1
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
DESCRIPTION
■Up to 2.5Gbps operation
■25mA peak drive current
■Separate modulation control
■Separate output enable for laser safety
■Differential inputs for data
■75KΩ input pulldown resistor
■Designed for use with SY88923, SY88904 or SY88905
■Available in a tiny 10-pin (3mm) MSOP
The SY88922 is a high-speed current switch for driving
a semiconductor laser diode in optical transmission
applications. The output current, or modulation current
IMOD, is DC current controlled by IRSET, current through
the resistor RSET. The output OUT is HIGH when output
enable is HIGH.
The device incorporates complementary open collector
outputs with a capability of driving peak current of 25mA.
The resistor REXT must be placed between /OUT and
VCC to dissipate the worst case power. RSER is
recommended to compensate for laser diode matching
issues.
The SY88922 utilizes the high performance bipolar
ASSET™ technology.
FEATURES
SDH/SONET 2.5Gbps
LASER DIODE DRIVER
BLOCK DIAGRAM
SY88922
■1.25Gbps Gigabit Ethernet
■531Mbps and 1062Mbps Fibre Channel
■622Mbps SONET
■Gigabit Interface Converter
■2.5Gb/s SDH/SONET
APPLICATIONS
D
IN
V
CC
R
EXT
OUT
OUT
R
SER
to Laser Diode
D
IN
Modulation Control
Internal Logic
BIAS
Control
EN
I
MOD
V
REF
40X
R
SET
GND
V
CC
GND
R
SET
Rev.: D Amendment: /0
Issue Date: September 2006
2
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
PACKAGE/ORDERING INFORMATION
10-Pin MSOP (K10-1)
Ordering Information
Package Operating Package Lead
Part Number Type Range Marking Finish
SY88922KC K10-1 Commercial 922 Sn-Pb
SY88922KCTR(1) K10-1 Commercial 922 Sn-Pb
SY88922KG K10-1 Commercial 922 with Pb-Free
Pb-Free bar-line indicator NiPdAu
SY88922KGTR(1) K10-1 Commercial 922 with Pb-Free
Pb-Free bar-line indicator NiPdAu
Note:
1. Tape and Reel.
1/EN
D
IN
/D
IN
V
REF
R
SET
10 V
CC
OUT
/OUT
GND
GND
9
8
7
6
2
3
4
5
MSOP
K10-1
Pin Function
VCC Most positive power supply input, +5V for PECL
operation.
GND Ground
DIN, /DIN These differential PECL 100K compatible inputs
receive NRZ data.
/EN This PECL 100K compatible input enables
Laser Driver. Modulation current goes to zero
when asserted HIGH.
OUT, /OUT Open collector outputs from the modulation
buffer drive these differential current outputs.
VREF Voltage reference for use with RSET.
RSET An external resistor sets up the source current
for modulation Imod.
DD/EN OUT(2) /OUT
LHLHL
HLLLH
XXHHL
Notes:
1. L = LOW, H = HIGH, X = don't care
2. H = IOUT = 0mA
PIN NAMES TRUTH TABLE(1)
3
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
Symbol Rating Value Unit
VCC Power Supply Voltage 0 to +7.0 V
VIInput Voltage 0 to VCC V
IOOutput Current 25 mA
TAOperating Temperature Range 0 to +85 °C
Tstore Storage Temperature Range –55 to +125 °C
TJMaximum Operating Junction Temperature +125 °C
Ptot Power Dissipation 250 mW
ABSOLUTE MAXIMUM RATINGS(1)
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.
