SY88353BL
3.3V, 3.2 Gbps Limiting Post Amplifier with
Programmable Decision Threshold
General Description
The SY88353BL limiting post amplifier is designed for
use in fiber-optic receivers, and is specially optimized for
WDM applications where optical amplifiers such as
EDFAs and Raman amplifier are used. The device
connects to typical transimpedance amplifiers (TIAs).
The linear signal from TIAs can contain significant
amounts of noise that is unevenly distributed between
top and bottom rails due to the ASE noise generated by
the optical amplifiers, crosstalk, or non-linear effect in
the fiber. In order to optimize the BER in such noisy
conditions, the decision threshold between bit 1 and bit
0, needs to be moved to the rail that contains less noise.
The SY88353BL features a pin at which an external
voltage can be applied to move the crossing point up
and down, from 20% to 80%, for BER optimization
purposes.
The SY88353BL operates from a single +3.3V power
o
o
supply, over temperatures ranging from –40 C to +85 C.
Signals with data rates from 155Mbps up to 3.2Gbps,
and as small as10mV
pp
, can be amplified to drive
devices with CML or PECL inputs.
The SY88353L features a Loss-of-Signal (LOS) open-
collector TTL output. A programmable Loss-of-Signal
level set pin (LOS
LVL
) sets the sensitivity of the input
amplitude detection. LOS asserts high if the input
amplitude falls below the threshold sets by LOS
LVL
and
de-asserts low otherwise. The enable bar input (/EN)
de-asserts the true output signal without removing the
input signal. The LOS output can be fed back to the /EN
input to maintain output stability under a loss-of-signal
condition. Typically, 3.3dB LOS hysteresis is provided to
prevent chattering.
All support documentation can be found on Micrel’s web
site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
Single 3.3V power supply
Fast LOS release/assert
155Mbps to 3.2Gbps operation
Low-noise CML data outputs
Chatter-free Open-Collector TTL loss-of-signal (LOS)
output.
TTL /EN input
Programmable LOS level set (LOS
LVL
)
Programmable Decision Threshold
Available in a tiny 3mm x 3mm MLF™ package
Applications
•
•
•
•
WDM Systems
Gigabit Ethernet, 1X and 2X Fibre Channel
SONET/SDH: OC-3/12/24/48 – STM1/4/8/16
Low-gain TIA interface
Markets
•
Datacom/telecom
•
Optical transceiver
MLF and
MicroLeadFrame
are trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2006
1
M9999-020706-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88353BL
Typical Application Circuit
Programmable Decision Threshold
Fixed Decision Threshold
Ordering Information
Part Number
SY88353BLKG
SY88353BLKGTR
Notes:
1. Tape and Reel.
(1)
Package
Type
MLF-16
MLF16
Operating
Range
Industrial
Industrial
Package Marking
SY88353BL with Pb-Free bar line indicator
SY88353BL with Pb-Free bar line indicator
Lead Finish
NiPdAu Pb-Free
NiPdAu Pb-Free
Pin Configuration
16-Pin MLF™ (MLF-16)
February 2006
2
M9999-020706-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88353BL
Pin Description
Pin Number
1
4
5
Pin Name
DIN
/DIN
VTHN
Type
Data Input
Data Input
DC Input
True data input.
Complementary data input.
Tie this pin to pin 6 (VTHREF) and apply a DC voltage on pin 16
(VTHP) for signal crossing adjustment. Connect to ground if no
crossing adjustment is needed.
1.25V Reference voltage (referenced to ground) for decision
threshold adjustment.
Open-collector TTL
output
CML Output
CML Output
Input
Loss-of-Signal: asserts high when the data input amplitude falls
below the threshold set by LOS
LVL
.
Complementary data output.
True data output.
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.
/Enable: This input enables the outputs when it is LOW. Note
that this input is internally connected to a 25kΩ pull-up resistor
and will default to a logic HIGH state if left open.
Apply a DC voltage from 0 to 2.4V to adjust the signal crossing
level when pin 5 (VTHN) is tied to pin 6 (VTHREF). 1.25V sets
the crossing close to 50%. Connect to ground if no crossing
adjustment is needed.
Device ground.
Positive power supply.
Pin Function
6
7
9
12
14
VTHREF
LOS
/DOUT
DOUT
LOSLVL
15
/EN
TTL Input: Default is
HIGH.
DC Input
16
VTHP
2, 3, 10, 11
8, 13
GND
VCC
Ground
Power Supply
February 2006
3
M9999-020706-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88353BL
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
) .......................................... 0V to +4.0V
Input Voltage (DIN, /DIN) ......................................... 0 to V
CC
Output Current (I
OUT
)
Continuous ...........................................................±25mA
/EN Voltage............................................................... 0 to V
CC
V
REF
Current............................................. -800µA to +500µA
LOS
LVL
Voltage .................................................... V
REF
to V
CC
Lead Temperature (soldering, 20sec.) ..................... +260°C
Storage Temperature (T
s
) ......................... –65°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
CC
) ............................... +3.0V to +3.6V
Ambient Temperature (T
A
) ..................... –40°C to +85°C
Junction Temperature (T
J
).................... –40°C to +120°C
Supply Voltage (V
CC
).............................. +3.0V to +3.6V
Ambient Temperature (T
A
).................... –40°C to +85°C
(3)
Package Thermal Resistance
MLF™
(θ
JA
) Still-air.................................................. 60°C/W
(ψ
JB
) .............................................................. 33°C/W
DC Electrical Characteristics
V
CC
= 3.0 to 3.6V; T
A
= –40°C to +85°C, typical values at V
CC
= 3.3V, T
A
= 25°C.
