參數(shù)資料
型號: LMH6503
廠商: National Semiconductor Corporation
英文描述: Wideband, Low Power, Linear Variable Gain Amplifier
中文描述: 寬帶,低功耗,線性可變增益放大器
文件頁數(shù): 16/20頁
文件大?。?/td> 1009K
代理商: LMH6503
Application Information
(Continued)
NOISE
Figure 5
describes the LMH6503’s output-referred spot
noise density as a function of frequency with A
VMAX
= 10V/V.
The plot includes all the noise contributing terms. However,
with both inputs terminated in 50
, the input noise contribu-
tion is minimal.AtA
= 10V/V, the LMH6503 has a typical
flat-band input-referred spot noise density (e
) of 6.6nV/
. For applications with 3dB BW extending well into the
flat-band region, the input RMS voltage noise can be deter-
mined from the following single-pole model:
(7)
CIRCUIT LAYOUT CONSIDERATIONS
Good high-frequency operation requires all of the de-
coupling capacitors shown in
Figure 6
to be placed as close
as possible to the power supply pins in order to insure a
proper high-frequency low-impedance bypass. Adequate
ground plane and low inductive power returns are also
required of the layout. Minimizing the parasitic capacitances
at pins 3, 4, 5, 6, 9, 10 and 12 will assure best high frequency
performance. The parasitic inductance of component leads
or traces to pins 4, 5 and 9 should also be kept to a
minimum. Parasitic or load capacitance, C
, on the output
(pin 10) degrades phase margin and can lead to frequency
response peaking or circuit oscillation. The LMH6503 is fully
stable when driving a 100
load. With reduced load (e.g.
1k
) there is a possibility of instability at very high frequen-
cies beyond 400MHz especially with a capacitive load.
When the LMH6503 is connected to a light load as such, it is
recommended to add a snubber network to the output (e.g.
100
and 39pF in series tied between the LMH6503 output
and ground). C
L
can also be isolated from the output by
placing a small resistor in series with the output (pin 10).
Component parasitics also influence high frequency results.
Therefore it is recommended to use metal film resistors such
as RN55D or leadless components such as surface mount
devices. High profile sockets are not recommended.
National Semiconductor suggests the following evaluation
board as a guide for high frequency layout and as an aid in
device testing and characterization:
Device
Package
Evaluation Board Part
Number
CLC730033
CLC730146
LMH6503MA
LMH6503MT
SOIC-14
TSSOP-14
The evaluation board is shipped when a device sample
request is placed with National Semiconductor.
SINGLE SUPPLY OPERATION
It is possible to operate the LMH6503 with a single supply. To
do so, tie pin 11 (GND) to a potential about mid point
between V
+
and V
. Two examples are shown in
Figure 7
&
Figure 8
.
20073922
FIGURE 5. Output Referred Voltage Noise vs.
Frequency
20073957
FIGURE 6. Required Power Supply Decoupling
20073935
FIGURE 7. AC Coupled Single Supply VGA
L
www.national.com
16
相關(guān)PDF資料
PDF描述
LMH6504 Wideband, Low Power, Variable Gain Amplifier
LMH6504MA Wideband, Low Power, Variable Gain Amplifier
LMH6504MAX Wideband, Low Power, Variable Gain Amplifier
LMH6504MM Wideband, Low Power, Variable Gain Amplifier
LMH6504MMX Wideband, Low Power, Variable Gain Amplifier
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LMH6503MA 功能描述:特殊用途放大器 RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比(最小值): 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel
LMH6503MA/NOPB 功能描述:特殊用途放大器 WDBD, LO PWR, LINEAR -IN-DB VAR GAIN AMP RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比(最小值): 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel
LMH6503MAX 功能描述:特殊用途放大器 RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比(最小值): 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel
LMH6503MAX/NOPB 功能描述:特殊用途放大器 RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比(最小值): 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel
LMH6503MT 功能描述:特殊用途放大器 RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比(最小值): 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel