参数资料
| 型号： | AD8018ARZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 19/19页 |
| 文件大小： | 0K |
| 描述： | IC XDSL LINE DVR R-R 8-SOIC |
| 标准包装： | 98 |
| 类型： | 驱动器 |
| 驱动器/接收器数： | 2/0 |
| 规程： | xDSL |
| 电源电压： | 3.3 V ~ 8 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
| 产品目录页面： | 772 (CN2011-ZH PDF) |
| 配用： | AD8018ARU-EVAL-ND - BOARD EVAL FOR AD8018 AD8018AR-EVAL-ND - BOARD EVAL FOR AD8018 |
REV. A
AD8018
–9–
Table I. Resistor Selection Guide
Gain
RF ( )RG ( )
–1
681
+1
1 k
∞
+2
750
+3
511
256
+4
340
113
+5
230
59
POWER-DOWN FEATURES
Two digitally programmable logic pins, PWDN1 and PWDN0,
are available on the TSSOP-14 package to select among three
different modes of operation, full power, standby and shutdown.
The DGND pin is the logic ground reference. The logic thresh-
old voltage is established 1 V above DGND. In a typical 5 V
single-supply application, the DGND pin is connected to analog
ground. If PWDN1, PWDN0, and DGND are left unconnected,
the AD8018 will operate at full power.
Table II. Power-Down Features and Truth Table
Supply
Output
PWDN0
PWDN1
State
Current
Impedance
High
Full Power
18 mA
Low
High
Standby
9 mA
Low
High
Low
Standby
9 mA
Low
Disabled
300
A
High
POWER SUPPLY AND DECOUPLING
The AD8018 can be powered with a good quality (i.e., low-noise)
supply anywhere in the range from 3.3 V to 8 V. However, in
order to optimize the ADSL upstream drive capability to +13 dBm
and maintain the best Spurious Free Dynamic Range (SFDR),
the AD8018 circuit should be supplied with a well regulated 5 V
supply. The 5 V supplied at the Universal Serial Bus (USB) port
may be poorly regulated. Improving the quality of the 5 V supply
will optimize the performance of the AD8018 in a Universal Serial
Bus-supplied CPE ADSL modem. This can be accomplished
through the use of a step-up dc-to-dc converter or switching
power supply followed by a low dropout (LDO) regulator such
as the ADP3331 (see Figure 6). Setting R1 to be 953 k
and
R2 to be 301 k
will result in a VOUT of 5 V.
Careful attention must be paid to decoupling the power supply
pins at the output of the dc-to-dc converter, the output of the
LDO regulator and the supply pins of the AD8018. High-quality
capacitors with low equivalent series resistance (ESR) such as
multilayer ceramic capacitors (MLCCs) should be used to mini-
mize supply voltage ripple and power dissipation. A large, usually
tantalum, 10
F to 47 F capacitor located in proximity to the
AD8018 is required to provide good decoupling for lower fre-
quency signals. In addition, 0.1
F MLCC decoupling capacitors
should be located as close to each of the power supply pins as is
physically possible, no more than 1/8 inch away. An additional
large (4.7
F to 10 F) tantalum capacitor should be placed on the
board near the supply terminals to supply current for fast, large-
signal changes at the AD8018 outputs.
ADP3331
C1
0.47 F
VIN
ON
OFF
VOUT
EOUT
C2
0.47 F
R3
330k
IN
SD
GND
OUT
FB
ERR
R1
953k
R2
301k
Figure 6. ADP3331 LDO
METHOD FOR GENERATING A MIDSUPPLY VOLTAGE
To operate an amplifier on a single voltage supply, a voltage
midway between the supply and ground must be generated to
properly bias the inputs and the outputs.
A voltage divider can be created with two equal value resistors
(Figure 7). There is a trade-off between the power consumed by
the divider and the voltage drop across these resistors due to the
positive input bias currents. Selecting 2.5 k
for R1 and R2 will
create a voltage divider that draws only 1 mA from a 5 V supply.
The voltage generated with this topology can vary due to the
temperature coefficient (TC) of resistance. Resistors that are
closely matched and have a low TC will minimize variations in
the voltage reference due to temperature. One should also be
sure to use a decoupling capacitor (0.1
F) at the node where
VREF is generated.
5V
R1
2.5k
R2
2.5k
VREF
0.1 F
Figure 7. Midsupply Reference
DIFFERENTIAL TESTING
The test circuit shown in TPC 13 is used for measuring the dif-
ferential distortion of the AD8018. A single-ended test signal is
applied to the inverting input of the AD8138 differential driver
with the noninverting input grounded. Applying the differential
output of the AD8138 through 100
resistors serves to isolate
the inputs of the AD8018 differential driver and provide a well-
balanced low-distortion input signal. The differential load (RL)
of the AD8018 can be set to the equivalent of the line imped-
ance reflected through a transformer. The AD9632 converts
the differential output voltage back to a single-ended signal.
The differential-to- single-ended converter using the AD9632
has an attenuation of –26 dB and is wired with precision resis-
tors to optimize the balance of differential input signal. The
resulting smaller output signal can be easily measured using a
50
spectrum analyzer.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD8018ARZ | 制造商:Analog Devices 功能描述:LINE DRIVER, DUAL, 300 V/us, WSOIC-8 |
| AD8018ARZ-REEL | 功能描述:IC LINE DRIVER XDSL R-R 8SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 标准包装:27 系列:- 类型:收发器 驱动器/接收器数:3/3 规程:RS232，RS485 电源电压:4.75 V ~ 5.25 V 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC 包装:管件 |
| AD8018ARZ-REEL7 | 功能描述:IC LINE DRIVER XDSL R-R 8SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 标准包装:27 系列:- 类型:收发器 驱动器/接收器数:3/3 规程:RS232，RS485 电源电压:4.75 V ~ 5.25 V 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC 包装:管件 |
| AD8019 | 制造商:AD 制造商全称:Analog Devices 功能描述:DSL Line Driver with Power-Down |
| AD80190ABBCZ | 制造商:Analog Devices 功能描述: |
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