SX8801IRXXMLTRT View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX8801IRXXMLTRT' PDF : 135 Pages View PDF
XE8801A – SX8801R
Symbol
Rh_oscin
Rh_oscout
Rh_oscin_oscout
Cp_oscin
Cp_oscout
Cp_oscin_oscout
Description
Resistance OSCIN-VSS
Resistance OSCOUT-VSS
Resistance OSCIN-OSCOUT
Capacitance OSCIN-VSS
Capacitance OSCOUT-VSS
Capacitance OSCIN-OSCOUT
Min
10
10
50
0.5
0.5
0.2
Typ
Max
3.0
3.0
1.0
Table 7-9. Board layout specifications.
Unit Comments
MΩ
MΩ
MΩ
pF
pF
pF
The oscillator characteristics are given in Table 7-10. The characteristics are valid only if the crystal and board
layout meet the specifications above.
Symbol
fXtal
St_xtal
Fstab
Description
Nominal frequency
Start-up time
Frequency deviation
Min
-100
Typ
32768
1
Max Unit
Hz
2
s
300 ppm
Table 7-10. Crystal oscillator characteristics.
Comments
Note 1
Note 1. This gives the relative frequency deviation from nominal for a crystal with CL=8.2pF and within the
temperature range -40°C to 85°C. The crystal tolerance, crystal aging and crystal temperature drift are not included
in this figure.
7.5.3
External clock
7.5.3.1 External clock configuration
The user can provide an external clock instead of the internal oscillators. Only the CPU can use the external clock.
The external clock input pin is OSCIN.
The system is configured for external clock by bit EnExtClock in register RegSysClock.
When EnExtClock is set to 1, the external clock is detected after 4 pulses on pin OSCIN. The ExtClk bit shows
when the external clock is available.
Note: when using the external clock, the Xtal is not available.
7.5.3.2 External clock specification
The external clock has to satisfy the specifications in the table below. Correct behavior of the circuit can not be
guaranteed if the external clock signal does not respect the specifications below.
Symbol
FEXT
PW_1
PW_0
Description
Min
Typ
Max
External
clock
2
frequency
Pulse 1 width
0.2
Pulse 0 width
0.2
Table 7-11. External clock specifications.
Unit
MHz
µs
µs
Comments
© Semtech 2005
www.semtech.com
7-7
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