SPRACZ9A November 2021 – December 2022 TMS320F2800132 , TMS320F2800133 , TMS320F2800135 , TMS320F2800137 , TMS320F2800152-Q1 , TMS320F2800153-Q1 , TMS320F2800154-Q1 , TMS320F2800155 , TMS320F2800155-Q1 , TMS320F2800156-Q1 , TMS320F2800157 , TMS320F2800157-Q1 , TMS320F280021 , TMS320F280021-Q1 , TMS320F280023 , TMS320F280023-Q1 , TMS320F280023C , TMS320F280025 , TMS320F280025-Q1 , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280033 , TMS320F280034 , TMS320F280034-Q1 , TMS320F280036-Q1 , TMS320F280036C-Q1 , TMS320F280037 , TMS320F280037-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038-Q1 , TMS320F280038C-Q1 , TMS320F280039 , TMS320F280039-Q1 , TMS320F280039C , TMS320F280039C-Q1 , TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
The F2800x devices offer only a few requirements to ensure proper power sequencing. Prior to powering the device, ensure that no voltage larger than 0.3 V above VDDIO is applied to any digital pins; likewise, ensure that no voltage larger than 0.3 V above VDDA is applied to any of the analog pins. For these respective pins, also ensure that no voltage 0.3 V below VSS and VSSA should be applied. All of the 3.3 V power pins—VDDIO, VDDIO_SW (on F28004x), and VDDA—should be powered up together and kept within 0.3 V of each other during functional operation.
The ADC inputs can be damaged when the above voltage requirements are not maintained. In instances where there is the potential to drive a higher voltage than VDDA on the ADC pins, care should be taken to isolate the signals. This can be done by buffering the signal with an op-amp that is powered by VDDA or to use an enable controlled by the C28x core. An analog mux or switch can be used in place of an op-amp buffer. An alternative to these designs would be to design current limiting on the pins, keeping in mind the maximum clamping current outlined in the device-specific data sheet.
When using the internal VREG, the VDD sequencing requirements are handled by the device. For devices with VREGENZ, internal VREG mode corresponds to when VREGENZ is tied to VSS. However, when supplying VDD externally (VREGENZ is tied to VDDIO) on devices without the Power Management Module (PMM) (ex. F28004x), be sure that VDD is powered up together with the 3.3 V supplies. VDDIO should thus not be powered on when VDD is off. During the ramp, VDD should be kept no more than 0.3 V above VDDIO.
On those devices with PMM (ex. F28003x) , VDD can be powered on after VDDIO, meaning that VDD and VDDIO do not have to power at the same time. For more information on the power sequencing requirements, see the Power Sequencing section in the device-specific data sheet.