PIC16F1783-I Datasheet, PDF (164/444 Pages) Microchip Technology – 28-Pin 8-Bit Advanced Analog Flash Microcontrollers

PIC16(L)F1782/3
18.1 Effects of Reset
A device Reset forces all registers to their Reset state.
This disables the OPA module.
18.2 OPA Module Performance
Common AC and DC performance specifications for
the OPA module:
• Common Mode Voltage Range
• Leakage Current
• Input Offset Voltage
• Open Loop Gain
• Gain Bandwidth Product
Common mode voltage range is the specified voltage
range for the OPA+ and OPA- inputs, for which the OPA
module will perform to within its specifications. The
OPA module is designed to operate with input voltages
between 0 and VDD-1.4V. Behavior for Common mode
voltages greater than VDD-1.4V, or below 0V, are not
guaranteed.
Leakage current is a measure of the small source or
sink currents on the OPA+ and OPA- inputs. To mini-
mize the effect of leakage currents, the effective imped-
ances connected to the OPA+ and OPA- inputs should
be kept as small as possible and equal.
Input offset voltage is a measure of the voltage differ-
ence between the OPA+ and OPA- inputs in a closed
loop circuit with the OPA in its linear region. The offset
voltage will appear as a DC offset in the output equal to
the input offset voltage, multiplied by the gain of the cir-
cuit. The input offset voltage is also affected by the
Common mode voltage. The OPA is factory calibrated
to minimize the input offset voltage of the module.
Open loop gain is the ratio of the output voltage to the
differential input voltage, (OPA+) - (OPA-). The gain is
greatest at DC and falls off with frequency.
Gain Bandwidth Product or GBWP is the frequency
at which the open loop gain falls off to 0 dB. The lower
GBWP is optimized for systems requiring low fre-
quency response and low power consumption.
18.3 OPAxCON Control Register
The OPAxCON register, shown in Register 18-1,
controls the OPA module.
The OPA module is enabled by setting the OPAxEN bit
of the OPAxCON register. When enabled, the OPA
forces the output driver of OPAxOUT pin into tri-state to
prevent contention between the driver and the OPA
output.
The OPAxSP bit of the OPAxCON register controls the
power and gain bandwidth of the amplifier. Higher
power and greater bandwidth operations are selected
by setting the OPAxSP bit. The default is low power
reduced bandwidth.
Note:
When the OPA module is enabled, the
OPAxOUT pin is driven by the op amp out-
put, not by the PORT digital driver. Refer
to the Electrical specifications for the op
amp output drive capability.
DS41579C-page 164
Preliminary
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