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SN65C1168E: the differences between SN65C1168EPWR and SN65C1168PWR

Noriyuki Takahashi
Genius 11040 points
Part Number: SN65C1168E

Hi team

Q1. We can find 5 differences between SN65C1168EPWR and SN65C1168PWR as the attached. Could you tell the reasons of these differences and differences of electrical characteristics caused by 5 differences?

SN65C1168PWR.xlsm

As you know SN65C1168PWR is EOL, they need to use SN65C1168EPWR. So they need to understand backgrounds of these differences.

Q2. Is there any problem with the combination of different parts as shown in the example below?
Example: SN65C1168EPWR on the driver side, SN65C1168PWR on the receiver side

Regards,

Noriyuki Takahashi

  • 0
    Guru 317320 points

    1. The E device uses a more complex ESD protection circuit; the schematic shows just a diode, but it actually handles both positive and negative events. The differences in the outputs do not really matter (the E device has a slightly higher drive strength, which is usually a good thing). There are also slight timing differences. If you stay inside the recommended operating conditions, there will be no noticeable difference between these two devices.

    2. All RS-422 drivers and receivers are compatible with each other, as long as you stay inside the limits of the RS-422 specification (which in practice means a 100 Ω termination resistor).

  • +1
    TI__Guru 52412 points

    Takahashi-san,

    First - those circuits are equivalent models - they aren't showing the nuance  of the device and should not be used for design reasons. Use the parameter tables and treat this as a black box - there is no benefit to focusing on those models and if they focused on the parameter tables instead they would already know the answer. We don't put them in modern datasheets for a reason. 

    1. The main differences are due to enhanced ESD protection on the "E" version of the device ("E" at the end indicates improved ESD for RS-422/RS-485/RS-232 devices at the very least). The "E" version has slightly higher drive strength typically but they both have have the same minimum output. 

    2. RS-422 is compatible with other RS-422 devices- so they can communicate with one another as long as electrical and timing specs are respected (they are in this device) - but you shouldn't design systems around both these parts - you should pick one, preferably the "E" version, and go from there because its the better performing device and you reduce ESD protection on the bus by using both - so don't if a new system is being designed - if its legacy compatibility then it's most likely fine (could be some edge cases). 

    Best,

    Parker Dodson