OMAP3515DCBC Datasheet, PDF (137/264 Pages) Texas Instruments – OMAP3515/03 Applications Processor

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sys.xtalin
OCS0
OMAP3515/03 Applications Processor
SPRS505F – FEBRUARY 2008 – REVISED SEPTEMBER 2009
OCS1
OCS1
030-011
Figure 4-4. Crystal Oscillator in Bypass Mode
4.1.4 External 32-kHz CMOS Input Clock
A 32.768-kHz clock signal (often abbreviated to 32-kHz) can be supplied by an external 1.8-V CMOS
signal on pin sys_32k.
Table 4-6 summarizes the electrical constraints imposed to the clock source.
NAME
f
C_I
R_I
Table 4-6. 32-kHz Input Clock Source Electrical Characteristics
DESCRIPTION
MIN
TYP
Frequency
32.768
Input capacitance
0.44
Input resistance
0.25
MAX
10⁶
Table 4-7 details the input requirements of the 32-kHz input clock.
Table 4-7. 32-kHz Input Clock Source Timing Requirements⁽¹⁾
NAME
DESCRIPTION
MIN
TYP
CK0
CK3
CK4
CK5
1 / t_c(32k)
t_R(32k)
t_F(32k)
t_J(32k)
Frequency, sys_32k
Rise time, sys_32k
Fall time, sys_32k
Frequency stability, sys_32k
32.768
(1) See Table 3-4, Electrical Characteristics, Standard LVCMOS IOs part for sys_32k V_IH/V_IL parameters.
UNIT
kHz
pF
GΩ
MAX
20
20
±200
UNIT
kHz
ns
ns
ppm
sys_32k
CK0
Figure 4-5. 32-kHz CMOS Clock
CK1
CK1
030-012
4.1.5 External sys_altclk CMOS Input Clock
A 48-, 54-, or up to 59- MHz clock signal can be supplied by an external 1.8-V CMOS signal on pin
sys_altclk.
Table 4-8 summarizes the electrical constraints imposed by the clock source.
NAME
f
C_I
R_I
Table 4-8. 48-, 54-, or up to 59- MHz Input Clock Source Electrical Characteristics
DESCRIPTION
Frequency , sys_altclk
Input capacitance
Input resistance
MIN
TYP
MAX
48-, 54-, or up to 59- MHz
0.74
0.25
10⁶
UNIT
MHz
pF
GΩ
Table 4-9 details the input requirements of the input clock.
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CLOCK SPECIFICATIONS 137