- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄373972 > AD9985AKSTZ-140 (ANALOG DEVICES INC) 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays PDF資料下載
參數(shù)資料
| 型號： | AD9985AKSTZ-140 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 其它接口 |
| 英文描述： | 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays |
| 中文描述： | SPECIALTY INTERFACE CIRCUIT, PQFP80 |
| 封裝： | LEAD FREE, MS-026-BEC, PLASTIC, LQFP-80 |
| 文件頁數(shù)： | 29/32頁 |
| 文件大?。?/td> | 344K |
| 代理商： | AD9985AKSTZ-140 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁當前第29頁第30頁第31頁第32頁
AD9985A
PCB LAYOUT RECOMMENDATIONS
The AD9985A is a high precision, high speed analog device.
Consequently, to get the maximum performance out of the part,
it is important to have a board with a good layout. This section
provides guidelines for designing a board using the AD9985A.
Rev. 0 | Page 29 of 32
ANALOG INTERFACE INPUTS
Using the following layout techniques on the graphics inputs is
extremely important.
Minimize the trace length running into the graphics inputs.
This is accomplished by placing the AD9985A as close as
possible to the graphics VGA connector. Long input trace
lengths are undesirable because they pick up more noise from
the board and other external sources.
Place the 75 Ω termination resistors (see Figure 1) as close as
possible to the AD9985A chip. Any additional trace length
between the termination resistors and the input of the
AD9985A increases the magnitude of reflections, which
corrupts the graphics signal.
Use 75 Ω matched impedance traces. Trace impedances other
than 75 Ω also increase the chance of reflections.
The AD9985A has very high input bandwidth (500 MHz).
While this is desirable for acquiring a high resolution PC
graphics signal with fast edges, it means that it also captures any
high frequency noise present. Therefore, it is important to
reduce the amount of noise that is coupled to the inputs. Avoid
running any digital traces near the analog inputs.
Due to the high bandwidth of the AD9985A, low-pass filtering
the analog inputs can sometimes help to reduce noise. (For
many applications, filtering is unnecessary.) Experiments
have shown that placing a series ferrite bead prior to the 75 Ω
termination resistor is helpful in filtering out excess noise.
Specifically, the part used was the #2508051217Z0 from Fair-
Rite, but each application can work best with a different bead
value. Alternately, placing a 100 Ω to 120 Ω resistor between the
75 Ω termination resistor and the input coupling capacitor can
also be beneficial.
POWER SUPPLY BYPASSING
It is recommended to bypass each power supply pin with a
0.1 μF capacitor. The exception is when two or more supply
pins are adjacent to each other. For these groupings of powers/
grounds, it is necessary to have only one bypass capacitor. The
fundamental idea is to have a bypass capacitor within about
0.5 cm of each power pin. Also, avoid placing the capacitor on
the opposite side of the PC board from the AD9985A, as that
interposes resistive vias in the path.
The bypass capacitors should be physically located between the
power plane and the power pin. Current should flow from the
power plane to the capacitor to the power pin. Do not make the
power connection between the capacitor and the power pin.
Placing a via underneath the capacitor pads, down to the power
plane, is generally the best approach.
It is particularly important to maintain low noise and good
stability of PV
D
(the clock generator supply). Abrupt changes in
PV
D
can result in similarly abrupt changes in sampling clock
phase and frequency. This can be avoided by careful attention to
regulation, filtering, and bypassing. It is highly desirable to
provide separate regulated supplies for each of the analog
circuitry groups (V
D
and PV
D
).
Some graphic controllers use substantially different levels of
power when active (during active picture time) and when idle
(during horizontal and vertical sync periods). This can result in
a measurable change in the voltage supplied to the analog
supply regulator, which can, in turn, produce changes in the
regulated analog supply voltage. This can be mitigated by
regulating the analog supply, or at least PV
D
, from a different,
cleaner power source (for example, from a 12 V supply).
It is recommended to use a single ground plane for the entire
board. Experience has repeatedly shown that the noise
performance is the same or better with a single ground plane.
Using multiple ground planes can be detrimental because each
separate ground plane is smaller, and long ground loops can
result.
When using separate ground planes is unavoidable, it is
recommended to minimally place a single ground plane under
the AD9985A. The location of the split should be at the receiver
of the digital outputs. For this case, it is even more important to
place components wisely because the current loops are much
longer (current takes the path of least resistance). Figure 15
shows an example of a current loop.
A
N
A
L
O
G
G
R
O
U
N
D
P
L
A
N
E
P
O
W
E
R
P
L
A
N
E
A
D
9
9
8
5
A
D
I
G
I
T
A
L
U
T
P
U
T
R
A
C
E
D
I
G
I
T
A
L
G
R
O
U
N
D
P
L
A
N
E
D
I
G
I
T
A
L
D
A
T
A
R
E
C
E
I
V
E
R
0
Figure 15. Current Loop
PLL
Place the PLL loop filter components as close to the FILT pin as
possible.
Do not place any digital or other high frequency traces near
these components.
Use the values suggested in the data sheet with 10% tolerances
or less.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD9985BSTZ-110 | 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays |
| AD9985 | 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays |
| AD9985KSTZ-110 | 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays |
| AD9985KSTZ-140 | 110 MSPS/140 MSPS Analog Interface for Flat Panel Displays |
| AD9990 | Dual Channel, 14-Bit CCD Signal Processor with V-Driver and Precision Timing |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD9985BST-110 | 制造商:Analog Devices 功能描述:110 MSPS/140 MSPS ANLG INTRFC FOR FLAT PNL DISPLAYS 80LQFP - Bulk |
| AD9985BSTZ-110 | 功能描述:IC INTERFACE 8BIT 110MSPS 80LQFP RoHS:是 類別:集成電路 (IC) >> 接口 - 專用 系列:- 特色產(chǎn)品:NXP - I2C Interface 標準包裝:1 系列:- 應(yīng)用:2 通道 I²C 多路復用器 接口:I²C，SM 總線 電源電壓:2.3 V ~ 5.5 V 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:剪切帶 (CT) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:825 (CN2011-ZH PDF) 其它名稱:568-1854-1 |
| AD9985KST-110 | 制造商:Analog Devices 功能描述:110 MSPS/140 MSPS ANLG INTRFC FOR FLAT PNL DISPLAYS 80LQFP - Bulk |
| AD9985KSTZ-110 | 功能描述:IC INTERFACE 8BIT 110MSPS 80LQFP RoHS:是 類別:集成電路 (IC) >> 接口 - 專用 系列:- 特色產(chǎn)品:NXP - I2C Interface 標準包裝:1 系列:- 應(yīng)用:2 通道 I²C 多路復用器 接口:I²C，SM 總線 電源電壓:2.3 V ~ 5.5 V 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:剪切帶 (CT) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:825 (CN2011-ZH PDF) 其它名稱:568-1854-1 |
| AD9985KSTZ-140 | 功能描述:IC INTERFACE 8BIT 140MSPS 80LQFP RoHS:是 類別:集成電路 (IC) >> 接口 - 專用 系列:- 標準包裝:3,000 系列:- 應(yīng)用:PDA，便攜式音頻/視頻，智能電話 接口:I²C，2 線串口 電源電壓:1.65 V ~ 3.6 V 封裝/外殼:24-WQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-QFN 裸露焊盤（4x4） 包裝:帶卷 (TR) 安裝類型:表面貼裝 產(chǎn)品目錄頁面:1015 (CN2011-ZH PDF) 其它名稱:296-25223-2 |
發(fā)布緊急采購，3分鐘左右您將得到回復。