PIC16F690DM-PCTLHS Microchip Technology, PIC16F690DM-PCTLHS Datasheet - Page 21

• 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

4.1
4.2
© 2005 Microchip Technology Inc.
INTRODUCTION
THE “REDUCED CURRENT” CIRCUIT
The modifications described here will reduce the current going into the integrator (I
by a factor of 100 ×, so the measurement resolution increases by the same factor.
These modifications are intended for measuring small capacitances. See AN1016 for
more details on this modified circuit’s performance.
4.2.1
Figure 4-1 shows the Humidity Sensor PICtail™ Demo Board top silk-screen.
Figure 4-1 also shows the locations of the resistors that need to be modified to
implement the “Reduced Current” circuit discussed in application note AN1016:
1. Remove (de-solder) the 1 resistor, RA1, already on the board.
2. Refer to Appendix B. “Bill Of Materials (BOM)”, Section B.3 for the BOM for
3. Solder RA1, RA2 and RA3 onto the board.
FIGURE 4-1:
the three resistors (provided by the user) that need to be soldered onto the board.
- RA1 = 1 M
- RA2 = RA3 = 20 k
Chapter 4. Modified Circuit
Modifications
Resistor Modifications.
HUMIDITY SENSOR PICTAIL™
DEMO BOARD USER’S GUIDE
resistors to
to modify
DS51594A-page 17
INT
)