Datasheet

Table Of Contents
NOTE
It is safe to supply ADC_IOVDD at a higher or lower voltage than IOVDD, e.g. to power the ADC at 3.3V, for optimum
performance, while supporting 1.8V signal levels on the digital IO. But the voltage on the ADC analogue inputs must
not exceed IOVDD, e.g. if IOVDD is powered at 1.8V, the voltage on the ADC inputs should be limited to 1.8V. Voltages
greater than IOVDD will result in leakage currents through the ESD protection diodes. See Section 5.2.3, “Pin
Specifications” for details.
ADC_IOVDD should be decoupled with a 100nF capacitor close to the chip’s ADC_IOVDD pin.
2.8.6. Power Supply Sequencing
RP2040’s power supplies may be powered up or down in any order. However, small transient currents may flow in the
ADC supply (ADC_IOVDD) if it is powered up before, or powered down after, the digital core supply (DVDD). This will not
damage the chip, but can be avoided by powering up DVDD before or at the same time as ADC_IOVDD, and powering
down DVDD after or at the same time as ADC_IOVDD. In the most common power supply scheme, where the chip is
powered from a single 3.3V supply, DVDD will be powered up shortly after ADC_IOVDD due to the startup time of the on-
chip voltage regulator. This is acceptable behaviour. See Section 2.8.7.1, “Single 3.3V Supply”.
2.8.7. Power Supply Schemes
2.8.7.1. Single 3.3V Supply
In most applications, RP2040 will be powered from a single 3.3V supply, as shown in Figure 14. The digital IO (IOVDD),
USB PHY (USB_IOVDD) and ADC (ADC_IOVDD) will be powered directly from the 3.3V supply, and the 1.1V digital core
supply (DVDD) will be regulated from the 3.3V supply by the on-chip voltage regulator. Note that the regulator output pin
(VREG_VOUT) must be connected to the chip’s DVDD pins off-chip.
For more details on the on-chip voltage regulator see On-Chip Voltage Regulator.
Figure 14. powering
the chip from a single
3.3V supply
(simplified diagram
omitting decoupling
components)
RP2040 Datasheet
2.8. Power Supplies 137