KESTX01

The bias current for the power amplifier directly controls the output current (and hence the output power). The bias current is set by the external resistor connected between PWRC and ground. The bias voltage on pin PWRC is nominally 1.20V and hence the modulation current Imod is given by 1.20/R.

To a first order neither the linearity (harmonic spurii relative to fundamental) nor the amplifier efficiency are affected by Imod. The graph below shows typical simulation results for the amplifier current output with Imod variation.

The KESTX01 is a single chip ASK (Amplitude Shift Key) transmitter IC. KESTX01  is designed to operate in a variety of low power radio applications including keyless entry, general domestic and industrial remote control, RF tagging and local paging systems.

The transmitter KESTX01 offers a high level of integration and performance, which enables the harmonic rejection and fundamental power requirements of the ESTI 300 220, and other governing bodies, to be met.

The basic architecture KESTX01 utilises a crystal reference oscillator, an integrated frequency multiplying PLL and a power output stage. The design is centred around the popular 433.92MHz operating frequency and particular emphasis has been placed on low current drain, including a powerdown eature which greatly increases battery life.