RL78/G1H CHAPTER 18 RF TRANSCEIVER
R01UH0575EJ0120 Rev. 1.20 Page 550 of 920
Dec 22, 2016
18.3.3 Oscillator block
The oscillator block generates the reference clock to be supplied to the internal circuit of RF unit. This block also
has the function to externally output the generated reference clock.
RF reference clock and RF clock output are classified into the following types.
(1) RF reference clock
RF reference clock is supplied to the digital baseband block entirely.
• XTAL_RF oscillator
Connection of XIN and XOUT pins to 48-MHz crystal oscillator enables 48-MHz clock to oscillate.
It takes the oscillation stabilization time from the oscillation stop until the stabilization.
The oscillation stabilization time requires the stabilization wait time 500 μs + α (α varies depending on the
oscillation circuit).
• REFCLKIN_RF external clock
This clock can input the 48-MHz square wave to REFCLKIN pin. Use OSCDRVSEL pin that is an internal
pin of RF unit with High level fixed in order to use this external input.
(2) RF reference clock output
The divided clock of RF reference clock can be output from CLKOUT pin. The frequencies 12 MHz, 8 MHz,
and 4 MHz can be specified for outputting.
18.3.4 Power supply block
The power supply block consists of DC-DC converter and regulator.
(1) DC-DC converter
The switching regulator is provided to generate a stabilized power from the power supply (1.8 to 3.6 V) for
the internal power supply. Control of DON pin (RF internal pin) enables to set ON/OFF.
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