Jul 27, 2002 #1 W wizz Junior Member level 1 Joined Jun 26, 2002 Messages 19 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 83 74lvc07 3.3v to 5v I used 3.3V MCU and CPLD to control several 5V MC14052/4053/4066s. The 3.3V mcu/cpld 's Vohmin = 2.4V. The MC14052 datasheet said the Vihmin = 3.5V, but VihTYP = 2.75V. Can they work? (BTW: I don't want to use 74lvc2425/74lvc07 to change IO level.) thx.
74lvc07 3.3v to 5v I used 3.3V MCU and CPLD to control several 5V MC14052/4053/4066s. The 3.3V mcu/cpld 's Vohmin = 2.4V. The MC14052 datasheet said the Vihmin = 3.5V, but VihTYP = 2.75V. Can they work? (BTW: I don't want to use 74lvc2425/74lvc07 to change IO level.) thx.
Jul 27, 2002 #2 B bman Newbie level 6 Joined Feb 21, 2002 Messages 13 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 28 mc14052 -mac As you guessed from the data sheets, CD405x's with a 5V supply won't work reliably when driven by 3.3V logic. Try the 74HCT405x series or 74LC405x. They have TTL input logic levels (2.4V Vh, 3.15V max) See **broken link removed** for data sheets. You should also probably use pull-up resistors on the 3.3V drive signals to be sure the "1" voltage goes all the way up.
mc14052 -mac As you guessed from the data sheets, CD405x's with a 5V supply won't work reliably when driven by 3.3V logic. Try the 74HCT405x series or 74LC405x. They have TTL input logic levels (2.4V Vh, 3.15V max) See **broken link removed** for data sheets. You should also probably use pull-up resistors on the 3.3V drive signals to be sure the "1" voltage goes all the way up.
Jul 28, 2002 #3 W wizz Junior Member level 1 Joined Jun 26, 2002 Messages 19 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 83 logic levels for a 4053 Thank you very much.
Jul 28, 2002 #4 F flowers Member level 1 Joined Dec 2, 2001 Messages 33 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,286 Activity points 189 mc14052 Hi, wizz: If your cpld has the 5V input tolerence, you can simple driver the TTL 5V input by cpld by sending the 'Z' in VHDL with an extra pull resistor to 5V. regards flowers
mc14052 Hi, wizz: If your cpld has the 5V input tolerence, you can simple driver the TTL 5V input by cpld by sending the 'Z' in VHDL with an extra pull resistor to 5V. regards flowers