SY88232L/AL
2.5Gbps Laser Diode Driver with Integrated
Limiting Amplifier
General Description
The SY88232L is a single supply 3.3V integrated laser
driver and post amplifier for telecom/datacom applications
with data rates from 155Mbps up to 2.5Gbps. The driver
can deliver modulation current up to 85mA, and provides a
high compliance voltage that makes it suitable for high-
current operation with the laser DC-coupled to it. The post
amplifier can detect signals with amplitude as low as
5mV
PP
.
The SY88232AL is a version of the SY88232L without 50Ω
termination resistors at the inputs of the driver and the post
amplifier. The SY88232AL is to be used specially in SFF
modules mounted on mother boards which have
preinstalled terminations. Removing post amplifier input
terminations will allow for receiver gain control.
All support documentation can be found on Micrel’s web
site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
2.4V minimum laser compliance voltage
Operation up to 2.5Gbps
Integrated APC circuit
Modulation current up to 85mA
Bias current up to 70mA
Bias, Modulation, and power monitoring
High input sensitivity post amplifier, 5mV
PP
Programmable LOS level
Available in 32-pin (5mm x 5mm) QFN package
Applications
•
Multi-rate burst mode applications: A-PON, B-PON,
G-PON, E-PON, GE-PON
___________________________________________________________________________________________________________
Typical Application
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2009
M9999-063009-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88232L/AL
Ordering Information
(1)
Part Number
SY88232LMG
SY88232LMGTR
SY88232ALMG
SY88232ALMGTR
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= +25°C, DC Electricals only.
2. Tape and Reel.
(2)
(2)
Voltage
3.3V
3.3V
3.3V
3.3V
Temperature
Range
–40° to +85°C
–40° to +85°C
–40° to +85°C
–40° to +85°C
Package Type
QFN-32
QFN-32
QFN-32
QFN-32
Package Marking
SY88232L with
Pb-Free bar-line indicator
SY88232L with
Pb-Free bar-line indicator
SY88232A with
Pb-Free bar-line indicator
SY88232A with
Pb-Free bar-line indicator
Lead
Finish
NiPdAu
Pb-Free
NiPdAu
Pb-Free
NiPdAu
Pb-Free
NiPdAu
Pb-Free
June 2009
2
M9999-063009-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88232L/AL
Pin Configuration
32-Pin QFN
Pin Description
Pin Number
1
2
3
Pin Name
LOS/SD_SEL
LOSLVL
LOS/SD
Pin Function
LOS or SD selection, TTL input. Set high, connect to VCC, or leave open to select LOS. Set low
or connect to GND to select SD.
Loss-of-Signal Level Set. A resistor from this pin to V
CC
sets the threshold for the data input
amplitude at which LOS will be asserted.
Loss-of-Signal (LOS selected): asserts high when the data input amplitude falls below the
threshold set by LOS
LVL
.
Signal Detect (SD selected): asserts low when the data input amplitude falls below the threshold
set by LOS
LVL
.
4
JAM
Active low TTL/CMOS. Internally pulled-up with 75kΩ.
Connect to GND or apply a low level
signal (<0.8 V) to enable the post amp output. Can be shorted to LOS/SD (pin 3) to create a
squelch function. The polarity of this input follows the polarity of LOS/SD.
SY88232L: Driver Non-inverting input data. Internally terminated with 50
Ω to a reference
voltage.
SY88232AL: Driver Non-inverting input data. No internal termination.
7
DIN-
SY88232L: Driver inverting input data. Internally terminated with 50
Ω to a
reference voltage.
SY88232AL: Driver inverting input data. No internal termination.
9
/TXDIS
Transmitter Complementary Fast Disable. TTL input. The transmitter is enabled when this pin is
asserted High or left open and disabled when this pin is asserted Low. A 6.3kΩ
resistor must be
installed between pin 10 and GND if /TXDIS is used as TTL input.
