PCA9306: Current flow through 200k resistor

Den L

Intellectual 970 points

Part Number: PCA9306

Hi,

just curious, what is the current through the 200k pull-up resistor with Vref2 being 5V?

Regards,
Den

over 6 years ago

0 fhoude over 6 years ago

TI__Genius 17205 points

Hello DenLi,
It depends on what the Vref1 voltage is. Here is a post that show the voltage across the resistor in a typical application. You can figure out from that what the current would be.
e2e.ti.com/.../2231793
-Francis Houde

0 Den L over 6 years ago in reply to fhoude

Intellectual 970 points

Hi Francis,

Vref1 is 3.3V.

I also have another case where Vref1 is 1.8V and Vref2 is 3.3V.

Regards,
Den

0 fhoude over 6 years ago in reply to Den L

TI__Genius 17205 points

Hell Den,
The equation for current through 200 k resistor is: (Vref2-(Vref1+Vth)) / 200 k Ohms
Vth=0.7V
1) current through resistor : (5-(3.3+0.7)) / 200 k) = 5 micro amps
2) current through resistor : (3.3-(1.8+0.7)) / 200 k) = 4 micro amps

Is this clear?
-Francis Houde

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PCA9306: Current flow through 200k resistor