参数资料
| 型号： | MAX3273ETG+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/18页 |
| 文件大小： | 0K |
| 描述： | IC LASR DRVR 2.7GBPS 3.6V 24TQFN |
| 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： | 3.14 V ~ 3.6 V |
| 电流 - 电源： | 30mA |
| 电流 - 调制： | 60mA |
| 电流 - 偏置： | 100mA |
| 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 |
+3.3V, 2.5Gbps Low-Power Laser Driver
Programming the Bias Current
with APC Disabled
When using the MAX3273 in open-loop operation, the
bias current is determined by the R BIASMAX resistor. To
select this resistor, 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
I BIASMAX at +25°C. Ground the APCFILT1 pin for open-
loop operation.
Programming the Bias Current
with APC Enabled
When the MAX3273’s APC feature is used, program the
average optical power by adjusting the APCSET resis-
tor. To select this resistor, determine the desired moni-
tor current to be maintained over temperature and life.
See the I MD vs. R APCSET graph in the Typical
Operating Characteristics and select the value of R APC-
SET that corresponds to the required current.
When using the MAX3273 in closed-loop operation, the
R BIASMAX resistor sets the maximum bias current avail-
able to the laser diode over temperature and life. 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.
Interfacing with Laser Diodes
To minimize optical output aberrations caused by sig-
nal reflections at the electrical interface to the laser
diode, a series-damping resistor (R D ) is required (see
the Typical Application Circuit ). Additionally, the
MAX3273 outputs are optimized for a 25 Ω load.
Therefore, the series combination of R D and R L (where
R L represents the laser-diode resistance) should equal
25 Ω . Typical values for RD are 18 Ω to 23 Ω . 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 characteristics
of the laser diode and PC board layout, a resistor (R P )
of 50 Ω to 100 Ω in parallel with pullup inductor L P1 can
be useful in damping overshoot and ringing in the opti-
cal output.
In some applications (depending on laser-diode para-
sitic inductance), an RC-shunt network between the
laser cathode and ground helps minimize optical out-
put aberrations. Starting values for most coaxial lasers
are R = 75 Ω in series with C = 3.3pF. These values
should be experimentally adjusted until the optical out-
put 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 APCFILT ), which domi-
nates the APC loop time constant; pullup inductor (L P );
and AC-coupling capacitor (C D ).
To filter out noise effects and guarantee loop stability,
the recommended value for C APCFILT is 0.01μF. This
results in an APC loop bandwidth of 100kHz or a time
constant of 15μs. As a result, the PDJ associated with
an APC loop time constant can be ignored.
The time constant associated with the output pullup
inductor (L P ≈ L P2 ) and the AC-coupling capacitor (C D )
affects the PDJ. For such a second-order network, the
PDJ is dominated by L P because of the low frequency
cutoff. For a data rate of 2.5Gbps, the recommended
value for C D is 0.056μF. During the maximum CID peri-
od, limit the peak voltage droop to less than 12% of the
average (6% of the amplitude). The time constant can
be estimated by:
? t
12 % = 1 ? e τ LP
τ LP = 7 . 8 t
If τ LP = L P / 25 Ω , 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).
To achieve even greater immunity to droop, use an
optional third inductor (33μH, L P3 in Figure 2).
Input Termination Requirement
The MAX3273 data and clock inputs are CML compati-
ble. However, it is not necessary to drive the IC with a
standard CML signal. As long as the specified differen-
tial voltage swings are met, the MAX3273 operates
properly.
Calculating Power Consumption
The junction temperature of the MAX3273 dice must be
kept below +150°C at all times. The total power dissipa-
tion of the MAX3273 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 BIASMAX , I MOD is the modulation current, and V f is the
typical laser forward voltage.
Junction temperature = P(W) ? 37 (°C/W)
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3273EVKIT | 功能描述:激光驱动器 Evaluation Kit for the MAX3273 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 |
| MAX3274UGE | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX3277EVKIT | 制造商:Maxim Integrated Products 功能描述:LOW-NOISE, FIBRE CHANNEL TRANSIMPED - Boxed Product (Development Kits) |
| MAX3277U/D | 功能描述:特殊用途放大器 RoHS:否 制造商:Texas Instruments 通道数量:Single 共模抑制比（最小值）: 输入补偿电压: 工作电源电压:3 V to 5.5 V 电源电流:5 mA 最大功率耗散: 最大工作温度:+ 70 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:QFN-20 封装:Reel |
| MAX327C/D DIE | 制造商:Maxim Integrated Products 功能描述: |
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