参数资料
| 型号： | AD8307ARZ-REEL |
| 厂商： | Analog Devices Inc |
| 文件页数： | 9/24页 |
| 文件大小： | 0K |
| 描述： | IC AMP LOGARITHMIC 8SOIC |
| 标准包装： | 2,500 |
| 类型： | 对数放大器 |
| 应用： | 接收器信号强度指示（RSSI） |
| 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-SO |
| 包装： | 带卷 (TR) |
AD8307
Rev. D | Page 17 of 24
THEORY OF OPERATION
The AD8307 has very high gain and a bandwidth from dc to
over 1 GHz, at which frequency the gain of the main path is
still over 60 dB. Consequently, it is susceptible to all signals
within this very broad frequency range that find their way to
the input terminals. It is important to remember that these are
indistinguishable from the wanted signal, and has the effect
of raising the apparent noise floor (that is, lowering the useful
dynamic range). For example, while the signal of interest can
be an IF of 50 MHz, any of the following could easily be larger
than the IF signal at the lower extremities of its dynamic range:
60 Hz hum (picked up due to poor grounding techniques),
spurious coupling (from a digital clock source on the same PC
board), and local radio stations, for example.
Careful shielding is essential. A ground plane should be used to
provide a low impedance connection to the common pin, COM,
for the decoupling capacitors used at VPS, and as the output
ground. It is inadvisable to assume that the ground plane is
equipotential. Neither of the inputs should be ac-coupled directly
to the ground plane, but should be kept separate from it, being
returned instead to the low associated with the source. This can
mean isolating the low side of an input connector with a small
resistance to the ground plane.
BASIC CONNECTIONS
Figure 32 shows the simple connections suitable for many
applications. The inputs are ac coupled by C1 and C2, which
should have the same value, for example, CC. The coupling time
constant is RIN CC/2, thus forming a high-pass corner with a
3 dB attenuation at fHP = 1/(pRINCC ). In high frequency applica-
tions, fHP should be as large as possible to minimize the coupling
of unwanted low frequency signals. Conversely, in low frequency
applications, a simple RC network forming a low-pass filter
should be added at the input for the same reason. For the case
where the generator is not terminated, the signal range should
be expressed in terms of the voltage response and should extend
from 85 dBV to +6 dBV.
C2 = CC
C1 = CC
OUTPUT
25mV/dB
0
108
2-
0
32
AD8307
RT
INPUT
–75dBm TO
+16dBm
NC
INP VPS ENB INT
INM COM OFS OUT
NC
NC = NO CONNECT
87
6
5
23
4
1
1.1k
4.7
0.1F
RIN ≈
VP, 2.7V TO 5.5V
AT ~8mA
Figure 32. Basic Connections
Where it is necessary to terminate the source at a low impedance,
the resistor RT should be added, with allowance for the shunting
effect of the basic 1.1 kΩ input resistance (RIN) of the AD8307.
For example, to terminate a 50 Ω source, a 52.3 Ω 1% tolerance
resistor should be used. This can be placed on the input side or
the log amp side of the coupling capacitors; in the former case,
smaller capacitors can be used for a given frequency range; in
the latter case, the effective RIN is lowered directly at the log
amp inputs.
Figure 33 shows the output vs. the input level, in dBm, when
driven from a terminated 50 Ω generator, for sine inputs at
10 MHz, 100 MHz, and 500 MHz; Figure 34 shows the typical
logarithmic conformance under the same conditions. Note that
10 dBm corresponds to a sine amplitude of 1 V, equivalent to an
rms power of 10 mW in a 50 Ω termination. However, if the
termination resistor is omitted, the input power is negligible.
The use of dBm to define input level therefore needs to be
considered carefully in connection with the AD8307.
3.0
2.5
0
2.0
1.5
1.0
0.5
500MHz
100MHz
10MHz
01
08
2-
03
3
–80
–70
–60
–50
–40
–30
–20
–10
0
10
20
OU
TP
U
T
V
O
L
T
A
G
E
(V
)
INPUT LEVEL (dBm)
Figure 33. Log Response at 10 MHz, 100 MHz, and 500 MHz
5
4
3
2
1
–4
–5
500MHz
100MHz
10MHz
–3
–2
–1
0
01
08
2-
03
4
–80
–70
–60
–50
–40
–30
–20
–10
0
10
20
E
R
RO
R
(
d
B
)
INPUT LEVEL (dBm)
Figure 34. Logarithmic Law Conformance at 10 MHz, 100 MHz, and 500 MHz
相关PDF资料 |
PDF描述 |
|---|---|
| LTC6420IUDC-20#PBF | IC DIFF AMP/ADC DRIVER DL 20QFN |
| VE-2T1-IV-F3 | CONVERTER MOD DC/DC 12V 150W |
| LTC6421IUDC-20#TRPBF | IC ADC DRIVER DIFF 20-QFN |
| SY88993VKG | IC POST AMP CML LIMITING 10-MSOP |
| SY88793VKG | IC POST AMP PECL LP LIMIT 10MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD8307ARZ-RL7 | 功能描述:IC AMP LOGARITHMIC 8-SOIC RoHS:是 类别:集成电路 (IC) >> 线性 - 放大器 - 专用 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:60 系列:- 类型:可变增益放大器 应用:CATV 安装类型:表面贴装 封装/外壳:20-WQFN 裸露焊盘 供应商设备封装:20-TQFN-EP（5x5） 包装:托盘 |
| AD8307-EB | 制造商:Analog Devices 功能描述:AD8307 EVALUATION BOARD - Bulk |
| AD8309 | 制造商:AD 制造商全称:Analog Devices 功能描述:5 MHz.500 MHz 100 dB Demodulating Logarithmic Amplifier with Limiter Output |
| AD8309ARU | 功能描述:IC LOGARITHM AMP 100DB 16-TSSOP RoHS:否 类别:集成电路 (IC) >> 线性 - 放大器 - 专用 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:60 系列:- 类型:可变增益放大器 应用:CATV 安装类型:表面贴装 封装/外壳:20-WQFN 裸露焊盘 供应商设备封装:20-TQFN-EP（5x5） 包装:托盘 |
| AD8309ARU-REEL | 制造商:Analog Devices 功能描述: |
发布紧急采购，3分钟左右您将得到回复。