1
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
DESCRIPTION
■Single 3.3V power supply
■Up to 2.7Gbps operation
■Rise/Fall times: < 75ps
■Independent programmable laser modulation and
bias currents
■Bias current to 100mA and modulation current to
90mA
■Automatic average laser power control
■Bias and modulation current monitors
■Operating temperature range of –40°C to +85°C
■Complies with ANSI, ITU, and Bellcore SDH/SONET
specifications
■Available in DIE form and 32-pin (5mm ××
××
× 5mm)
EPAD-MLF™ package
FEATURES
3.3V, 2.7Gbps SDH/SONET
LASER DRIVER WITH AUTOMATIC
POWER CONTROL SY88952L
APPLICATIONS
■OC-48 transceivers and transponders
■SONET/SDH transmission system
■Add drop mux
■Metro area network
■2.5Gbps optical transmitter
■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 IMOD. It does not enable/disable IBIAS.
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. IBIAS and IMOD still flow under
this condition.
2. /FAIL asserts when IBIASMAX or IMODSET are too
high (implying IBIAS or IMOD will be too high). All currents
will shut off under this condition.
MLF and
Micro
LeadFrame 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 (IBIAS).
11 BIASMON Bias Current Monitor: Sinks current that is proportional to IBIAS, (IBIAS /40). An external current
path must exist to VCC.
31 BIASMAX A resistor (RBIASMAX) connected to ground sets the maximum bias current.
See “Typical Operating Characteristics” (IBIAS vs. RBIASMAX).
26 SLOW Connect a capacitor (CSLOW) to ground to provide a slow-start.
5, 6 CLK,/CLK Differential Clock Input. 75KΩ pull-down on CLK, 75kΩ pull-up and 75kΩ pull-down on /CLK.
2, 3 D, /D Differential Data Input. 75KΩ pull-down on D, 75kΩ pull-up and 75kΩ pull-down on /D.
9 EN TTL Input with 75kΩ pull-up: Default HIGH for normal operation; LOW to disable modulation
current.
8 LATCH TTL Input with 75kΩ pull-up: Default HIGH for latched (clocked) data; LOW for direct data.
25 MD Connect this pin to a monitor photodiode anode, a resistor (RAPCSET) and a capacitor (CAPCSET).
This sets the desired average optical power.
19, 20, 22, 23 Q, /Q Differential Output: Modulation current output (IMOD).
12 MODMON Modulation Current Monitor: Sinks current that is proportional to IMOD, (IMOD /45). An external
current path must exist to VCC.
30 MODSET A resistor (RMODSET) connected to ground sets the modulation current.
See “Typical Operating Characteristics” (IMOD vs. RMODSET).
13 /FAIL TTL Open-Collector Output: Connect a 5kΩ resistor to VCC. 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
910111213141516
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 MLF™ (MLF-32)
Note 1. L = LOW, H = HIGH, X = don't care.
Note 2. H = IOUT ≤ IMOD_OFF.
D /D EN OUT(2) /OUT
L HHHL
HLHLH
XXLHL
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 TA = +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 (VCC) ..................................... +0V to +7.0V
Input Voltage (VIN) ............................................ +0V to VCC
Output Current (IOUT)...............................................100mA
Lead Temperature (soldering, 10 sec.) ..................... 300°C
Storage Temperature (TS) .......................–65°C to +150°C
Operating Ratings(2, 3)
Supply Voltage (VCC) .................................. +3.0V to +3.6V
Ambient Temperature (TA).........................–40°C to +85°C
Junction Temperature (TJ) ........................................ 120°C
Package Thermal Resistance
MLF™
(θJA) still-air .....................................................34°C/W
(ψJB) still-air.....................................................19°C/W
VCC = 3.0V to 3.6V; VEE = GND; RLOAD = 5Ω; TA = –40°C to +85°C
Symbol Parameter Condition Min Typ Max Units
ICC Supply Current Note 4 85 mA
IBIAS Bias Current Range Note 5 1 100 mA
IMOD Modulation Current Range Note 5 190mA
IMOD_OFF Modulation Off Current Note 6 750 µA
VID Differential Input Voltage 200 1600 mVPP
VICMR Common Mode Range
V
CC
–1.49 V
CC
–V
ID
/4
V
VIH TTL Input HIGH Voltage 2.0 VCC V
VIL TTL Input LOW Voltage 0.8 V
VOL /FAIL Output LOW Voltage Note 6 0.5 V
IOH /FAIL Output Leakage Current Note 7 100 µA
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 IBIAS and IMOD output currents.
5. Voltage at Q, /Q must not drop below VCC –1.5V. Voltage BIAS, MODMON and BIASMON must not drop below VCC –2V.
6. EN = LOW.
7. IOL = +2mA.
8. VOH = 3.6V.
DC ELECTRICAL CHARACTERISTICS
4
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
VCC = 3.0V to 3.6V; VEE = GND; TA = –40°C to +85°C; typical values @VCC = 3.3V, TA = 25°C, IMOD = 40mA, IBIAS = 50mA, RLOAD = 5Ω
Symbol Parameter Condition Min Typ Max Units
CID Maximum Consecutive 80 bits
Identical Digits
PWD Pulse Width Distortion Note 10, 11 50 ps
tSLatch Set-Up Time 40 ps
tHLatch Hold Time 40 ps
tr, tfOutput 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
tCLK = 400ps
tH
tS
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
IMOD (mA)
RMODSET (Ω)
IMOD vs. RMODSET
0
20
40
60
80
100
120
140
160
10 100 1000 10000
IBIAS (mA)
RBIASMAX (Ω)
IBIAS vs. RBIASMAX Modulation-Current Monitor Gain
vs. Temperature
0
10
20
30
40
50
60
-40 -20 0 20 40 60 80
GAIN (IMOD/IMODMON)
TEMPERATURE (°C)
IMOD = 40mA,
IBIAS = 50mA
IMOD = 10mA,
IBIAS = 10mA
Bias-Current Monitor Gain
vs. Temperature
0
10
20
30
40
50
60
-40 -20 0 20 40 60 80
GAIN (IBIAS/IBIASMON)
TEMPERATURE (°C)
IMOD = 40mA,
IBIAS = 50mA
IMOD = 10mA,
IBIAS = 10mA
IAPCSET vs. RAPCSET
0
0.5
1
1.5
2
1 10 100
IAPCSET (mA)
RAPCSET (KΩ)
VCC = 3.3V, TA = 25°C, unless otherwise stated.
Note 1. IBIAS and IMOD must never exceed 100mA and 90mA, respectively.
6
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
BLOCK DIAGRAM
DQ
0
1
MUX
X40
I
MOD
45 Failure
Detect
D
CLK
EN
BIASMAX
V
REF
/FAIL
MD
BIAS
Q
/Q
V
CC
MODMON
BIASMON
LATCH
I
BIAS
40
R
BIAS MAX
R
MODSET
RD
R
APCSET
C
APCSET
V
CC
X40
SLOW
5kΩ
C
SLOW
MODSET
V
CC
100Ω
V
CC
100Ω
7
SY88952L
Micrel, Inc.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
32 LEAD EPAD-
Micro
LEADFRAME™ (MLF-32)
Package
EP- Exposed Pad
Die
CompSide Island
Heat Dissipation
Heavy Copper Plane
Heavy Copper Plane
V
EE
V
EE
Heat Dissipation
PCB Thermal Consideration for 32-Pin MLF™ Package
(Always solder to equivalent or PCB)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.
