- 您现在的位置：买卖IC网 > PDF目录20066 > MAX3656ETG+T (Maxim Integrated)IC LASR DRVR 2.5GBPS 3.6V 24TQFN PDF资料下载
参数资料
| 型号： | MAX3656ETG+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 9/15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： | 1 |
| 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： | 标准包装 |
| 安装类型： | 表面贴装 |
| 产品目录页面： | 1423 (CN2011-ZH PDF) |
| 其它名称： | MAX3656ETG+TDKR |
155Mbps to 2.5Gbps Burst-Mode
Laser Driver
Detailed Description
The MAX3656 laser driver has three main parts: a high-
speed modulator, a high-speed bias driver, and a laser-
biasing block with automatic power control (see the
Functional Diagram). Both the bias and modulation output
stages are composed of differential pairs with program-
mable current sources. The circuit design is optimized for
high-speed, low-voltage (3.3V), DC-coupled operation.
The device is ideal for burst-mode operation with turn-on
and turn-off times less than 2ns. The MAX3656 can be
configured for nonburst-mode applications (continuous
mode) by connecting BEN high.
Automatic Power Control
To maintain constant average optical power, the
MAX3656 incorporates a digital automatic power-con-
trol (APC) loop to compensate for the changes in laser
threshold current over temperature and lifetime. A
back-facet photodiode mounted in the laser package
converts the optical power into a photocurrent. The
APC loop adjusts the laser bias current so the monitor
current is matched to a reference current set by R APCSET .
At startup, the APC loop traverses through a pseudo-
binary search algorithm to set the proper monitor current
that translates to the proper bias current. When BEN is
high, the APC loop maintains constant optical power by
digitally controlling the bias current. When BEN is low,
the APC loop digitally stores the bias current value of the
previous burst. The APC loop is reset in two ways, either
power cycling or toggling the EN pin.
An external resistor (R BIASMAX ) sets the maximum allow-
able bias current during closed-loop operation and sets
the bias current during open-loop operation. An APC fail-
ure flag ( FAIL ) is set low during initialization and when
the bias current cannot be adjusted to achieve the
desired average optical power.
APC closed-loop operation requires that the user set
three currents with external resistors connected between
maintain the desired monitor current. For example, the
laser diode requires more bias current (to maintain a
constant optical output) than maximum bias current set
by R BIASMAX . The bias current is limited and FAIL is
asserted. In an alternate example, assume that a circuit
failure causes the cathode of the laser diode to be short-
ed to GND, thereby causing an uncontrolled high optical
output. In this case, the APC loop cannot decrease the
user current, and FAIL is asserted. FAIL is also set low
during initialization.
Slow-Start
For safety reasons, at initial power-up or after toggling
EN , the MAX3656 incorporates a slow-start circuit that
provides a typical delay of 450ns during the beginning
of APC loop initialization.
Enable Control
The MAX3656 features a chip-enable function. When
EN is high, the bias and modulation currents are off and
the digital state of the APC loop is reset. When EN is
toggled from a high to a low, the APC loop begins ini-
tialization. The initialization time is typically 2.1μs
(LONGB = low) and 3.72μs (LONGB = high).
APC Loop Initialization
The digital APC loop is reset whenever the power is
turned off and/or the EN input is driven high. When
power is turned on or when EN is toggled low, the APC
loop automatically performs an initialization routine that
quickly adjusts the bias current from its reset level to its
initialized level. The initialized bias current level is
defined to be within 3.8mA of the final bias current level
set by the APCSET resistor. Once initialized, the APC
loop enters its fine-adjustment mode of operation and
adjusts the bias current to match the level set by the
APCSET resistor. There are three different cases in
which the APC loop starts initialization, and each has a
unique initialization time. These cases are defined
as follows:
GND, BIASMAX, MODSET, and APCSET pins. Detailed
guidelines for these resistor settings are described in the
Design Procedure section.
If necessary, the MAX3656 is fully operational without
APC. To operate the MAX3656 open loop, connect a
50k Ω resistor from APCSET to ground and leave the
MD pin unconnected. In this case, two external resis-
tors connected from BIASMAX and MODSET to GND
directly set the laser current.
APC Failure Monitor
The MAX3656 provides an APC failure monitor (TTL) to
indicate an APC loop-tracking failure. FAIL is set low
when the APC loop cannot adjust the bias current to
?
?
Continuous-Mode Power-Up
In continuous-mode power-up, the chip is enabled
( EN = low) and the burst-enable input is high (BEN =
high) when power is applied to the laser driver. APC
loop initialization begins when the power-supply volt-
age rises above the minimum specified limit of +3.0V.
The BEN input remains high indefinitely and the laser
driver operates in continuous (nonbursting) mode. In
this case, the initialization time is 12μs (typ).
Chip-Enable Reset
In chip-enable reset, the power-supply voltage is
within the specified limits and BEN is high. The chip-
enable input ( EN ) is initially high (chip disabled and
_______________________________________________________________________________________
9
相关PDF资料 |
PDF描述 |
|---|---|
| VY2150K29U2JS63V5 | CAP CER 15PF 300V 10% RADIAL |
| NH35BP-2F10 | BATTERY PACK NIMH 12.0V 2500MAH |
| EMA36DTMZ-S664 | CONN EDGECARD 72POS R/A .125 SLD |
| GRM1885C1H5R0CZ01D | CAP CER 5PF 50V NP0 0603 |
| EBC20DRTI | CONN EDGECARD 40POS DIP .100 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3656EVKIT | 功能描述:激光驱动器 Evaluation Kit for the MAX3656 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 |
| MAX3656EVKIT+ | 功能描述:电源管理IC开发工具 MAX3656 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX3657BE/D | 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 |
| MAX3657BE/D DIE | 制造商:Maxim Integrated Products 功能描述: |
| MAX3657E/D | 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 |
发布紧急采购，3分钟左右您将得到回复。