Symbol Rating Value Unit
VCC Power Supply Voltage +4.5 to +5.5 V
REXT Resistor to Dissipate Power 10 to 50 Ω
RSER Laser Diode Serial Resistor 0 to 50 Ω
RSET Resistor to Adjust Current 1500 to 50,000 Ω
θJA Thermal Resistance of Package to Ambient(2) 113 °C/W
COUT Capacitance on OUT + /OUT 2.5 typical pf
OPERATIONING CONDITIONS(1)
Notes:
1. The voltage drop across REXT and RSER plus Laser Diode should not be greater than 2V.
2. Still air without heatsink.
TA = 0°CTA = +25°CTA = +85°C
Symbol Parameter Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit
VIH Input HIGH Voltage
V
CC
–1165 —V
CC
–880 V
CC
–1165 —V
CC
–880 V
CC
–1165 —V
CC
–880
mV
(DIN, /DIN, /EN)
VIL Input LOW Voltage
V
CC
–1810 —V
CC
–1475 V
CC
–1810 —V
CC
–1475 V
CC
–1810 —V
CC
–1475
mV
(DIN, /DIN, /EN)
VREF Reference Voltage — 3.12 — — 3.00 — — 2.80 — V
IIL Input LOW Current(1) 0.5 — — 0.5 — — 0.5 — — uA
(DIN, /DIN, /EN)
IIH Input HIGH Current — — 100 — — 100 — — 100 uA
(DIN, /DIN, /EN)
ICC Supply Current(2) —1625 —16 25 — 16 25 mA
IOL Output LOW Current — — 500 — — 500 — — 500 uA
(/EN = HIGH)
IOUT Modulation Current 5 15 25 5 15 25 5 15 25 mA
IRSET Modulation Control 0.125 — 0.625 0.125 — 0.625 0.125 — 0.625 mA
ARSET =IOUT/IRSET 30 38 44 30 38 44 30 38 44 —
Notes:
1. VI = VIL(Min.)
2. IMOD = 25mA.
DC ELECTRICAL CHARACTERISTICS
GND = 0V; VCC = +5.0V ±10%; TA = 0°C to + 85°C
4
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
TA = 0°CTA = +25°CTA = +85°C
Symbol Parameter Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit Conditions
tpd DPropagation Delay — — 1000 — 500 1000 — — 1000 ps
DIN - OUT
tpd EN Propagation Delay — — 1000 — 450 1000 — — 1000 ps
/EN - OUT
trRise/Fall Time — — 160 — 110 160 — — 160 ps Load = 25Ω
tf(20% to 80%)
IOR Output Current Ringing(2) ——10——10——10%
AC ELECTRICAL CHARACTERISTICS(1)
IMOD =10mA; GND = 0V; VCC = +5V ±10%; TA = 0°C to + 85°C.
Notes:
1. REXT = RSER = 25Ω ±1%, RSER connects to VCC directly without Laser Diode.
2. IOH = 5 to 25mA
PERFORMANCE CURVES
10
20
25
30
I
O
(mA)
I
O
and
R
SET
0.0
0.0
15
5
4.0K 6.0K 8.0K 10K
2.0K
R
SET
(ohm)
12K
5
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION
DIN
DIN
GBIC Terminal
EN
RX_DATA–
RX_DATA+
TX_DATA–
TX_DATA+
RX_LOS
ENABLE/DISABLE
200Ω
VCC GND
200Ω
68Ω
68Ω
VCC
EN
VCC GND
VCC GND
DOUT
DOUT
130Ω
130Ω
82Ω
82Ω
VCC
OUT
OUT
DIN
24Ω
VCC
REXT
RSER
Laserdiode
Photodiode
VREF
MD
IBIAS
LOSOUT
LOSIN
DIN
LOSLVL
IBIAS SET
SY88905
20kΩ
20kΩ
1000pF
BLM21A102S
Laser
Module
IBIAS FB
IPIN SET
LOS
VREF
SY88923
0.1µF
20kΩ
0.1µF
130Ω
130Ω
82Ω
82Ω
VCC
20kΩ
SY88922
VREF RSET
The value of RSER
depends on the Laser Diode.
VCC
VCC
6
SY88922
Micrel, Inc.
M9999-091906
hbwhelp@micrel.com or (408) 955-1690
10 LEAD MSOP (K10-1)
Rev. 00
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 data sheet 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.
