[nRF51822] Some quetions about nRF51822

[Jeffery]

Hi I cannot find the answers from your documents. Please help me answer them. Thanks.

1. DC supply voltage of core cell of nRF51822 chip?
2. DC supply voltage of IO pad of nRF51822 chip?
3. Efficiency rate of DC/DC converter = (Vo * Io / Vi * Ii) * 100% =? Did you have measured it? It cannot be found in the product specification.

[Stefan Birnir Sverrisson]

Hi Jeffery

The supply voltage for the nRF51822 is specified in table 17 in the product specification nRF51822_PS v2.0 for the different operating modes, if that is what you are asking.

GPIO voltage is equal to the chip supply voltage, i.e. the voltage applied to the VDD pins.

The efficiency of the DC/DC converter is described in the nRF51 Series Reference Manual v2.1 (RM), Power chapter. Efficiency of the DC/DC converter increases with higher supply voltage and increased load current.

[Jeffery]

Hi (1) About question 1, I want to know internal volatge level of nRF51822. VDD is voltage level for GPIO input or output. nRF51822 use this VDD level to communicate with other IC.

For example, if IC fabrication is 0.18um, power supply of IC core cell would be 1.8V. But, VDD could be 3.3V for IO pad.

[Jeffery]

Dear sir Please answer my question. Thanks.

Regards, Jeffery

[FormerMember]

Hi Jeffery, The answer to your questions reside in Table 17 and 56 in the product specification document of nrf51822. As I can understand the processor works on 1.7 V. And some of the peripherals work on 1.2 V. The input VDD voltage can be different ranges depending on the mode (Table 17). The IO pads input and output characteristics based on this VDD is mentioned in Table 56. Hope this helps.