参数资料
| 型号： | MAX3656ETG+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/15页 |
| 文件大小： | 0K |
| 描述： | IC LASR DRVR 2.5GBPS 3.6V 24TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 75 |
| 类型： | 激光二极管驱动器（光纤） |
| 数据速率： | 2.5Gbps |
| 通道数： | 1 |
| 电源电压： | 3 V ~ 3.6 V |
| 电流 - 电源： | 40mA |
| 电流 - 调制： | 85mA |
| 电流 - 偏置： | 70mA |
| 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： | 管件 |
| 安装类型： | 表面贴装 |
| 产品目录页面： | 1422 (CN2011-ZH PDF) |
155Mbps to 2.5Gbps Burst-Mode
Laser Driver
?
APC loop reset), and then it is driven low (chip-
enabled). In this case, APC loop initialization begins
when the voltage at EN drops below the specified
EN input low voltage of 0.8V. After initialization
begins, the laser driver can be operating in burst
mode (BEN toggling high and low) or continuous
mode (BEN = high). In this case, the initialization
time is 2.1μs (typ).
Burst-Mode Startup
In burst-mode startup, the power-supply voltage is
within the specified limits and the chip is enabled
( EN = low). The burst-enable input is low (BEN =
low) and has not been in the high state since the
APC loop was reset. APC loop initialization begins
when the BEN input is driven high. After initialization
begins, the laser driver can be operating in burst
Design Procedure
When designing a laser transmitter, the optical output is
usually expressed in terms of average power and
extinction ratio. Table 1 shows the relationships helpful
in converting between the optical average power and
the modulation current. These relationships are valid if
the mark density and duty cycle of the optical wave-
form are 50%.
Programming the Modulation Current
For a given laser power (P AVG ), slope efficiency ( η ),
and extinction ratio (r e ), the modulation current can be
calculated using Table 1. See the I MOD vs. R MODSET
graph in the Typical Operating Characteristics, and
select the value of R MODSET that corresponds to the
required current at +25 ° C.
mode (BEN toggling high and low) or continuous
mode (BEN = high). In this case, the initialization
time is 1.6μs (typ).
In each of the three cases listed, initialization is complete
within three bursts (bursts must comply with specified
burst on- and burst off-time) or the time specified in the
Electrical Characteristics table, whichever comes first.
Burst-Mode Operation
The bias and modulation outputs (BIAS+ and OUT+)
can be switched on and off quickly using the differential
burst-enable inputs (BEN+ and BEN-). Once the APC
loop has initialized, the bias and modulation outputs are
switched on when BEN+ = high and BEN- = low and are
switched off when BEN+ = low and BEN- = high.
When BEN is switched on, the laser driver sinks the bias
and modulation currents set by the APCSET, BIASMAX,
and MODSET resistors within the maximum BEN delay
time of 2.3ns. For stable APC loop operation, the mini-
mum burst length is limited to the burst on-time listed in
the Electrical Characteristics table. The maximum burst-
Programming the Bias Current
When the MAX3656 is used in open-loop operation, the
R BIASMAX resistor determines the bias current. To
select this resistor, determine the required bias current.
See the I BIASMAX vs. R BIASMAX graph in the Typical
Operating Characteristics , and select the value of
R BIASMAX that corresponds to the required current. For
open-loop operation, connect a 50k Ω resistor from
R APCSET to GND, and leave the MD pin open.
When using the MAX3656 in closed-loop operation, the
R BIASMAX resistor sets the maximum bias current avail-
able to the laser diode over temperature and lifetime.
The APC loop can subtract from this maximum value,
but cannot add to it. See the I BIASMAX vs. R BIASMAX
graph in the Typical Operating Characteristics and
select the value of R BIASMAX that corresponds to the
end-of-life bias current at +85 ° C. The R BIASMAX resistor
should not be set less than 5k Ω .
Table 1. Optical Power Definition
on time is unlimited.
When BEN is switched off, the bias and modulation cur-
rents fall below the specified bias-off and modulation-
off currents within the maximum burst disable delay
time of 2.0ns. For stable APC loop operation, the mini-
mum burst off-time is limited to the value listed in the
Electrical Characteristics table. The maximum burst off-
PARAMETER
Average power
Extinction ratio
Optical power high
Optical power low
Optical amplitude
SYMBOL
P AVG
r e
P 1
P 0
P P-P
RELATION
P AVG = (P 0 + P 1 ) / 2
r e = P 1 / P 0
P 1 = 2P AVG × r e / (r e + 1)
P 0 = 2P AVG / (r e + 1)
P P-P = P 1 - P 0
time is unlimited.
Short-Circuit Protection
Laser slope
efficiency
η
η = P P-P / I MOD
The MAX3656 provides short-circuit protection for the
modulation and bias-current sources. If BIASMAX or
MODSET is shorted to ground, the bias and modulation
outputs are turned off.
Modulation current
Laser-to-monitor
diode gain
I MOD
A LMD
I MOD = P P-P / η
(2 x I MD / I MOD )((r e - 1) /
(r e + 1))
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3656ETG+ | 功能描述:激光驱动器 .155-2.5Gbps Burst Mode 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 |
| MAX3656ETG+ | 制造商:Maxim Integrated Products 功能描述:IC LASER DIODE DRIVER 2.5GBPS TQFN-24 |
| MAX3656ETG+D | 制造商:Maxim Integrated Products 功能描述:LASER DRVR 2.5GBPS 1CH 24TQFN EP - Rail/Tube |
| MAX3656ETG+T | 功能描述:激光驱动器 .155-2.5Gbps Burst Mode 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 |
| MAX3656ETG+TD | 制造商:Maxim Integrated Products 功能描述:LASER DRVR 2.5GBPS 1CH 24TQFN EP - Tape and Reel |
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