The SY88923V limiting post amplifier with its high gain
and wide bandwidth is ideal for use as a post amplifier in
fiber-optic receivers with data rates up to 2.5Gbps.
Signals as small as 5mV
PP
can be amplified to drive
devices with PECL inputs. The SY88923V generates a
chatter-free Loss of Signal (LOS) open collector TTL
output.
The SY88923V incorporates a programmable level detect
function to identify when the input signal has been lost.
The LOS output will change from logic “LOW” to logic
“HIGH” when input signal is smaller than the swing set by
LOS
LVL
. This information can be fed back to the EN input
of the device to maintain stability under loss of signal
condition. Using LOS
LVL
pin, the sensitivity of the level
detection can be adjusted. The LOS
LVL
voltage can be set
by connecting a resistor divider between V
CC
and V
REF
show in Figure 3. Performance Curves show the relationship
between input level sensitivity and the voltage set on
LOS
LVL.
The LOS output is a TTL open collector output that
requires a pull-up resistor for proper operation, Figure 1.
V
CC
SY88923V
LOS
2.5kΩ
s
TTL /EN Input
s
Differential PECL inputs for data
s
Single power supply
s
Designed for use with Micrel's Laser Diode Driver
and Controller
s
Available in a tiny 10-pin (3mm) MSOP
APPLICATIONS
s
s
s
s
s
s
1.25Gbps and 2.5Gbps Gigabit Ethernet
531Mbps, 1062Mbps and 2.12Gbps Fibre Channel
622Mbps SONET
Gigabit Interface Converter
2.5Gbps SDH/SONET
2.5Gbps Proprietary Links
Figure 1. LOS Output with Desired Rise Time
BLOCK DIAGRAM
D
IN
Limiting
Amplifer
ECL
Buffer
D
OUT
/D
OUT
/EN
/D
IN
V
REF
Enable
V
CC
GND
Level
Detect
LOS
LVL
LOS
M9999-051706
hbwhelp@micrel.com or (408) 955-1690
Rev.: E
Amendment: /0
1
Issue Date: May 2006
Micrel, Inc.
SY88923V
PACKAGE/ORDERING INFORMATION
Ordering Information
(1)
/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
SY88923VKC
SY88923VKCTR
(2)
SY88923VKG
(3)
SY88923VKGTR
(2, 3)
Package
Type
K10-1
K10-1
K10-1
K10-1
Operating
Range
Commercial
Commercial
Industrial
Industrial
Package
Marking
923V
923V
923V with
Pb-Free bar-line indicator
923V with
Pb-Free bar-line indicator
Lead
Finish
Sn-Pb
Sn-Pb
Pb-Free
NiPdAu
Pb-Free
NiPdAu
10-Pin MSOP (K10-1)
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= 25°C, DC Electricals only.
2. Tape and Reel.
3. Pb-Free package is recommended for new designs.
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
PECL Output
PECL Output
Power Supply
Output
Function
Data Input
Inverting Data Input
LOS Limit Set
Output Enable (Active Low)
Loss of Signal Indicator
(Active High)
Ground
Inverting Data Output
Data Output
Positive Power Supply
Reference Voltage Output for
LOS Level Set (see Fig. 3)
GENERAL DESCRIPTION
General
The SY88923V is an integrated limiting amplifier intended
for high-frequency fiber-optic applications. The circuit
connects to typical trans-impedance amplifiers found within
a fiber-optics link. The linear signal output from a trans-
impedance amplifier can contain significant amounts of noise,
and may vary in amplitude over time. The SY88923V 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
D
OUT
, /D
OUT
/EN
LOS
LVL
V
REF
T
A
T
store
Rating
Power Supply Voltage
Input Voltage
Output Voltage (with 50Ω load)
Input Voltage
Input Voltage
Output Voltage
Operating Temperature Range
Storage Temperature Range
Value
0 to +7.0
0 to V
CC
V
CC
–2.5 to V
CC
+0.3
0 to V
CC
0 to V
CC
V
CC
–2.0 to V
CC
–40 to +85
–55 to +125
Unit
V
V
V
V
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.
M9999-051706
hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88923V
DC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
±10%
or +3.3V
±10%,
R
LOAD
= 50Ω to V
CC
–2V
T
A
= –40
°
C
Symbol
I
CC
I
IL
I
IH
V
CMR
V
offset
LOS
LVL
V
OL
I
OH
V
OH
V
OL
V
REF
I
REF
V
IH
V
IL
Parameter
Power Supply
Current
(1)
5V
3.3V
Min.
—
—
–0.3
(6)
—
—
GND +2.0
T
A
= 0
°
C
Min.
