CC1110-RTR1 datasheet(153/203 Pages) TI

153 / 203 page

CC1110

CC1110 PRELIMINARY Datasheet (Rev. 1.01) SWRS033A

Page 153 of 202

14 Crystal Oscillator

A crystal in the frequency range 26 MHz-

27 MHz must be connected between the

XOSC_Q1 and XOSC_Q2 pins. The

oscillator is designed for parallel mode

operation of the crystal. In addition,

loading capacitors (C201 and C211) for

the crystal are required. The loading

capacitor values depend on the total load

capacitance, CL, specified for the crystal.

The total load capacitance seen between

the crystal terminals should equal CL for

the crystal to oscillate at the specified

frequency.

parasitic

201

211

The parasitic capacitance is constituted by

pin input capacitance and PCB stray

capacitance. Total parasitic capacitance is

typically 2.5 pF.

The crystal oscillator circuit is shown in

Figure 6. Typical component values for

different values of CL are given in Table 8.

The

crystal

oscillator

amplitude

regulated. This means that a high current

is used to start up the oscillations. When

the amplitude builds up, the current is

reduced to what is necessary to maintain

approximately 0.4 Vpp signal swing. This

ensures a fast start-up, and keeps the

drive level to a minimum. The ESR of the

crystal should be within the specification in

order to ensure a reliable start-up (see

section Table 8 on page 16).

CC1110-RTR1 데이터시트(PDF) 153 Page - Texas Instruments