Our company is using it for RS-485 communication.
1) MAX3088 uses existing mass-produced products
2) Scheduled to be changed to MAX3485 for new mass production
For the reasons above, please answer the following three questions.
1. Mixed use of MAX3088 and MAX3485.
- Existing products use MAX3088 for RS-485 communication.
- Additional production products use the MAX3485 for RS-485 communication.
- When using mixed products, check if there are any abnormalities.
2. Whether to remove the terminating resistor.
- The length of the line using RS-485 Max. Within 100M.
- Connected products max. Within 7 devices.
- Termination resistance 110Ω is connected to each product.
- As a result of the current test, if a product is added to the RS-485 line, the RS-485 communication voltage level is low.
3. Combination of RS-485 A/B line protection circuit.
- Existing products have 485 A-line pull-down and 485 B-line pull-up applied.
- 485 -> 4 of 1N4148WS (switch diode) is applied to 485 A/B Line 1st Fix due to poor communication. (VCC/GND line)
- 2 SM712-02HTG(TVS) 485 A/B Line applied -> 2nd correction due to poor communication of 485 ground line)
- When using mixed using protect diode, check if there are any abnormalities.
Please reply to confirm whether it is applicable to mass production.