- 您现在的位置：买卖IC网 > PDF目录20045 > LTC5100EUF (Linear Technology)IC DRIVER VCSEL 3.2GBPS 16QFN PDF资料下载
参数资料
| 型号： | LTC5100EUF |
| 厂商： | Linear Technology |
| 文件页数： | 22/52页 |
| 文件大小： | 0K |
| 描述： | IC DRIVER VCSEL 3.2GBPS 16QFN |
| 标准包装： | 91 |
| 类型： | 激光二极管驱动器 |
| 数据速率： | 3.2Gbps |
| 通道数： | 1 |
| 电源电压： | 3.135 V ~ 3.465 V |
| 电流 - 电源： | 54mA |
| 电流 - 调制： | 12mA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN（4x4） |
| 包装： | 管件 |
| 安装类型： | 表面贴装 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页当前第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页
LTC5100
OPERATIO
Im_ adc n n – 1 +
= Im_ adc
( )
= Im_ adc n ? 1 +
approximately second order characteristics. The design
maximizes the flatness of the step response over extended
periods, giving optimal performance during long strings
of ones or zeros in the data.
MODULATION CURRENT CONTROL
IN APC AND CCC MODES
The LTC5100 controls the modulation current with a
digital servo control loop using feedback from the on-chip
ADC. Figure 3 and Figure 4 are Functional Diagrams of the
LTC5100 operating in Automatic Power Control (APC)
mode and Constant Current Control (CCC) modes, respec-
tively. These diagrams show the organization and opera-
tion of the servo control loops for laser bias and laser
modulation. Either diagram can be used to understand the
modulation current control loop.
Servo Control
The average modulation current is controlled by a digital
The ADC input for average modulation current is scaled
such that code 512 is the nominal full-scale value, corre-
sponding to 4.5mA per range. Thus, if Im_rng = 0 and
Im = 4.5mA, the ADC digitizes code 512. The control
system for the modulation current effectively has 9-bit
resolution, because at most one-half of the 10-bit ADC
range is utilized. This provision maximizes the compliance
voltage range of the modulation output.
The difference equation for the modulation servo loop is:
Im_ gain
?Im_ error ( 16 )
8
Im_ gain
? Im_ set – Im_ adc n ? 1
8
Im_gain is a 3-bit digital value, so the scaling factor,
Im_gain/8, takes on the discrete values 0, 1/8, 2/8, …, 7/8.
If Im_gain = 4, then Im_gain/8 = 0.5 and the error in the
control loop is cut in half with each servo iteration. In this
case the step response of the loop is given by:
? 1 – ? 1 – Im_ gain ? ?
?
?
? ? ? ?
? ?
? ?
servo loop (shown in the lower half of Figure 3). The
nominal modulation current, Im_nom, is multiplied by a
temperature compensation factor, producing a 10-bit
digital set point value, Im_set. Im_set is the target value
Im_ adc n = Im_ set ?
8
? n ?
(17)
for average modulation current. The ADC digitizes the
average modulation current, producing a 10-bit value
Im_adc. The difference between the target value and the
actual value produces the servo loop error signal, Im_error.
Im_error is multiplied by a constant, Im_gain, to set the
loop gain. The result is integrated in a digital accumulator
and applied to a 10-bit DAC, increasing or decreasing the
modulation amplitude as required to drive the loop error to
zero. The servo loop adjusts the modulation amplitude
every four milliseconds, producing 250 servo iterations
per second.
The modulation servo loop operates on the average modu-
The step response has the familiar exponential settling
characteristic of a first order system. The step response is
shown in Figure 22 for Im_gain = 4. The remaining error
is reduced by one-half with each servo iteration. In seven
iterations, or about 28ms, the modulation current settles
to under 1% in this example. The measured step response,
including the modulation envelope, is shown in the Typical
Performance Characteristics.
Im_set
Im_adc
lation current, which is one-half of the peak-to-peak value
for a 50% duty cycle signal. The analog electronics in the
1
2
3
4
5
6
7
8
SERVO
ITERATIONS
high speed modulator ensure that controlling the average
modulation current is equivalent to controlling the peak-
0
4
8
12
16
20
24
28
32
TIME (ms)
5100 F22
to-peak current.
Figure 22. Step Response of the Average Modulation Current
for Im_gain = 4
sn5100 5100fs
22
相关PDF资料 |
PDF描述 |
|---|---|
| AMC19DRTH-S734 | CONN EDGECARD 38POS DIP .100 SLD |
| T86D476M010EAAL | CAP TANT 47UF 10V 20% 2917 |
| VE-240-CX-F4 | CONVERTER MOD DC/DC 5V 75W |
| TACL105K010XTA | CAP TANT 1UF 10V 10% 0603 |
| T86D476K010EAAL | CAP TANT 47UF 10V 10% 2917 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC5100EUF#PBF | 功能描述:IC DRIVER VCSEL 3.2GBPS 16QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 激光驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:60 系列:- 类型:激光二极管驱动器 数据速率:- 通道数:4 电源电压:3.3V 电流 - 电源:- 电流 - 调制:- 电流 - 偏置:- 工作温度:0°C ~ 70°C 封装/外壳:40-TQFN 裸露焊盘 供应商设备封装:40-TQFN EP 包装:托盘 安装类型:表面贴装 |
| LTC5100EUF#TR | 功能描述:IC DRIVER VCSEL 3.2GBPS 16QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 激光驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:60 系列:- 类型:激光二极管驱动器 数据速率:- 通道数:4 电源电压:3.3V 电流 - 电源:- 电流 - 调制:- 电流 - 偏置:- 工作温度:0°C ~ 70°C 封装/外壳:40-TQFN 裸露焊盘 供应商设备封装:40-TQFN EP 包装:托盘 安装类型:表面贴装 |
| LTC5100EUF#TRPBF | 功能描述:IC DRIVER VCSEL 3.2GBPS 16QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 激光驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:60 系列:- 类型:激光二极管驱动器 数据速率:- 通道数:4 电源电压:3.3V 电流 - 电源:- 电流 - 调制:- 电流 - 偏置:- 工作温度:0°C ~ 70°C 封装/外壳:40-TQFN 裸露焊盘 供应商设备封装:40-TQFN EP 包装:托盘 安装类型:表面贴装 |
| LTC511P | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic |
| LTC5336E | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic |
发布紧急采购，3分钟左右您将得到回复。