参数资料
| 型号： | MAX3863ETJ+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 9/15页 |
| 文件大小： | 0K |
| 描述： | IC LASR DRVR 2.7GBPS 3.6V 32TQFN |
| 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： | 2.7Gbps |
| 通道数： | 1 |
| 电源电压： | 3.15 V ~ 3.6 V |
| 电流 - 电源： | 58mA |
| 电流 - 调制： | 80mA |
| 电流 - 偏置： | 100mA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
| 安装类型： | 表面贴装 |
2.7Gbps Laser Driver with Modulation
Compensation
Table 1. Optical Power Relations
the current from the inductor flows to the bias input.
This reduces the current through the laser diode from
PARAMETER
Average Power
Extinction Ratio
Optical Power of a 1
SYMBOL
P AVG
r e
P 1
RELATION
P AVG = (P 0 + P 1 )/2
r e = P 1 /P 0
P 1 = 2P AVG r e /(r e + 1)
the average of I BIAS by half of I MOD . The resulting
peak-to-peak current through the laser diode is then
I MOD . See the Typical Operating Circuit. The require-
ment for compliance in the AC-coupled circuit:
Optical Power of a Zero
Optical Amplitude
Laser Slope Efficiency
Modulation Current
P 0
P P-P
η
I MOD
P 0 = 2P AVG /(r e + 1)
P P-P = P 1 - P 0
η = P P-P /I MOD
I MOD = P P-P / η
?
?
?
?
V D —Diode bias point voltage (1.2V typ)
R L —Diode bias point resistance (5 Ω typ)
L—Diode lead inductance (1nH typ)
R D —Series matching resistor (20 Ω typ)
V CC ? MOD × ( R D + R L ) ≥ 1 . 8 V
Threshold Current
Bias Current
Laser to Monitor
Transfer
I TH
I BIAS
ρ MON
P 0 at I ≥ I TH
I BIAS ≥ I TH + I MOD /2
I MD /P AVG
I
2
The time constant associated with the output pullup
use information about the effects of temperature and
aging. The laser driver automatically adjusts the bias to
maintain the constant average power. The new bias con-
dition requires proper compensation of the modulation
inductor and the AC-coupling capacitor, impacts the
pattern-dependent jitter. For this second-order network
L P usually limits the low-frequency cutoff. The capacitor
C D is selected so:
current. The designer must predict the slope efficiency of
the laser after its bias threshold current has changed.
The modulation and bias currents under a single operat-
C D × ( R D + R L ) >
L P
( R D + R L )
ing condition:
Keep the peak voltage droop less than 3% of the peak-
I MOD = 2 × ×
P AVG
η
r e ? 1
r e + 1
to-peak amplitude during the maximum CID period t.
The required time constant:
I BIAS = I TH + MOD
For AC-coupled diodes:
I
2
2 . 8 % = 1 ? e
τ = 35 × t
? t
τ
The required compensation factor is then:
If τ = L P /25 Ω , and t = 100UI = 40ns, then L P = 35μH.
Place a good high-frequency inductor of 2μH on the
transmission line to the laser. Then you can place a
K = MOD 2
I
I BIAS 2
? I MOD 1
? I BIAS 1
low-frequency inductor of 33μH at a convenient dis-
tance from the driver output.
Programming the Bias Current
When the APC loop is enabled, the actual bias current is
Once the value of the compensation factor is known, the
fixed portion of the modulation current is calculated from:
I MODS = I MOD ? K × I BIAS
Current Limits
To allow larger modulation current, the laser is AC-
coupled to the MAX3863. In this configuration, a con-
stant current is supplied from the inductor L P . When the
MOD pin is conducting, half of I MOD is supplied from
L P and half is from the laser diode. When MOD is off,
reduced from the maximum value to maintain constant
current from the monitor diode. With closed-loop control,
the bias current will be set by the transfer function of the
monitor diode to laser diode current. For example, if the
transfer function to the monitor diode is 10.0μA/mA, then
setting I MD for 500μA results in I BIAS equal to 50mA.
The bias current must be limited in case the APC loop
becomes open. The bias current also needs a set point
in case the APC control is not used. The BIASMAX pin
sets the maximum bias current. The BIASMAX current is
established by an internal current regulator, which main-
tains the bandgap voltage of 1.2V across the external
_______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3863EVKIT | 功能描述:激光驱动器 Evaluation Kit for the MAX3863 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 |
| MAX3864E/D | 功能描述:跨阻抗放大器 MAX3864E/D RoHS:否 制造商:Maxim Integrated 封装 / 箱体: 带宽: 工作电源电压: 电源电流: 工作温度范围: 封装: |
| MAX3864E/D+C8R | 制造商:Maxim Integrated Products 功能描述:2.5GBPS, +3V TO +5.5V, WIDE DYNAMIC RANG |
| MAX3864E/D-B3A | 制造商:Maxim Integrated Products 功能描述:2.5GBPS +3V TO +5.5V WIDE DYNAMIC RANGE TRANSIMPEDANCE PREAM - Gel-pak, waffle pack, wafer, diced wafer on film |
| MAX3864ESA | 功能描述:跨阻抗放大器 RoHS:否 制造商:Texas Instruments 封装 / 箱体:SOIC-14 带宽:3 MHz 工作电源电压:36 V 电源电流:5.5 mA 工作温度范围:- 40 C to + 85 C 封装:Tube |
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