參數(shù)資料
型號(hào): AD8106ASTZ
廠商: Analog Devices Inc
文件頁數(shù): 8/28頁
文件大?。?/td> 0K
描述: IC CROSSPOINT SWITCH 16X5 80LQFP
標(biāo)準(zhǔn)包裝: 1
功能: 視頻交叉點(diǎn)開關(guān)
電路: 1 x 16:5
電壓電源: 雙電源
電壓 - 電源,單路/雙路(±): ±4.5 V ~ 5.5 V
電流 - 電源: 30mA
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 80-LQFP
供應(yīng)商設(shè)備封裝: 80-LQFP(12x12)
包裝: 托盤
AD8106/AD8107
Rev. 0 | Page 16 of 28
THEORY OF OPERATION
The AD8106 (G = 1) and AD8107 (G = 2) share a common core
architecture consisting of an array of 80 transconductance (gm)
input stages that are organized as five 16:1 multiplexers with a
common, 16-line analog input bus. Each multiplexer is
essentially a folded-cascode high speed voltage, feedback
amplifier with 16 input stages. The input stages are NPN
differential pairs whose differential current outputs are
combined at the output stage, which contains the high
impedance node, compensation, and a complementary emitter
follower output buffer. In the AD8106, the output of each
multiplexer is fed directly back to the inverting inputs of its
16 gm stages. In the AD8107, the feedback network is a voltage
divider consisting of two equal-value resistors.
This switched-gm architecture results in a low power crosspoint
switch that is able to directly drive a back-terminated video load
(150 Ω) with low distortion (differential gain and differential
phase errors are better than 0.02% and 0.02°, respectively). This
design also achieves high input resistance and low input
capacitance without the signal degradation and power
dissipation of additional input buffers. However, the small input
bias current at any input increases almost linearly with the
number of outputs programmed to that input.
The output disable feature of these crosspoints allows larger
switch matrices to be built simply by busing together the
outputs of multiple 16 × 5 ICs. However, while the disabled
output impedance of the AD8106 is very high (10 MΩ), the
AD8107 output impedance is limited by the resistive feedback
network, which has a nominal total resistance of 1 kΩ and
appears in parallel with the disabled output. If the outputs of
multiple AD8107s are connected through separate back
termination resistors, the loading lowers the effective back
termination impedance of the overall matrix because of these
finite output impedances. This problem is eliminated if the
outputs of multiple AD8107s are connected directly and share a
single back-termination resistor for each output of the overall
matrix. This configuration increases the capacitive loading of
the disabled AD8107 on the output of the enabled AD8107.
POWER-ON RESET
When powering up the AD8106/AD8107, it is usually necessary
to have the outputs be in the disabled state. The RESET pin,
when taken low, causes all outputs to be in the disabled state.
The RESET pin has a 20 kΩ pull-up resistor to DVDD that can
be used to create a simple power-up reset circuit. A capacitor
from RESET to ground holds RESET low for some time while
the rest of the device stabilizes. The low condition causes all the
outputs to disable. The capacitor then charges through the pull-
up resistor to the high state, allowing full programming
capability of the device.
INITIALIZATION
The AD8106/AD8107 should be initialized after power up to
control the supply and bias currents, and to make sure that no
unexpected program states are encountered. Initialization is
performed by writing a data word of 00000 into all address
locations 00 to 07 (000 to 111 binary).
GAIN SELECTION
The 16 × 5 crosspoints come in two versions depending on the
desired gain of the analog circuit paths. The AD8106 device is
unity gain and can be used for analog logic switching and other
applications where unity gain is desired. The AD8106 can also
be used for the input and interior sections of larger crosspoint
arrays where termination of output signals is not usually used.
The AD8106 outputs have very high impedance when their
outputs are disabled.
For devices that drive a terminated cable with its outputs, the
AD8107 can be used. This device has a built-in gain of two that
eliminates the need for a gain-of-two buffer to drive a video
line. Because of the presence of the feedback network in these
devices, the disabled output impedance is about 1 kΩ.
CREATING LARGER CROSSPOINT ARRAYS
The AD8106/AD8107 are high density building blocks that
create crosspoint arrays for dimensions larger than 16 × 5.
Various features such as output disable, chip enable, and gain-
of-one and gain-of-two options are useful for creating larger
arrays. For very large arrays, they can be used with the
AD8114/AD8115, 16 × 16 video crosspoint devices, or the
AD8110/AD8111, 16 x 8 video crosspoint devices. When required
for customizing a crosspoint array size, the parts can also be
used with the AD8108 and AD8109, a pair (unity gain and
gain-of-two) of 8 × 8 video crosspoint switches.
The first consideration in constructing a larger crosspoint is to
determine the minimum number of required devices. The 16 × 5
architecture of the AD8106/AD8107 contains 80 points. For a
nonblocking crosspoint, the number of points required is the
product of the number of inputs multiplied by the number of
outputs. Nonblocking requires that the programming of a given
input to one or more outputs does not restrict the availability of
that input to be a source for any other output.
Some nonblocking crosspoint architectures require more than this
minimum as calculated above. In addition, there are blocking
architectures that can be constructed with fewer devices than this
minimum. These systems have connectivity available on a statistical
basis that is determined when designing the overall system.
The basic concept in constructing larger crosspoint arrays is to
connect inputs in parallel in a horizontal direction and to wire-OR
the outputs together in a vertical direction.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD8106-EB 制造商:AD 制造商全稱:Analog Devices 功能描述:260 MHz, 16 】 5 Buffered Video Crosspoint Switches
AD8107 制造商:AD 制造商全稱:Analog Devices 功能描述:260 MHz, 16 】 5 Buffered Video Crosspoint Switches
AD8107ASTZ 功能描述:IC CROSSPOINT SWITCH 16X5 80LQFP RoHS:是 類別:集成電路 (IC) >> 接口 - 模擬開關(guān),多路復(fù)用器,多路分解器 系列:- 其它有關(guān)文件:STG4159 View All Specifications 標(biāo)準(zhǔn)包裝:5,000 系列:- 功能:開關(guān) 電路:1 x SPDT 導(dǎo)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,F(xiàn)CBGA 供應(yīng)商設(shè)備封裝:7-覆晶 包裝:帶卷 (TR)
AD8107-EB 制造商:AD 制造商全稱:Analog Devices 功能描述:260 MHz, 16 】 5 Buffered Video Crosspoint Switches
AD8108 制造商:AD 制造商全稱:Analog Devices 功能描述:325 MHz, 8 x 8 Buffered Video Crosspoint Switches