CSTCW24M0X53-R0 Datasheet, PDF (24/32 Pages) Murata Manufacturing Co., Ltd. – Ceramic Resonator

P17E.pdf
2012.10.31 ^{Note • Please read rating and CAUTION (for storage, operating, rating, soldering, mounting and handling) in this catalog to prevent smoking and/or burning, etc.}
• This catalog has only typical specifications because there is no space for detailed specifications. Therefore, please review our product specifications or consult the approval sheet for product specifications before ordering.
5 _{Characteristics of CERALOCK}^® _{Oscillation Circuit}
3. Characteristics of Oscillation Rise Time
Oscillation rise time means the time when oscillation
develops from a transient area to a steady state
condition, at the time the power of the IC is activated.
1.00
With a CERALOCK^®, this is defined as the time to
reach 90% of the oscillation level under steady state
conditions as shown in Fig. 5-3.
Rise time is primarily a function of the oscillation circuit
design. Generally, smaller loading capacitance, higher
frequency of ceramic resonator, and lower mechanical Q
0.50
of ceramic resonator cause a faster rise time. The effect
of load capacitance becomes more apparent as the
capacitance of the resonator decreases.
Fig. 5-4 shows how the rise time increases as the load
capacitance of the resonator increases. Also, Fig. 5-4
0
shows how the rise time varies with supply voltage.
It is noteworthy that the rise time of the ceramic
resistor is one or two decades faster than a quartz
5
crystal.
Fig. 5-5 shows comparison of rise time between the two.
1.00
ON
VDD
0V
0.50
0.9ⅹVp-p
Vp-p
Supply Voltage Characteristics
2
4
6
VDD (V) ⁸
CL (CL1 = CL2) Characteristics
VDD = +5V
t=0
Rise Time
Time
Fig. 5-3 Definition of Rise Time
0
0
1
10
CL (pF) ¹⁰⁰
Fig. 5-4 Examples of Characteristics of Oscillation Rise Time
(IC: TC74HCU04 (TOSHIBA),
CERALOCK^®: CSACW33M8X51–B0)
CRYSTAL
(33.868MHz)
CSACW33M8X51–B0
IC : TC74HCU04AP(TOSHIBA)
VDD=+5V, CL1=CL2=6pF
↑ 2.0V/div.
→0.1msec./div.
Fig. 5-5 Comparison of the Rise Time of
a Ceramic Resonator vs. a Quartz Crystal
22