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Электронный компонент: SY88905KC

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DESCRIPTION
s
DC bias current adjustable to 25mA
s
Buffered Loss-of-Signal output when used with
SY88903
s
Monitor Diode power control circuit
s
Designed for use with SY88902 and SY88903
s
Single power supply
s
Available in 10-pin (3mm) MSOP
The SY88905 is an integrated Laser Diode controller for
the SY88902 Laser Driver and SY88903 Laser Receiver
that provides power control functions for a complete module
solution. The SY88905 is designed to provide the laser
diode with an independent DC threshold current (I
BIAS
)
source to assure optimum laser diode performance. The
SY88905 also provides buffered Loss-of-Signal (LOS) output
in PECL level. The device is designed for fast and accurate
calibration of the laser diode.
Once the optimal operating point is determined and set
for a specific laser diode, the threshold current (I
BIAS
) is
designed to automatically compensate for laser diode aging
and module temperature.
FEATURES
LASER DIODE
CONTROLLER
WITH APC
SY88905
PIN CONFIGURATION
APPLICATIONS
s
Controller for High Speed Optical Data Transmission
s
1.25Gbps Gigabit Ethernet
s
531 Mbps and 1062Mbps Fibre Channel
s
622Mbps SONET
s
Gigabit Interface Converter
BLOCK DIAGRAM
1
LOS
IN
LOS
OUT
GND
I
BIAS
V
CC
10 V
REF
I
BIAS SET
I
BIAS FB
I
PIN SET
MD
9
8
7
6
2
3
4
5
MSOP
K10-1
I
PIN
SET
V
CC
I
BIAS FB
I
BIAS
MD
V
REF 2
-
+
I
BIAS
SET
V
REF
GND
40X
V
REF2
LOS
IN
LOS
OUT
1
Rev.: B
Amendment: /1
Issue Date:
July 2000
2
SY88905
Micrel
T
A
= 0
C
T
A
= +25
C
T
A
= +85
C
Symbol
Parameter
Min.
Max.
Min.
Max.
Min.
Max.
Unit
Condition
V
OH
Output HIGH Voltage
V
CC
1025 V
CC
880 V
CC
1025 V
CC
880 V
CC
1025 V
CC
880
mV
50
to V
CC
2V
V
OL
Output LOW Voltage
V
CC
1810 V
CC
1620 V
CC
1810 V
CC
1620 V
CC
1810 V
CC
1620
mV
50
to V
CC
2V
LOGIC DIAGRAM
100H ECL DC ELECTRICAL
(1)
V
CC
= +5V
10%
NOTE:
1. 100H circuits are designed to meet the DC specifications shown in the table where transverse airflow greater than 500lfpm is maintained.
Symbol
Rating
Value
Unit
V
CC
Power Supply Voltage
0 to +7.0
V
LOS
IN
Input Voltage
0 to V
CC
V
LOS
OUT,
I
PIN SET
Others; I/O Voltage
0.3, V
CC
+0.3
V
I
BIASFB,
I
BIAS SET
T
A
Operating Temperature Range
0 to +85
C
T
store
Storage Temperature Range
55 to +125
C
I
PIN SET,
I
BIAS SET,
I
MD
Max. Sink Current
1
mA
I
BIASFB
Max. Source Current
1
mA
I
BIAS
Max. Sink Current
30
mA
I
VREF
Max. Source Current
2
mA
NOTE:
1. Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. This is a stress rating only and functional operation is not implied
at conditions other than those detailed in the operational sections of this data sheet. Exposure to ABSOLUTE MAXIMUM RATlNG conditions for extended
periods may affect device reliability.
ABSOLUTE MAXIMUM RATINGS
(1)
PIN DEFINITIONS
Pin
Type
Description
V
CC
Power
Positive Power supply
GND
Power
Ground
LOS
IN
TTL Input
Loss-of-Signal Input from SY88903
V
REF
Analog Output
Reference Voltage
I
PIN SET
Analog Input
Adjustable, Resistor to V
REF
sets Monitor Diode Photo Current Reference
LOS
OUT
PECL Output
Loss-of-Signal PECL output
I
BIASFB
Analog Output
Monitor Diode Feedback
I
BIASSET
Analog Input
Adjustable, Resistor to V
REF
sets the DC bias current for the Laser Diode
MD
Analog Input
Monitor Diode Connection
I
BIAS
Analog Input
DC bias current for the Laser Diode
3
SY88905
Micrel
DETAILED DESCRIPTION
The SY88905 is an integrated control circuit for laser
diode modules intended for high-frequency fiber-optic
applications. The device is designed to operate with the
SY88902 laser diode driver providing Automatic Power
Control (APC) which provides bias current control and
monitor diode interface. The device also interfaces with the
SY88903 high-speed limiting amplifier providing chatter-free
Loss of Signal function.
