a workaround for our application.

While it seems kind of obvious now, I feel like this should be called out a bit more clearly on the datasheet for that part, it's a shared data sheet for parts that can be used in a multi-drop bus (LTC2850 and LTC2852) and that bus configuration is frequently eluded to in the datasheet without any specific mention of the limitations of this particular part, in fact there is no mention of a point-to-point application anywhere in the datasheet.

Hi,

Thank you for your feedback. We can add application information for LTC2851 when we revise this datasheet. Though the current LTC2850/LTC2851/LTC2852 datasheet does not provide the typical application circuit for LTC2851, we provide two typical multinode network applications on page 13 for half-duplex transceiver (LTC2850) and on page 18 for full-duplex transceiver (LTC2852).

Best,

Jane