DM240021 Microchip Technology, DM240021 Datasheet - Page 31

• Manufacturer Part Number: DM240021
• Description: KIT STARTER MPLAB FOR PIC24H
• Manufacturer: Microchip Technology
• Series: MPLAB®r
• Type: MCUr

Specifications of DM240021

• Contents: Board, Cable, CD
• Processor To Be Evaluated: PIC24H128GP504
• Data Bus Width: 16 bit
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC24
• Silicon Core Number: PIC24H
• Silicon Family Name: PIC24HJxxxGPxxx
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC24H
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

© 2008 Microchip Technology Inc.
4.1.4
The starter kit features an analog conditioning circuit (see schematics in Figure A-4),
which can be used by the user to plug in a wide range of external analog sensors. The
analog conditioning circuit has a differential amplifier followed by an anti-aliasing low
pass filter. The gain of the differential amplifier is given by Equation 4-1 in terms of the
resistors used and differential input voltages at input points TP11 and TP12. The gain
is fixed at 100. Any sensor with a differential compensated output voltage of less than
33mV can be used.
EQUATION 4-1:
The anti-aliasing filter is a 2nd-order low-pass filter, with a cut-off frequency of ~500 Hz
(483.78 Hz). The highest frequency of the base band sensor signal is assumed to be
less than 500 Hz. The output of the low-pass filter is connected to the ADC input AN7
on the PIC24H MCU device.
Analog Conditioning Circuitry
DIFFERENTIAL AMPLIFIER GAIN
Gain
R
R
f
i
=
=
=
R
---- - V
R
R57
R51
f
i
(
TP11
=
=
R58
R53
–
V
TP12
)
Hardware
DS51780A-page 27