PIC18C858-I/L Microchip Technology, PIC18C858-I/L Datasheet - Page 232

• Manufacturer Part Number: PIC18C858-I/L
• Description: IC PIC MCU OTP 16KX16 84PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C858-I/L

• Core Size: 8-Bit
• Program Memory Size: 32KB (16K x 16)
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Number Of I /o: 68
• Program Memory Type: OTP
• Ram Size: 1.5K 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: 84-PLCC
• Controller Family/series: PIC18
• No. Of I/o's: 68
• Ram Memory Size: 1.5KB
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1536 B
• Interface Type: 3-Wire, I2C, SPI, USART, CAN
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 68
• Number Of Timers: 4 bit
• Operating Supply Voltage: 2.5 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: ICE2000, DM163007, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164310 - MODULE SKT FOR PM3 84PLCCDVA18XL840 - ADAPTER DEVICE ICE 84PLCCAC174012 - MODULE SKT PROMATEII 84PLCC
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: PIC18C858I/L

PIC18CXX8
18.1
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 18-2. 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 2.5k . After the analog input channel is
selected (changed), this acquisition must be done
before the conversion can be started.
EQUATION 18-1:
EQUATION 18-2:
EXAMPLE 18-1: CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
DS30475A-page 232
T
T
Temperature coefficient is only required for temperatures > 25 C.
T
T
T
ACQ
V
or
Tc
ACQ
ACQ
C
ACQ
DD
Note:
HOLD
=
). The source impedance affects the offset voltage
=
=
=
=
=
A/D Acquisition Requirements
SS
SS
When the conversion is started, the hold-
ing capacitor is disconnected from the
input pin.
) impedance varies over the device voltage
) impedance directly affect the time
Amplifier Settling Time +
Holding Capacitor Charging Time +
Temperature Coefficient
T
=
=
T
2 s + Tc + [(Temp - 25 C)(0.05 s/ C)]
-C
-120 pF (1 k
-120 pF (10.5 k ) ln(0.0004885)
-1.26 s (-7.6241)
9.61 s
2 s + 9.61 s + [(50 C - 25 C)(0.05 s/ C)]
11.61 s + 1.25 s
12.86 s
AMP
AMP
HOLD
(V
-(120 pF)(1 k + R
+ T
+ T
REF
(R
C
ACQUISITION TIME
A/D MINIMUM CHARGING TIME
C
S
) and the internal sampling
+ T
- (V
IC
+ T
+ R
COFF
COFF
REF
+ 7 k + 2.5 k ) ln(0.0004885)
SS
HOLD
/2048)) • (1 - e
+ R
HOLD
) must be allowed
SS
S
) ln(1/2047)
. The sampling
+ R
Advanced Information
S
) ln(1/2047)
(-Tc/C
HOLD
(R
IC
+ R
SS
To
Equation 18-1 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 18-1 shows the calculation of the minimum
required acquisition time T
based on the following application system assump-
tions:
C
Rs
Conversion Error
V
Temperature
V
+ R
HOLD
DD
HOLD
S
))
calculate
)
the
=
=
=
=
=
minimum
2000 Microchip Technology Inc.
120 pF
2.5 k
1/2 LSb
5V
50 C (system max.)
0V @ time = 0
ACQ
. This calculation is
Rss = 7 k
acquisition
time,