—
—
–0.3
(6)
—
—
GND +2.0
T
A
= +25
°
C
Min.
—
—
–0.3
(6)
—
—
GND +2.0
T
A
= +85
°
C
Max.
40
40
—
20
(4)
100
(5)
V
CC
±100
V
CC
0.5
100
Min.
—
—
–0.3
(6)
—
—
GND +2.0
Max.
40
40
—
20
(4)
100
(5)
V
CC
±100
V
CC
0.5
100
Max.
40
40
—
20
(4)
100
(5)
V
CC
±100
V
CC
0.5
100
Typ.
30
28
—
—
—
—
±17
—
—
—
Max.
45
45
—
20
(4)
100
(5)
V
CC
±100
V
CC
0.5
100
Unit
mA
mA
µA
V
mV
V
V
uA
mV
mV
V
mA
V
V
/EN Input LOW Current
/EN Input HIGH Current
Common Mode Range
Differential Output Offset
LOS
LVL
Level
LOS Output Low Level
(2)
LOS Output Leakage
(3)
D
OUT
and /D
OUT
HIGH Output
D
OUT
and /D
OUT
LOW Output
Reference Supply
V
REF
Output Current
/EN Input HIGH Voltage
/EN Input LOW Voltage
—
V
REF
—
—
—
V
REF
—
—
—
V
REF
—
—
—
V
REF
—
—
V
CC
–1085 V
CC
–880 V
CC
–1025 V
CC
–880 V
CC
–1025 V
CC
–955 V
CC
–880 V
CC
–1025 V
CC
–880
V
CC
–1830 V
CC
–1555 V
CC
–1810 V
CC
–1620 V
CC
–1810 V
CC
–1705 V
CC
–1620 V
CC
–1810 V
CC
–1620
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
–0.8
2.0
—
0.5
—
0.8
–0.8
2.0
—
0.5
—
0.8
4. V
IN
= 2.7V
5. V
IN
= V
CC
6. V
IN
= 0.5V
–0.8
2.0
—
—
—
—
0.5
—
0.8
–0.8
2.0
—
0.5
—
0.8
Notes:
1. No output load
2. I
OL
= + 2mA
3. V
OH
= 5.5V
AC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
±10%
or +3.3V
±10%,
R
LOAD
= 50Ω to V
CC
–2V
T
A
= –40
°
C
Symbol
PSRR
V
ID
V
OD
t
OFFL
t
ONL
t
OFFH
V
SR
HYS
t
r
, t
f
Parameter
Power Supply
(1)
Rejection Ratio
Input Voltage Range
Differential Output
Voltage Swing
(2)
LOS Release Time
(3)
Minimum Input
LOS Assert Time
(3)
LOS Release Time
(4)
Maximum Input
LOS Sensitivity Range
LOS Hysteresis
Output Rise/Fall Time
Min.
—
5
—
—
—
—
—
5
2
—
—
Max.
—
1800
—
—
0.5
0.5
0.5
50
8
175
—
T
A
= 0
°
C
Min.
—
5
—
—
—
—
—
5
2
—
—
Max.
—
1800
—
—
0.5
0.5
0.5
50
8
175
—
—
5
—
—
—
—
—
5
2
—
—
T
A
= +25
°
C
Min.
Typ.
35
—
700
300
0.1
0.2
0.1
—
4.6
150
t
rin
,t
fin
Max.
—
1800
—
—
0.5
0.5
0.5
50
8
175
—
T
A
= +85
°
C
Min.
—
5
—
—
—
—
—
5
2
—
—
Max.
—
1800
—
—
0.5
0.5
0.5
50
8
175
—
Unit
dB
mV
PP
mV
mV
µs
µs
µs
mV
PP
dB
ps
2
23
-1 pattern
2
23
-1 pattern
V
ID
> 100mV
PP
V
ID
< 100mV
PP
V
ID
= 15mV
PP
V
ID
= 5mV
PP
Conditions
Input referred,
55MHz
Notes:
1. Input referred noise = RMS output noise/low frequency gain.
2. Input is a 622MHz square wave.
M9999-051706
hbwhelp@micrel.com or (408) 955-1690
3. Input is a 200MHz square wave, t
r
< 300ps, 8mV
PP
.
4. Input is a 200MHz square wave, t
r
< 300ps, 1.8V
PP
.
3
Micrel, Inc.
SY88923V
DESIGN PROCEDURE
Output Termination
The SY88923V outputs must be terminated with a 50Ω
load to V
CC
– 2V (or Thevenin equivalent).
Layout and PCB Design
Since the SY88923V 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 the
power supply.
The SY88923V 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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