PIC16F685-I/SS Microchip Technology, PIC16F685-I/SS Datasheet - Page 118

• Manufacturer Part Number: PIC16F685-I/SS
• Description: IC PIC MCU FLASH 4KX14 20SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F685-I/SS

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 20-SSOP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 18
• Eeprom Size: 256 x 8
• Ram Size: 256 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: 256 B
• Interface Type: I2C/SPI/SSP/EUSART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 3
• Operating Supply Voltage: 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
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163029, DV164120
• 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: XLT20SS1-1 - SOCKET TRANSITION 20DIP 20SSOPXLT20SS-1 - SOCKET TRANSITION 18DIP 20SSOPAC162061 - HEADER INTRFC MPLAB ICD2 20PINAC164307 - MODULE SKT FOR PM3 28SSOP
• Connectivity: -
• 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 kΩ. As the source impedance is
decreased, the acquisition time may be decreased.
After the analog input channel is selected (or changed),
EQUATION 9-1:
DS41262E-page 116
The value for T
Solving for T
Therefore:
Assumptions:
V
V
V
Note: Where n = number of bits of the ADC.
A/D Acquisition Requirements
AP P LI ED
AP P LI ED
AP P LI ED
HOLD
T
S
ACQ
T
) and the internal sampling switch (R
T
C
. The sampling switch (R
ACQ
:
C
C
⎛
⎝
⎛
⎜
⎝
⎛
⎜
⎝
Temperature
can be approximated with the following equations:
=
=
=
=
=
1
1 e
1 e
HOLD
=
=
=
ACQUISITION TIME EXAMPLE
–
2μ
–
4.67μ
–
–
–
1.37
C
10pF 1k
Amplifier Settling Time
T
2μs
--------------------------
(
S
) must be allowed to fully
AMP
HOLD
2
–
--------- -
–
-------- -
RC
RC
+
μs
T
Tc
n
S
+
C
1.37μ
+
(
⎞
⎟
⎠
⎞
⎟
⎠
+
1
T
(
1
R
C
) 1
=
=
Ω
T
DD
IC
+
C
–
=
S
+
V
), see Figure 9-4.
V
+
+
+
[
(
7k
A PP LIE D
⎞
⎠
CHOLD
50°C and external impedance of 10k
Temperature - 25°C
T
R
[
SS
(
Ω
COFF
SS
50°C- 25°C
=
) impedance
+
+
V
10k
R
CHOLD
⎛
⎝
S
1
) ln(1/2047)
+
Ω
SS
–
)
Hold Capacitor Charging Time
ln(0.0004885)
)
) 0.05μ
--------------------------
(
(
2
n
+
) 0.05μs/°C
1
1
(
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.
–
)
]
⎞
⎠
;[1] V
;[2] V
;combining [1] and [2]
)
]
Ω
CHOLD
CHOLD
5.0V V
+
charged to within 1/2 lsb
charge response to V
DD
Temperature Coefficient
© 2008 Microchip Technology Inc.
APPLIED