欢迎访问ic37.com |
会员登录 免费注册
发布采购

AD8321AR 参数 Datasheet PDF下载

AD8321AR图片预览
型号: AD8321AR
PDF下载: 下载PDF文件 查看货源
内容描述: 增益可编程有线电视线路驱动器 [Gain Programmable CATV Line Driver]
分类和应用: 驱动器电视有线电视
文件页数/大小: 19 页 / 663 K
品牌: AD [ ANALOG DEVICES ]
 浏览型号AD8321AR的Datasheet PDF文件第2页浏览型号AD8321AR的Datasheet PDF文件第3页浏览型号AD8321AR的Datasheet PDF文件第4页浏览型号AD8321AR的Datasheet PDF文件第5页浏览型号AD8321AR的Datasheet PDF文件第6页浏览型号AD8321AR的Datasheet PDF文件第7页浏览型号AD8321AR的Datasheet PDF文件第8页浏览型号AD8321AR的Datasheet PDF文件第9页  
a
FEATURES
Linear in dB Gain Response Over >53 dB Range
Drives Low Distortion >11 dBm Signal into 75 Load:
–53 dBc SFDR at 42 MHz
Very Low Output Noise Level
Maintains Constant 75 Output Impedance
Power-Up and Power-Down Condition
No Line Transformer Required
Upper Bandwidth: 235 MHz (Min Gain)
9 V Single Supply Operation
Power-Down Functionality
Supports SPI Interface
Low Cost
APPLICATIONS
Gain Programmable Line Driver
HFC High Speed Data Modems
Interactive CATV Set-Top Boxes
CATV Plant Test Equipment
General Purpose IF Variable Gain Block
VCC
Gain Programmable
CATV Line Driver
AD8321
FUNCTIONAL BLOCK DIAGRAM
GND
AD8321
VIN+
INV
VIN–
ATTENUATOR CORE
PWR
AMP
VOUT
REVERSE
AMP
DATA LATCH
DATA SHIFT REGISTER
POWER-
DOWN/
SWITCH
INTER
PD
DATA SHIFT REGISTER
DATEN
CLK
SDATA
DESCRIPTION
The AD8321 is a low cost digitally controlled variable gain
amplifier optimized for coaxial line driving applications such as
cable modems that are designed to the DOCSIS* (upstream)
standard. An 8-bit serial word determines the desired output
gain over a 53.4 dB range, resulting in gain changes of 0.75 dB/
LSB.
The AD8321 comprises a digitally controlled variable attenuator
of 0 dB to –53.4 dB, which is preceded by a low noise, fixed
gain buffer and followed by a low distortion high power ampli-
fier. The AD8321 accepts a differential or single-ended input
signal. The output is specified for driving a 75
load, such as
coaxial cable, although the AD8321 is capable of driving other
loads. Performance of –53 dBc is achieved with an output level
up to 11 dBm at 42 MHz bandwidth using a 9 V supply.
A key performance and cost advantage of the AD8321 results
from the ability to maintain a constant 75
output impedance
during power-up and power-down conditions. This eliminates
the need for external 75
termination, resulting in twice the
effective output voltage when compared to a standard opera-
tional amplifier, thus eliminating the need for a transformer.
*Data-Over-Cable Service Interface Specifications
The AD8321 is packaged in a low cost 20-lead SOIC, operates
from a single +9 V supply, and has an operational temperature
range of –40°C to +85°C.
–40
f
O
= 42MHz
V
IN
= 137mV p-p
(P
IN
= –15dBm)
(P
OUT
= 11dBm @
MAX GAIN)
–50
DISTORTION – dBc
–60
HD3
–70
HD2
–80
–90
0
8
16
24
32
40
48
GAIN CONTROL – Decimal
56
64
72
Figure 1. Harmonic Distortion vs. Gain Control
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1999