1
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
DESCRIPTION
s
Single 3.3V power supply
s
Up to 2.7Gbps operation
s
Rise/Fall times: < 75ps
s
Independent programmable laser modulation and
bias currents
s
Bias current to 100mA and modulation current to
90mA
s
Automatic average laser power control
s
Bias and modulation current monitors
s
Operating temperature range of 40
C to +85
C
s
Complies with ANSI, ITU, and Bellcore SDH/SONET
specifications
s
Available in DIE form and 32-pin (5mm
5mm)
EPAD-MLFTM package
FEATURES
3.3V, 2.7Gbps SDH/SONET
LASER DRIVER WITH AUTOMATIC
POWER CONTROL
SY88952L
APPLICATIONS
s
OC-48 transceivers and transponders
s
SONET/SDH transmission system
s
Add drop mux
s
Metro area network
s
2.5Gbps optical transmitter
s
Fiber optical module
Rev.: B
Amendment: /0
Issue Date:
August 2005
SY88952L is a highly integrated and programmable
laser driver for SONET/SDH application up to 2.7Gbps.
The device accepts differential PECL or LVDS data and
clock inputs. It provides programmable bias and
modulation currents for driving a laser. The modulation
output of SY88952L can be DC-coupled to drive the laser
diode, providing a significant power saving over AC-
coupled operation. A synchronizing TTL input latch can
be used to reduce jitter if a clock signal is available. A
TTL enable is also incorporated in the device. EN only
enables/disables I
MOD
. It does not enable/disable I
BIAS
.
An automatic power controller (APC) is integrated into
SY88952L to maintain a constant average optical output
power over temperature and lifetime. The modulation
current can be externally temperature compensated to
minimize the variation of extinction ratio of the optical
output.
Several safety features will enable an alarm function
when the output signal is too high, or bias current is too
high.
There are two alarm conditions:
1. /FAIL asserts when bias current loop goes to
maximum of it's range. I
BIAS
and I
MOD
still flow under
this condition.
2. /FAIL asserts when I
BIASMAX
or I
MODSET
are too
high (implying I
BIAS
or I
MOD
will be too high). All currents
will shut off under this condition.
MLF and
MicroLeadFrame are trademarks of Amkor Technology, Inc.
2
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
PACKAGE/ORDERING INFORMATION
Pin Number
Pin Name
Pin Function
16
BIAS
Bias Current Output (I
BIAS
).
11
BIASMON
Bias Current Monitor: Sinks current that is proportional to I
BIAS
, (I
BIAS
/40). An external current
path must exist to V
CC
.
31
BIASMAX
A resistor (R
BIASMAX
) connected to ground sets the maximum bias current.
See "Typical Operating Characteristics" (I
BIAS
vs. R
BIASMAX
).
26
SLOW
Connect a capacitor (C
SLOW
) to ground to provide a slow-start.
5, 6
CLK,/CLK
Differential Clock Input. 75K
pull-down on CLK, 75k
pull-up and 75k
pull-down on /CLK.
2, 3
D, /D
Differential Data Input. 75K
pull-down on D, 75k
pull-up and 75k
pull-down on /D.
9
EN
TTL Input with 75k
pull-up: Default HIGH for normal operation; LOW to disable modulation
current.
8
LATCH
TTL Input with 75k
pull-up: Default HIGH for latched (clocked) data; LOW for direct data.
25
MD
Connect this pin to a monitor photodiode anode, a resistor (R
APCSET
) and a capacitor (C
APCSET
).
This sets the desired average optical power.
19, 20, 22, 23
Q, /Q
Differential Output: Modulation current output (I
MOD
).
12
MODMON
Modulation Current Monitor: Sinks current that is proportional to I
MOD
, (I
MOD
/45). An external
current path must exist to V
CC
.
30
MODSET
A resistor (R
MODSET
) connected to ground sets the modulation current.
See "Typical Operating Characteristics" (I
MOD
vs. R
MODSET
).
13
/FAIL
TTL Open-Collector Output: Connect a 5k
resistor to V
CC
. Indicates APC failure when LOW.
1, 4, 7, 18, 21, 24, 32
VCC
Positive Power Supply.
10, 14, 15, 17,
VEE
Device Ground: Ensure the exposed pad is also connected to ground.
27, 28, 29, EP
PIN DESCRIPTION
24
23
22
21
20
19
18
17
VCC
/Q
/Q
VCC
Q
Q
VCC
VEE
VCC
D
/D
VCC
CLK
/CLK
VCC
LATCH
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
32 31 30 29 28 27 26 25
VEE
VEE
MODSET
BIASMAX
VCC
VEE
SLOW
MD
/FAIL
MODMON
BIASMON
VEE
EN
VEE
VEE
BIAS
32-Pin MLFTM (MLF-32)
Note 1.
L = LOW, H = HIGH, X = don't care.
Note 2.
H = I
OUT
I
MOD_OFF
.
