PIC16F677-I/P Microchip Technology, PIC16F677-I/P Datasheet - Page 118

• Manufacturer Part Number: PIC16F677-I/P
• Description: IC PIC MCU FLASH 2KX14 20DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F677-I/P

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 20-DIP (0.300", 7.62mm)
• Mfg Application Notes: Intro to Capacitive Sensing Appl Notes Layout and Physical Design Appl Note
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 18
• Eeprom Size: 256 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 2
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162061 - HEADER INTRFC MPLAB ICD2 20PINACICE0203 - MPLABICE 20P 300 MIL ADAPTER
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC16F631/677/685/687/689/690
9.3
For the ADC to meet its specified accuracy, the charge
holding capacitor (C
charge to the input channel voltage level. The Analog
Input model is shown in Figure 9-4. The source
impedance (R
impedance directly affect the time required to charge the
capacitor C
varies over the device voltage (V
The maximum recommended impedance for analog
sources is 10 k . As the source impedance is
decreased, the acquisition time may be decreased.
After the analog input channel is selected (or changed),
EQUATION 9-1:
DS41262C-page 116
Note 1: The reference voltage (V
The value for T
Solving for T
Therefore:
Assumptions:
2: The charge holding capacitor (C
3: The maximum recommended impedance for analog sources is 10 k . This is required to meet the pin
A/D Acquisition Requirements
HOLD
leakage specification.
T
V
S
V
V
ACQ
T
) and the internal sampling switch (R
AP PLIE D
T
. The sampling switch (R
AP P LI ED
ACQ
AP P LIED
C
C
=
=
=
=
:
=
HOLD
C
=
=
=
ACQUISITION TIME EXAMPLE
Temperature
–
–
5µ
7.67µ
can be approximated with the following equations:
1.37
10pF 1k
⎛
⎝
C
Amplifier Settling Time
T
5µs
⎛
⎜
⎝
⎛
⎜
⎝
S
1
) must be allowed to fully
AMP
HOLD
1 e
1 e
+
µs
–
S
+
–
–
1.37µ
----------- -
2047
+
T
1
–
--------- -
R
C
–
-------- -
RC
RC
T
T
DD
Tc
IC
+
C
C
S
+
⎞
⎠
⎞
⎟
⎠
⎞
⎟
⎠
), see Figure 9-4.
+
+
+
REF
7k
=
Temperature - 25°C 0.05µs/°C
T
=
=
=
R
SS
COFF
) has no effect on the equation, since it cancels itself out.
SS
50°C- 25°C 0.05µ
) impedance
50°C and external impedance of 10k
V
V
V
+
+
CHOLD
A P PLIE D
HOLD
CHOLD
10k
R
S
+
) is not discharged after each conversion.
Preliminary
ln(1/2047)
SS
Hold Capacitor Charging Time
ln(0.0004885)
)
⎛
⎝
1
–
----------- -
2047
S
1
/°C
an A/D acquisition must be done before the conversion
can be started. To calculate the minimum acquisition
time, Equation 9-1 may be used. This equation
assumes that 1/2 LSb error is used (1024 steps for the
ADC). The 1/2 LSb error is the maximum error allowed
for the ADC to meet its specified resolution.
⎞
⎠
;[2] V
;combining [1] and [2]
;[1] V
CHOLD
CHOLD
5.0V V
+
charge response to V
charged to within 1/2 lsb
Temperature Coefficient
© 2006 Microchip Technology Inc.
DD
APPLIED