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參數(shù)資料
| 型號： | MAX3668EHJ |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 其它接口 |
| 英文描述： | +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control |
| 中文描述： | SPECIALTY INTERFACE CIRCUIT, PQFP32 |
| 封裝： | 5 X 5 MM, 1 MM HEIGHT, MS-026AAA-HD, TQFP-32 |
| 文件頁數(shù)： | 9/12頁 |
| 文件大小： | 435K |
| 代理商： | MAX3668EHJ |
ratio is r
e
= 6.6 (8.2dB), the operating temperature is
-40
°
C to +85
°
C, and the laser diode has the following
characteristics:
Wavelength:
Threshold Current:
Threshold Temperature
Coefficient:
Laser to Monitor Transfer:
Laser Slope Efficiency:
λ
= 1.3μm
Ι
TH
= 22mA at +25
°
C
β
TH
= 1.3%/
°
C
ρ
MON
= 0.2A/W
η
= 0.05mW/mA
at +25
°
C
Determine R
APCSET
The desired monitor diode current is estimated by
I
MD
= P
AVE
×
ρ
MON
= 200μA. The Monitor Diode Current
vs. APC Set Resistor graph in the
Typical Operating
Characteristics
shows that R
APCSET
should be 6k
.
Determine R
MODSET
To achieve a minimum extinction ratio (r
e
) of 6.6 over
temperature and lifetime, calculate the required extinc-
tion ratio at +25
°
C. Assuming r
e
= 20, the peak-to-peak
optical power P
p-p
= 1.81mW according to Table 1. The
required modulation current is 1.81(mW) / 0.05(mW/mA)
= 36.2mA. The Modulation Current vs. Modulation Set
Resistor graph in the
(see Typical Operating Characteri-
stics)
shows that R
MODSET
should be 5k
.
Determine R
BIASMAX
Calculate the maximum threshold current (I
TH(MAX)
) at
T
A
= +85
°
C and end of life. Assuming I
TH(MAX)
=
50mA, the maximum bias current should be:
I
BIAS
= I
TH(MAX)
+ I
MOD
/ 2
In this example, I
BIAS
= 68.1mA. The Bias Current vs.
Maximum Bias Set Resistor graph in the
Typical
Operating Characteristics
shows that R
BIASMAX
should
be 3k
.
Modulation Current More than 50mA
To drive modulation currents greater than 50mA at
3.3V, external pull-up inductors (Figure 5) should be
used to DC-bias the modulation output at V
CC
. Such a
configuration isolates the laser forward voltage from the
output circuitry and allows the output at OUT+ to swing
above and below the supply voltage V
CC
.
At +5V power supply, the headroom voltage for the
MAX3668 is significantly improved. In this case, it is
possible to achieve a modulation current of more than
50mA (using resistor pull-ups as shown in the
Typical
Operating Circuit
). The MAX3668 can also be DC-coupled
to a laser diode when operating at +5V supply; the volt-
age at OUT+ should be
≥
2.0V for proper operation.
Wire Bonding Die
For high current density and reliable operation, the
MAX3668 uses gold metalization. Make connections to
the die with gold wire only, using ball-bonding tech-
niques. Wedge bonding is not recommended. Die-pad
size is 4 mils (100μm) square, and die thickness is 12
mils (300μm) mils.
Layout Considerations
To minimize inductance, keep the connections between
the MAX3668 output pins and LD as close as possible.
Optimize the laser diode performance by placing a
bypass capacitor as close as possible to the laser
anode. Use good high-frequency layout techniques
and multilayer boards with uninterrupted ground planes
to minimize EMI and crosstalk.
Laser Safety and IEC 825
Using the MAX3668 laser driver alone does not ensure
that a transmitter design is compliant with IEC 825. The
entire transmitter circuit and component selections must
be considered. Customers must determine the level of
fault tolerance required by their application, recognizing
that Maxim products are not designed or authorized for
use as components in systems intended for surgical
implant into the body, for applications intended to sup-
port or sustain life, or for any other application where the
failure of a Maxim product could create a situation
where personal injury or death may occur.
M
+3.3V, 622Mbps SDH/SONET
Laser Driver with Automatic Power Control
_______________________________________________________________________________________
9
LD
C
D
R
FILT
C
FILT
1000pF
1.0
μ
F
5
10
R
D
V
CC
FERRITE
BEADS
FERRITE BEAD
MD
BIAS
OUT+
OUT-
MAX3668
Figure 5. Output Termination for Maximum Modulation Current
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| MAX3672 | Low-Jitter 155MHz/622MHz Clock Generator |
| MAX3675EHJ | 622Mbps, Low-Power, 3.3V Clock-Recovery and Data-Retiming IC with Limiting Amplifier |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX3668EHJ+ | 功能描述:激光驅(qū)動(dòng)器 3.3V 622Mbps SDH/SONET RoHS:否 制造商:Micrel 數(shù)據(jù)速率:4.25 Gbps 工作電源電壓:3 V to 3.6 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-16 封裝:Tube |
| MAX3668EHJ+T | 功能描述:激光驅(qū)動(dòng)器 3.3V 622Mbps SDH/SONET RoHS:否 制造商:Micrel 數(shù)據(jù)速率:4.25 Gbps 工作電源電壓:3 V to 3.6 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-16 封裝:Tube |
| MAX3668EHJ-T | 功能描述:激光驅(qū)動(dòng)器 3.3V 622Mbps SDH/SONET RoHS:否 制造商:Micrel 數(shù)據(jù)速率:4.25 Gbps 工作電源電壓:3 V to 3.6 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-16 封裝:Tube |
| MAX3668EVKIT | 功能描述:激光驅(qū)動(dòng)器 Evaluation Kit for the MAX3668 RoHS:否 制造商:Micrel 數(shù)據(jù)速率:4.25 Gbps 工作電源電壓:3 V to 3.6 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-16 封裝:Tube |
| MAX3669E/D | 功能描述:激光驅(qū)動(dòng)器 DICE SALES DICE12 RoHS:否 制造商:Micrel 數(shù)據(jù)速率:4.25 Gbps 工作電源電壓:3 V to 3.6 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-16 封裝:Tube |
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