ST72334N2(2003) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72334N2
(Rev.:2003)

8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY, ADC, 16-BIT TIMERS, SPI, SCI INTERFACES

STMicroelectronics 

ST72334J/N, ST72314J/N, ST72124J

CLOCK AND TIMING CHARACTERISTICS (Cont’d)

16.5.3 Crystal and Ceramic Resonator Oscillators

The ST7 internal clock can be supplied with four

different Crystal/Ceramic resonator oscillators. All

the information given in this paragraph are based

on characterization results with specified typical

external components. In the application, the reso-

nator and the load capacitors have to be placed as

close as possible to the oscillator pins in order to

minimize output distortion and start-up stabiliza-

tion time. Refer to the crystal/ceramic resonator

manufacturer for more details (frequency, pack-

age, accuracy...).

Symbol

Parameter

Conditions

Min

Max

Unit

fOSC

Oscillator Frequency 3)

LP: Low power oscillator

MP: Medium power oscillator

MS: Medium speed oscillator

HS: High speed oscillator

1

2

>2

>4

4

8

MHz

>8

16

RF

Feedback resistor

CL1

CL2

Recommended load capacitance ver-

sus equivalent serial resistance of the

crystal or ceramic resonator (RS)

RS=200Ω

RS=200Ω

RS=200Ω

RS=100Ω

i2

OSC2 driving current

VDD=5V

VIN=VSS

20

40

kΩ

LP oscillator 38

56

MP oscillator 32

46

MS oscillator 18

26

pF

HS oscillator 15

21

LP oscillator 40

100

MP oscillator 110

190

MS oscillator 180

360

µA

HS oscillator 400

700

16.5.3.1 Typical Crystal Resonators

Option

Byte

Config.

LP

MP

MS

HS

Reference

Freq.

Characteristic 1)

S-200-30-30/50

SS3-400-30-30/30

SS3-800-30-30/30

SS3-1600-30-30/30

2MHz ∆fOSC=[±30ppm25°C,±30ppm∆Ta], Typ. RS=200Ω

4MHz ∆fOSC=[±30ppm25°C,±30ppm∆Ta], Typ. RS=60Ω

8MHz ∆fOSC=[±30ppm25°C,±30ppm∆Ta], Typ. RS=25Ω

16MHz ∆fOSC=[±30ppm25°C,±30ppm∆Ta], Typ. RS=15Ω

Figure 68. Application with a Crystal Resonator

CL1 CL2 tSU(osc)

[pF] [pF] [ms] 2)

33 34 10~15

33 34 7~10

33 34 2.5~3

33 34 1~1.5

i2

CL1

OSC1

fOSC

RESONATOR

RF

CL2

OSC2

ST72XXX

Notes:

1. Resonator characteristics given by the crystal 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 manufacturer for more details.

117/153

Share Link: