CC2640: CC2640 SCHEMATIC VERIFICATION

- Why do you have load caps on the 24 MHz xtal? See processors.wiki.ti.com/.../CC13xx_CC26xx_Crystal_Tuning
- C11: Why this value?
- NTC_TH1, NTC_TH2: Are both analog signals and need an analog input? If so, have you checked that the DIOs you have connected these nodes to are analog capable?

Hello Ter,

Thank you for your response.

The impedence matching circuitry is updated according to your reference design(tidrmq3). Attaching the same. As we are using PCB antenna (MIFA antenna in our design) and for flux PCB(0.4mm thickness) is this impedence matching circuitry is capable?mcu_tidrmq3(reference).pdf

NTC_TH1, NTC_TH2 are connected to the analog pins. Attaching the datasheet from CC2640 where the pin 20(DIO_7) and pin 27(DIO_14) has analog driving capability.

Attaching the latest schematic for verification.BLE_MCU1.pdf

Thanks and Regards,

Gayathri Devi

For the network from the output of the IPC to the antenna: Normally we recommend a placeholder for a pi filter here. With two components used (a shunt component placed either before or after the series component you are able to match all impedances in the smith chart. For some of our reference designs we know which half of the smith chart the antenna impedance is and therefore one or more components in the pi filter is removed.

You have placed some extra components between the IPC and the antenna. In the reference design you are referring to, C30 is a AC coupling. This is integrated in the IPC leaving R15 and C33 as antenna matching.

Hello Ter,

Thank you Ter we will update the circuit accordingly. Please let us know whether it is ok to connect the thermisters at the pin 20(DIO_7) and pin 27(DIO_14) for analog inputs?