PIC16F688-I/ML Microchip Technology, PIC16F688-I/ML Datasheet - Page 75

• Manufacturer Part Number: PIC16F688-I/ML
• Description: IC PIC MCU FLASH 4KX14 16QFN
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/ML

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 16-QFN
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• 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: EUSART/RS- 232/SCI/USB
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• 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, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164324 - MODULE SKT FOR MPLAB 8DFN/16QFNXLT16QFN1 - SOCKET TRANSITION 14DIP TO 16QFNAC162061 - HEADER INTRFC MPLAB ICD2 20PINAC162056 - HEADER INTERFACE ICD2 16F688
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

8.3
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 8-4. 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),
an A/D acquisition must be done before the conversion
EQUATION 8-1:
© 2009 Microchip Technology Inc.
Note 1: The reference voltage (V
The value for T
Solving for T
Therefore:
Assumptions:
2: The charge holding capacitor (C
3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin
A/D Acquisition Requirements
HOLD
T
leakage specification.
V
S
V
ACQ
V
T
) and the internal sampling switch (R
AP PLIE D
T
. The sampling switch (R
AP P LI ED
ACQ
AP P LIED
C
C
=
=
=
=
=
:
C
HOLD
=
=
=
2
ACQUISITION TIME EXAMPLE
Temperature
–
–
4.67
can be approximated with the following equations:
1.37
ΜS
10pF 1k
⎛
⎝
C
Amplifier Settling Time
T
2µs
⎛
⎜
⎝
⎛
⎜
⎝
1
) must be allowed to fully
AMP
HOLD
1 e
1 e
+
ΜS
µs
–
+
–
–
1.37
(
----------- -
2047
+
T
(
1
–
--------- -
R
C
–
-------- -
RC
RC
Ω
T
ΜS
DD
T
Tc
IC
+
C
C
+
⎞
⎠
⎞
⎟
⎠
⎞
⎟
⎠
), see Figure 8-4.
+
+
[
+
REF
(
7k
=
Temperature - 25°C
T
=
=
=
R
[
SS
(
Ω
COFF
) has no effect on the equation, since it cancels itself out.
SS
50°C- 25°C
) impedance
50°C and external impedance of 10k
V
V
V
+
+
CHOLD
CHOLD
A P PLIE D
HOLD
10k
R
S
) ln(1/2047)
+
Ω
) is not discharged after each conversion.
SS
)
Hold Capacitor Charging Time
ln(0.0004885)
)
) 0.05
⎛
⎝
(
1
–
) 0.05µs/°C
----------- -
2047
ΜS
(
1
/°C
can be started. To calculate the minimum acquisition
time, Equation 8-1 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.
⎞
⎠
)
]
;[2] V
;combining [1] and [2]
;[1] V
)
]
CHOLD
CHOLD
Ω
5.0V V
+
charged to within 1/2 lsb
charge response to V
Temperature Coefficient
DD
PIC16F688
DS41203E-page 73
APPLIED