Input leakage current ESP8266EX

[Prodigity]

Hello everyone,

I have noticed some strange behaviour with GPIO pins being configured as inputs.
According to the datasheet the input leakage current should be 50nA max,
however under some circumstances the current shoots up to about 4uA and stays there until the pin has
been reconfigured as output and driven low / high.

I have already tested with several WROOM-02 modules and they all display the same behaviour.

How to recreate

Flash nodemcu on the WROOM-02 module with ESP8266Flasher (stable or dev, doesn't seem to matter)
Attach 480K (or higher) resistor between GPIO14 and a currentmeter with +3.3v on the other side (I'm using the uCurrent from EEVblog)
Attach oscilloscope / DMM to ground of module and GPIO14
Configure GPIO14 as input with "gpio.mode(5, gpio.INPUT)" in the serial terminal.
Measure current and voltage, these will most likely be around 30nA and +3.2v
Disattach probe from GPIO14 and reattach.
Measure current and voltage again, suddenly current consumption is up 100-fold and voltage drops significantly . (if not repeat the previous step)

Notes:
Using a higher resistance resistor seems to increase the likelihood of the current consumption going up, up to the point where it starts happening without attaching a probe (in the 1M Ohm area).
It seems that the capacity of the probe is playing a big role in forcing the GPIO into a faulty state.
Maybe the push-pull output configuration of the GPIO is left floating when the pin is in input mode and the pin
is unintentionally capacitively coupled with the gates.. that would explain why a rapid pull to ground by the oscillator probe
could trigger a fet to open partially.

I have a deadline approaching and I would hate to do a redesign but my options are running low, can someone help me?

Kind regards,
Prodigity

[Espressif_Kelly]

Dear Sir,

1. Please disable pull-up resistance
e.g.;
PIN_PULLUP_DIS(PERIPHS_IO_MUX_MTMS_U);

2. It seems the leakage current is from the 3.3v not the IO itself.
If so, that's why the current would be 3.3v/1Mohm = 3.3uA.

We will verify this issue and let you know the result.

Thanks.

[Prodigity]

Dear Kelly,

Thank you for your response.
1) The pullup was disabled at the time of the test.
2) If the other end of the resistor was attached to ground I would fully agree but it's attached to a GPIO configured as input so that shouldn't be the case.

I do not mean to rush you but is it possible that I could get a status update?

Kind regards,
Joshua de Haan