D
/D
EN
OUT
(2)
/OUT
L
H
H
H
L
H
L
H
L
H
X
X
L
H
L
TRUTH TABLE
(1)
Ordering Information
(1)
Package
Operating
Package
Lead
Part Number
Type
Range
Marking
Finish
SY88952LMI
MLF-32
Industrial
SY88952L
Sn-Pb
SY88952LMITR
(2)
MLF-32
Industrial
SY88952L
Sn-Pb
SY88952LMG
MLF-32
Industrial
SY88952L with
Pb-Free
Pb-Free bar-line indicator
NiPdAu
SY88952LMGTR
(2)
MLF-32
Industrial
SY88952L with
Pb-Free
Pb-Free bar-line indicator
NiPdAu
Notes:
1.
Dice are designed to operate from 40
C to +85
C, but are tested and guaranteed to T
A
= +25
C
only.
2.
Tape and Reel.
3
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
) ..................................... +0V to +7.0V
Input Voltage (V
IN
) ............................................ +0V to V
CC
Output Current (I
OUT
) ............................................... 100mA
Lead Temperature (soldering, 10 sec.) ..................... 300
C
Storage Temperature (T
S
) ....................... 65
C to +150
C
Operating Ratings
(2, 3)
Supply Voltage (V
CC
) .................................. +3.0V to +3.6V
Ambient Temperature (T
A
) ......................... 40
C to +85
C
Junction Temperature (T
J
) ........................................ 120
C
Package Thermal Resistance
MLFTM
(
JA
) still-air ..................................................... 34
C/W
(
JB
) still-air ..................................................... 19
C/W
V
CC
= 3.0V to 3.6V; V
EE
= GND; R
LOAD
= 5
; T
A
= 40
C to +85
C
Symbol
Parameter
Condition
Min
Typ
Max
Units
I
CC
Supply Current
Note 4
85
mA
I
BIAS
Bias Current Range
Note 5
1
100
mA
I
MOD
Modulation Current Range
Note 5
1
90
mA
I
MOD_OFF
Modulation Off Current
Note 6
750
A
V
ID
Differential Input Voltage
200
1600
mV
PP
V
ICMR
Common Mode Range
V
CC
1.49
V
CC
V
ID
/4
V
V
IH
TTL Input HIGH Voltage
2.0
V
CC
V
V
IL
TTL Input LOW Voltage
0.8
V
V
OL
/FAIL Output LOW Voltage
Note 6
0.5
V
I
OH
/FAIL Output Leakage Current
Note 7
100
A
Notes:
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.
2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.
3. Devices are ESD sensitive. Handling precautions recommended.
4. Excluding actual I
BIAS
and I
MOD
output currents.
5. Voltage at Q, /Q must not drop below V
CC
1.5V. Voltage BIAS, MODMON and BIASMON must not drop below V
CC
2V.
6. EN = LOW.
7. I
OL
= +2mA.
8. V
OH
= 3.6V.
DC ELECTRICAL CHARACTERISTICS
4
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
V
CC
= 3.0V to 3.6V; V
EE
= GND; T
A
= 40
C to +85
C; typical values @V
CC
= 3.3V, T
A
= 25
C, I
MOD
= 40mA, I
BIAS
= 50mA, R
LOAD
= 5
Symbol
Parameter
Condition
Min
Typ
Max
Units
CID
Maximum Consecutive
80
bits
Identical Digits
PWD
Pulse Width Distortion
Note 10, 11
50
ps
t
S
Latch Set-Up Time
40
ps
t
H
Latch Hold Time
40
ps
t
r
,
t
f
Output Rise/Fall Time
75
ps
(20% to 80%)
Notes:
9.
AC characteristics are guaranteed by design and characterization.
10. Measured with 622Mbps 0-1 pattern, latch = HIGH.
11. PWD = (Wider pulse narrower pulse) /2.
AC ELECTRICAL CHARACTERISTICS
(9)
TIMING DIAGRAM
t
CLK
= 400ps
t
H
t
S
CLK
D
Setup/Hold Time Definition
5
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
TYPICAL OPERATING CHARACTERISTICS
(NOTE 1)
0
20
40
60
80
100
120
140
160
10
100
1000
10000
I
MOD
(mA)
R
MODSET
(
)
I
MOD
vs. R
MODSET
0
20
40
60
80
100
120
140
160
10
100
1000
10000
I
BIAS
(mA)
R
BIASMAX
(
)
I
BIAS
vs. R
BIASMAX
Modulation-Current Monitor Gain
vs. Temperature
0
10
20
30
40
50
60
-40
-20
0
20
40
60
80
GAIN (I
MOD
/I
MODMON
)
TEMPERATURE (
C)
I
MOD
= 40mA,
I
BIAS
= 50mA
I
MOD
= 10mA,
I
BIAS
= 10mA
Bias-Current Monitor Gain
vs. Temperature
0
10
20
30
40
50
60
-40
-20
0
20
40
60
80
GAIN (I
BIAS
/I
BIASMON
)
TEMPERATURE (
C)
I
MOD
= 40mA,
I
BIAS
= 50mA
I
MOD
= 10mA,
I
BIAS
= 10mA
I
APCSET
vs
. R
APCSET
0
0.5
1
1.5
2
1
10
100
I
APCSET
(mA)
R
APCSET
(K
)
V
CC
= 3.3V, T
A
= 25
C, unless otherwise stated.
Note 1.
I
BIAS
and I
MOD
must never exceed 100mA and 90mA, respectively.
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