AM3352: GPIO current issue

yimin bai34

Genius 4755 points

Part Number: AM3352

Hi Sir

we set E17 as GPIO to control TLP291 device.

below is the schematic

1. we measured the U910 pin 1 and the current is over 25mA.

2. we removed R915 and found the current of U910 pin 1 is 2.5mA.

3. we replace U910 device with a new one and the result is the same.

It means the max current of pin E17 of AM3352 is over the max. current 4mA.

Could you advise why E17 pin can offer the current over the spec?

Yimin

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Hi,

Your schematic is completely wrong. When UART0_DTRN is high you are directly injecting the pin output voltage to U910 pin 1. Additionally you inject 3.3V through R911 and the current limiting resistor R920 is 33Ohm. What you should do is remove R911 and choose a suitable value for R920.

0 yimin bai34 over 7 years ago in reply to Biser Gatchev-XID

Genius 4755 points

Hi Sir

thanks for your reply.

For E17pin, the buffer strengthen is 4mA. does it mean the output current limit is 4mA ?

Or the max. output current might be over 4mA for output mode ?

Yimin

0 yimin bai34 over 7 years ago in reply to Biser Gatchev-XID

Genius 4755 points

Hi Sir

Could you advise

BR
Yimin

0 Biser Gatchev-XID over 7 years ago in reply to yimin bai34

TI__Guru**** 393215 points

4mA is the maximum output current at which low/high output voltage levels are guaranteed to be within specifications. There is a specified maximum current for each VDDSHVx power rail, which is the combined output current of all I/O pins powered from this respective rail.

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AM3352: GPIO current issue