PIC16LC621-04I/SO Microchip Technology, PIC16LC621-04I/SO Datasheet - Page 50
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PIC16LC621-04I/SO
Manufacturer Part Number
PIC16LC621-04I/SO
Description
IC MCU OTP 1KX14 COMP 18SOIC
Manufacturer
Microchip Technology
Series
PIC® 16Cr
Datasheet
1.PIC16C620A-04SO.pdf
(128 pages)
Specifications of PIC16LC621-04I/SO
Core Processor
PIC
Core Size
8-Bit
Speed
4MHz
Peripherals
Brown-out Detect/Reset, POR, WDT
Number Of I /o
13
Program Memory Size
1.75KB (1K x 14)
Program Memory Type
OTP
Ram Size
80 x 8
Voltage - Supply (vcc/vdd)
2.5 V ~ 6 V
Oscillator Type
External
Operating Temperature
-40°C ~ 85°C
Package / Case
18-SOIC (7.5mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Data Converters
-
Connectivity
-
Other names
PIC16LC621-04I/SOR
PIC16LC621-04I/SOR
PIC16LC621-04I/SOR
PIC16C62X
9.2.3
Either a prepackaged oscillator can be used or a simple
oscillator circuit with TTL gates can be built.
Prepackaged oscillators provide a wide operating
range and better stability. A well-designed crystal
oscillator will provide good performance with TTL
gates. Two types of crystal oscillator circuits can be
used; one with series resonance or one with parallel
resonance.
Figure 9-3 shows implementation of a parallel resonant
oscillator circuit. The circuit is designed to use the
fundamental frequency of the crystal. The 74AS04
inverter performs the 180° phase shift that a parallel
oscillator requires. The 4.7 kΩ resistor provides the
negative
potentiometers bias the 74AS04 in the linear region.
This could be used for external oscillator designs.
FIGURE 9-3:
Figure 9-4 shows a series resonant oscillator circuit.
This circuit is also designed to use the fundamental
frequency of the crystal. The inverter performs a 180°
phase shift in a series resonant oscillator circuit. The
330 kΩ resistors provide the negative feedback to bias
the inverters in their linear region.
FIGURE 9-4:
DS30235J-page 48
74AS04
330 kΩ
10k
+5V
20 pF
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
feedback
10k
0.1 µF
XTAL
74AS04
XTAL
4.7k
20 pF
74AS04
330 kΩ
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
for
10k
74AS04
stability.
74AS04
To Other
Devices
To Other
Devices
PIC16C62X
The
CLK
PIC16C62X
CLK
IN
10 kΩ
IN
9.2.4
For timing insensitive applications the “RC” device
option offers additional cost savings. The RC oscillator
frequency is a function of the supply voltage, the
resistor (R
operating temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal
process
difference in lead frame capacitance between package
types will also affect the oscillation frequency,
especially for low C
take into account variation due to tolerance of external
R and C components used. Figure 9-5 shows how the
R/C combination is connected to the PIC16C62X. For
R
become unstable or stop completely. For very high
R
sensitive to noise, humidity and leakage. Thus, we
recommend to keep R
Although the oscillator will operate with no external
capacitor (C
above 20 pF for noise and stability reasons. With no or
small external capacitance, the oscillation frequency
can vary dramatically due to changes in external
capacitances, such as PCB trace capacitance or
package lead frame capacitance.
See Section 13.0 for RC frequency variation from part
to part due to normal process variation. The variation is
larger for larger R (since leakage current variation will
affect RC frequency more for large R) and for smaller
C (since variation of input capacitance will affect RC
frequency more).
See Section 13.0 for variation of oscillator frequency
due to V
frequency variation due to operating temperature for
given R, C and V
The oscillator frequency, divided by 4, is available on
the OSC2/CLKOUT pin, and can be used for test
purposes or to synchronize other logic (Figure 3-2 for
waveform).
FIGURE 9-5:
EXT
EXT
C
R
V
EXT
EXT
DD
values below 2.2 kΩ, the oscillator operation may
V
values (e.g., 1 MΩ), the oscillator becomes
DD
DD
parameter
EXT
RC OSCILLATOR
EXT
for given R
) and capacitor (C
F
= 0 pF), we recommend using values
OSC
DD
EXT
/4
values.
EXT
RC OSCILLATOR MODE
OSC1
variation.
values. The user also needs to
OSC2/CLKOUT
2003 Microchip Technology Inc.
EXT
between 3 kΩ and 100 kΩ.
/C
EXT
PIC16C62X
EXT
values, as well as
Furthermore,
) values, and the
Internal Clock
the