CD00001237 Datasheet, PDF (74/105 Pages) STMicroelectronics – 8-bit MCUs with A/D converter

ST6215C ST6225C
CLOCK AND TIMING CHARACTERISTICS (Cont’d)
11.5.3 Crystal and Ceramic Resonator Oscillators
The ST6 internal clock can be supplied with sever-
al different Crystal/Ceramic resonator oscillators.
Only parallel resonant crystals can be used. All the
information given in this paragraph are based on
characterization results with specified typical ex-
ternal components. Refer to the crystal/ceramic
resonator manufacturer for more details (frequen-
cy, package, accuracy...).
Symbol
R_F
C_L1
C_L2
Parameter
Conditions
Feedback resistor
f_OSC=32 kHz,
Recommended load capacitances versus equiva-
lent crystal or ceramic resonator frequency
f_OSC=1 MHz
f_OSC=2 MHz
f_OSC=4 MHz
f_OSC=8 MHz
Typ
Unit
3
MΩ
120
47
33
pF
33
22
Oscillator
Typical Crystal or Ceramic Resonators
Reference
Freq.
Characteristic ¹⁾
CSB455E
455KHz Δf_OSC=[±0.5KHz_tolerance,±0.3%_ΔTa,±0.5%_aging]
CSB1000J
1MHz Δf_OSC=[±0.5KHz_tolerance,±0.3%_ΔTa,±0.5%_aging]
CSTCC2.00MG0H6 2MHz Δf_OSC=[±0.5%_tolerance,±0.5%_ΔTa,±0.3%_aging]
CSTCC4.00MG0H6 4MHz Δf_OSC=[±0.5%_tolerance,±0.3%_ΔTa,±0.3%_aging]
CSTCC8.00MG
8MHz Δf_OSC=[±0.5%_tolerance,±0.3%_ΔTa,±0.3%_aging]
C_L1 C_L2 t_SU(osc)
[pF] [pF] [ms] ¹⁾
220 220
100 100
47 47
47 47
15 15
Notes:
1. Resonator characteristics given by the crystal/ceramic resonator manufacturer.
2. t_SU(OSC) is the typical oscillator start-up time measured between V_DD=2.8V and the fetch of the first instruction (with a
quick V_DD ramp-up from 0 to 5V (<50μs).
3. The oscillator selection can be optimized in terms of supply current using an high quality resonator with small R_S value.
Refer to crystal/ceramic resonator manufacturer for more details.
Figure 50. Typical Application with a Crystal or Ceramic Resonator
V_DD
C_L1
OSC_IN
RESONATOR
C_L2
R_F
OSC_OUT
F_OSC
ST62XX
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