I have a question regarding the VPP voltage the GQ-4X applies to 27C256 CMOS EPROMS during programming.
While checking the details in the GQ-4X software I found that the programmer only applies 12 volts to VPP. While in an ST datasheet it says to apply 12.7 volts.
I then looked at the exact same size EPROM of the NMOS variety a 27256 and found the programmer applies 12.7 volts which falls into the tolerance specified on that parts datasheet (12.5V +- 0.3V).
Is there any particular reason less voltage is applied to VPP on the CMOS EPROMS compared to the NMOS or is that extra 3/4 of a volt just not that critical?
I've programmed both of these parts the code verified and they operate fine but I'm just curious.
GQ-4X 27C256 and 27256 VPP Voltage Value Settings
Posted - 06/29/2015 : 00:06:45
