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PCA9306: EN pin limits for PCA9306 and TCA39306

Part Number: PCA9306
Other Parts Discussed in Thread: TCA9509, TCA39306

Dear team

there are some questions when my customer use PCA9306. in case we are discussing same application, using 1.8V to 3.3V open drain  as an example.

I have learn from LSF training video, and understand why we use pull-up res 200K in EN and vref2 pin. but still confused by these questions like below

  • PCA9306 must have pull-up resistor in EN pin when open drain application, why other sockets like pull up resistor for TCA9509 EN pin is not must.
  • TCA39306 is the P2P solution with Pca9306, which has better performance, wider voltage range, and higher speed rate. there are no limit for EN pull-up resistor in TCA39306, why? could you help to explain in schematic view?

BR

Chi

  • The TCA9509 has a completely different architecture; its EN pin is a digital input. The PCA9306 is pretty much an analog device; the EN pin is connected directly to the gate of the reference transistor, and the 200 kΩ resistor (which is not a pull-up resistor but a current-limiting resistor) ensures that the gate voltage has an offset of the gate threshold voltage above VREF1.

    With both the PCA9306 and the TCA39306, you could use a resistor smaller than 200 kΩ; the only effect would be a higher current flowing through the device.