Z8FMC16100 Datasheet, PDF (217/402 Pages) Zilog, Inc. – Z8 Encore-R Motor Control Flash MCUs

Z8FMC16100 Series Flash MCU
Product Specification
195
Comparator and Operational Amplifier
The Z8FMC16100 Series Flash MCU devices feature a general-purpose comparator and
an operational amplifier. The comparator is a moderate speed (200 ns propagation delay)
device that is designed for a maximum input offset of 5 mV. The comparator can be used to
compare two analog input signals. General-purpose input pins (CINP and CINN) provide
the comparator inputs. The output is available as an interrupt source.
The operational amplifier is a two-input, one-output operational amplifier with a typical
open loop gain of 10,000 (80 dB). One general-purpose input pin, OPINP, provides a non-
inverting amplifier input, while another general-purpose input pin, OPINN, provides the
inverting amplifier input. The output is available at the output pin, OPOUT.
The key operating characteristics of the operational amplifier are:
• Frequency compensated for unity gain stability
• Input common-mode range from GND (0.0V) to V_DD – 1V
• Input offset voltage less than 15mV
• Output voltage swing from GND + 0.1V to V_DD – 0.1V
• Input bias current less than 1nA
• Operating the operational amplifier open loop (no feedback) effectively provides an-
other on-chip comparator, if appropriate
Comparator Operation
The comparator output reflects the relationship between the noninverting input and the
inverting (reference) input. If the voltage on the noninverting input is higher than the volt-
age on the inverting input, the comparator output is at a high state. If the voltage on the
noninverting input is lower than the voltage on the inverting input, the comparator output
is at a low state.
To operate, the comparator must be enabled by setting the CMPEN bit in the Comparator
and Op Amp Register to 1. In addition the CINP and CINN comparator input alternate
functions must be enabled on their respective general-purpose I/O pins. Refer to the GPIO
Alternate Functions section on page 36 for more information.
The comparator does not automatically power-down. To reduce operating current when
not in use, the comparator may be disabled by clearing the CMPEN bit to 0.
PS024604-1005
PRELIMINARY
Comparator Operation