The SY88993AV limiting post amplifier with its high and
wide bandwidth is ideal for use as a post amplifier in fiber-
optic receivers with data rates up to 3.2Gbps. Signals as
small as 4mVp-p can be amplified to drive devices with
CML inputs or AC coupled PECL inputs. The SY88993AV
generates a chatter-free Loss of Signal (LOS) open collector
TTL output.
The SY88993AV incorporates a programmble level detect
function to identify when the input signal has been lost.
This information can be fed back to the /EN input of the
device to maintain stability under loss of signal conditions.
Using LOS
LVL
pin the sensitivity of the level detect can be
adjusted. The LOS
LVL
voltage can be set by connecting a
resistor divider between V
CC
and V
REF
, Figure 3.
V
CC
SY88993AV
LOS
4.7k to 10k
s
Differential PECL inputs for data
s
Single 3.3V or 5V power supply
s
Designed for use with SY88922V and SY88905
s
Available in a tiny 10-pin (3mm) MSOP
APPLICATIONS
s
1.25Gbps and 2.1Gbps Gigabit Ethernet
s
531Mbps, 1062Mbps and 2.5Gbps SONET/SDH
Fibre Channel
s
622Mbps
s
Gigabit interface converter (GBIC)
s
Small form factor trancievers
s
Parallel 10G Ethernet
BLOCK DIAGRAM
D
IN
/D
IN
V
REF
V
CC
GND
Limiting
Amplifer
CML
Buffer
D
OUT
/D
OUT
Enable
/EN
Level
Detect
LOS
LVL
LOS
M9999-091207
hbwhelp@micrel.com or (408) 955-1690
Rev.: D
Amendment: /0
1
Issue Date: September 2007
Micrel, Inc.
SY88993AV
PACKAGE/ORDERING INFORMATION
Ordering Information
/EN 1
DIN 2
/DIN 3
VREF 4
LOSLVL 5
MSOP
K10-1
10 VCC
9 DOUT
8 /DOUT
7 LOS
6 GND
Part Number
SY88993AVKI
SY88993AVKITR
(1)
SY88993AVKG
SY88993AVKGTR
(1)
Note:
1.
Tape and Reel.
Package
Type
K10-1
K10-1
K10-1
K10-1
Operating
Range
Industrial
Industrial
Industrial
Industrial
Package
Marking
993A
993A
993A with
Pb-Free bar-line indicator
993A with
Pb-Free bar-line indicator
Lead
Finish
Sn-Pb
Sn-Pb
Pb-Free
NiPdAu
Pb-Free
NiPdAu
10-Pin MSOP (K10-1)
PIN NAMES
Pin
D
IN
/D
IN
LOS
LVL
/EN
LOS
GND
D
OUT
/D
OUT
V
CC
V
REF
Type
Data Input
Data Input
Input
TTL Input
TTL Output
(Open Collector)
Ground
CML Output
CML Output
Power Supply
Output
Function
Data Input
Inverting Data Input
Loss of Signal Level Set
Output Enable (Active Low)
Loss of Signal Indicator
(Active High)
Ground
Data Output
Inverting Data Output
Positive Power Supply
Reference Voltage Output
for LOS Level Set (see Fig. 3)
GENERAL DESCRIPTION
General
The SY88993AV is an integrated limiting amplifier
intended for high-frequency fiber-optic applications. The
circuit connects to typical transimpedance amplifiers found
within a fiber-optics link. The linear signal output from a
transimpedance amplifier can contain significant amounts
of noise, and may vary in amplitude over time. The
SY88993AV limiting amplifier quantizes the signal and
outputs a voltage-limited waveform.
The /EN pin allows the user to disable the output signal
without removing the input signal.
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
CC
D
IN
, /D
IN
T
A
T
STORE
Input Voltage
Operating Temperature Range
Storage Temperature Range
Rating
Power Supply Voltage
Value
0 to +7.0
0 to V
CC
–40 to +85
–55 to +85
Unit
V
V
°C
°C
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.
M9999-091207
hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88993AV
DC ELECTRICAL CHARACTERISTICS
V
CC
= +3.3V
±10%
or +5V
±10%,
R
LOAD
= 50Ω to V
CC
T
A
= –40
°
C
Symbol
I
CC
I
IL
I
IH
I
OH
LOS
LVL
V
OL
V
REF
V
IH
V
IL
Parameter
Power Supply
Current
(1)
/EN Input LOW
Current
/EN Input HIGH
Current
LOS Output Leakage
(2)
LOS
LVL
Level
LOS Output Low
Level
(3)
Reference Voltage
/EN Input HIGH Voltage
/EN Input LOW Voltage
5V
3.3V
Min.
—
—
–0.3
(4)
—
—
—
V
REF
—
Max.
55
50
—
20
(5)
100
(6)
100
V
CC
0.5
T
A
= 0
°
C
Min.
—
—
–0.3
(4)
—
—
—
V
REF
—
Max.
