September 18, 2006 Document No. 001-05356 Rev. *B 19
CY8C20234, CY8C20334, CY8C20434 Final Data Sheet 2. Electrical Specifications
2.4.5 AC External Clock Specifications
The following tables list guaranteed maximum and minimum specifications for the voltage and temperature ranges: 4.75V to 5.25V
and -40°C ≤ T
A
≤ 85°C, 3.0V to 3.6V and -40°C ≤ T
A
≤ 85°C, or 2.4V to 3.0V and -40°C ≤ T
A
≤ 85°C, respectively. Typical parameters
apply to 5V, 3.3V, or 2.7V at 25°C and are for design guidance only.
Table 2-16. 5V AC External Clock Specifications
Symbol Description Min Typ Max Units Notes
F
OSCEXT
Frequency 0.750 – 12.6 MHz
– High Period 38
– 5300 ns
– Low Period 38
– –ns
– Power Up IMO to Switch 150
– – µs
Table 2-17. 3.3V AC External Clock Specifications
Symbol Description Min Typ Max Units Notes
F
OSCEXT
Frequency with CPU Clock divide by 1 0.750 – 12.6 MHz Maximum CPU frequency is 12 MHz at 3.3V.
With the CPU clock divider set to 1, the external
clock must adhere to the maximum frequency
and duty cycle requirements.
– High Period with CPU Clock divide by 1 41.7
– 5300 ns
– Low Period with CPU Clock divide by 1 41.7
– –ns
– Power Up IMO to Switch 150
– – µs
Table 2-18. 2.7V AC External Clock Specifications
Symbol Description Min Typ Max Units Notes
F
OSCEXT
Frequency with CPU Clock divide by 1 0.750 –
3.08
0
MHz Maximum CPU frequency is 3 MHz at 2.7V.
With the CPU clock divider set to 1, the external
clock must adhere to the maximum frequency
and duty cycle requirements.
F
OSCEXT
Frequency with CPU Clock divide by 2 or greater 0.15 – 6.35 MHz If the frequency of the external clock is greater
than 3 MHz, the CPU clock divider must be set
to 2 or greater. In this case, the CPU clock
divider will ensure that the fifty percent duty
cycle requirement is met.
– High Period with CPU Clock divide by 1 160
– 5300 ns
– Low Period with CPU Clock divide by 1 160
– –ns
– Power Up IMO to Switch 150
– – µs
