參數(shù)資料
型號: OQ2545BHP
廠商: NXP SEMICONDUCTORS
元件分類: 其它接口
英文描述: SDH/SONET STM16/OC48 laser drivers
中文描述: SPECIALTY INTERFACE CIRCUIT, PDSO48
封裝: 7 X 7 MM, 1.40 MM, PLASTIC, SOT-313, LQFP-48
文件頁數(shù): 9/28頁
文件大?。?/td> 688K
代理商: OQ2545BHP
1999 Aug 24
9
Philips Semiconductors
Product specification
SDH/SONET STM16/OC48 laser drivers
OQ2545HP; OQ2545BHP
Automatic laser shutdown
A HIGH-level (TTL) on pin ALS switches off the laser
modulation and bias currents. This function allows the
circuit to be switched off in the event of an optical system
malfunction or for system maintenance. When not
connected, pin ALS is pulled to a LOW-level (TTL) by an
internal pull-down resistor.
Data monitoring
Pins MON and MONQ can be used as data monitor
outputs. They need to be AC-coupled, e.g. to a 50
matched RF amplifier with sufficient bandwidth.
Output polarity selection
Pin SMOD is used to set the correct logic assignment
between the data input on pins DIN and DINQ (or
pins DLOOP and DLOOPQ) and the data output on
pins LA, LAQ, MON and MONQ. This is necessary
because a directly modulated laser diode and an EAM
have different output voltage requirements.
If a laser diode is used and connected between pin LA and
ground, a high current through pin LA corresponds to a
logic HIGH, while a low current through pin LA
corresponds to a logic LOW.
The opposite is the case with an EAM, where a high
current (i.e. a large voltage across the load) activates the
EAM, thereby causing a logic LOW. Therefore, an
inversion is needed between input and output. This
happens in the second multiplexer when pin SMOD is
connected to V
EE1
. When left open-circuit, pin SMOD is
pulled-up to ground, which is the laser diode setting.
Modulation current setting
Pin SIMOD is used to adjust the modulation current on
pins LA and LAQ (see Fig.6). This is achieved by
regulating the internal current mirror, which serves as a
reference current for the modulation driver. The reference
port of the control operational amplifier is connected to
ground through an internal 4 k
resistor, thus establishing
a ‘virtual earth’ on pin SIMOD (DC level is 0 V).
An external (approximately) 4 k
resistor connected to an
adjustable voltage source is needed to regulate the
internal current mirror. This adjustable voltage source can
be a part of the laser current control box (see Fig.15).
The ratio between the current into pin SIMOD and the total
modulation current depends on the polarity setting via
pin SMOD. When pin SMOD = 0 V the value of
I
mod
= 92
×
I
SIMOD
(approximately) and whereas
pin SMOD = V
EE1
the value of I
mod
= 107
×
I
SIMOD
(approximately).
Fig.6 Schematic of laser modulation outputs.
handbook, full pagewidth
k
×
ISIMOD
ISIMOD
SIMOD
4 k
100
100
VEE2
71
×
k
×
ISIMOD
(1)
LA
LAQ
MGL733
+
(1) k = 1.3 when pin SMOD = 0 V.
k = 1.5 when pin SMOD = V
EE1
.
相關(guān)PDF資料
PDF描述
OQ2545HP SDH/SONET STM16/OC48 laser drivers
OQ8844 Digital Servo Driver DSD-2
OQ8868 Digital Servo Integrated Circuit Silent DSICS
OR2C40A-5BC600 Field Programmable Gate Array (FPGA)
OR2C40A-5BC600I Field Programmable Gate Array (FPGA)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
OQ2545HP 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:SDH/SONET STM16/OC48 laser drivers
OQ8844 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Digital Servo Driver DSD-2
OQ8868 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Digital Servo Integrated Circuit Silent DSICS
OQ9224HP / C2 制造商:PHILIPS-SEMI 功能描述:
OR AAA74791901 制造商:LG Corporation 功能描述:LG REMOTE