SY88722VKC Micrel Inc, SY88722VKC Datasheet - Page 5

• Manufacturer Part Number: SY88722VKC
• Description: IC LASR DRVR 622MBPS 5.5V 10MSOP
• Manufacturer: Micrel Inc
• Type: Laser Diode Driver (Fiber Optic)r

Specifications of SY88722VKC

• Number Of Channels: 1
• Data Rate: 622Mbps
• Voltage - Supply: 3 V ~ 3.6 V, 4.5 V ~ 5.5 V
• Current - Supply: 25mA
• Current - Modulation: 30mA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Mounting Type: Surface Mount
• Operating Supply Voltage (typ): 3.3/5V
• Operating Temperature (min): 0C
• Mounting: Surface Mount
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Micrel, Inc.
get anything to work! Where should I start?
V
supply current should be ~48mA, including the SY88722V’s
current and current through the on-board 50
termination network. Excessive current usually means the
power supply leads have been connected backwards. Be
careful of this!
amplitude is large enough to drive the SY88722V PECL
amplitudes, which are typically 800mV (1600mV
a good starting point, and you can reduce or enlarge the
swing from here, depending on your application. Another
not so obvious setting is the modulation current. Ensure
that you’ve set it to output a current! If the SY88722V is
disabled (by shorting J3) or RSET is too large (make sure
to short J1), then you’ll not get an output on the scope.
on the scope, then there’s most likely a trigger setup issue
with the scope. Look on the scope’s front panel and verify
that the instrument is triggered. The Trigger Source button
should be lit if a trigger signal is present. If not, press the
button until the external trigger is selected. Also, try adjusting
the level until a signal is found. If this does not work, verify
the 70004A is set to output a CLK/8 trigger signal as
described in the “Setup for Measurements” section of this
document.
input HIGH?
current through the laser diode during the high state. This
means that, with a resistive load, the output will be LOW
when the input is HIGH. But optically, the output will be
HIGH when the input is HIGH.
M9999-102405
[e-mail] or [phone]
CC
FREQUENTLY ASKED QUESTIONS
I just got my SY88722V evaluation board and I cannot
First, check the power supplies. Remember, the board is
After checking the power supplies, ensure the input
If the above are okay and there’s still nothing displaying
Why is the OUT output LOW when I set the Data
The SY88722V is a laser driver and is meant to conduct
referenced and uses a negative supply. Typical power
pp
equivalent
). This is
5
used for the SY88722V evaluation board. The “Bill of
Materials” section at the end of this document lists the
supplier and component values. We have found this
arrangement to be an excellent starting point.
coplanar construction techniques for high-speed signal paths.
should be matched to within 10ps.
analysis of signal traces.
possible to the device’s power pins.
path. Many interconnects, such as SMA, if not launched
correctly onto the PCB, will exhibit inductive-like resonance
with an abrupt capacitive discontinuity. This discontinuity
will subtract signal from the inputs and outputs, effectively
closing the resulting data eye. The 86100A allows TDR
testing and is a useful tool to help evaluate your PCB.
you.
[e-mail] for assistance.
5%. If in doubt, perform Time Domain Reflectometry (TDR)
Can you suggest a bypass/decoupling scheme?
Figure 2 shows the power supply decoupling scheme
What layout tips do you have?
1. Establish controlled impedance stripline, microstrip or
2. All differential paths are critical timing paths and skew
3. Signal trace impedance should not vary more than
4. Place power supply decoupling capacitors as close as
What is Time Domain Reflectometry (TDR)?
TDR is used to verify impedance continuity along a signal
I still have questions. Who should I contact?
Micrel's HBW Applications helpline is available to assist
Please
call
(408)
SY88722V Evaluation Board
955-1690
or
e-mail