PIC16F872-I/SP Microchip Technology, PIC16F872-I/SP Datasheet - Page 84

• Manufacturer Part Number: PIC16F872-I/SP
• Description: IC MCU FLASH 2KX14 EE 28DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F872-I/SP

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 28-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C/SPI/SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 4 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, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC16F872
10.1
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (C
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 10-2. The
source impedance (R
switch (R
required to charge the capacitor C
switch (R
(V
impedance for analog sources is 10 k . As the
impedance is decreased, the acquisition time may be
EQUATION 10-1:
FIGURE 10-2:
DS30221B-page 82
T
T
T
DD
ACQ
C
ACQ
Note 1: The reference voltage (V
), Figure 10-2. The maximum recommended
A/D Acquisition Requirements
SS
2: The charge holding capacitor (C
3: The maximum recommended impedance for analog sources is 10 k . This is required to meet the pin
SS
=
=
=
=
=
=
=
) impedance varies over the device voltage
leakage specification.
) impedance directly affect the time
Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
T
2 s + T
C
16.47 s
2 s + 16.47 s + [(50°C -25°C)(0.05 s/°C)
19.72 s
AMP
HOLD
Legend C
+ T
(R
C
VA
C
ACQUISITION TIME
ANALOG INPUT MODEL
+ [(Temperature -25°C)(0.05 s/°C)]
IC
S
+ T
V
I
R
SS
C
) and the internal sampling
R
+ R
LEAKAGE
PIN
T
IC
HOLD
S
COFF
SS
ANx
+ R
C
5 pF
HOLD
PIN
= input capacitance
= threshold voltage
= leakage current at the pin due to
= interconnect resistance
= sampling switch
= sample/hold capacitance (from DAC)
HOLD
S
) In(1/2047) - 120 pF (1 k + 7 k + 10 k ) In(0.0004885)
various junctions
) must be allowed
REF
. The sampling
) has no effect on the equation, since it cancels itself out.
HOLD
V
DD
V
V
) is not discharged after each conversion.
T
T
= 0.6V
= 0.6V
I
± 500 nA
LEAKAGE
decreased. After the analog input channel is selected
(changed), this acquisition must be done before the
conversion can be started.
Equation 10-1 may be used to calculate the minimum
acquisition time. This equation assumes that 1/2 LSb
error is used (1024 steps for the A/D). The 1/2 LSb
error is the maximum error allowed for the A/D to meet
its specified resolution.
To calculate the minimum acquisition time, T
the
(DS33023).
R
IC
PICmicro™
1k
V
SS R
DD
Sampling
Switch
6V
5V
4V
3V
2V
SS
Mid-Range
Sampling Switch
5 6 7 8 9 10 11
V
C
= DAC capacitance
= 120 pF
SS
(k )
HOLD
2002 Microchip Technology Inc.
Reference
ACQ
Manual
, see