SY88053AL
3.3V, 12.5Gbps Limiting Post Amplifier
with Programmable Decision Threshold
General Description
The SY88053AL, limiting post amplifier is designed for
use in fiber-optic receivers for applications up to
12.5Gbps. It features a decision threshold control that
can be used for offset compensation or to optimize the
Bit Error Rate (BER) in noisy applications as WDM
where optical amplifiers such as EDFAs and Raman
amplifier are used. This device connects to typical
transimpedance amplifiers (TIAs). The signal from TIAs
can contain significant amounts of noise unevenly
distributed between its top and bottom rails due to the
Amplified Spontaneous Emission (ASE) noise generated
by the optical amplifiers. 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. An external voltage applied at the
VTHP pin on the SY88053AL will move the crossing
point up and down, from 20% to 80%, to achieve the
best BER.
The SY88053AL operates from a single +3.3V power
o
o
supply, over temperatures ranging from –40 C to +85 C,
and can detect and amplify signals up to 12.5Gbps and
amplitude as low as 15mV
PP
.
The SY88053AL generates 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 set by LOS
LVL
and
de-asserts low otherwise. The enable 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 implement the squelch function that maintains output
stability under a loss-of-signal condition.
All support documentation can be found on Micrel’s web
site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
Single 3.3V power supply
Up to 12.5Gbps operation
Programmable Decision Threshold
Low-noise CML data outputs
TTL /EN input
Programmable LOS level (LOS
LVL
)
Available in a tiny 3mm x 3mm QFN package
Applications
•
•
•
•
WDM Systems
10xGigabit Ethernet, 8xFibre Channel
SONET/SDH:OC192 – STM64
Low-gain TIA interface
Markets
•
Datacom/telecom
•
Optical transceiver
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
May 2010
M9999-052610-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88053AL
Typical Application Circuit
Fixed Decision Threshold
Programmable Decision Threshold
Ordering Information
Part Number
SY88053ALMG
SY88053ALMGTR
Note:
1. Tape and Reel.
(1)
Package
Type
QFN-16
QFN16
Operating
Range
Industrial
Industrial
Package Marking
053A with Pb-Free bar line indicator
053A with Pb-Free bar line indicator
Lead Finish
NiPdAu Pb-Free
NiPdAu Pb-Free
Pin Configuration
16-Pin (3mm x 3mm) QFN
May 2010
2
M9999-052610-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88053AL
Pin Description
Pin Number
2, 3
5
6
7
8
10, 11
13, 14
15
Pin Name
DIN, /DIN
VTHN
VTHREF
LOS
LOSLVL
/DOUT, DOUT
NC, NC
/EN
Type
Data Input
DC Input
DC Output
Open-collector
TTL output
DC Input
CML Output
No Connection
TTL Input
Pin Function
Differential data inputs. Each input is internally terminated to
approximately VCC – 1.3V by a 50Ω
resistor. AC-Couple
input signals.
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.
Loss-of-Signal: asserts high when the data input amplitude falls below
the threshold set by LOS
LVL
.
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.
Differential data outputs. Unused output should be terminated 50
Ω-to-
VCC.
Unused pins.
/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. Exposed pad must be soldered (or equivalent) to the
same potential as the ground pins.
Positive power supply. Bypass with 0.1µF||0.01µF low ESR capacitors.
0.01µF capacitors should be as close as possible to VCC pins.
16
1,4
9, 12
VTHP
GND
VCC
DC Input
Ground
Power Supply
May 2010
3
M9999-052610-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88053AL
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
) ....................................... 0V to +4.0V
Input Voltage (DIN, /DIN) ............ (V
CC
-1.0V) to (V
CC
+0.5V)
Output Current (I
OUT
) ............................................... ±25mA
EN Voltage .............................................................0 to V
CC
LOS
LVL
Voltage .......................................... V
CC
-1.3V 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
(3)
Package Thermal Resistance
QFN
(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
45
45
VTHP and VTHN tied to GND
1.25
50
50
55
55
Condition
Note 4
V
CC
-1.3
V
CC
-0.020 V
CC
-0.005
Min
Typ
50
Max
70
V
CC
V
CC
±80
Units
mA
V
V
V
mV
V
Ω
Ω
V
CC
-0.400 V
CC
-0.350 V
CC
-0.300
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
V
OH
V
OL
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 unless otherwise stated.
4. VTHN and VTHP are both at GND potential and with outputs Q and /Q loaded and with the device enabled.
5. VTHN connected to VTHREF and DC voltage between 0V and 2.4V applied to VTHP. Input at DIN is between 15mVpp to 60mVpp. See Figure
on page 7
Condition
Min
Typ
Max
20
Units
%
%
V
Note 5
80
2.0
0.8
V
IN
= 2.7V
V
IN
= V
CC
V
IN
= 0.5V
Sourcing 100µA
Sinking 2mA
-0.3
2.4
0.5
20
100
/EN Input HIGH Voltage
/EN Input LOW Voltage
/EN Input HIGH Current
/EN Input LOW Current
LOS Output HIGH Level
LOS Output LOW Level
V
µA
µA
mA
V
V
May 2010
4
M9999-052610-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88053AL
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
HSY
L
LOS
AM
LOS
DM
HSY
M
LOS
AH
LOS
DH
HSY
H
B
-3dB
A
V(Diff)
S
21
Notes:
6. Amplifier in limiting mode. Input is a 200MHz square wave.
7. Deterministic jitter measured using 10 Gbps K28.5 pattern, V
ID
= 60mV
PP
.
8. Random jitter measured using 10Gbps K28.7 pattern, V
ID
= 60mV
PP
.
9. 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.
10. 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 on 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.
11. 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 6
Note 7
Note 8
Min
Typ
25
10
1
Max
35
Units
ps
ps
PP
ps
RMS
15
Note 6
Note 11
Note 11
R
LOSLVL
= 10kΩ, Note 9
R
LOSLVL
= 10kΩ, Note 9
R
LOSLVL
= 10kΩ, Note 10
R
LOSLVL
= 5kΩ, Note 9
R
LOSLVL
= 5kΩ, Note 9
R
LOSLVL
= 5kΩ, Note 10
R
LOSLVL
= 100Ω, Note 9
R
LOSLVL
= 100Ω, Note 9
R
LOSLVL
= 100Ω, Note 10
2
2
35
2
10
5
600
700
100
100
14
20
3.0
21
30
3.0
55
76
3.0
10
38
26
32
1800
800
500
500
25
6
40
6
85
6
mV
PP
mV
PP
ns
ns
mV
PP
mV
PP
dB
mV
PP
mV
PP
dB
mV
PP
mV
PP
dB
GHz
dB
dB
May 2010
5
M9999-052610-A
hbwhelp@micrel.com
or (408) 955-1690
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