The SY88993V 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 4mV
PP
can be amplified to drive devices with CML
inputs. The SY88993V generates a chatter-free Loss of
Signal (LOS) open collector TTL output.
The SY88993V 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 2.
s
TTL /EN Input
s
Differential PECL inputs for data
s
Single power supply
s
Available in a tiny 10-pin (3mm) MSOP
APPLICATIONS
s
1.25Gbps Gigabit Ethernet
s
s
s
s
531Mbps and 1062Mbps Fibre Channel
622Mbps SONET
Gigabit interface converter
2.5Gbps SDH/SONET
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
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
Rev.: C
Amendment: /0
1
Issue Date: August 2005
Micrel, Inc.
SY88993V
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
SY88993VKC
SY88993VKCTR
(1)
SY88993VKG
SY88993VKGTR
(1)
Package
Type
K10-1
K10-1
K10-1
K10-1
Operating
Range
Commercial
Commercial
Commercial
Commercial
Package
Marking
993V
993V
993V with
Pb-Free bar-line indicator
993V with
Pb-Free bar-line indicator
Lead
Finish
Sn-Pb
Sn-Pb
Pb-Free
NiPdAu
Pb-Free
NiPdAu
10-Pin MSOP (K10-1)
Note:
1.
Tape and Reel.
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 SY88993V 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
SY88993V 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.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88993V
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
CC
D
IN
, /D
IN
T
A
T
store
Rating
Power Supply Voltage
Input Voltage
Operating Temperature Range
Storage Temperature Range
Value
0 to +7.0
0 to V
CC
–40 to +85
–55 to +125
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.
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
(6)
—
—
—
V
REF
—
Max.
40
35
—
20
(4)
100
(5)
100
V
CC
0.5
T
A
= 0
°
C
Min.
—
—
–0.3
(6)
—
—
—
V
REF
—
Max.
40
35
—
20
(4)
100
(5)
100
V
CC
0.5
Min.
—
—
–0.3
(6)
—
—
—
V
REF
—
T
A
= +25
°
C
Typ.
34
30
—
—
—
—
—
—
Max.
40
35
—
20
(4)
100
(5)
100
V
CC
0.5
T
A
= +85
°
C
Min.
—
—
–0.3
(6)
—
—
—
V
REF
—
Max.
45
40
—
20
(4)
100
(5)
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
—
—
±10
—
—
—
±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
= 2.7V
5. V
IN
= V
CC
6. V
IN
= 0.5V
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
3
Micrel, Inc.
SY88993V
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
(3)
Maximum Input
LOS Assert Time
(2)
Differential Output
(3)
Rise/Fall Time
Input Voltage Range
Differential Output
Voltage Swing
(4)
LOS Sensitivity Range
Min.
2
—
—
—
—
—
4
—
4
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
2
—
—
—
—
—
4
—
4
T
A
= 0
°
C
Min.
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
Min.
2
—
—
—
—
—
4
—
4
T
A
= +25
°
C
Typ.
5.6
35
0.1
0.1
0.2
70
—
400
(5)
—
Max.
8
—
0.5
0.5
0.5
120
1800
—
50
T
A
= +85
°
C
Min.
2
—
—
—
—
—
4
—
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
Single-Ended Output
(7)
Impedance
V
CC
–20
40
V
CC
60
V
CC
–20
40
V
CC
60
V
CC
–20
40
V
CC
–5
50
V
CC
60
V
CC
–20
40
V
CC
60
Output LOW Voltage
(6)
V
CC
–280 V
CC
–140 V
CC
–280 V
CC
–140 V
CC
–280
V
CC
–200 V
CC
–140 V
CC
–280 V
CC
–140
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
38
2.5
32
—
—
—
—
—
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
> 5mV
PP
.
4. Input is a 200MHz square wave, t
r
< 300ps, 50Ω load.
5. V
ID
> 5mV
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.
M9999-082205
hbwhelp@micrel.com or (408) 955-1690
4
Micrel, Inc.
SY88993V
APPLICATION NOTE
Output Termination
The SY88993V outputs must be terminated with a 50Ω
load to V
CC
.
Layout and PCB Design
Since the SY88993V 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 SY88993V 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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