參數(shù)資料
型號： PIC16C620
廠商： Microchip Technology Inc.
英文描述： EPROM-Based 8-Bit CMOS Microcontroller(每個I/O口有25mA驅(qū)動/吸收電流,可編程VREF,2.5V的微控制器)
中文描述： 存儲器為基礎(chǔ)的8位CMOS微控制器（每個的I / O口有25毫安驅(qū)動/吸收電流，可編程參考電壓，為2.5V的微控制器）
文件頁數(shù)： 48/112頁
文件大?。?/td> 1205K
代理商： PIC16C620
PIC16C62X(A)
DS30235F-page 48
Preliminary
1997 Microchip Technology Inc.
9.2.3
EXTERNAL CRYSTAL OSCILLATOR
CIRCUIT
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 9-4 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 k
resistor provides the
negative
feedback
for
potentiometers bias the 74AS04 in the linear region.
This could be used for external oscillator designs.
stability.
The
10 k
FIGURE 9-4:
EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
Figure 9-5 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 k
resistors provide the negative feedback to bias
the inverters in their linear region.
FIGURE 9-5:
EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
20 pF
+5V
20 pF
10k
4.7k
10k
74AS04
XTAL
10k
74AS04
PIC16C62X(A)
CLK
IN
To other
Devices
330 k
74AS04
74AS04
PIC16C62X
CLK
IN
To other
Devices
XTAL
330 k
74AS04
0.1
μ
F
9.2.4
RC OSCILLATOR
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 (Rext) and capacitor (Cext) values, and the
operating temperature. In addition to this, the oscillator
frequency will vary from unit to unit due to normal
process
parameter
variation.
difference in lead frame capacitance between package
types will also affect the oscillation frequency,
especially for low Cext values. The user also needs to
take into account variation due to tolerance of external
R and C components used. Figure 9-6 shows how the
R/C combination is connected to the PIC16C62X(A).
For Rext values below 2.2 k
, the oscillator operation
may become unstable, or stop completely. For very
high Rext values (e.g., 1 M
), the oscillator becomes
sensitive to noise, humidity and leakage. Thus, we
recommend to keep Rext between 3 k
and 100 k
.
Although the oscillator will operate with no external
capacitor (Cext = 0 pF), we recommend using values
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 fre-
quency more).
See Section 13.0 for variation of oscillator frequency
due to V
DD
for given Rext/Cext values as well as
frequency variation due to operating temperature for
given R, C, and V
DD
values.
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).
Furthermore,
the
FIGURE 9-6:
RC OSCILLATOR MODE
OSC2/CLKOUT
Cext
Rext
V
DD
PIC16C62X(A)
OSC1
Fosc/4
Internal Clock
V
DD
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PIC16C620/JW 功能描述:8位微控制器 -MCU .875KB 80 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16C620-04/P 功能描述:8位微控制器 -MCU .875KB 80 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16C620-04/P 制造商:Microchip Technology Inc 功能描述:IC 8BIT CMOS MCU 16C620 DIP18
PIC16C620-04/SO 功能描述:8位微控制器 -MCU .875KB 80 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16C620-04/SS 功能描述:8位微控制器 -MCU .875KB 80 RAM 13 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
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