CMOS Logic Levels
CMOS logic levels are dependent on the power supply voltage:
VOHmin = VCC – 0.1 volts
VIHmin = 70 % of VCC
VILmax = 30 % of VCC
VOLmax = ground + 0.1 volts
For example if VCC = 5V,
VOHmin = VCC – 0.1 volts = 4.9 volts
VIHmin = 70 % of VCC = 3.5 volts
VILmax = 30 % of VCC = 1.5 volts
VOLmax = ground + 0.1 volts = 0.1 volts
Thus CMOS has symmetric logic levels and also symmetric noise
margins
University of KwaZulu-Natal 1
5-1
ENEL2EBH2 2010
, CMOS Logic Levels
University of KwaZulu-Natal 2
5-2
ENEL2EBH2 2010
CMOS logic levels are dependent on the power supply voltage:
VOHmin = VCC – 0.1 volts
VIHmin = 70 % of VCC
VILmax = 30 % of VCC
VOLmax = ground + 0.1 volts
For example if VCC = 5V,
VOHmin = VCC – 0.1 volts = 4.9 volts
VIHmin = 70 % of VCC = 3.5 volts
VILmax = 30 % of VCC = 1.5 volts
VOLmax = ground + 0.1 volts = 0.1 volts
Thus CMOS has symmetric logic levels and also symmetric noise
margins
University of KwaZulu-Natal 1
5-1
ENEL2EBH2 2010
, CMOS Logic Levels
University of KwaZulu-Natal 2
5-2
ENEL2EBH2 2010
