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參數(shù)資料
| 型號(hào)： | MAX3558 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Quad-Output LNA with AGC for Cable TV Applications |
| 中文描述： | 四輸出LNA，帶有AGC，適用于有線電視應(yīng)用 |
| 文件頁(yè)數(shù)： | 9/13頁(yè) |
| 文件大小： | 398K |
| 代理商： | MAX3558 |
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Applications Information
High-Power and Low-Noise Modes
The MAX3503 has two transmit modes, high power
(HP) and low noise (LN). Each of these modes is actu-
ated by the high-order bit, D7, of the 8-bit programming
word. When D7 is a logic 1, HP mode is enabled. When
D7 is a logic 0, LN mode is enabled.
Each of these modes is characterized by the activation
of a distinct output stage. In HP mode, the output stage
exhibits 10.5dB higher gain than LN mode. The lower
gain of LN output stage allows for significantly lower
output noise and lower transmit-enable/transmit-disable
transients.
The full range of gain codes (D6
–
D0) can be used in
either mode. For DOCSIS applications, HP mode is rec-
ommended for output levels at or above 10.5dBmV (D7
= 1, gain code = 83), LN mode when the output level is
below 9.5dBmV (D7 = 0, gain code = 112).
Shutdown Mode
In normal operation, the shutdown pin (
SHDN
) is held
high. When
SHDN
is taken low, all circuits within the IC
are disabled. Only leakage currents flow in this state.
Data stored within the serial-data interface latches are
lost upon entering this mode. Current consumption is
reduced to 5μA (typ) in shutdown mode.
Transformer
To match the output of the MAX3503 to a 75
load, a
1:1 transformer is required. This transformer must have
adequate bandwidth to cover the intended application.
Note that most RF transformers specify bandwidth with
a 50
source on the primary and a matching resis-
tance on the secondary winding. Operating in a 75
system tends to shift the low-frequency edge of the
transformer bandwidth specification up by a factor of
1.5, because of primary inductance. Keep this in mind
when specifying a transformer.
Bias to the output stage is provided through the center
tap on the transformer primary. This greatly diminishes
the on/off transients present at the output when switch-
ing between transmit and transmit-disable modes.
Commercially available transformers typically have
adequate balance between half-windings to achieve
substantial transient cancellation.
Finally, keep in mind that transformer core inductance
varies proportionally with temperature. If the application
requires low temperature extremes (less than 0
°
C),
adequate primary inductance must be present to sus-
tain low-frequency output capability as temperatures
drop. In general this is not a problem, as modern RF
transformers have adequate bandwidth.
Input Circuit
To achieve rated performance, drive the inputs of the
MAX3503 differentially with an appropriate input level.
The differential input impedance is approximately 2k
.
Most applications requires a differential lowpass filter
preceding the device. The filter design dictates a termi-
nating impedance of a specified value. Place this load
impedance across the AC-coupled input pins (see the
Typical Operating Circuit
).
The MAX3503 has sufficient gain to produce an output
level of 61dBmV (QPSK) when driven with a 34dBmV
input signal. When a lower input level is present, the
maximum output level is reduced proportionally and
output linearity increases. If an input level greater than
34dBmV is used, the 3rd-order distortion performance
degrades slightly.
If single-ended sources drive the MAX3503, one of the
input terminals must be capacitively coupled to ground
M
Upstream CATV Amplifier
_______________________________________________________________________________________
9
A. t
SENS
B. t
SDAS
C. t
SDAH
D. t
SCKL
E. t
SCKH
F. t
SENH
G. t
DATAH
/t
DATAL
D0
D7
D6
D5
A
G
B
C
D
E
F
D4
D3
D2
D1
Figure 1. Serial-Interface Timing Diagram
BIT
MSB 7
6
5
4
3
2
1
LSB 0
MNEMONIC
D7
D6
D5
D4
D3
D2
D1
D0
DESCRIPTION
High-power/low-noise mode select
Gain code, bit 6
Gain code, bit 5
Gain code, bit 4
Gain code, bit 3
Gain code, bit 2
Gain code, bit 1
Gain code, bit 0
Table 1. Serial-Interface Control Word
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| MAX3558EVKIT | Evaluation Kit for the MAX3558 |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX3558CGI+ | 制造商:Maxim Integrated Products 功能描述:QUAD-OUTPUT LNA WITH AGC FOR CABLE TV APPLICA - Rail/Tube |
| MAX3558CGI+T | 制造商:Maxim Integrated Products 功能描述:QUAD-OUTPUT LNA WITH AGC FOR CABLE TV APPLICA - Tape and Reel |
| MAX3558CTI+ | 功能描述:射頻放大器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:Low Noise Amplifier 工作頻率:2.3 GHz to 2.8 GHz P1dB:18.5 dBm 輸出截獲點(diǎn):37.5 dBm 功率增益類型:32 dB 噪聲系數(shù):0.85 dB 工作電源電壓:5 V 電源電流:125 mA 測(cè)試頻率:2.6 GHz 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 封裝:Reel |
| MAX3558CTI+T | 功能描述:射頻放大器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:Low Noise Amplifier 工作頻率:2.3 GHz to 2.8 GHz P1dB:18.5 dBm 輸出截獲點(diǎn):37.5 dBm 功率增益類型:32 dB 噪聲系數(shù):0.85 dB 工作電源電壓:5 V 電源電流:125 mA 測(cè)試頻率:2.6 GHz 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 封裝:Reel |
| MAX3558EVKIT | 功能描述:射頻開發(fā)工具 MAX3558 Eval Kit RoHS:否 制造商:Taiyo Yuden 產(chǎn)品:Wireless Modules 類型:Wireless Audio 工具用于評(píng)估:WYSAAVDX7 頻率: 工作電源電壓:3.4 V to 5.5 V |
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