TLA2518: Missing GPIO clamp diode specification

Attila Varhelyi

Intellectual 615 points

Part Number: TLA2518
Other Parts Discussed in Thread: TLA2528,

l would like to know the exact specification of TLA2518 and TLA2528 IO pin clamp diodes in case of digital and analog.

Unforunately I did not find it in datasheets and manuals. The only available info is a drawing about diode:

NXP specifies this in K10 datasheet as IICDIO and IICAIO.

Microchip defines this as IK absolute clamp diode current.

Used references:

TLA2518 Small, 8-Channel, 12-Bit ADC with SPI Interface and GPIOs datasheet (Rev. B) (ti.com)

Solved: Re: GPIO protection - NXP Community

Kinetis K10: 100MHz Cortex-M4 up to 512KB Flash 144pin (nxp.com)

64-Pin, Low-Power, High-Performance Microcontrollers with XLP Technology Data Sheet (microchip.com)

over 1 year ago

0 RahulVK over 1 year ago

TI__Expert 3775 points

Hi Attila,

The ESD protection diode is common for the pin of the device independent of whether it is configured as analog input or GPIO. The absolute maximum ratings table provides the maximum voltage and current specifications for the AINx/GPIO pins.

https://www.ti.com/document-viewer/TLA2518/datasheet/absolute-maximum-ratings-a-ads7xx8-elec-absmax#a_ADS7xx8_Elec_AbsMax

The output-high source/sink current specifications in electrical characteristics provide the output current limit when the pin is configured as a digital output.

https://www.ti.com/document-viewer/TLA2518/datasheet/thermal-information-a-ads7xx8-elec-thermal-bga-sf1-sf1-sf1#a_ADS7xx8_Elec_Thermal_BGA_SF1_SF1_SF1

Regards,

Rahul

0 Attila Varhelyi over 1 year ago in reply to RahulVK

Intellectual 615 points

Hi Rahul,

Sorry, but this is indirect inference. Clamp diode current could be smaller than pin current.

My opinion, this parameter means absolute maximum source/shink current in case of GPIO output. Take a look, to IOH and IOL as 5mA maximum recommended output current of IO pin.

I agree, this is the only available +/-10mA max pin current in this theme to estimate the diode currect, without clamp diode specification.

Here is an example from MCP datasheet:

Please ask product dev team for exact response.

+1 RahulVK over 1 year ago in reply to Attila Varhelyi

TI__Expert 3775 points

Hi Attila,

I am from the development team for the TLA2518. The AINx/GPIO pin has an ESD diode. The ESD diode will turn on when the voltage on the pin is less than GND - 0.3V or greater than AVDD + 0.3V. The current through the ESD diode should be limited to less than 10mA by external means, typically a series resistor, to prevent damage to the device.

There is no additional clamp diode or any additional specification for the ESD diode.

Regards,

Rahul

0 Attila Varhelyi over 1 year ago in reply to RahulVK

Intellectual 615 points

It's clear now. Thank you.

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TLA2518: Missing GPIO clamp diode specification