参数资料
型号: 7548
厂商: Renesas Technology Corp.
英文描述: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
中文描述: 单芯片8位CMOS微机
文件页数: 56/73页
文件大小: 1255K
代理商: 7548
Rev.2.00
REJ03B0210-0200
Mar 15, 2007
Page 56 of 70
7548 Group
PRELIMINARY
Notice: This is not a final specification.
Some parametric limits are subject to change.
4. Oscillator concerns
Take care to prevent an oscillator that generates clocks for a mi-
crocomputer operation from being affected by other signals.
(1) Keeping oscillator away from large current signal lines
Install a microcomputer (and especially an oscillator) as far as
possible from signal lines where a current larger than the toler-
ance of current value flows.
<Reason>
In the system using a microcomputer, there are signal lines for
controlling motors, LEDs, and thermal heads or others. When a
large current flows through those signal lines, strong noise
occurs because of mutual inductance.
(2) Installing oscillator away from signal lines where potential
levels change frequently
Install an oscillator and a connecting pattern of an oscillator
away from signal lines where potential levels change frequently.
Also, do not cross such signal lines over the clock lines or the
signal lines which are sensitive to noise.
<Reason>
Signal lines where potential levels change frequently (such as the
CNTR pin signal line) may affect other lines at signal rising edge
or falling edge. If such lines cross over a clock line, clock wave-
forms may be deformed, which causes a microcomputer failure
or a program runaway.
Fig 76.
Wiring for a large current signal line/Writing of signal
lines where potential levels change frequently
(3) Oscillator protection using V
SS
pattern
As for a two-sided printed circuit board, print a V
SS
pattern on
the underside (soldering side) of the position (on the component
side) where an oscillator is mounted.
Connect the V
SS
pattern to the microcomputer V
SS
pin with the
shortest possible wiring. Besides, separate this V
SS
pattern from
other V
SS
patterns.
Fig 77. V
SS
pattern on the underside of an oscillator
X
IN
X
OUT
V
SS
M
Microcomputer
Mutual inductance
Large
current
GND
X
IN
X
OUT
V
SS
CNTR
Do not cross
N.G.
(1) Keeping oscillator away from large current
signal lines
(2) Installing oscillator away from signal lines
where potential levels change frequently
Oscillator wiring
pattern example
An example of V
SS
patterns on the
underside of a printed circuit board
Separate the V
SS
line for oscillation from other V
SS
lines
X
IN
X
OUT
V
SS
相关PDF资料
PDF描述
7549 SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
75HQ SCHOTTKY RECTIFIER
75HQ030 SCHOTTKY RECTIFIER
75HQ035 SCHOTTKY RECTIFIER
75HQ040 SCHOTTKY RECTIFIER
相关代理商/技术参数
参数描述
7548_07 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:Standard Characteristics
7548_0710 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
75481-001 功能描述:集管和线壳 BACKPANEL PINS RoHS:否 产品种类:1.0MM Rectangular Connectors 产品类型:Headers - Pin Strip 系列:DF50 触点类型:Pin (Male) 节距:1 mm 位置/触点数量:16 排数:1 安装风格:SMD/SMT 安装角:Right 端接类型:Solder 外壳材料:Liquid Crystal Polymer (LCP) 触点材料:Brass 触点电镀:Gold 制造商:Hirose Connector
75481-002 功能描述:集管和线壳 BERGPIN - WITH LARGE STA-R RoHS:否 产品种类:1.0MM Rectangular Connectors 产品类型:Headers - Pin Strip 系列:DF50 触点类型:Pin (Male) 节距:1 mm 位置/触点数量:16 排数:1 安装风格:SMD/SMT 安装角:Right 端接类型:Solder 外壳材料:Liquid Crystal Polymer (LCP) 触点材料:Brass 触点电镀:Gold 制造商:Hirose Connector
75481-004 功能描述:集管和线壳 BERGPIN RoHS:否 产品种类:1.0MM Rectangular Connectors 产品类型:Headers - Pin Strip 系列:DF50 触点类型:Pin (Male) 节距:1 mm 位置/触点数量:16 排数:1 安装风格:SMD/SMT 安装角:Right 端接类型:Solder 外壳材料:Liquid Crystal Polymer (LCP) 触点材料:Brass 触点电镀:Gold 制造商:Hirose Connector