ZHCSJU4I November 2006 – September 2018 CC1020
PRODUCTION DATA.
The CC1020 device has two digital output pins, PA_EN and LNA_EN, which can be used to control an external LNA or PA. The functionality of these pins are controlled through the INTERFACE register. The outputs can also be used as general digital output control signals.
EXT_PA_POL and EXT_LNA_POL control the active polarity of the signals.
EXT_PA and EXT_LNA control the function of the pins. If EXT_PA = 1, then the PA_EN pin will be activated when the internal PA is turned on. Otherwise, the EXT_PA_POL bit controls the PA_EN pin directly. If EXT_LNA = 1, then the LNA_EN pin will be activated when the internal LNA is turned on. Otherwise, the EXT_LNA_POL bit controls the LNA_EN pin directly.
These two pins can therefore also be used as two general control signals, see Section 5.19.2. In the TI reference design LNA_EN and PA_EN are used to control the external T/R switch.