TMS320F28069M: The internal circuit diagram of ADC input PIN required

Zhihong Huang

Hi team

My customer uses the internal ADC of TMS320F28069M to monitor the DC BUS voltage, but the voltage of the ADC input pin just reached 3.9V when he short circuited the external resistor for experiment. So he wanted to check the internal circuit diagram of ADC input PIN to see if there is any clamp circuits.

Best Regards,

Wesley Huang

Field Application Engineer,China

Texas Instruments Semiconductor Technologies (Shanghai) Co., Ltd, Guangzhou Branch

Cell : +86-189-2449-8998

Email: wesley-huang@ti.com

over 6 years ago

0 Joseph Casuga over 6 years ago

TI__Mastermind 43520 points

Hi Wesley,

ADC inputs have clamping circuits but we're checking design just to be sure. Will get back to you once i get that confirmation.

Regards,

Joseph

0 Joseph Casuga over 6 years ago in reply to Joseph Casuga

TI__Mastermind 43520 points

Hi Wesley,

There is a diode protection circuit in the analog inputs to safe guard the inputs from transients exceeding the ADC input levels but there is limitation on the clamping value and duration. See related post in https://e2e.ti.com/support/microcontrollers/c2000/f/171/p/847254/3133987#3133987

Regards,

Joseph

0 Zhihong Huang over 6 years ago in reply to Joseph Casuga

TI__Intellectual 1550 points

Hi Casuga,

Can you offer me the complete internal connection of the ADC in TMS320F28069M? because my customer need to know the connection of the ADC to identify which part of the TMS320F28069M could be damaged if the DC bus voltage is too high.

Best Regards,

Wesley Huang

Email: wesley-huang@ti.com

0 tlee over 6 years ago in reply to Zhihong Huang

TI__Guru 62975 points

Wesley,

No, we are not authorized to share proprietary design information.

The diodes on the pins should not be used to shunt excessive power -- they are only designed to meet the ESD Ratings in the datasheet and the diodes are susceptible to permanent damage if they conduct current under other conditions:

TI only supports device functionality within the Recommend Operating Conditions. These conditions must be regulated externally:

-Tommy

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28069M: The internal circuit diagram of ADC input PIN required