参数资料
| 型号： | MAX4207ETE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 4/15页 |
| 文件大小： | 0K |
| 描述： | IC AMP TRANS LOG 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 75 |
| 放大器类型： | 对数 |
| 电路数： | 1 |
| 转换速率： | 12 V/µs |
| 增益带宽积： | 5MHz |
| -3db带宽： | 1MHz |
| 电流 - 输入偏压： | 10pA |
| 电压 - 输入偏移： | 600µV |
| 电流 - 电源： | 5mA |
| 电流 - 输出 / 通道： | 58mA |
| 电压 - 电源，单路/双路(±)： | 2.7 V ~ 11 V，±2.7 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（4x4） |
| 包装： | 管件 |
MAX4207
Precision Transimpedance Logarithmic
Amplifier with Over 5 Decades of Dynamic Range
12
______________________________________________________________________________________
Output Offset
The inverting configuration utilized by the MAX4207
facilitates large output-offset voltage adjustments. The
magnitude of the offset voltage is given by the following
equation:
A resistive divider between REFVOUT, OSADJ, and
GND can be used to adjust VOSADJ (see Figure 5).
Scale Factor
The scale factor, K, is the slope of the logarithmic output.
For the LOGV1 amplifier, K = -0.25V/decade. Adjust the
overall scale factor for the MAX4207 using the uncom-
mitted LOGV2 amplifier and the following equation,
which refers to Figure 5:
Select R2 between 1k and 100k.
Design Example
Desired:
Logarithmic intercept: 1A
Overall scale factor = +1V/decade
Select R1 = 10k:
Photodiode Current Monitoring
Figure 6 shows the MAX4207 in an optical-power
measurement circuit, common in fiberoptic applications.
The MAX4007 current monitor converts the sensed APD
current to an output current that drives the MAX4207
LOGIIN input (APD current is scaled by 0.1). The
MAX4007 also buffers the high-voltage APD voltages
from the lower MAX4207 voltages. The MAX4207’s inter-
nal current reference sources 10nA (RSET = 5M) to the
REFIIN input. This configuration sets the logarithmic inter-
cept to 10nA, corresponding to an APD current of 100nA.
The unity-gain configuration of the output buffer maintains
the -0.25V/decade gain present at the LOGV1 output.
Measuring Optical Absorbance
A photodiode provides a convenient means of measur-
ing optical power, as diode current is proportional to
the incident optical power. Measure absolute optical
power using a single photodiode connected at LOGIIN,
with the MAX4207’s internal current reference driving
REFIIN. Alternatively, connect a photodiode to each of
the MAX4207’s logging inputs, LOGIIN and REFIIN, to
measure relative optical power (Figure 7).
In absorbance measurement instrumentation, a refer-
ence light source is split into two paths. The unfiltered
path is incident upon the photodiode of the reference
channel, REFIIN. The other path passes through a sam-
ple of interest, with the resulting filtered light incident on
the photodiode of the second channel, LOGIIN. The
MAX4207 outputs provide voltages proportional to the
log ratio of the two optical powers—an indicator of the
optical absorbance of the sample.
In wavelength-locking applications, often found in
fiberoptic communication modules, two photodiode cur-
rents provide a means of determining whether a given
optical channel is tuned to the desired optical frequen-
cy. In this application, two bandpass optical filters with
overlapping “skirts” precede each photodiode. With
proper filter selection, the MAX4207 output can vary
monotonically (ideally linearly) with optical frequency.
Rk
V decade
k
210
1
025
40
=×
=
/
.
R
V
A
k
SET =
×
=
05
10 1
50
.
RR
K
21
025
=
.
VV
R
RR
OSADJ
REFOUT
=
+
4
34
VV
R
OS
OSADJ
=+
1
2
1
Table 1. MAX4207 Example Configurations
LOGV2 AMPLIFIER CONFIGURATION
INPUT CONDITIONS
VLOGV1
VLOGV2
ILOG > IREF (constant)
Negative
Positive
Inverting
ILOG < IREF (constant)
Positive
Negative
ILOG > IREF (constant)
Negative
Noninverting
ILOG < IREF (constant)
Positive
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX4207ETE+ | 功能描述:对数放大器 Transimpedance w/ 100Db Dynamic Range RoHS:否 制造商:Texas Instruments 通道数量:3 带宽:3 dB 共模抑制比（最小值）: 输入补偿电压:+/- 7 mV 输入电压范围（最大值）:5.5 V 工作电源电压:4.5 V to 5.5 V 电源电流:+/- 15 mA 工作温度范围:- 40 C to +85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-16 封装:Reel |
| MAX4207ETE+T | 功能描述:对数放大器 Transimpedance w/ 100Db Dynamic Range RoHS:否 制造商:Texas Instruments 通道数量:3 带宽:3 dB 共模抑制比（最小值）: 输入补偿电压:+/- 7 mV 输入电压范围（最大值）:5.5 V 工作电源电压:4.5 V to 5.5 V 电源电流:+/- 15 mA 工作温度范围:- 40 C to +85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-16 封装:Reel |
| MAX4207ETE-T | 功能描述:对数放大器 Transimpedance w/ 100Db Dynamic Range RoHS:否 制造商:Texas Instruments 通道数量:3 带宽:3 dB 共模抑制比（最小值）: 输入补偿电压:+/- 7 mV 输入电压范围（最大值）:5.5 V 工作电源电压:4.5 V to 5.5 V 电源电流:+/- 15 mA 工作温度范围:- 40 C to +85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-16 封装:Reel |
| MAX4208AUA+ | 功能描述:仪表放大器 Low Offset/Drift Instrumentation Amp RoHS:否 制造商:Texas Instruments 通道数量: 输入补偿电压:150 V 可用增益调整: 最大输入电阻:10 kOhms 共模抑制比（最小值）:88 dB 工作电源电压:2.7 V to 36 V 电源电流:200 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:MSOP-8 封装:Bulk |
| MAX4208AUA+T | 功能描述:仪表放大器 Low Offset/Drift Instrumentation Amp RoHS:否 制造商:Texas Instruments 通道数量: 输入补偿电压:150 V 可用增益调整: 最大输入电阻:10 kOhms 共模抑制比（最小值）:88 dB 工作电源电压:2.7 V to 36 V 电源电流:200 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:MSOP-8 封装:Bulk |
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