參數(shù)資料
型號(hào)： AD8320
廠商： Analog Devices, Inc.
英文描述： Serial Digital Controlled Variable Gain Amplifier(串行數(shù)字驅(qū)動(dòng)可變?cè)鲆娣糯笃?
中文描述： 串行數(shù)字控制可變?cè)鲆娣糯笃鳎ù袛?shù)字驅(qū)動(dòng)可變?cè)鲆娣糯笃鳎?/td>
文件頁(yè)數(shù)： 12/20頁(yè)
文件大?。?/td> 513K
代理商： AD8320
AD8320
–12–
REV. 0
75
, a supply voltage of at least +10 V is required. T o achieve
a signal level of +12 dBm (about 3.1 V p-p) into 75
, a mini-
mum supply level of +5 V is required. However, for the lowest
possible distortion, the power supply voltage should be raised as
high as possible. In varying the power supply from +5 V to
+12 V, the quiescent current increases from 80 mA to 97 mA.
Careful attention must be paid to decoupling the power supply
pins. A 10
μ
F capacitor, located fairly close to the device, is
required to provide good decoupling for lower frequency signals.
In addition, five 0.1
μ
F decoupling capacitors should be located
close to each of the five power supply pins (7, 8, 9, 17 and 20).
A 0.1
μ
F capacitor must also be connected to the pin labeled
BYP (Pin 14), to provide decoupling to an internal node of the
device. All six ground pins should be connected to a low imped-
ance ground plane.
Alternative Power-Down Mode
As previously mentioned, the AD8320 can be put into a low
power sleep mode by pulling the
PD
pin low. If lower power
consumption is required during power-down mode, an alternative
scheme can be used as shown in Figure 46.
AD8320
*
75
V
AS103
(
SEE TEXT)
J2
GND
VCC
75
V
PD
*ADDITIONAL PINS AND DECOUPLING CAPACITORS
OMITTED FOR CLARITY
VCC+12V
+5V
VOUT
0.1
m
F
0.1
m
F
V1
V2
0.01
m
F
V2
V1
SDATA
CLK
DATEN
VOUT
VOCM
0.1
m
F
IRLML5103
0.1
m
F
D
G
S
J1
J3
VDD
POWER-
DOWN
PD
V2
V1
SDATA
CLK
DATEN
POWER-
DOWN
PD
OUTPUT
QUIESCENT
CURRENT
10–12V
0V
0V
3–5V
0V
3–5V
0V
97mA
0mA
32mA
97mA
14
0.1
m
F
Figure 46. Alternative Power-Down Mode with Timing
A HEX FET power MOSFET (International Rectifier part num-
ber IRLML5103) is used to turn on and off the current to the
supply pins of the AD8320. Under normal operating conditions,
the gate (labeled POWER-DOWN) should be grounded. Pull-
ing the gate to within 2 V of the supply will open the switch and
reduce the current to the amplifier to zero.
In cable modem and cable telephony applications the modem
must always present an output impedance of 75
to the line.
T his forces the line driver to always present a 75
impedance
to the diplexer. In this application, a single pole double throw
RF switch (AS103, Alpha Semiconductor) is used to switch in
an external 75
impedance when the AD8320 is turned off.
T his resistor then mimics the dynamic output impedance of the
AD8320. T T L or CMOS logic can be used to drive the two
voltages driving the RF switch (V1 and V2).
Before the AD8320 is turned back on again, the gain needs to
be set to a known level. T his can be done by holding the
PD
pin
of the AD8320 low after POWER-DOWN has gone high. While
PD
is held low, the 8-bit serial data stream can be clocked into
the AD8320. During this time the quiescent current will in-
crease to 32 mA. However, this time period can be as small as
about 1
μ
s. In this mode the output settles about 45 ns after the
rising edge of
PD
.
Alternatively, if
DATEN
is held low as the AD8320 is powered
on, the device will power up in minimum gain. In this mode, the
output settles after about 200
μ
s. Note that for both cases, the
capacitor on VOCM has been reduced from 0.1
μ
F to 0.01
μ
F
to facilitate a faster turn-on time. All other capacitors in the
circuit should be connected as shown in Figure 45.
相關(guān)PDF資料
PDF描述
AD8321 Gain Programmable CATV Line Driver(可編程增益CATV線(xiàn)驅(qū)動(dòng)器)
AD8324 3.3 V Upstream Cable Line Driver
AD8324ACP 3.3 V Upstream Cable Line Driver
AD8324ACP-EVAL 3.3 V Upstream Cable Line Driver
AD8324ACP-REEL7 3.3 V Upstream Cable Line Driver
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD8320ARP 制造商:Analog Devices 功能描述:SP Amp Line Driver Amp Single 12V 20-Pin PSOP-II Tube 制造商:Rochester Electronics LLC 功能描述:PSOP 8-BIT SER, 200MHZ DIGITAL CTRL VGA - Bulk
AD8320ARP-REEL 制造商:Analog Devices 功能描述:SP Amp Line Driver Amp Single 12V 20-Pin PSOP-II T/R
AD8320ARPZ 制造商:Analog Devices 功能描述:SP Amp Line Driver Amp Single 12V 20-Pin PSOP-II Tube
AD8320-EB 制造商:Analog Devices 功能描述:
AD8321 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Gain Programmablea CATV Line Driver
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*