TC1762 Datasheet, PDF (66/114 Pages) Infineon Technologies AG – 32-Bit Single-Chip Microcontroller TriCore

TC1762
Preliminary
Functional Description
Oscillation measurement with the final target system is strongly recommended to verify
the input amplitude at XTAL1 and to determine the actual oscillation allowance (margin
negative resistance) for the oscillator-crystal system.
When using an external clock signal, the signal must be connected to XTAL1. XTAL2 is
left open (unconnected). The external clock frequency can be in the range of 0 - 40 MHz
if the PLL is bypassed, and 4 - 40 MHz if the PLL is used.
The oscillator can also be used in combination with a ceramic resonator. The final
circuitry must also be verified by the resonator vendor.
Figure 3-15 shows the recommended external oscillator circuitries for both operating
modes, external crystal mode and external input clock mode. A block capacitor is
recommended to be placed between V_DDOSC/V_DDOSC3 and V_SSOSC.
V_DDOSC V_DDOSC3
V_DDOSC V_DDOSC3
4 - 25
MHz
R_Q
C_X1
X TA L 1
TC1762
Oscillator
R_X2
X TA L 2
C_X2
f _OSC
Fu n d a m e n ta l
Mode Crystal
V_SSOSC
Crystal Frequency C_X1, C_X21)
4 MHz
33 pF
8 MHz
18 pF
12 MHz
12 pF
16 - 25 MHz
10 pF
R _X2 ¹⁾
0
0
0
0
1) Note that these are evaluation start values!
External Clock
Signal _{4 - 40}
X TA L 1
f_OSC
MHz
TC1762
Os c illa t or
X TA L 2
V _SSOSC
MCS06084
Figure 3-15 Oscillator Circuitries
Note: For crystal operation, it is strongly recommended to measure the negative
resistance in the final target system (layout) to determine the optimum parameters
for the oscillator operation. Please refer to the minimum and maximum values of
the negative resistance specified by the crystal supplier.
Data Sheet
62
V1.0, 2008-04