55
50
—
20
(5)
100
(6)
100
V
CC
0.5
Min.
—
—
–0.3
(4)
—
—
—
V
REF
—
T
A
= +25
°
C
Typ.
43
40
—
—
—
—
—
—
Max.
55
50
—
20
(5)
100
(6)
100
V
CC
0.5
T
A
= +85
°
C
Min.
—
—
–0.3
(4)
—
—
—
V
REF
—
Max.
65
60
—
20
(5)
100
(6)
100
V
CC
0.5
Unit
mA
mA
µA
uA
V
V
V
V
V
mV
V
V
CC
–1.38 V
CC
–1.26 V
CC
–1.38 V
CC
–1.26 V
CC
–1.38 V
CC
–1.32 V
CC
–1.26 V
CC
–1.38 V
CC
–1.26
2.0
—
—
—
—
±80
2.0
0.8
—
—
—
±80
V
CC
–0.2
2.0
0.8
—
GND±2
—
—
±9
—
—
—
±80
V
CC
–0.2
2.0
0.8
—
—
—
±80
V
OFFSET
Differential Output
Offset
V
CMR
Common Mode Range
GND±2 V
CC
–0.2 GND±2
GND±2 V
CC
–0.2
Notes:
1. No output load.
2. V
OH
= 5.5V.
3. I
OL
= +2mA.
4. V
IN
= 0.5V.
5. V
IN
= 2.7V.
6. V
IN
=V
CC.
M9999-091207
hbwhelp@micrel.com or (408) 955-1690
3
Micrel, Inc.
SY88993AV
AC ELECTRICAL CHARACTERISTICS
V
CC
= +3.3V
±10%
or +5V
±10%,
R
LOAD
= 50Ω to V
CC
T
A
= –40
°
C
Symbol
HYS
PSRR
t
OFFL
t
OFFH
t
ONL
t
r
t
f
V
ID
V
OD
V
SR
V
OH
V
OL
Z
O
Parameter
LOS Hysteresis
Power Supply
(1)
Rejection Ratio
LOS Release Time
(2)
Minimum Input
LOS Release Time
(2)
Maximum Input
LOS Assert Time
(2)
Differential Output
(3)
Rise/Fall Time (20%-80%)
Input Voltage Range
Differential Output
Voltage Swing
(4)
LOS Sensitivity Range
Min.
2
—
—
—
—
—
4
600
4
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
2
—
—
—
—
—
4
600
4
T
A
= 0
°
C
Min.
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
Min.
2
—
—
—
—
—
4
600
4
T
A
= +25
°
C
Typ.
4.6
35
0.1
0.1
0.2
60
—
800
(5)
—
Max.
8
—
0.5
0.5
0.5
120
1800
1200
50
T
A
= +85
°
C
Min.
2
—
—
—
—
—
4
600
4
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
Unit
dB
dB
µs
µs
µs
ps
mV
PP
mV
PP
mV
PP
mV
mV
Ω
Output Spec (D
OUT
and /D
OUT
)
Output HIGH Voltage
Output LOW Voltage
(6)
Single-Ended Output
(7)
Impedance
V
CC
–20
—
40
V
CC
V
CC
–300
60
V
CC
–20
—
40
V
CC
V
CC
–300
60
V
CC
–20
—
40
V
CC
–5
50
V
CC
60
V
CC
–20
—
40
V
CC
V
CC
–300
60
V
CC
–400 V
CC
–300
Input Spec (D
IN
and /D
IN
)
A
V(Diff)
B
–3dB
S
21
Differential Voltage
Gain
3dB Bandwidth
Single-Ended Small
Signal-Gain
—
—
26
—
—
—
—
—
26
—
—
—
—
—
26
39
2.5
33
—
—
—
—
—
26
—
—
—
dB
GHz
dB
Notes:
1. Input referred noise = RMS output noise/low frequency gain. Input referred, 55MHz.
2. Input is a 200MHz square wave, t
r
< 300ps, 1.8V
PP
.
3. With input signal V
ID
> 50mV
PP
with 50Ω load.
4. Input is a 200MHz square wave, t
r
< 300ps, 50Ω load.
5. V
ID
> 10mV
PP
.
6. Output levels are based on 50Ω impedance. If the load impedance is different, the output level will be changed.
7. See output structure.
M9999-091207
hbwhelp@micrel.com or (408) 955-1690
4
Micrel, Inc.
SY88993AV
APPLICATION NOTE
Output Termination
The SY88993AV outputs must be terminated with a 50Ω
load to V
CC.
Layout and PCB Design
Since the SY88993AV is a high-frequency component,
performance can largely be determined by board layout
and design. A common problem with high-gain amplifiers is
feedback from the large swing outputs to the input via power
supply.
The SY88993AV ground pin should be connected to the
circuit board ground. Use multiple PCB vias close to the
part to connect to ground. Avoid long, inductive runs which
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