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參數(shù)資料
| 型號： | AD8390AACPZ-R7 |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 3/12頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC AMP DIFF LP LDIST 16LFCSP |
| 標準包裝： | 1,500 |
| 放大器類型： | 差分 |
| 電路數(shù)： | 1 |
| 輸出類型： | 差分 |
| 轉(zhuǎn)換速率： | 300 V/µs |
| -3db帶寬： | 60MHz |
| 電流 - 輸入偏壓： | 4µA |
| 電壓 - 輸入偏移： | 1000µV |
| 電流 - 電源： | 10mA |
| 電流 - 輸出 / 通道： | 400mA |
| 電壓 - 電源，單路/雙路(±)： | 10 V ~ 24 V，±5 V ~ 12 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 16-VQFN 裸露焊盤，CSP |
| 供應商設備封裝： | 16-LFCSP-VQ |
| 包裝： | 帶卷 (TR) |
Data Sheet
AD8390A
Rev. B | Page 11 of 12
ADSL AND ADSL2+ APPLICATIONS
In a typical ADSL/ADSL2+ application, a differential line driver
drives the signal from the analog front end (AFE) onto the
twisted pair telephone line. Referring to the typical circuit
representation in Figure 17, the differential input appears at
VIN+ and VIN from the AFE. The differential output is
transformer-coupled to the telephone line at tip and ring. The
common-mode operating point, generally midway between the
supplies, is set through VCOM.
In ADSL/ADSL2+ applications, it is common practice to
conserve power by using positive feedback (R3 in Figure 17) to
synthesize the output resistance, lowering the required value of
the line matching resistors, RM.
P
D1
P
D0
RM
RL VOUT, DM
+
–
–OUT
+OUT
RM
R3
R2
R1
R3
0.1F
I ADJ
RADJ
R2
1:N
10F
0.1F
VCC
+IN
VCOM
–IN
10F
0.1F
VEE
07094-
018
Figure 17. ADSL/ADSL2+ Application Circuit
The differential input impedance to the circuit is 2 × R1.
R1 is chosen by the designer to match system requirements.
The synthesized value of the back termination resistor is given
by the following equation.
2
2 N
R
k
R
L
M
×
=
where RL is the line impedance, and N is the turns ratio of the
transformer.
The factor k defines the relationship between the negative and
positive feedback resistors and is given by
2
1
R
R3
k
=
Commonly used values for k are between 0.1 and 0.25. Values
less than 0.1 can lead to instability and are not recommended.
Assuming low values for back termination resistor RM, R3 is
approximated as
V
A
k
R1
R3
×
2
where AV is the voltage gain.
R2 is given by
k
R3
R2
=
1
With RM, R3, and R2 calculated, the closest 1% resistors are
chosen and the gain rechecked with the following equation:
(
)
[
]
R3
k
R2
R
R1
R3
R2
A
M
V
+
×
=
1
Table 6 compares the results of the exact values, the simplified
approximation, and the closest 1% resistor value calculations. In
this example, R1 = 1.0 k, AV = 10, and k = 0.1.
Note that decreasing the value of the back termination resistors
attenuates the receive signal by approximately 1/k. Advances in
low noise receive amplifiers permit the use of k values as small
as 0.1.
The line impedance, turns ratio, and k factor specify the output
voltage and current required from the AD8390A. To accom-
modate higher crest factors or lower supply rails, the turns ratio,
N, may need to be increased. Because higher turns ratios and
smaller k factors both attenuate the receive signal, a large
increase in N may require an increase in k to maintain the
desired noise performance. Any particular design process
requires that these trade-offs be addressed.
Table 6. Resistor Selection
Component
Exact
Value
Approximate
Calculation
Standard 1%
Resistor Value
R1 ()
1000
R2 ()
2246.95
2222.22
2210
R3 ()
2022.25
2000
RM ()
5
4.99
Actual AV
10.000
9.889
10.138
Actual k
0.1
0.095
LIGHTNING AND AC POWER FAULT
When the AD8390A is an ADSL/ADSL2+ line driver, it is
transformer-coupled to the twisted pair telephone line. In this
environment, the AD8390A is subject to large line transients
resulting from events such as lightning strikes or downed power
lines. Additional circuitry is required to protect the AD8390A
from damage due to these events.
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| AD8390AACPZ-RL | 功能描述:IC AMP DIFF LP LDIST 16LFCSP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:2,500 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.11 V/µs 增益帶寬積:350kHz -3db帶寬:- 電流 - 輸入偏壓:4nA 電壓 - 輸入偏移:20µV 電流 - 電源:260µA 電流 - 輸出 / 通道:20mA 電壓 - 電源，單路/雙路(±):2.7 V ~ 36 V，±1.35 V ~ 18 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:8-SO 包裝:帶卷 (TR) |
| AD8390ACP-EVAL | 制造商:AD 制造商全稱:Analog Devices 功能描述:Low Power, High Output Current Differential Amplifier |
| AD8390ACP-R2 | 功能描述:IC AMP DIFF LP LDIST 16LFCSP RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:2,500 系列:- 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.11 V/µs 增益帶寬積:350kHz -3db帶寬:- 電流 - 輸入偏壓:4nA 電壓 - 輸入偏移:20µV 電流 - 電源:260µA 電流 - 輸出 / 通道:20mA 電壓 - 電源，單路/雙路(±):2.7 V ~ 36 V，±1.35 V ~ 18 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:8-SO 包裝:帶卷 (TR) |
| AD8390ACP-REEL | 制造商:Analog Devices 功能描述:SP Amp DIFF AMP Single ±12V/24V 16-Pin LFCSP EP T/R |
| AD8390ACP-REEL7 | 制造商:Analog Devices 功能描述:SP Amp DIFF AMP Single 制造商:Rochester Electronics LLC 功能描述:ADSL LINE DRIVER - Tape and Reel 制造商:Analog Devices 功能描述:IC AMP LOW POWER |
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