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參數(shù)資料
| 型號： | SA5222 |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | 運動控制電子 |
| 英文描述： | Low-Power FDDI Transimpedance Amplifier(低功耗FDDI互阻抗放大器) |
| 中文描述： | 低功耗FDDI的互阻抗放大器（低功耗FDDI的互阻抗放大器） |
| 文件頁數(shù)： | 1/12頁 |
| 文件大?。?/td> | 270K |
| 代理商： | SA5222 |
Philips Semiconductors Data Communications Products
Applications Note
AN4003
Fiber optic receiver applications note
1
October 12, 1992
I. A NEW FIBER OPTIC RECEIVER CHIP SET FOR
100Mb/s FDDI DATA LINKS
SA5222 Transimpedance Amplifier.
NE/SA5224 and NE/SA5225 Post Amplifiers
Figure 1. SA5222 Low Power Transimpedance Amplifier
A1
A2
A3
A4
INPUT
3
6
+
7
V
OUT
I
IN
R
F
V
OUT
The 140MHz Transimpedance Amplifier (Figure 1)
Designed specifically to meet the requirements of the ANSI Fiber
Distributed Data Interface (FDDI) 100Mb/s LAN systems, the
SA5222 is a new addition to Philips Semiconductors family of fiber
optic devices. Table 1 shows a comparison of the features of this
device in relation to the existing transimpedance amplifiers.
Particular attention has been paid to improving the power supply
rejection ratio (PSRR). This reduces the chance of oscillation due to
coupling onto the supply line. The PSRR specification, as noted in
Table 1, is 57dB. In addition the supply current is reduced to 9mA, a
particular advantage in remote, high density applications.
Figure 2. SA5222 Input Stage (Simplified)
C
M
R
M
150
V
I
Q
1
Q
2
13k
PIN
3
2.6V
+5V
RTR
2
Table 1.
Differential
Transresistance
Bandwidth
i
n
Input Max
μ
A
I
CC
PSRR
SA5222
16.6k
140MHz
1.8pA/
√
Hz
±
115
μ
A
9mA
57dB
NE5212
14k
140MHz
2.5pA/
√
Hz
±
120
μ
A
26mA
33dB
NE5211
28k
180MHz
1.8pA/
√
Hz
±
60
μ
A
24mA
32dB
NE5210
7k
280MHz
3.5pA/
√
Hz
±
240
μ
A
26mA
36dB
Theory of Operation – SA5222
The SA5222 is an all-bipolar amplifier with a -3dB bandwidth of
140MHz. The device operates in the inverting mode with the first
stage loop closed by a shunt feedback resistance (see Figure 2).
The advantage in this topology is its inherent insensitivity to shunt
capacitance at the input. The node at Pin 3 of the amplifier acts to
sum the input current from the photo or PIN diode with the negative
feedback from the shunt resistance. The input node is dominated by
the Miller feedback capacitance from the collector-base junction of
Q1 (C
M
). This capacitance in conjunction with the Miller resistance
(R
M
= R
IN
), acts to set the upper frequency bandwidth of the
amplifier.
f
3dB
1
R
IN
2
C
IN
The first stage Miller capacitance is approximately 7pF and the
Miller resistance is equal to the rated input resistance of 150
.
The upper 3dB bandwidth is then
f
3dB
1
2
150
7
10
12
F
150MHz
which agrees with the device specifications.
The virtual capacitance now dominates the frequency response of
the amplifier desensitizing it to small values of input shunt
capacitance.
Figure 3. SA5222 Differential Output Stage (Simplified)
1k
V
I
I
B
1.9k
+5V
1.9k
V
O
1k
2mA
2mA
The major advantage of this configuration over a cascade amplifier
with FET input is that the input frequency response limit is stabilized
and the noise gain is not drastically affected by the external circuit
capacitances.
For example, with the rated 1pF package capacitance plus 1pF of
external capacitance combined with 150
, the input bandwidth is
approximately 120MHz. This demonstrates the amplifier’s
intolerance to shunt capacitance. Adding external shunt
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SA5223 | Wide Dynamic Range AGC Transimpedance Amplifier (150MHz)(寬動態(tài)范圍AGC互阻抗放大器(150MHz)) |
| SA5223D | Wide dynamic range AGC transimpedance amplifier 150MHz |
| SA5230FE | Low Voltage Operational Amplifier |
| SA5230 | Low voltage operational amplifier(低壓運算放大器) |
| SA5230D | Low Voltage Operational Amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SA5222D | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Low-power FDDI transimpedance amplifier |
| SA5223 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Wide dynamic range AGC transimpedance amplifier 150MHz |
| SA5223D | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Wide dynamic range AGC transimpedance amplifier 150MHz |
| SA5224 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:FDDI fiber optic postamplifier |
| SA5224D | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:FDDI fiber optic postamplifier |
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