PIC16F690DM-PCTLHS Microchip Technology, PIC16F690DM-PCTLHS Datasheet - Page 8

• Manufacturer Part Number: PIC16F690DM-PCTLHS
• Description: BOARD DEMO PICTAIL HUMIDITY SNSR
• Manufacturer: Microchip Technology
• Series: PICtail™r

Specifications of PIC16F690DM-PCTLHS

• Sensor Type: Humidity
• Sensing Range: 1 ~ 99% RH
• Interface: Analog
• Voltage - Supply: 5V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP6291, PIC16F690
• Processor To Be Evaluated: MCP6291 and PIC16F690
• Interface Type: ICSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162061 - HEADER INTRFC MPLAB ICD2 20PIN
• Sensitivity: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AN1016
TABLE 3:
Possible Improvements
The V
some microcontrollers, by internally connecting an
ADC to the V
accuracy than the V
be improved.
Components with tighter tolerance will directly improve
the RH accuracy. The resistor, R
are two important examples.
DS01016A-page 8
Current (I
R
V
I
Average Count (k)
V
R
Comparator CMRR
Comparator V
Oscillator
f
Calculating C
C
B
Quantization Error
Calculating RH
HS1101LF, Nominal Error —
HS1101LF, Drift per Year
PWL Lookup Table
Note 1:
B_OA
GBWP
OS_OA
RH
1
CM1
INT
PAR
– V
REF
and R
(Note 4)
2:
3:
4:
5:
RL
Cause
INT
levels (V
It is assumed that V
age errors.
The error in V
The error magnitudes are calculated one at a time, except when converting from to
column) for the current imbalance. In the latter case, the relative errors are added together before
squaring.
This error becomes bigger as the ambient temperature increases. At +125°C, I
imbalance is ±5 nA or ±1.1%, causing the RH error to be ±0.6%.
Both V
value of 0.375V
sense to obtain the ±4% value shown above.
(Note 5)
CM2
) Imbalance
REF
OS
SEN
ERROR ANALYSIS AT ROOM TEMPERATURE
RL
output. Since the ADC has better
RH
REF
and V
Error Sources
and V
ladder, the measurement can
CM
RH
DD
—
—
—
—
—
—
—
internal
external
for HS1101LF
at C
not corrected
corrected
—
—
—
—
is given as a percentage of V
RL
, each error becomes ±0.0278(V
have a maximum specified error of ±0.0104V
DD
Conditions
) can be corrected, in
SEN
INT,
Special
is at its lowest value (3.0V for this design) when converting errors in mV to percent-
and the oscillator
= 0.6 pF
Worst Case
–0.002%
±0.05 pF
(Note 1)
±10 mV
±0.18%
±0.01%
±0.1 pF
±0.01%
±3 mV
–0.5%
0.5 pF
0.25%
Error
±1%
±4%
±1%
±1%
±3%
±1%
20 pA
DD
/2, which is the same as the relative error .
Imbalance
RH
Most of the remaining errors can be corrected with
appropriate calibration procedures and calculations.
The calculated RH can be corrected for errors across
temperature; both the sensor and the circuit can be
calibrated at the same time. Once the decision is made
to calibrate the errors, there is no need to correct the
V
±0.004%
(Note 2)
REF
±2.0%
±0.2%
– V
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
RL
levels using the internal ADC.
). The two errors were added in the RMS
DD
Error in k
–0.002%
(Note 3)
±0.05%
±0.18%
±0.01%
. Since (V
–0.5%
±4%
±1%
±1%
0%
—
—
—
—
—
—
—
Effects
© 2005 Microchip Technology Inc.
RH
Error in C
B_OA
– V
–0.002%
±0.05 pF
±0.05%
±0.18%
±0.01%
±0.1 pF
–0.5%
0.5 pF
0.25%
±4%
±1%
±1%
0%
RL
—
—
—
’s contribution to the
) has a nominal
2
SEN
(“Error in k”
Error in RH
–0.01%
±0.01%
±0.3%
±1.1%
±0.1%
±0.3%
±0.3%
±24%
1.6%
1.5%
±6%
±6%
±3%
±1%
N/A
0%