Symbol
I
CC
LOS
LVL
V
OH
V
OL
V
OFFSET
V
THREF
Z
0
Z
I
Parameter
Power Supply Current
LOS
LVL
Voltage
DOUT, /DOUT HIGH Voltage
DOUT, /DOUT LOW Voltage
Differential Output Offset
Decision Threshold Reference
Voltage
Single-Ended Output Impedance
Single-Ended Input Impedance
40
40
1.25
50
50
60
60
Condition
No output load
V
CC
-1.3
V
CC
-0.020 V
CC
-0.005
Min
Typ
45
Max
62
V
CC
V
CC
±80
Units
mA
V
V
V
mV
V
Ω
Ω
V
CC
-0.475 V
CC
-0.400 V
CC
-0.350
TTL DC Electrical Characteristics
V
CC
= 3.0 to 3.6V; T
A
= –40°C to +85°C, typical values at V
CC
= 3.3V, T
A
= 25°C.
Symbol
Parameter
Output signal Crossing Range
Lower Limit
Output signal Crossing Range
Upper Limit
V
IH
V
IL
I
IH
I
IL
I
CEX
V
OL
/EN Input HIGH Voltage
/EN Input LOW Voltage
/EN Input HIGH Current
/EN Input LOW Current
LOS Output Leakage Current
LOS Output LOW Level
V
IN
= 2.7V
V
IN
= V
CC
V
IN
= 0.5V
V
OUT
= V
CC
Sinking 2mA
-0.3
100
0.5
Condition
VTHN connected to VTHREF and 0-
2.4V applied to VTHP.
20
≤
DIN
≤
100(mVpp), see Figure on
page 6.
Min
Typ
Max
20
Units
%
%
V
80
2.0
0.8
20
100
V
µA
µA
mA
µA
V
February 2006
4
M9999-020706-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88353BL
AC Electrical Characteristics
V
CC
= 3.0 to 3.6V; R
Load
= 50Ω to V
CC
; T
A
= –40°C to +85°C, typical values at V
CC
= 3.3V, T
A
= 25°C.
Symbol
t
r
, t
f
t
JITTER
V
ID
V
OD
T
OFF
T
ON
LOS
AL
LOS
DL
HYS
L
LOS
AM
LOS
DM
HYS
M
LOS
AH
LOS
DH
HSY
H
B
-3dB
A
V(Diff)
S
21
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 ratings 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. Package Thermal Resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB.
ψ
JB
uses a 4-
layer and
θ
JA
in still-air number, unless otherwise stated.
4. Amplifier in limiting mode. Input is a 200MHz square wave.
5. Deterministic jitter measured using 2.5Gbps K28.5 pattern, V
ID
= 10mV
PP
.
6. Random jitter measured using 2.5Gbps K28.7 pattern, V
ID
= 10mV
PP
.
7. See “Typical Operating Characteristics” for a graph showing how to choose a particular R
LOSLVL
for a particular LOS assert and its associated de-
assert amplitude.
8. This specification defines electrical hysteresis as 20log (LOS De-Assert/LOS Assert). The ratio between optical hysteresis and electrical
hysteresis is found to vary between 1.5 and 2, depending upon the level of received optical power and ROSA characteristics. Based upon that
ratio, the optical hysteresis corresponding to the electrical hysteresis range 1dB-4.5 dB, shown in the AC characteristics table, will be 0.5dB-3dB
Optical Hysteresis.
9. In real world applications, the LOS Release/Assert time can be strongly influenced by the RC time constant of the AC-coupling cap and the 50Ω
input termination. To keep this time low, use a decoupling cap with the lowest value that is allowed by the data rate and the number of
consecutive identical bits in the application. Typical values are in the range of 0.001µF to 1.0µF.
Parameter
Output Rise/Fall Time
(20% to 80%)
Deterministic
Random
Differential Input Voltage Swing
Differential Output Voltage
Swing
LOS Release Time
LOS Assert Time
Low LOS Assert Level
Low LOS De-assert Level
Low LOS Hysteresis
Medium LOS Assert Level
Medium LOS De-assert Level
Medium LOS Hysteresis
High LOS Assert Level
High LOS De-assert Level
High LOS Hysteresis
3dB Bandwidth
Differential Voltage Gain
Single-Ended Small-Signal Gain
Condition
Note 4
Note 5
Note 6
Min
Typ
60
15
5
Max
100
Units
ps
ps
PP
ps
RMS
20
Note 4
Note 9
Note 9
R
LOSLVL
= 15kΩ, Note 7
R
LOSLVL
= 15kΩ, Note 7
R
LOSLVL
= 15kΩ, Note 8
R
LOSLVL
= 5kΩ, Note 7
R
LOSLVL
= 5kΩ, Note 7
R
LOSLVL
= 5kΩ, Note 8
R
LOSLVL
= 100Ω, Note 7
R
LOSLVL
= 100Ω, Note 7
R
LOSLVL
= 100Ω, Note 8
700
800
2
2
9
13
3.2
17
25
3.3
47
70
3.4
2.0
38
26
32
1800
950
10
10
mV
PP
mV
PP
µs
µs
mV
PP
mV
PP
dB
mV
PP
mV
PP
dB
mV
PP
mV
PP
dB
GHz
dB
dB
February 2006
5
M9999-020706-A
hbwhelp@micrel.com
or (408) 955-1690
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