PIC16F690DM-PCTLHS Microchip Technology, PIC16F690DM-PCTLHS Datasheet - Page 24

• 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

A.4
A.5
DS51594A-page 20
THE “REDUCED CURRENT” MODIFICATION
ADDITIONAL COMMENTS
The test points, TP3 – TP5, have 10 k
external measurement equipment. This will help prevent over-voltage events, and will
help the op amp, U2, operate in a stable condition.
Figure A-1 shows the Humidity Sensor PICtail™ Demo Board as it comes from
Microchip. This board can be modified by the user to implement the “Reduced Current”
circuit discussed in application note AN1016 and Chapter 4. “Modified Circuit”.
The demonstration board includes test points for convenience on the bench. The “+5V”
and “GND” test points (TP1 and TP2) connect to the board’s supply voltages.
The “V
square wave into the integrator. The “V
the op amp’s common mode input voltage. The “V
tion to the op amps output to allow the user to monitor the triangle wave at the integra-
tor’s output.
The PICkit™ 1 Flash Starter Kit provides a +5V single supply voltage. It can drive up to
5 μF on the supply; a larger capacitive load causes current loading and timing issues.
This demonstration board also uses the +5V single supply voltage. It has two 1 μF bulk
bypass capacitors and two 0.1 μF local bypass capacitors.
High frequency design practices are used to minimize digital interference:
• Solid ground plane
• Surface mount devices for the analog circuitry
• Separate digital and analog lines and sections
Note:
a) This is a two-layer board. It has a solid ground plane on the bottom layer to
INT
minimize EMC issues, and routes the traces in the top layer. The complete
schematic is in Figure A-1 and Figure A-2, the board layer plots in Figure A-3,
Figure A-4 and Figure A-5. The Bill of Materials (BOM) is in Appendix
B. “Bill Of Materials (BOM)”. The Gerber files for this board are available on
the Microchip web site (www.microchip.com) and are contained in the zip file
00084R1.zip.
” test point (TP3) connects to U1’s pin 14 to allow the user to monitor the
Do NOT connect a power supply to the “+5V” and “GND” test points, unless
the board is NOT connected to the PICkit™ 1 Flash Starter Kit (i.e., it
stands alone).
CM
placed in series to isolate the circuit from
” test point (TP4) allows the user to measure
SEN
” test point (TP5) allows connec-
© 2005 Microchip Technology Inc.