參數(shù)資料
型號: ADM208EAR
廠商: Analog Devices Inc
文件頁數(shù): 6/20頁
文件大小: 0K
描述: IC TX/RX RS-232 5V 0.1UF 24SOIC
標(biāo)準(zhǔn)包裝: 31
類型: 收發(fā)器
驅(qū)動器/接收器數(shù): 4/4
規(guī)程: RS232
電源電壓: 4.5 V ~ 5.5 V
安裝類型: 表面貼裝
封裝/外殼: 24-SOIC(0.295",7.50mm 寬)
供應(yīng)商設(shè)備封裝: 24-SOIC W
包裝: 管件
ADM206E/ADM207E/ADM208E/ADM211E/ADM213E
Rev. E | Page 14 of 20
Table 10. Test Severity Levels (IEC 1000-4-3)
Level
Field Strength (V/m)
1
2
3
10
EMISSIONS/INTERFERENCE
EN 55022, CISPR 22 defines the permitted limits of radiated
and conducted interference from information technology (IT)
equipment. The objective of the standard is to minimize the
level of emissions, both conducted and radiated.
For ease of measurement and analysis, conducted emissions are
assumed to predominate below 30 MHz, and radiated emissions
are assumed to predominate above 30 MHz.
CONDUCTED EMISSIONS
This is a measure of noise that is conducted onto the line power
supply. Switching transients from the charge pump that are 20 V
in magnitude and that contain significant energy can lead to
conducted emissions. Another source of conducted emissions is
the overlap in switch-on times in the charge pump voltage
converter. In the voltage doubler shown in Figure 31, if S2 has
not fully turned off before S4 turns on, a transient current glitch
occurs between VCC and GND that results in conducted emis-
sions. Therefore, it is important that the switches in the charge
pump guarantee break-before-make switching under all condi-
tions so instantaneous short-circuit conditions do not occur.
The ADM2xxE have been designed to minimize the switching
transients and ensure break-before-make switching, thereby
minimizing conducted emissions. This results in emission
levels well below specified limits. Other than the recom-
mended 0.1 μF capacitor, no additional filtering/decoupling
is required.
Conducted emissions are measured by monitoring the line
power supply. The equipment used consists of a line impedance
stabilizing network (LISN) that essentially presents a fixed
impedance at RF and a spectrum analyzer. The spectrum
analyzer scans for emissions up to 30 MHz. A plot for the
ADM211E is shown in Figure 33.
+
VCC
GND
S1
S2
C1
S3
S4
C3
V+ = 2VCC
VCC
INTERNAL
OSCILLATOR
00
06
8-
031
Figure 31. Charge Pump Voltage Doubler
1
2
SWITCHING GLITCHES
0
006
8-
03
2
Figure 32. Switching Glitches
LOG FREQUENCY (MHz)
80
70
0
0.33
30
0.6
60
50
10
40
30
20
6
3
118
LIMIT
(dB
V)
00
068
-03
3
Figure 33. Conducted Emissions Plot
RADIATED EMISSIONS
Radiated emissions are measured at frequencies in excess of
30 MHz. RS-232 outputs designed for operation at high baud
rates while driving cables can radiate high frequency EM
energy. The previously described causes of conducted emissions
can also cause radiated emissions. Fast RS-232 output tran-
sitions can radiate interference, especially when lightly loaded
and driving unshielded cables. Charge pump devices are also
prone to radiating noise due to the high frequency oscillator
and the high voltages being switched by the charge pump. The
move toward smaller capacitors in order to conserve board
space has resulted in higher frequency oscillators being em-
ployed in the charge pump design, resulting in higher levels of
conducted and radiated emissions.
The RS-232 outputs on the ADM2xxE products feature a con-
trolled slew rate in order to minimize the level of radiated
emissions, yet they are fast enough to support data rates of up to
230 kbps.
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ADM208EARSZ 功能描述:IC TX/RX RS-232 5V 0.1UF 24SSOP RoHS:是 類別:集成電路 (IC) >> 接口 - 驅(qū)動器,接收器,收發(fā)器 系列:- 產(chǎn)品培訓(xùn)模塊:RS-232 & USB Transceiver 標(biāo)準(zhǔn)包裝:2,000 系列:- 類型:收發(fā)器 驅(qū)動器/接收器數(shù):1/1 規(guī)程:RS232 電源電壓:3 V ~ 5.5 V 安裝類型:表面貼裝 封裝/外殼:16-SSOP(0.209",5.30mm 寬) 供應(yīng)商設(shè)備封裝:16-SSOP 包裝:帶卷 (TR) 其它名稱:296-19849-2
ADM208EARSZ1 制造商:AD 制造商全稱:Analog Devices 功能描述:EMI/EMC-Compliant, ?±15 kV ESDProtected, RS-232 Line Drivers/Receivers