ElectroTech forum,
I'm using a CD4026BE decade counter/7-segment driver
to drive a seven segment display.
The datasheet for this part specs VOH at 4.95 volts min
with VDD of 5V.
I measure 5V VOH with no load but as soon as I use this
output drive a segment through a 330 OHM resistor the
voltage drops to about 2.7 volts measured to ground.
It drives the segment OK but I also want to use this to
drive the input of a CD4082BE Quad AND gate. Unfortunately
the datasheet for the 4082 specs the VIH at 3.5 volts min
with a VDD of 5V.
Measuring just across the resistor I get .99V and just
across the segment diode I get 1.7V. The datasheet
doesn't say anything about load or no-load conditions
so I don't understand I why I don't get the full 5V VOH.
Any suggestions?
jerryd
I'm using a CD4026BE decade counter/7-segment driver
to drive a seven segment display.
The datasheet for this part specs VOH at 4.95 volts min
with VDD of 5V.
I measure 5V VOH with no load but as soon as I use this
output drive a segment through a 330 OHM resistor the
voltage drops to about 2.7 volts measured to ground.
It drives the segment OK but I also want to use this to
drive the input of a CD4082BE Quad AND gate. Unfortunately
the datasheet for the 4082 specs the VIH at 3.5 volts min
with a VDD of 5V.
Measuring just across the resistor I get .99V and just
across the segment diode I get 1.7V. The datasheet
doesn't say anything about load or no-load conditions
so I don't understand I why I don't get the full 5V VOH.
Any suggestions?
jerryd