DRA790 Datasheet, PDF (160/436 Pages) Texas Instruments – Infotainment Applications Processor

DRA790, DRA791
DRA793, DRA797
SPRS968A – AUGUST 2016 – REVISED FEBRUARY 2017
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Device
xi_osc0
xo_osc0
vssa_osc0
Crystal
Rd
(Optional)
C_f1
C_f2
SPRS906_CLK_03
Figure 5-8. OSC0 Crystal Implementation
NOTE
The load capacitors, C_f1 and C_f2 in Figure 5-8, should be chosen such that the below
equation is satisfied. C_L in the equation is the load specified by the crystal manufacturer. All
discrete components used to implement the oscillator circuit should be placed as close as
possible to the associated oscillator xi_osc0, xo_osc0, and vssa_osc0 pins.
CL=
C C _{f1 f2}
(C_f1+C_f2)
Figure 5-9. Load Capacitance Equation
The crystal must be in the fundamental mode of operation and parallel resonant. Table 5-15 summarizes
the required electrical constraints.
and Table 5-19
Table 5-15. OSC0 Crystal Electrical Characteristics
NAME
DESCRIPTION
f_p
C_f1
C_f2
ESR(C_f1,C_f2)
(1)
Parallel resonance crystal frequency
C_f1 load capacitance for crystal parallel resonance with C_f1 = C_f2
C_f2 load capacitance for crystal parallel resonance with C_f1 = C_f2
Crystal ESR
ESR = 30 Ω
ESR = 40 Ω
19.2 MHz, 20 MHz, 27 MHz
19.2 MHz, 20 MHz
ESR = 50 Ω
27 MHz
C_O
Crystal shunt capacitance
19.2 MHz, 20 MHz
ESR = 60 Ω
27 MHz
19.2 MHz, 20 MHz
ESR = 80 Ω
27 MHz
19.2 MHz, 20 MHz
ESR = 100 Ω
27 MHz
L_M
Crystal motional inductance for f_p = 20 MHz
C_M
Crystal motional capacitance
MIN TYP
19.2, 20, 27
12
12
MAX
24
24
UNIT
MHz
pF
pF
100 Ω
Not Supported
Not Supported
Not Supported
10.16
3.42
7 pF
7 pF
5 pF
7 pF
-
5 pF
-
3 pF
-
mH
fF
160 Specifications
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