Transmitter Fast Disable. TTL Input. The transmitter is enabled when this pin is asserted Low
and disabled when this pin is asserted High or left open. A 6.3kΩ
resistor must be installed
between pins 9 and GND if TXDIS is used as TTL input.
Active low TTL/CMOS. Internally pulled-up. Pull-down with a 22kΩ
or lower resistance or apply
a low level signal (<0.8V) to enable bias and modulation. Keep floating or apply a high level
(>2V) to disable.
6
DIN+
10
TXDIS
11
/TXEN
June 2009
3
M9999-063009-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88232L/AL
Pin Description
(continued)
Pin Number
12
13
14
Pin Name
APCSET
MODSET
BIASMAX
Pin Function
Bias current setting and control. The bias current is set by installing an external resistor from this
pin to ground or using a current source. Connect a 50kΩ
resistor to GND for open loop operation.
Modulation current setting and control. The modulation current is set by installing an external
resistor from this pin to ground or using a current source.
Install a resistor between this pin and GND to set the maximum bias current for the closed loop
operation. The APC loop controls the bias current up to the level of BIASMAX. When the bias
current reaches the maximum value set through this pin, the driver continues to sink a current
equal to this maximum. For open loop operations, this pin sets the bias current.
Modulation Current Monitor. Provides a current, which represents 1/100 of the modulation
current. Install a resistor between this pin and GND to convert that current to a voltage
proportional to the modulation current.
Inverted modulation current output. Provides modulation current when input data is negative.
Non-inverted modulation current output. Provides modulation current when input data is positive.
Bias current output, sources current when /TXDIS is high. Connect to the cathode of the laser
through a resistor.
Input from the laser monitoring photodiode. Connect to the anode of the laser photodiode for APC
operation.
Bias Monitor. Provides a current, which represents 1/50 of the bias current. Install a resistor
between this pin and GND to convert that current to a voltage.
Received Signal Strength Indicator. Install a resistor from this pin to GND to get a voltage
proportional to the received signal.
Indicates APC failure when High. Active High TTL/CMOS. Use a 10kΩ
Pull up.
SY88232L:
Post amplifier Non-inverting input data. Internally terminated with 50
Ω to a reference
voltage.
SY88232AL:
Post amplifier Non-inverting input data. No internal termination.
28
30
31
5, 8, 16, 24, 29
17, 20, 32
RIN-
ROUT-
ROUT+
GND
SY88232L:
Driver inverting input data. Internally terminated with 50
Ω to a reference vol
tage.
SY88232AL:
Driver inverting input data. No internal termination.
Post Amplifier Complementary CML data output.
Post Amplifier true CML data output.
Ground. Ground and exposed pad must be connected to the plane of the most negative potential.
Supply Voltage. Bypass with a 0.1µF//0.01µF low ESR capacitor as close to VCC pin as possible.
15
MODMON
18
19
21
22
23
24
25
27
MOD-
MOD+
BIAS
MD
BIASMON
RSSI
APCFAULT
RIN+
June 2009
4
M9999-063009-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88232L/AL
Truth Tables
DIN+
DIN-
/TXEN
MOD+
(2)
MOD-
Laser
Output
(3)
Power
L
H
L
(1, 3)
LOS/SD_SEL
H
H
L
L
Function
Selected
LOS
LOS
SD
SD
JAM
L
H
L
H
Output
Enabled
Disabled
Disabled
Enabled
L
H
X
H
L
X
L
L
X
H
L
H
L
H
L
Table 1. Modulation Output Truth Table
Table 3. Post Amp Output Truth Table
/TXEN
L
L
H
BIAS
ON
OFF
OFF
(1)
Table 2. BIAS Output Truth Table
Notes:
1. Assuming /TXDIS = H and a 6.3kΩ
resistor installed between TXDIS
and GND or TXDIS = L and a 6.3kΩ
resistor installed between
/TXDIS and GND
2. I
MOD
= 0 when MOD+ = H.
3. Assuming that the cathode of the laser is connected to MOD+.
June 2009
5
M9999-063009-A
hbwhelp@micrel.com
or (408) 955-1690
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