HT45R22E Holtek Semiconductor, HT45R22E Datasheet - Page 46

• Manufacturer Part Number: HT45R22E
• Description: Remote Type 8-bit OTP MCU
• Manufacturer: Holtek Semiconductor

Operational Amplifier Offset Cancellation function
Each of the internal OPAs allows for a commode mode
adjustment method of its input offset voltage.
The calibration steps are as following:
1. Set A0OFM=1 to setup the offset cancellation mode,
2. Set A0RS to select which input pin is to be used as
3. Adjust A0OF0~A0OF3 until the output status
4. Set A0OFM = 0 to restore the normal OPA mode
5. Repeat the same procedure from steps 1 to 4
Rev. 1.00
here S3A is closed.
the reference voltage - S1 or S2 is closed
changes
for OPA1.
A0RS
A1RS
0
0
1
1
0
0
1
1
A0OFM
A1OFM
0
1
0
1
0
1
0
1
OFF
OFF
S1A
S1B
ON
ON
ON
ON
ON
ON
S2A
OFF
S2B
OFF
ON
ON
ON
ON
ON
ON
S3A
OFF
OFF
S3B
OFF
OFF
ON
ON
ON
ON
46
Comparator
The device contains a fully integrated Comparator
whose operation is controlled by the Comparator control
registers, known as the CMP0C, CMP1C, COPA0C,
COPA2C and COPA3C registers. The CEN bit within
CMP0C register is used as the enable or disable bit for
the comparator function. The advantages of multiple in-
put resources, multiple reference voltage options, out-
put polarity control, output to Timer counter, multiple
output interrupt triggers, comparator output wakeup
MCU function, comparator output with de-bounce op-
tions, comparator operating current selection and power
down control for low power consumption enhance the
flexibility of this comparator to suit a wide range of appli-
cation possibilities.
Functions
The Comparator can work with OPAs or standalone as
shown in the main functional blocks of the OPAs and
Comparator in this device. This comparator provides
three operating current options, which are 200 A, 5 A
and 1 A. The purpose of this design is to provide the suit-
able comparator power consumption for different operat-
ing modes of the device. The higher the operating
current, the shorter the comparator response time, there-
fore, the designer can select the higher operating current
for the device working at normal mode and a lower one
for the device entering power down mode. By this way,
this comparator can operate under very low power con-
sumption and perform as a wakeup resource when the
device enters power down mode. In addition, this device
provides different comparator output de-bounce time op-
tions for different input signal. If the input signal is noise
sensitive, then the better choice will be the longer
de-bounce time. The designer could select the suitable
de-bounce time according to the input signal.
HT45R22E
March 17, 2010
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