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參數(shù)資料
| 型號(hào)： | ADM2490EBRWZ |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 通用總線功能 |
| 英文描述： | High Speed, ESD-Protected, Full-Duplex, iCoupler, Isolated RS-485 Transceiver |
| 中文描述： | LINE TRANSCEIVER, PDSO16 |
| 封裝： | ROHS COMPLIANT, MS-103AA, SOIC-16 |
| 文件頁(yè)數(shù)： | 14/16頁(yè) |
| 文件大?。?/td> | 470K |
| 代理商： | ADM2490EBRWZ |
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ADM2490E
THERMAL SHUTDOWN
The ADM2490E contains thermal-shutdown circuitry that protects
the part from excessive power dissipation during fault conditions.
Shorting the driver outputs to a low impedance source can result in
high driver currents. The thermal sensing circuitry detects the
increase in die temperature under this condition and disables
the driver outputs. This circuitry is designed to disable the driver
outputs when a die temperature of 150°C is reached. As the device
cools, the drivers are re-enabled at a temperature of 140°C.
FAIL-SAFE RECEIVER INPUTS
The receiver inputs include a fail-safe feature that guarantees a
logic high on the RxD pin when the A and B inputs are floating
or open-circuited.
MAGNETIC FIELD IMMUNITY
Because
i
Couplers use a coreless technology, no magnetic
components are present and the problem of magnetic saturation
of the core material does not exist. Therefore,
i
Couplers have
essentially infinite dc field immunity. The following analysis
defines the conditions under which this may occur. The 3 V
operating condition of the ADM2409E is examined because it
represents the most susceptible mode of operation.
The limitation on the ac magnetic field immunity of the
i
Coupler is set by the condition that induced an error voltage in
the receiving coil (the bottom coil in this case) that was large to
either falsely set or reset the decoder. The voltage induced
across the bottom coil is given by
Rev. 0 | Page 14 of 16
∑
=
2
n
r
dt
d
V
π
β
;
N
n
,
,
=
where, if the pulses at the transformer output are greater than
1.0 V in amplitude:
β
= magnetic flux density (gauss).
N
= number of turns in receiving coil.
r
n
= radius of n
th
turn in receiving coil (cm).
The decoder has a sensing threshold of about 0.5 V; therefore,
there is a 0.5 V margin in which induced voltages can be
tolerated.
Given the geometry of the receiving coil and an imposed
requirement that the induced voltage is, at most, 50% of the
0.5 V margin at the decoder, a maximum allowable magnetic
field is calculated, as shown in Figure 22.
MAGNETIC FIELD FREQUENCY (Hz)
1k
10k
100k
100M
1M
10M
100
10
1
0.1
0.01
0.001
M
F
0
Figure 22. Maximum Allowable External Magnetic Flux Density
For example, at a magnetic field frequency of 1 MHz, the
maximum allowable magnetic field of 0.2 kGauss induces a
voltage of 0.25 V at the receiving coil. This is about 50% of the
sensing threshold and does not cause a faulty output transition.
Similarly, if such an event occurs during a transmitted pulse and
is the worst-case polarity, it reduces the received pulse from
>1.0 V to 0.75 V—still well above the 0.5 V sensing threshold of
the decoder.
Figure 23 shows the magnetic flux density values in terms of
more familiar quantities, such as maximum allowable current
flow, at given distances away from the ADM2490E transformers.
MAGNETIC FIELD FREQUENCY (Hz)
1k
10k
100k
100M
1M
10M
DISTANCE = 1m
DISTANCE = 100mm
DISTANCE = 5mm
1000
100
0.1
1
10
0.01
M
0
Figure 23. Maximum Allowable Current for
Various Current-to-ADM2490E Spacings
With combinations of strong magnetic field and high frequency,
any loops formed by printed circuit board traces could induce
error voltages large enough to trigger the thresholds of succeeding
circuitry. Care should be taken in the layout of such traces to
avoid this possibility.
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| ADM2490EBRWZ-REEL7 | 功能描述:IC TXRX RS-485 HS ESD 16-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 驅(qū)動(dòng)器，接收器，收發(fā)器 系列:iCoupler® 標(biāo)準(zhǔn)包裝:27 系列:- 類型:收發(fā)器 驅(qū)動(dòng)器/接收器數(shù):3/3 規(guī)程:RS232，RS485 電源電壓:4.75 V ~ 5.25 V 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:28-SOIC 包裝:管件 |
| ADM2490EBRWZ-REEL71 | 制造商:AD 制造商全稱:Analog Devices 功能描述:High Speed, ESD-Protected, Full-Duplex, iCoupler, Isolated RS-485 Transceiver |
| ADM2491E | 制造商:AD 制造商全稱:Analog Devices 功能描述:High Speed, ESD-Protected, Half-/Full-Duplex, iCoupler Isolated RS-485 Transceiver |
| ADM2491EBRWZ | 功能描述:IC TXRX ISO RS-485 HS ESD 16SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 驅(qū)動(dòng)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(dòng)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 |
| ADM2491EBRWZ | 制造商:Analog Devices 功能描述:IC RS-485 TRANSCEIVER 5.5V SOIC-16 制造商:Analog Devices 功能描述:IC, RS-485 TRANSCEIVER, 5.5V, SOIC-16 |
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