PIC18F8525-I/PT Microchip Technology, PIC18F8525-I/PT Datasheet - Page 240

• Manufacturer Part Number: PIC18F8525-I/PT
• Description: IC PIC MCU FLASH 24KX16 80TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F8525-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 48KB (24K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.75K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TFQFP
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 3840 B
• Interface Type: MSSP, SPI, I2C, EUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 69
• Number Of Timers: 2 x 8 bit
• Operating Supply Voltage: 4.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136, DM163032
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 16 bit
• For Use With: XLT80PT3 - SOCKET TRAN ICE 80MQFP/TQFPAC164320 - MODULE SKT MPLAB PM3 80TQFPAC174011 - MODULE SKT PROMATEII 80TQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC18F6525/6621/8525/8621
20.1
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 20-2. The
source impedance (R
switch (R
required to charge the capacitor C
switch (R
(V
at the analog input (due to pin leakage current). The
maximum recommended impedance for analog
sources is 2.5 kΩ. After the analog input channel is
selected (changed), this acquisition must be done
before the conversion can be started.
EQUATION 20-1:
EQUATION 20-2:
EQUATION 20-3:
DS39612B-page 238
T
V
or
Tc
T
Temperature coefficient is only required for temperatures > 25°C.
T
T
T
ACQ
ACQ
ACQ
C
ACQ
DD
Note:
HOLD
). The source impedance affects the offset voltage
A/D Acquisition Requirements
SS
=
=
=
=
=
=
SS
=
=
) impedance varies over the device voltage
When the conversion is started, the hold-
ing capacitor is disconnected from the
input pin.
) impedance directly affect the time
T
2 µs + T
-C
-120 pF (1 kΩ + 7 kΩ + 2.5 kΩ) ln(0.0004885)
-120 pF (10.5 kΩ) ln(0.0004885)
-1.26 µs (-7.6241)
9.61 µs
2 µs + 9.61 µs + [(50°C – 25°C)(0.05 µs/°C)]
11.61 µs + 1.25 µs
12.86 µs
Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
T
(V
-(120 pF)(1 kΩ + R
AMP
AMP
REF
HOLD
+ T
+ T
– (V
ACQUISITION TIME
A/D MINIMUM CHARGING TIME
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
C
S
(R
C
) and the internal sampling
C
+ [(Temp – 25°C)(0.05 µs/°C)]
IC
REF
+ T
+ T
+ R
/2048)) • (1 – e
COFF
COFF
SS
HOLD
SS
+ R
HOLD
+ R
) must be allowed
S
) ln(1/2047)
S
. The sampling
) ln(1/2047)
(-Tc/C
HOLD
(R
IC
+ R
SS
+ R
S
))
To
Equation 20-1 may be used. 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.
Example 20-3 shows the calculation of the minimum
required acquisition time, T
based
assumptions:
C
Rs
Conversion Error
V
Temperature
V
)
DD
HOLD
HOLD
calculate
on
the
the
=
=
≤
=
=
=
following
minimum
 2005 Microchip Technology Inc.
120 pF
2.5 kΩ
1/2 LSb
5V → Rss = 7 kΩ
50°C (system max.)
0V @ time = 0
ACQ
. This calculation is
application
acquisition
system
time,