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参数资料
| 型号： | MAX3869EHJ+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/15页 |
| 文件大小： | 0K |
| 描述： | IC LASER DRIVR 2CHAN 5.5V 32TQFP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 激光二极管驱动器（光纤） |
| 数据速率： | 2.5Gbps |
| 通道数： | 2 |
| 电源电压： | 3.14 V ~ 5.5 V |
| 电流 - 电源： | 64mA |
| 电流 - 调制： | 60mA |
| 电流 - 偏置： | 100mA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 32-TQFP 裸露焊盘 |
| 供应商设备封装： | 32-TQFP-EP（5x5） |
| 包装： | 带卷 (TR) |
| 安装类型： | 表面贴装 |
+3.3V, 2.5Gbps SDH/SONET Laser Driver
with Current Monitors and APC
should equal 25 ? . Typical values for R D are 18 ? to
23 ? . For best performance, a bypass capacitor (0.01μF
typical) should be placed as close as possible to the
anode of the laser diode. Depending on the exact char-
acteristics of the laser diode and PC board layout, a
resistor (R P ) of 20 ? to 70 ? in parallel with pull-up induc-
tor L P1 can be useful in damping overshoot and ringing
in the optical output.
In some applications (depending on laser-diode para-
sitic inductance characteristics), an RC shunt network
between the laser cathode and ground will help mini-
mize optical output aberrations. Starting values for most
coaxial lasers are R = 75 ? in series with C = 3.3pF.
These values should be experimentally adjusted until
the optical output waveform is optimized.
Pattern-Dependent Jitter
When transmitting NRZ data with long strings of con-
secutive identical digits (CIDs), LF droop can occur
and contribute to pattern-dependent jitter (PDJ). To
minimize this PDJ, three external components must be
properly chosen: capacitor C APC , which dominates the
APC loop time constant; pull-up inductor L P ; and AC-
Calculating Power Consumption
The junction temperature of the MAX3869 dice must be
kept below +150°C at all times. The total power dissipa-
tion of the MAX3869 can be estimated by the following:
P = V CC ? I CC + (V CC - V f ) ? I BIAS
+ I MOD (V CC - 25 ? ? I MOD / 2)
where I BIAS is the maximum bias current set by R BIAS-
MAX , I MOD is the modulation current, and V f is the typi-
cal laser forward voltage.
Junction Temperature = P(W) ? 45 (°C/W)
___________Applications Information
An example of how to set up the MAX3869 follows.
Select Laser
A communication-grade laser should be selected for
2.488Gbps applications. Assume the laser output aver-
age power is P AVG = 0dBm, minimum extinction ratio is
r e = 6.6 (8.2dB), the operating temperature is -40°C to
+85°C, and the laser diode has the following character-
istics:
coupling capacitor C D .
To filter out noise effects and guarantee loop stability,
the recommended value for C APC is 0.1μF. This results
in an APC loop bandwidth of 10kHz or a time constant
of 16μs. As a result, the PDJ associated with an APC
loop time constant can be ignored.
The time constant associated with the output pull-up
inductor (L P ≈ L P2 ), and the AC-coupling capacitor (C D )
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
-t / τ L P
will also impact the PDJ. For such a second-order net-
work, the PDJ due to the low frequency cutoff will be
dominated by L P . For a data rate of 2.5Gbps, the rec-
ommended value for C D is 0.056μF. During the maxi-
mum CID period , it is recommended to limit the peak
voltage droop to less than 12% of the average (6% of
the amplitude). The time constant can be estimated by:
12% = 1 - e
τ LP = 7.8t
If τ LP = L P / 25 ? , and t = 100UI = 40ns, then L P = 7.8μH.
To reduce the physical size of this element (L P ), use of
SMD ferrite beads is recommended (Figure 2).
Input Termination Requirement
The MAX3869 data and clock inputs are PECL compat-
ible. However, it is not necessary to drive the MAX3869
with a standard PECL signal. As long as the specified
common-mode voltage and the differential voltage
swings are met, the MAX3869 will operate properly.
Determine R APCSET
The desired monitor diode current is estimated by
I MD = P AVG · ρ MON = 200μA. The I MD vs. R APCSET
graph in the Typical Operating Characteristics shows
that R APCSET should be 6.0k ? .
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 I MOD vs. R MODSET graph in the Typical
Operating Characteristics shows that R MODSET should
be 4.8k ? .
10
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| MAX3869ETJ+ | 功能描述:激光驱动器 3.3V 2.5Gbps SDH/ SONET Laser Driver RoHS:否 制造商:Micrel 数据速率:4.25 Gbps 工作电源电压:3 V to 3.6 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:QFN-16 封装:Tube |
| MAX3869ETJ+D | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX3869ETJ+T | 功能描述:激光驱动器 3.3V 2.5Gbps SDH/ SONET Laser Driver RoHS:否 制造商:Micrel 数据速率:4.25 Gbps 工作电源电压:3 V to 3.6 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:QFN-16 封装:Tube |
| MAX3869EVKIT | 功能描述:激光驱动器 Evaluation Kit for the MAX3869 RoHS:否 制造商:Micrel 数据速率:4.25 Gbps 工作电源电压:3 V to 3.6 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:QFN-16 封装:Tube |
| MAX3872AETJ+ | 功能描述:计时器和支持产品 Multirate Clock and Data Recovery with Limiting Amplifier RoHS:否 制造商:Micrel 类型:Standard 封装 / 箱体:SOT-23 内部定时器数量:1 电源电压-最大:18 V 电源电压-最小:2.7 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
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