ST7PSCR1E4M1/XXX 查看數據表（PDF） - STMicroelectronics

零件编号

产品描述 (功能)

生产厂家

ST7PSCR1E4M1/XXX

8-BIT LOW-POWER, FULL-SPEED USB MCU WITH 16K FLASH, 768 RAM, SMARTCARD I/F, TIMER

STMicroelectronics 

ST7SCR

CLOCK AND TIMING CHARACTERISTICS (Cont’d)

14.4.3 Crystal Resonator Oscillators

The ST7 internal clock is supplied with one Crystal

resonator oscillator. All the information given in

this paragraph are based on characterization re-

sults with specified typical external componants. In

the application, the resonator and the load capaci-

tors have to be placed as close as possible to the

oscillator pins in order to minimize output distortion

and start-up stabilization time. Refer to the crystal

resonator manufacturer for more details (frequen-

cy, package, accuracy...).

Symbol

Parameter

Conditions

Min

fOSC

Oscillator Frequency 3)

MP: Medium power oscillator

RF

Feedback resistor

20

Recommanded load capaci-

CL1

CL2

tances versus equivalent se-

rial resistance of the crystal

See Table 4 on page 20

(MP oscillator)

22

resonator (RS)

i2

OSC2 driving current

VDD=5V

VIN=VSS

(MP oscillator) 110

Typ Max Unit

4

MHz

40

kΩ

56

pF

190 µA

Oscil.

Reference

Typical Crystal Resonator

Freq.

Characteristic 1)

MP JAUCH SS3-400-30-30/30 4MHz ∆fOSC=[±30ppm25°C,±30ppm∆Ta], Typ. RS=60Ω

CL1 CL2 tSU(osc)

[pF] [pF] [ms] 2)

33 34 7~10

Figure 39. Typical Application with a Crystal Resonator

WHEN RESONATOR WITH

INTEGRATED CAPACITORS

CL1

OSC1

i2

fOSC

RESONATOR

RF

CL2

OSC2

ST7XXX

Notes:

1. Resonator characteristics given by the crystal resonator manufacturer.

2. tSU(OSC) is the typical oscillator start-up time measured between VDD=2.8V and the fetch of the first instruction (with a

quick VDD ramp-up from 0 to 5V (<50µs).

3. The oscillator selection can be optimized in terms of supply current using an high quality resonator with small RS value.

Refer to crystal resonator manufacturer for more details.

81/102

Share Link: