ST7FMC1K2B3 STMICROELECTRONICS [STMicroelectronics], ST7FMC1K2B3 Datasheet - Page 233

• Manufacturer Part Number: ST7FMC1K2B3
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

10.7 OPERATIONAL AMPLIFIER (OA)
10.7.1 Introduction
The ST7 Op-Amp module is designed to cover
various types of microcontroller applications
where analog signals amplifiers are used.
It may be used to perform a variety of functions
such as: differential voltage amplifier, comparator/
threshold detector, ADC zooming, impedance
adaptor, general purpose operational amplifier.
10.7.2 Main Features
This module includes:
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10.7.3 General Description
This Op-Amp can be used with 3 external pins
(see device pinout description) and can be inter-
nally connected to the ADC and the Motor Control
cells. The gain must be fixed with external compo-
nents.
1 stand alone Op-Amp that may be externally
connected using I/O pins
Op-Amp output can be internally connected to
the ADC inputs as well as to the motor control
current feedback comparator input
Input offset compensation with optional average
On/Off bit to reduce power consumption and to
enable
external pins
the
input/output
connections
with
The input/output pins are connected to the Op-
Amp as soon as it is switched ON (through the
OACSR register).
The analog input ports must be configured as in-
put, no pull-up, no interrupt. Refer to the “I/O ports”
chapter. Using these pins as analog inputs does
not affect the ability of the port to be read as a logic
input.
The output is not connected (HiZ) when the Op-
Amp is OFF. However the pin can still be used as
an ADC or MTC input in this case.
When the Op-Amp is ON the output is connected
to a dedicated pin which is not a standard I/O port.
The output can be also be connected to the ADC
or the MTC. The switches are controlled software
(refer to the MTC and ADC chapters).
10.7.4 Input Offset Compensation
The Op-Amp incorporates a method to minimize
the input offset which is dependant on process lot.
It is useable by setting the OFFCMP bit of the con-
trol register, which launch the compensation cycle.
The CMPVR bit is set by hardware as soon as this
cycle is completed. The compensation is valid as
long as the OFFCMP bit is high. It can be re-per-
formed by cycling OFFCMP ‘0’ then ‘1’.
The compensation can be improved by averaging
the calculation (over 16 times) setting the AVGC-
MP bit.
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