Laser Diode Supply Current
The SY88905 provides the adjustable drive current for
the laser diode, DC bias.
Monitor Diode
The MD pin on the SY88905 provides low frequency
light intensity, laser power out feedback from the monitor
diode in the laser diode package. This feedback is used to
adjust the I
BIAS
level through the Automatic Power Control
circuit to maintain a near constant power output from the
laser diode.
T
A
= 0
C
T
A
= +25
C
T
A
= +85
C
Symbol
Parameter
Min.
Typ.
Max.
Min.
Typ.
Max.
Min.
Typ. Max. Unit
Conditions
I
CC
Power Supply Current
--
--
40
--
28
40
--
--
40
mA
No output load
I
BIAS
SET
I
BIAS
SET
Input Current
--
--
0.9
--
--
0.9
--
--
0.9
mA
I
BIAS
I
BIAS
Output Current
0.5
--
25
0.5
--
25
0.5
--
25
mA
A
BIAS
I
BIAS
Current Gain
28
--
44
28
37
44
28
--
44
=I
BIAS
/ I
BIAS SET
V
REF
Reference Voltage
2.30
--
3.30
2.30
2.75
3.30
2.30
--
3.30
V
I
REF
= -100
A
V
PIN SET
V
PIN SET
Voltage Tracking
0.95
--
1.35
0.95
1.13
1.35
0.95
--
1.35
V
=V
REF
V
PIN SET
V
BIAS
SET
V
BIAS
Voltage Tracking
0.8
--
1.20
0.8
1.0
1.20
0.8
--
1.20
V
=V
REF
V
BIAS SET
V
COMP
BIAS
Compliance Voltage
0.1
--
1.0
0.1
0.4
1.0
0.1
--
1.0
V
I
BIAS
= 15mA
I
BIAS FB
Feedback Current
(1)
350
--
--
350
500
--
350
--
--
A
A
BIAS FB
Feedback Gain
(2)
4
--
14
4
--
14
4
--
14
DC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
10%
NOTE:
1.
|
I
MD
I
PIN SET
| =
100
A
2.
|
I
BIAS FB
| /
|
I
MD
I
PIN SET
|
NOTE:
1. Individual product specifications over-ride general specifications.
TTL DC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
10%
T
A
= 0
C
T
A
= +25
C
T
A
= +85
C
Symbol
Parameter
Min.
Max.
Min.
Max.
Min.
Max.
Unit
Condition
V
IH
Input HIGH Voltage
2.0
--
2.0
--
2.0
--
V
--
V
IL
Input LOW Voltage
--
0.8
--
0.8
--
0.8
V
--
I
IH
Input HIGH Current
--
20
--
20
--
20
A
V
IN
= 2.7V
--
100
--
100
--
100
V
IN
= V
CC
I
IL
Input LOW Current
--
0.3
--
0.3
--
0.3
mA
V
IN
= 0.5V
V
IK
Input Clamp Voltage
--
1.2
--
1.2
--
1.2
V
I
IN
= 12mA
4
SY88905
Micrel
SIMULATION GRAPHS
Figure 1. I
BIAS
v. I
BIAS SET
Figure 2. I
BIAS
v. R
BIAS SET
I
BIAS
vs I
BIAS SET
0.0E+00
5.0E-03
1.0E-02
1.5E-02
2.0E-02
2.5E-02
3.0E-02
3.5E-02
0.E+00 1.E-04 2.E-04 3.E-04 4.E-04 5.E-04 6.E-04 7.E-04 8.E-04
I
BIAS SET
(A)
I
BIAS
(A)
I
BIAS
vs R
BIAS SET
0.00E+00
5.00E-03
1.00E-02
1.50E-02
2.00E-02
2.50E-02
3.00E-02
1.00E+03
1.00E+04
1.00E+05
R
BIAS SET
(Ohm)
I
BIAS
(A)
5
SY88905
Micrel
SIMULATION GRAPHS
Figure 3. I
PIN
v. I
PIN SET
Figure 4. I
PIN SET
v. R
PIN SET
I
PIN SET
vs R
IPIN SET
0.00E+00
1.00E-04
2.00E-04
3.00E-04
4.00E-04
5.00E-04
6.00E-04
7.00E-04
1.00E+03
1.00E+04
1.00E+05
R
IPIN SET
(A)
I
PIN SET
(A)
I
PIN
vs I
PINSET
0.E+00
1.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
0.E+00
1.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
I
PIN SET
(A)
I
PIN
(A)