參數(shù)資料
型號: pic16ce623
廠商: Microchip Technology Inc.
英文描述: OTP 8-Bit CMOS MCU with EEPROM Data Memory(8位OTP CMOS微控制器)
中文描述: 檢察官辦公室8位CMOS微控制器EEPROM數(shù)據(jù)存儲器(8位檢察官辦公室的CMOS微控制器)
文件頁數(shù): 52/108頁
文件大?。?/td> 2355K
代理商: PIC16CE623
PIC16CE62X
DS40182A-page 52
Preliminary
1998 Microchip Technology Inc.
10.2.3
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 10-4 shows implementation of a parallel reso-
nant 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 10-4: EXTERNAL PARALLEL
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
Figure 10-5 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 10-5: EXTERNAL SERIES
RESONANT CRYSTAL
OSCILLATOR CIRCUIT
20 pF
+5V
20 pF
10k
4.7k
10k
74AS04
XTAL
10k
74AS04
PIC16CE62X
CLK
IN
To other
330
74AS04
74AS04
PIC16CE62X
CLK
IN
To other
XTAL
330
74AS04
0.1
μ
F
10.2.4
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 10-6 shows how the
R/C combination is connected to the PIC16CE62X. 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 14.0 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 14.0 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 10-6: RC OSCILLATOR MODE
OSC2/CLKOUT
Cext
Rext
V
DD
PIC16CE62X
OSC1
Fosc/4
Internal Clock
V
DD
相關(guān)PDF資料
PDF描述
pic16ce624 OTP 8-Bit CMOS MCU with EEPROM Data Memory(8位OTP CMOS微控制器)
pic16ce625 OTP 8-Bit CMOS MCU with EEPROM Data Memory(8位OTP CMOS微控制器)
pic16cr54c ROM-Based 8-Bit CMOS Microcontroller Series(8位CMOS微控制器)
PIC16CR73 28/40-Pin, 8-Bit CMOS ROM Microcontrollers
PIC16CR74 28/40-Pin, 8-Bit CMOS ROM Microcontrollers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PIC16CE623/JW 功能描述:8位微控制器 -MCU .875KB 96 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(shí)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
PIC16CE623-04/P 功能描述:8位微控制器 -MCU .875KB 96 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(shí)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
PIC16CE623-04/SO 功能描述:8位微控制器 -MCU .875KB 96 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(shí)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
PIC16CE623-04/SS 功能描述:8位微控制器 -MCU .875KB 96 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(shí)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
PIC16CE623-04E/P 功能描述:8位微控制器 -MCU .875KB 96 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(shí)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