PIC16F877A-I/P【PDF 55/234 页】IC MCU FLASH 8KX14 EE 40DIP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录3827

51页 52页 53页 54页 [55页]56页 57页 58页 59页

PIC16F87XA

DS39582B-page 146

2003 Microchip Technology Inc.

TABLE 14-2:

CAPACITOR SELECTION FOR

CRYSTAL OSCILLATOR

14.2.3

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 pro-

cess parameter variation. Furthermore, the 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 14-3 shows how the R/C

combination is connected to the PIC16F87XA.

FIGURE 14-3:

RC OSCILLATOR MODE

Osc Type

Crystal

Freq.

Cap. Range

32 kHz

33 pF

200 kHz

15 pF

200 kHz

47-68 pF

1 MHz

15 pF

4 MHz

15 pF

4 MHz

15 pF

8 MHz

15-33 pF

20 MHz

15-33 pF

These values are for design guidance only.

See notes following this table.

Crystals Used

32 kHz

Epson C-001R32.768K-A

± 20 PPM

200 kHz

STD XTL 200.000KHz

± 20 PPM

1 MHz

ECS ECS-10-13-1

± 50 PPM

4 MHz

ECS ECS-40-20-1

± 50 PPM

8 MHz

EPSON CA-301 8.000M-C

± 30 PPM

20 MHz

EPSON CA-301 20.000M-C

± 30 PPM

Note 1: Higher capacitance increases the stability

of oscillator but also increases the start-up

time.

2: Since each resonator/crystal has its own

characteristics, the user should consult

the resonator/crystal manufacturer for

appropriate

values

external

components.

3: Rs may be required in HS mode, as well

as XT mode, to avoid overdriving crystals

with low drive level specification.

4: When migrating from other PICmicro

devices, oscillator performance should be

verified.

OSC2/CLKO

CEXT

REXT

PIC16F87XA

OSC1

FOSC/4

Internal

Clock

VDD

VSS

Recommended values:

3 k

≤ REXT ≤ 100 k

CEXT > 20 pF

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式