PCF8575: VOH source current

cafain

Part Number: PCF8575

HI,Staff

PCF8575データシート(SCPS121H) page13
[8.2.2 Simplified Schematic Diagram of Each P-Port Input/Output]
I have a question on this schematic.

There is a 100mA current source at the point labeled IOH.

If the upper FET is turned on, it is possible to source 100mA when the port output is VOH.
In the actual data sheet, the IOH is 30uA (min), 300uA (max).

I want to output 20mA from the port to drive the LED.
Is it possible to output this 100mA current source as a port?

Thank you for your cooperation in solving the problem.

best regards

cafain

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 318050 points

It looks as if the current source is labelled wrong; it should be 100 µA.

This device can drive LEDs only from the cathode, with a low output.

0 Danny Bacic over 3 years ago

TI__Mastermind 26826 points

Cafain,

I agree with Clemens's assessment here. It looks to me like this might have been a typo that arose from updating an older figure. I have added this as an item to be updated next time we revise the data sheet.

Best,

Danny

+1 cafain over 3 years ago

Mastermind 6765 points

HI, Clemens-san, Danny-san

Thank you for your comment as soon as possible.

I also understand that 100uA is the correct value and the LED cannot be source driven.

Since we are planning to drive the LED with 20mA, we will consider connecting a transistor to the part.

regards

cafain

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PCF8575: VOH source current