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參數(shù)資料
| 型號： | SA5222 |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | 運(yùn)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)： | 5/12頁 |
| 文件大?。?/td> | 270K |
| 代理商： | SA5222 |
Philips Semiconductors Data Communications Products
Applications Note
AN4003
Fiber optic receiver applications note
October 12, 1992
5
Figure 9. Fiber Optic-based Point-to-Point Communication Link
TRANSMITTER
I
IN
V+
LED
LED DRIVER
DATA
RECEIVER
V+
PIN DIODE
TRANSIMPEDANCE
AMPLIFIER
DATA (ECL)
POSTAMPLIFIER
LINK STATUS
CLOCK
DATA
RETIMING
OPTICAL FIBER
DATA LINK
SA5222
NE/SA5224/5225
f
3dB
150
R
AZ
2
C
AZ
where R
AZ
is specified by the data sheet.
For example if a 0.1uF capacitor is used for C
AZ
, and R
AZ
= 250k
.
150
2
250x10
3
1x10
f
3dB
7
farad
1kHz
The lowest data frequency component must be above the –3dB
frequency by an order of magnitude in order to reliably be
reproduced at the ECL output. Lower frequencies will be filtered out
by the AZ loop. The customer is referred to AN1443 for a more
in-depth discussion of data rate response time versus the auto-zero
function.
Setting The Threshold Level
A user programmable signal level detector is provided in both the
NE/SA5224 and 5225. This circuit allows you to inhibit input signals
which are below the predefined level as desired to provide a high
quality output ECL signal, free of baseband noise. Setting the
threshold is simply a matter of choosing a
resistor divider ratio, R
1
:R
2
as shown in Table 2 above, which
connects from V
REF
, Pin 15 to V
SET
, Pin 16 (see Figure 4).
This provides the level detector with a threshold reference voltage.
A scaled, rectified and filtered copy of the input signal is then
compared to this threshold voltage. The programmable range is
4–24mV
P-P
at the input and is a function of V
SET
/100, a value which
represents the average of V
THIGH
and V
TLOW
.
The actual threshold levels are:
V
SET
139
V
Tlow
where R
1
is constant
R
2
5k
V
Thigh
V
SET
78
For example for V
SET
= 1.2V, V
TL
= 8.6mV and V
TH
= 15.4mV.
Table 2 shows various combinations of R
1
and R
2
with
corresponding values of V
SET
and threshold voltages.
V
HYST
= V
TH
– V
TL
Threshold levels as low as 4mV
P-P
can be reliably set up for signal
detection at the NE/SA5224,25 input. For sufficiently high signal
levels the threshold may be maintained at an elevated clipping
plateau allowing good rejection of incoming baseband noise.
(NOTE: 4mV
P-P
corresponds to
–33dBmo for an input PIN diode
conversion efficiency of 0.45A/W.)
II. A TYPICAL RECEIVER TEST BOARD WITH ECL
OUTPUT
The circuit shown in Figure 8 represents a simple printed circuit
receiver capable of 100MB/s data processing from fiber.
The input photo optic device is a Philips BPF31 PIN diode optimized
for a wavelength of 850nm.
The various waveforms (Figures 11–18) show signal levels
produced within the receiver, for different optical power and data
rates.
Supply voltages have been set for 5V on the SA5222 and +2V;
–3.2V on the SA5224. This allows grounded 50
loads to be used
at the output of the receiver.
The differential output of the transimpedance preamplifier is AC
coupled to the NE5224 postamplifier to prevent any DC bias offset in
the preamp from affecting the threshold accuracy of the output
stage.
The coupling capacitors are made sufficiently large (0.1
μ
F) in order
to pass the lowest frequency data component.
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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(yùn)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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