MCP2036-I/P Microchip Technology, MCP2036-I/P Datasheet - Page 9

• Manufacturer Part Number: MCP2036-I/P
• Description: IC KEYLESS ENTRY AFE 14-PDIP
• Manufacturer: Microchip Technology
• Type: Sensor Interfacer

Specifications of MCP2036-I/P

• Package / Case: 14-DIP (0.300", 7.62mm)
• Applications: Analog I/O
• Mounting Type: Through Hole
• Product: Analog Front End
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Supply Current: 6.8 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: Through Hole
• Number Of Channels: 1
• Clock Frequency Max: 2MHz
• Slew Rate: 0.6V/µs
• Turn On Time: 4µs
• Sensor Case Style: DIP
• Operating Temperature Range: -40°C To +85°C
• No. Of Pins: 14
• Rohs Compliant: Yes
• Supply Voltage Range: 2.7 To 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.1
Figure 3-3
Touch keyboard with key controlled by the IO pins of
the PIC
FIGURE 3-3:
The PIC
wave signal and to do all the necessary operations for
proper detection of the key press event.
Then, R
the PWM into a quasi-triangular waveform.
To calculate the amplitude of the triangular signal, the
standard charging time equation for an RC network will
be used, as shown in
EQUATION 3-1:
© 2009 Microchip Technology Inc.
®
Key Coils
IN
®
Application example
MCU.
-C
microcontroller is used to generate a square
shows an example for a 4-key Inductive
V t ( )
IN
filter converts the square wave output of
=
V
step
Equation
MCP2036 Typical Application
•
LREF
[
1
–
CD4052
exp
0
1
2
3
1
3
3-1:
0
2
10nF
– (
t RC
⁄
)
]
10nF
10Ω
I/O
I/O
I/O
I/O
I/O
PIC
LBTN
ISOL
REFSEL
DRVOUT
LREF
CS
For the first half of the square wave, the capacitor C
is charged through R
discharged through R
signal has a 50% duty cycle factor, we can consider:
EQUATION 3-2:
When the PWM signal switches from low-to-high or
from high-to-low, the step voltage applied to the
capacitor C
EQUATION 3-3:
®
MCP2036
Microcontroller
V
DETOUT
IN
V
V
DRVIN
PWM
V
ADC
DET-
will be:
DET+
CLK
REF
V
V
V
step
start
stop
=
=
=
C
C
IN
IN
R
(
FILTER
R
R
FILTER
V
V
V
, for the second half, it is
, and assuming that clock
IN
DD
GAIN
GAIN
DD
DD
C
ADC
2 ⁄ +ΔV
2 ⁄
2 ⁄ -ΔV
MCP2036
+
C
ΔV
IN
)
DS22186C-page 9
R
C
ADC
RGND
IN