TC1784 Datasheet, PDF (84/123 Pages) Infineon Technologies AG – 32-Bit Single-Chip Microcontroller

TC1784
5.2.4 Oscillator Pins
Electrical ParametersDC Parameters
Table 21 OSC_XTAL Parameters
Parameter
Symbol
Values
Unit Note /
Min. Typ. Max.
Test Condition
Input current at XTAL1 I_IX1 CC -25 −
Input frequency
f_OSC SR 4
−
25
μA V_IN<V_DDOSC3 ;
V_IN>0 V
40
MHz Direct Input
Mode selected
8
−
25
MHz External Crystal
Mode selected
Oscillator start-up time¹⁾ t_OSCS −
−
10
ms
CC
Input high voltage at
XTAL1²⁾
Input low voltage at
XTAL1
Input Hysteresis for
XTAL1 pad ³⁾
V_IHX SR 0.7 x −
V_DDOS
C3
V_ILX SR -0.5 −
HYSAX −
−
CC
V_DDOS V
C3 ⁺
0.5
0.3 x V
V_DDOS
C3
200 mV
1) t_OSCS is defined from the moment when V_DDOSC3 = 3.13V until the oscillations reach an amplitude at XTAL1 of
0.3 * V_DDOSC3. The external oscillator circuitry must be optimized by the customer and checked for negative
resistance as recommended and specified by crystral suppliers.
2) If the XTAL1 pin is driven by a crystal, reaching a minimum amplitude (peak-to-peak) of 0.4 * V_DDOSC3 is
necessary.
3) Hysteresis is implemented to avoid metastable states and switching due to internal ground bounce. It can´t be
guaranteed that it suppresses switching due to external system noise.
Note: It is strongly recommended to measure the oscillation allowance (negative
resistance) in the final target system (layout) to determine the optimal parameters
for the oscillator operation. Please refer to the limits specified by the crystal or
ceramic resonator supplier.
Data Sheet
77
V 1.1.1, 2014-05