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| 型号： | MAX3740AETG+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 12/15页 |
| 文件大小： | 0K |
| 描述： | IC DRIVER SFP VCSEL 24-TQFN |
| 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 |
| 数据速率： | 3.2Gbps |
| 通道数： | 1 |
| 电源电压： | 2.97 V ~ 3.63 V |
| 电流 - 电源： | 55mA |
| 电流 - 调制： | 15mA |
| 电流 - 偏置： | 15mA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 供应商设备封装： | 24-TQFN-EP（4x4） |
| 包装： | 带卷 (TR) |
| 安装类型： | 表面贴装 |
3.2Gbps SFP VCSEL Driver with Diagnostic
Monitors
[
]
? ?
I MOD = ( I MODSET ) × 30 × ?
?
? ? ? 200 + R MODSET ?
? ? ? OUT + + R LOAD ?
( SE 85 ? SE 25 )
SE 25 × ( 85 ? 25 )
? × 34
I BIAS = ?
Programming Modulation Current
The modulation current output of the MAX3740A is con-
trolled by a resistor (R MODSET ) placed between
MODSET and ground. The R MODSET resistor controls
the amount of current being sourced to the VCSEL. The
modulation current is given by the following:
R OUT +
? R OUT + + R LOAD ?
? ? 1 ? ? ? R OUT + ?
I MOD = ? ? ? × 30 ? × ? R ?
It is important to note that the modulation current being
sourced by the MAX3740A is affected by the load
impedance of the VCSEL. The Modulation Current vs.
R MODSET graph in the Typical Operating Characteristics
shows the current into a 50 Ω electrical load.
Programming Bias Current
The bias current output of the MAX3740A is controlled
by a resistor (R BIASSET ) placed between BIASSET and
ground. In open-loop operation the R BIASSET controls
the bias current level of the VCSEL. In closed-loop
operation the R BIASSET controls the maximum bias cur-
rent provided by the APC. The bias current is given by
the following:
I BIAS = ( I BIASSET ) × 34
? 1 . 2 ?
? 200 + R BIASSET ?
The Bias Current vs. R BIASSET graph is also shown in
0.021mW/mA at +25 ° C, which reduces to 0.018mW/mA
at +85 ° C. The temperature coefficient is given by the
following:
Laser tempco = × 1 E 6
= ? 2380 ppm / ° C
From the Typical Operating Characteristics, the value
of R TC , which offsets the tempco of the laser, is 9k Ω . If
modulation temperature compensation is not desired,
short TC1 and TC2.
Programming the APC Loop
Program the average optical power by adjusting
R PWRSET . To select the resistance, determine the
desired monitor current to be maintained over tempera-
ture and lifetime. See the Monitor Diode Current vs.
R PWRSET graph in the Typical Operating Characteristics
section, and select the value of R PWRSET that corre-
sponds to the required current.
Input Termination Requirements
The MAX3740A data inputs are SFP MSA compatible.
On-chip 100 Ω differential input impedance is provided
for optimal termination (Figure 4). Because of the on-chip
biasing network, the MAX3740A inputs self-bias to the
proper operating point to accommodate AC-coupling.
V CC
the Typical Operating Characteristics.
Photodiode Selection
To ensure stable operation of the APC circuit, the time
MAX3740A
PACKAGE
V CC
16k Ω
constant of the MD node should be shorter than the
IN+
1nH
APC time constant. (t APC = 5μs if C APC = 0.047μF).
0.5pF
50 Ω
t MD ≤
t APC
20
, R MD × C MD ≤
5 μ s
20
= 250 ns
V CC
50 Ω
For typical I PD = 400μA, R PWRSET = 500 Ω , select a
photodiode with capacitance less than 500pF.
Programming Modulation-Current Tempco
Compute the required modulation tempco from the
slope efficiency of the laser at T A = +25 ° C and at a
higher temperature. Then select the value of R TC from
the Typical Operating Characteristics. For example,
IN-
1nH
0.5pF
24k Ω
suppose a laser has a slope efficiency (SE) of
Figure 4. Simplified Input Structure
12
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相关代理商/技术参数 |
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|---|---|
| MAX3740AEVKIT | 功能描述:激光驱动器 Evaluation Kit for the MAX3740A 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 |
| MAX3740ETG | 制造商:Maxim Integrated Products 功能描述:3.2GBPS SFP VCSEL DRIVER WITH DIAGNOSTIC MONI - Rail/Tube |
| MAX3740ETG-T | 制造商:Maxim Integrated Products 功能描述:3.2GBPS SFP VCSEL DRIVER WITH DIAGNOSTIC MONI - Tape and Reel |
| MAX3741ETE | 功能描述:通信集成电路 - 若干 RoHS:否 制造商:Maxim Integrated 类型:Transport Devices 封装 / 箱体:TECSBGA-256 数据速率:100 Mbps 电源电压-最大:1.89 V, 3.465 V 电源电压-最小:1.71 V, 3.135 V 电源电流:50 mA, 225 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| MAX3741ETE-T | 功能描述:通信集成电路 - 若干 RoHS:否 制造商:Maxim Integrated 类型:Transport Devices 封装 / 箱体:TECSBGA-256 数据速率:100 Mbps 电源电压-最大:1.89 V, 3.465 V 电源电压-最小:1.71 V, 3.135 V 电源电流:50 mA, 225 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
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