VDDS_RTC
RTC_XTALOUT
t
sX
CAP_VDD_RTC (min.)
Time
V
oltage
VSS_RTC
VDDS_RTC (min.)
VSS_RTC
CAP_VDD_RTC
AM3359, AM3358, AM3357, AM3356, AM3354, AM3352
SPRS717H – OCTOBER 2011 – REVISED MAY 2015
Table 6-5. OSC1 Crystal Circuit Requirements
NAME
DESCRIPTION
MIN
TYP
MAX
UNIT
ƒ
xtal
Crystal parallel resonance
Fundamental mode oscillation only
32.768
kHz
frequency
Crystal frequency stability
Maximum RTC error = 10.512 minutes
–20.0
20.0
ppm
and tolerance
(1)
per year
Maximum RTC error = 26.28 minutes per
–50.0
50.0
ppm
year
C
C1
C
1
capacitance
12.0
24.0
pF
C
C2
C
2
capacitance
12.0
24.0
pF
C
shunt
Shunt capacitance
1.5
pF
ESR
Crystal effective series
ƒ
xtal
= 32.768 kHz, oscillator has nominal
80
k
Ω
resistance
negative resistance of 725 k
Ω
and worst-
case negative resistance of 250 k
Ω
(1)
Initial accuracy, temperature drift, and aging effects should be combined when evaluating a reference clock for this requirement.
Table 6-6. OSC1 Crystal Circuit Characteristics
NAME
DESCRIPTION
MIN
TYP
MAX
UNIT
C
pkg
Shunt capacitance of
ZCE package
0.17
pF
package
ZCZ package
0.01
pF
P
xtal
The actual values of the ESR, ƒ
xtal
, and C
L
should be used to yield a
P
xtal
= 0.5 ESR (2
π
ƒ
xtal
C
L
typical crystal power dissipation value. Using the maximum values
VDDS_RTC)
2
specified for ESR, ƒ
xtal
, and C
L
parameters yields a maximum power
dissipation value.
t
sX
Start-up time
2
s
Figure 6-14. OSC1 Start-up Time
112
Power and Clocking
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