Z86E3016PSG Datasheet, PDF (128/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 Family of Microcontrollers
User Manual
110
PIN
V_SS
Figure 64. OTP Diode Input Protection
The high-side input protection diodes were removed on these pins to
allow the application of +12.5V during the various OTP programming
modes.
For better noise immunity in applications that are exposed to system EMI,
a clamping diode to V_CC from these pins may be required to prevent
entering the OTP programming mode or to prevent high voltage from
damaging these pins.
Z8 CMOS Autolatches
I/O port bits that are configurable as inputs are protected against open cir-
cuit conditions using autolatches. An autolatch is a circuit which, in the
event of an open circuit condition, latches the input at a valid CMOS
level. This inhibits the tendency of the input transistors to self-bias in the
forward active region, thus drawing excessive supply current. A simplified
schematic of the CMOS Z8 I/O circuit is shown in Figure 65.
I/O Ports
UM001602-0904