參數資料
| 型號： | AD8177ABPZ |
| 廠商： | Analog Devices Inc |
| 文件頁數： | 28/40頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC VIDEO CROSSPOINT SWIT 676BGA |
| 標準包裝： | 1 |
| 功能： | 視頻交叉點開關 |
| 電路： | 3 x 16:5 |
| 電壓電源： | 單/雙電源 |
| 電壓 - 電源，單路/雙路(±)： | 4.5 V ~ 5.5 V，±2.5V |
| 電流 - 電源： | 460mA |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 676-BGA |
| 供應商設備封裝： | 676-BGA（27x27） |
| 包裝： | 管件 |
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AD8177
Rev. 0 | Page 34 of 40
In a general case, the power delivered by the digital supply and
dissipated into the digital output devices has to be taken into
account following a similar derivation. However, because the
loads driven by the H and V outputs are high and because the
voltage at these outputs typically sits close to either rail, the
correction to the on-chip power estimate is small. Furthermore,
the H and V outputs are active only briefly during sync genera-
tion and are returned to digital ground thereafter.
Short-Circuit Output Conditions
Although there is short-circuit current protection on the AD8177
outputs, the output current can reach values of 80 mA into
a grounded output. Any sustained operation with too many
shorted outputs can exceed the maximum die temperature
and can result in device failure (see the Absolute Maximum
Ratings section).
Crosstalk
Many systems (such as KVM switches) that handle numerous
analog signal channels have strict requirements for keeping the
various signals from influencing any of the other signals in the
system. Crosstalk is the term used to describe the coupling of
the signals of other nearby channels to a given channel.
When there are many signals in close proximity in a system, as
is undoubtedly the case in a system that uses the AD8177, the
crosstalk issues can be quite complex. A good understanding of
the nature of crosstalk and some definition of terms is required
to specify a system that uses one or more crosspoint devices.
Types of Crosstalk
Crosstalk can be propagated by means of any of three methods.
These fall into the categories of electric field, magnetic field,
and the sharing of common impedances. This section explains
these effects.
Every conductor can be both a radiator of electric fields and a
receiver of electric fields. The electric field crosstalk mechanism
occurs when the electric field created by the transmitter propagates
across a stray capacitance (for example, free space) and couples
with the receiver and induces a voltage. This voltage is an
unwanted crosstalk signal in any channel that receives it.
Currents flowing in conductors create magnetic fields that
circulate around the currents. These magnetic fields then
generate voltages in any other conductors whose paths they
link. The undesired induced voltages in these other channels are
crosstalk signals. The channels that crosstalk can be said to have
a mutual inductance that couples signals from one channel to
another.
The power supplies, grounds, and other signal return paths of
a multichannel system are generally shared by the various channels.
When a current from one channel flows in one of these paths,
a voltage that is developed across the impedance becomes an
input crosstalk signal for other channels that share the common
impedance.
All these sources of crosstalk are vector quantities, so the magni-
tudes cannot simply be added together to obtain the total crosstalk.
In fact, there are conditions where driving additional circuits in
parallel in a given configuration can actually reduce the crosstalk.
The fact that the AD8177 is a fully differential design means that
many sources of crosstalk either destructively cancel, or are
common mode to, the signal and can be rejected by a differential
receiver.
Areas of Crosstalk
A practical AD8177 circuit must be mounted to an actual circuit
board to connect it to power supplies and measurement equipment.
Great care has been taken to create an evaluation board (available
upon request) that adds minimum crosstalk to the intrinsic device.
This, however, raises the issue that system crosstalk is a combi-
nation of the intrinsic crosstalk of the devices, in addition to the
circuit board to which they are mounted. It is important to try
to separate these two areas when attempting to minimize the
effect of crosstalk.
In addition, crosstalk can occur among the inputs to a crosspoint
and among the outputs. It can also occur from input to output.
The following sections discuss techniques to diagnose which
part of a system is contributing to crosstalk.
Measuring Crosstalk
Crosstalk is measured by applying a signal to one or more
channels and measuring the relative strength of that signal on a
desired selected channel. The measurement is usually expressed
as decibels (dB) down from the magnitude of the test signal.
The crosstalk is expressed by
=
)
(
)
(
log
20
10
s
A
s
A
XT
TEST
SEL
(8)
where:
s
= jω, the Laplace transform variable.
ASEL
(s) is the amplitude of the crosstalk induced signal in the
selected channel.
ATEST
(s) is the amplitude of the test signal.
It can be seen that crosstalk is a function of frequency but not
a function of the magnitude of the test signal (to first order).
In addition, the crosstalk signal has a phase relative to the test
signal associated with it.
A network analyzer is most commonly used to measure
crosstalk over a frequency range of interest. It can provide both
magnitude and phase information about the crosstalk signal.
As a crosspoint system or device grows larger, the number of
theoretical crosstalk combinations and permutations can
become extremely large.
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相關代理商/技術參數 |
參數描述 |
|---|---|
| AD8177-EVALZ | 制造商:AD 制造商全稱:Analog Devices 功能描述:500 MHz, Triple 16 】 5 Video Crosspoint Switch |
| AD8178 | 制造商:AD 制造商全稱:Analog Devices 功能描述:450 MHz, Triple 16 】 5 Video Crosspoint Switch |
| AD8178ABPZ | 功能描述:IC VIDEO CROSSPOINT SWIT 676BGA RoHS:是 類別:集成電路 (IC) >> 接口 - 模擬開關，多路復用器，多路分解器 系列:- 其它有關文件:STG4159 View All Specifications 標準包裝:5,000 系列:- 功能:開關 電路:1 x SPDT 導通狀態(tài)電阻:300 毫歐 電壓電源:雙電源 電壓 - 電源，單路/雙路(±):±1.65 V ~ 4.8 V 電流 - 電源:50nA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:7-WFBGA，FCBGA 供應商設備封裝:7-覆晶 包裝:帶卷 (TR) |
| AD8178ABPZ1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:450 MHz, Triple 16 】 5 Video Crosspoint Switch |
| AD8178-EVALZ1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:450 MHz, Triple 16 】 5 Video Crosspoint Switch |
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