K20P48M50SF0 Datasheet, PDF (29/60 Pages) Freescale Semiconductor, Inc – K20 Sub-Family

Peripheral operating requirements and behaviors
5. The EXTAL and XTAL pins should only be connected to required oscillator components and must not be connected to any
other devices.
6.3.2.2 Oscillator frequency specifications
Table 15. Oscillator frequency specifications
Symbol
f_{osc_lo}
f_{osc_hi_1}
f_{osc_hi_2}
f_{ec_extal}
t_{dc_extal}
t_cst
Description
Oscillator crystal or resonator frequency — low
frequency mode (MCG_C2[RANGE]=00)
Oscillator crystal or resonator frequency — high
frequency mode (low range)
(MCG_C2[RANGE]=01)
Oscillator crystal or resonator frequency — high
frequency mode (high range)
(MCG_C2[RANGE]=1x)
Input clock frequency (external clock mode)
Input clock duty cycle (external clock mode)
Crystal startup time — 32 kHz low-frequency,
low-power mode (HGO=0)
Crystal startup time — 32 kHz low-frequency,
high-gain mode (HGO=1)
Crystal startup time — 8 MHz high-frequency
(MCG_C2[RANGE]=01), low-power mode
(HGO=0)
Crystal startup time — 8 MHz high-frequency
(MCG_C2[RANGE]=01), high-gain mode
(HGO=1)
Min.
32
3
8
—
40
—
—
—
—
Typ.
—
—
—
—
50
750
250
0.6
1
Max.
40
8
Unit
kHz
MHz
Notes
32
MHz
50
MHz
1, 2
60
%
—
ms
3, 4
—
ms
—
ms
—
ms
1. Other frequency limits may apply when external clock is being used as a reference for the FLL or PLL.
2. When transitioning from FBE to FEI mode, restrict the frequency of the input clock so that, when it is divided by FRDIV, it
remains within the limits of the DCO input clock frequency.
3. Proper PC board layout procedures must be followed to achieve specifications.
4. Crystal startup time is defined as the time between the oscillator being enabled and the OSCINIT bit in the MCG_S register
being set.
6.3.3 32 kHz Oscillator Electrical Characteristics
This section describes the module electrical characteristics.
6.3.3.1 32 kHz oscillator DC electrical specifications
Table 16. 32kHz oscillator DC electrical specifications
Symbol
V_BAT
R_F
Description
Supply voltage
Internal feedback resistor
Min.
1.71
—
Typ.
—
100
Max.
3.6
—
Table continues on the next page...
Freescale Semiconductor, Inc.
K20 Sub-Family Data Sheet, Rev. 4 5/2012.
Unit
V
MΩ
29