PIC12F683-E/P Microchip Technology Inc., PIC12F683-E/P Datasheet - Page 63

• Manufacturer Part Number: PIC12F683-E/P
• Description: 8 PIN, 3.5 KB FLASH, 128 RAM, 6 I/O, PDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC12F683-E/P

• A/d Inputs: 4 Channel, 10-Bit
• Comparators: 1
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Frequency: 20 MHz
• Input Output: 6
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 8-pin PDIP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Serial Interface: None
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

9.2
For the A/D converter to meet its specified accuracy, the
charge holding capacitor (C
fully charge to the input channel voltage level. The Ana-
log 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 .
EQUATION 9-1:
FIGURE 9-4:
 2004 Microchip Technology Inc.
Note 1: The reference voltage (V
Legend: C
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
T
T
leakage specification.
ACQ
ACQ
V
I
R
SS
C
S
LEAKAGE
T
T
PIN
IC
HOLD
) and the internal sampling switch (R
C
. The sampling switch (R
= T
= 2 s + T
= C
= -120 pF (1 k + 7 k +10 k ) In(0.0004885)
= 16.47 s
= Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
= 2 s + 16.47 s + [(50°C – 25°C)(0.05 s/°C)]
= 19.72 s
AMP
HOLD
VA
ACQUISITION TIME
ANALOG INPUT MODEL
= Input Capacitance
= Threshold Voltage
= Leakage Current at the pin due to
= Interconnect Resistance
= Sampling Switch
= Sample/Hold Capacitance (from DAC)
R
various junctions
+ T
S
(R
HOLD
C
C
ANx
IC
+ [(Temperature – 25°C)(0.05 s/°C)]
= T
C
5 pF
+ R
PIN
) must be allowed to
DD
COFF
SS
), see Figure 9-4.
REF
+ R
SS
) has no effect on the equation, since it cancels itself out.
) impedance
S
) In(1/2047)
HOLD
V
DD
V
V
) is not discharged after each conversion.
T
T
Preliminary
SS
= 0.6V
= 0.6V
)
I
± 500 nA
LEAKAGE
As the impedance is decreased, the acquisition time
may be decreased. After the analog input channel is
selected (changed), this 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 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 “PICmicro
Manual” (DS33023).
R
IC
1k
V
SS R
Sampling
Switch
DD
6V
5V
4V
3V
2V
®
SS
Mid-Range MCU Family Reference
Sampling Switch
5 6 7 8 9 10 11
V
SS
C
= DAC capacitance
= 120 pF
(k )
HOLD
PIC12F683
DS41211B-page 61
ACQ
, see