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參數(shù)資料
| 型號： | VSC7940 |
| 廠商： | Vitesse Semiconductor Corporation. |
| 英文描述： | SONET/SDH 3.125Gb/s Laser Diode Driver with Automatic Power Control |
| 中文描述： | SONET / SDH的3.125Gb / s的激光具有自動功率控制二極管驅動器 |
| 文件頁數(shù)： | 12/16頁 |
| 文件大?。?/td> | 167K |
| 代理商： | VSC7940 |
VITESSE
Preliminary Data Sheet
VSC7940
SONET/SDH 3.125Gb/s
Laser Diode Driver with Automatic Power Control
Page 12
G52357-0, Rev 3.2
05/11/01
VITESSE
SEMICONDUCTOR CORPORATION
741 Calle Plano
Camarillo, CA 93012
Tel: (800) VITESSE
FAX: (805) 987-5896
Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Applications Information
The following is a typical design example for the VSC7940 assuming 5V operation with APC.
Select a Laser
The Table 8 provides specifications for a typical communication-grade laser capable of operating at
2.5Gb/s.
Table 6: Typical Laser Characteristics
Select Resistor for APCSET
The monitor diode current is estimated by I
MD
= P
AVE
*
ρ
MON
= 6mW * 0.04mA/mW = 0.24mA. The I
MD
vs. R
APCSET
in
Typical Operating Characteristics
shows the resistor at APCSET should be 5k
.
Select Resistor for MODSET
To ensure some minimum extinction ratio over temperature and lifetime, assume an optimal extinction ratio
of 20 (13dB) at 25
°
C
. The modulation current may be calculated from the following equation:
I
MOD
= P
p-p
/
η
= 2 * P
AVE
* (r
e
-1) / (r
e
+1) /
η =
2 * 6mA * (20-1) / (20 + 1) / 0.4 = 27.1mA
The graph of I
MODSET
vs. R
MODSET
in
Typical Operating Characteristics
shows the resistor for MODSET
should be 8.5k
.
Select Resistor for BIASMAX
The maximum threshold current at +85
°
C and end of life must be determined. A graph of a typical laser
’
s
I
th
versus T
C
reveals a maximum threshold current of 30mA at 85
°
C
. Therefore, the maximum bias can be
approximated by:
I
BIASMAX
= I
TH-MAX
+ I
MOD
/ 2 = 30mA + 27.1mA / 2 = 43.6mA
The graph of I
BIASMAX
vs. R
BIASMAX
in
Typical Operating Characteristics
shows the resistor for BIASMAX
should be 5k
.
Symbol
Parameter
Value
Units
λ
P
AVE
I
th
ρ
MON
η
T
C
Wavelength
Average Optical Output Power
Threshold Current
Laser to Monitor Transfer
Laser Slope Efficiency
Operating Temperature Range
1310
6
6
0.04
0.4
nm
mW
mA
mA/mW
mW/mA
°
C
-40 to +85
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| VSC7940RP | 制造商:VITESSE 制造商全稱:Vitesse Semiconductor Corporation 功能描述:SONET/SDH 3.125Gb/s Laser Diode Driver with Automatic Power Control |
| VSC7940W | 制造商:VITESSE 制造商全稱:Vitesse Semiconductor Corporation 功能描述:SONET/SDH 3.125Gb/s Laser Diode Driver with Automatic Power Control |
| VSC7958 | 制造商:VITESSE 制造商全稱:Vitesse Semiconductor Corporation 功能描述:2.5Gb/s High Speed Limiting Post Amplifier for OC-48/SDH-16 Applications |
| VSC7958CC | 制造商:VITESSE 制造商全稱:Vitesse Semiconductor Corporation 功能描述:2.5Gb/s High Speed Limiting Post Amplifier for OC-48/SDH-16 Applications |
| VSC7958X | 制造商:VITESSE 制造商全稱:Vitesse Semiconductor Corporation 功能描述:2.5Gb/s High Speed Limiting Post Amplifier for OC-48/SDH-16 Applications |
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