The SY88913 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 1.25Gbps.
Signals as small as 5mVp-p can be amplified to drive
devices with PECL inputs. The SY88913 generates a
chatter-free PECL Loss of Signal (/LOS).
The SY88913 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. Figure 3 shows the relationship between input
level sensitivity and the voltage set on LOS
LVL
. Figure 4
shows the relationship between input level sensitivity and
resistor divider ratio.
s
Differential PECL inputs for data
s
/EN input is TTL with internal 27K pull-up
s
Single power supply
s
Designed for use with SY88902 and SY88904
s
Available in a tiny 10-pin (3mm x3 mm) MSOP
APPLICATIONS
s
s
s
s
1.25Gbps Gigabit Ethernet
531Mbps and 1062Mbps Fibre Channel
622Mbps SONET
Gigabit Interface Converter
BLOCK DIAGRAM
D
IN
Limiting
Amplifier
ECL
Buffer
D
OUT
D
OUT
D
IN
V
REF
Enable
EN
V
CC
Level
Detect
GND
LOS
LVL
LOS
M9999-081505
hbwhelp@micrel.com or (408) 955-1690
Rev.: F
Amendment: /0
1
Issue Date: August 2005
Micrel, Inc.
SY88913
PACKAGE/ORDERING INFORMATION
Ordering Information
/EN 1
D
IN
2
/D
IN
3
V
REF
4
LOS
LVL
5
MSOP
K10-1
10 V
CC
9 D
OUT
8 /D
OUT
7
6
/LOS
GND
Part Number
SY88913KC
SY88913KCTR
(1)
SY88913KG
SY88913KGTR
(1)
Package
Type
K10-1
K10-1
K10-1
K10-1
Operating
Range
Commercial
Commercial
Commercial
Commercial
Package
Marking
913
913
913 with
Pb-Free bar-line indicator
913 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
PECL Output
Ground
PECL Output
PECL Output
Power Supply
Output
Function
Data Input
Inverting Data Input
Loss of Signal Level Set
Output Enable (active Low)
Loss of Signal Indicator
(active Low)
Ground
Data Output
Inverting Data Output
Positive Power Supply
Reference Voltage Output
for LOS Level Set (see Fig. 2)
GENERAL DESCRIPTION
General
The SY88913 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 SY88913
limiting amplifier quantizes the signal and outputs a voltage-
limited waveform.
The TTL /EN pin allows the user to disable the signal
without removing the input signal.
M9999-081505
hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88913
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
CC
D
IN
, /D
IN
D
OUT
, /D
OUT
, /LOS
T
A
T
store
Rating
Power Supply Voltage
Input Voltage
Output Voltage (with 50Ω load)
Operating Temperature Range
Storage Temperature Range
Value
0 to +7.0
0 to V
CC
V
CC
–2.5, V
CC
+0.3
–40 to +85
–55 to +125
Unit
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.
DC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
±10%,
R
LOAD
= 50Ω to V
CC
–2V, T
A
= –40°C to +85°C.
T
A
= –40
°
C
Symbol
I
CC
I
IL
I
IH
V
CMR
Voffset
LOS
LVL
V
OH
V
OL
V
REF
V
IH
V
IL
Parameter
Power Supply Current
(1)
/EN Input LOW Current
/EN Input HIGH Current
Common Mode Range
Differential Output Offset
LOS
LVL
Level
DOUT and /DOUT
HIGH Output
DOUT and /DOUT
LOW Output
Reference Supply
(4)
/EN Input HIGH Voltage
/EN Input LOW Voltage
Min.
—
–0.3
(5)
—
—
Max.
35
—
20
(2)
100
(3)
±100
V
CC
T
A
= 0
°
C
Min.
—
–0.3
(5)
—
—
Max.
35
—
20
(2)
100
(3)
±100
V
CC
Min.
—
–0.3
(5)
—
—
T
A
= +25
°
C
Typ.
21
—
—
—
—
T
A
= +85
°
C
Max.
35
—
20
(2)
100
(3)
±100
V
CC
Min.
—
–0.3
(5)
—
—
Max.
35
—
20
(2)
100
(3)
±100
V
CC
V
CC
–880
Unit
mA
mA
µA
V
mV
V
mV
mV
V
V
V
GND +2.0 V
CC
–1.0 GND +2.0 V
CC
–1.0 GND +2.0
V
CC
–1.0 GND +2.0 V
CC
–1.0
—
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
–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
–2.625 V
CC
–2.325 V
CC
–2.625 V
CC
–2.325 V
CC
–2.625 V
CC
–2.475 V
CC
–2.325 V
CC
–2.625 V
CC
–2.325
2.0
—
—
0.8
2.0
—
—
0.8
2.0
—
—
—
—
0.8
2.0
—
—
0.8
Notes:
1. No output load.
2. V
IN
= 2.7V.
3. V
IN
= V
CC
.
4. I
REF
must be limited to be within –0.8mA (source) and 0.5mA (sink).
5. V
IN
= 0.5V.
M9999-081505
hbwhelp@micrel.com or (408) 955-1690
3
Micrel, Inc.
SY88913
AC ELECTRICAL CHARACTERISTICS
V
CC
= +5V
±10%,
R
LOAD
= 50Ω to V
CC
–2V, T
A
= –40°C to +85°C.
T
A
= –40
°
C
Symbol
PSRR
VID
t
r
, t
f
VOD
t
OFFL
t
OFFH
t
ONL
VSR
HYS
Parameter
Power Supply
(1)
Rejection Ratio
Input Voltage Range
Output Rise/Fall Time
Differential Output
Voltage Swing
(2)
/LOS Release Time
(3)
Minimum Input
/LOS Release Time
(4)
Maximum Input
/LOS Assert Time
(3)
/LOS Sensitivity Range
/LOS Hysteresis
Min.
—
5
—
—
—
—
—
—
—
5
2
Max.
—
1800
350
—
—
—
0.5
0.5
0.5
50
8
T
A
= 0
°
C
Min.
—
5
—
—
—
—
—
—
—
5
2
Max.
—
1800
350
—
—
—
0.5
0.5
0.5
50
8
—
5
—
—
—
—
—
—
—
5
2
T
A
= +25
°
C
Min.
Typ.
35
—
200
trin,tfin
600
200
0.1
0.1
0.2
—
4.6
Max.
—
1800
350
—
—
—
0.5
0.5
0.5
50
8
T
A
= +85
°
C
Min.
—
5
—
—
—
—
—
—
—
5
2
Max.
—
Unit
dB
Conditions
Input referred,
55MHz
1800 mV
PP
350
—
—
—
0.5
0.5
0.5
50
8
ps
mV
mV
µs
µs
µs
mV
PP
dB
V
ID
> 100mV
PP
V
ID
< 100mV
PP
V
ID
= 15mV
PP
V
ID
= 5mV
PP
Notes:
1. Input referred noise = RMS output noise/low frequency gain.
2. Input is 622MHz square wave.
3. Input is a 200MHz square wave, tr < 300ps, 8mV
PP
.
4. Input is a 200MHz square wave, tr < 300ps, 1.8V
PP
.
M9999-081505
hbwhelp@micrel.com or (408) 955-1690
4
Micrel, Inc.
SY88913
APPLICATION NOTE
Output Termination
The SY88913 outputs must be terminated with a 50Ω
load to V
CC
– 2V (or Thevenin equivalent).
Layout and PCB Design
Since the SY88913 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 SY88913 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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