Micrel, Inc.
5V/3.3V 3.2Gbps HIGH-SPEED
LIMITING POST AMPLIFIER
SY88923AV
SY88923AV
FEATURES
s
s
s
s
s
Single 3.3V or 5V power supply
Up to 3.2Gbps operation
Low noise PECL data outputs
Chatter-free open collector TTL LOS output
TTL /EN Input
DESCRIPTION
The SY88923AV 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
3.2Gbps. Signals as small as 5mV
PP
can be amplified
to drive devices with PECL inputs. The SY88923AV
generates a chatter-free Loss-of-Signal (LOS) open
collector TTL output.
The SY88923AV 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
shown in Figure 3. “Typical Operating Characteristics” on
page 6 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
SY88923AV
LOS
4.7kΩ to 10kΩ
s
Differential PECL inputs for data
s
Available in a tiny 10-pin (3mm) MSOP and 10-pin
(3mm) EPAD-MSOP
APPLICATIONS
s
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
Parallel 10G Ethernet
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
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
Rev.: F
Amendment: /0
1
Issue Date: November 2005
Micrel, Inc.
SY88923AV
PACKAGE/ORDERING INFORMATION
/EN 1
DIN 2
/DIN 3
VREF 4
LOSLVL 5
10 VCC
9 DOUT
8 /DOUT
7 LOST
6 GND
Ordering Information
(1)
Part Number
SY88923AVKC
SY88923AVKCTR
(2)
SY88923AVEC
SY88923AVECTR
(2)
SY88923AVKG
(3)
SY88923AVKGTR
(2, 3)
SY88923AVEY
(3)
SY88923AVEYTR
(2, 3)
Package
Type
K10-1
K10-1
K10-2
K10-2
K10-1
K10-1
K10-2
K10-2
Operating
Range
Commercial
Commercial
Commercial
Commercial
Industrial
Industrial
Industrial
Industrial
Package
Marking
923AV
923AV
923AV
923AV
923AV with
Pb-free bar-line indicator
923AV with
Pb-free bar-line indicator
Lead
Finish
Sn-Pb
Sn-Pb
Sn-Pb
Sn-Pb
NiPdAu
Pb-Free
NiPdAu
Pb-Free
10-Pin MSOP (K10-1)
10-Pin EPAD-MSOP (K10-2)
923AV with
Matte-Sn
Pb-free bar-line indicator Pb-Free
923AV with
Matte-Sn
Pb-free bar-line indicator Pb-Free
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 DESCRIPTION
Pin Number
MSOP
1
2
3
4
5
6
7
8
9
10
Pin Number
EPAD-MSOP
1
2
3
4
5
6,
(Exposed Pad)
7
8
9
10
Pin Name
/EN
DIN
/DIN
VREF
LOSLVL
GND
LOS
/DOUT
DOUT
VCC
Type
TTL Input
Data Input
Data Input
Output
Input
Ground
TTL Output
(Open Collector)
PECL Output
PECL Output
Power Supply
Pin Function
Output Enable (Active Low).
Data Input.
Inverting Data Input.
Reference Voltage Output for LOS Level Set (see Figure 3).
LOS Limit Set.
Ground. Exposed pad must be connected to PCB ground
plane.
Loss of Signal Indicator (Active High).
Inverting Data Output.
Data Output.
Positive Power Supply.
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88923AV
Absolute Maximum Ratings
(1)
Power Supply Voltage (V
CC
) ............................ 0V to +7.0V
Input Voltage
(D
IN
, /D
IN
) ........................................................ 0V to V
CC
(/EN) ................................................................ 0V to V
CC
(LOS
LVL
) .......................................................... 0V to V
CC
Output Voltage (with 50Ω load)
(D
OUT
, /D
OUT
) .......................... V
CC
–2.5V to V
CC
+0.3V
(V
REF
) .................................................. V
CC
–2.0V to V
CC
Lead Temperature (soldering, 20 sec.) ..................... 260°C
Storage Temperature (T
S
) ....................... –55°C to +125°C
Operating Ratings
(2)
Supply Voltage (V
CC
) .................................. +3.0V to +5.5V
Ambient Temperature (T
A
) ......................... –40°C to +85°C
Package Thermal Resistance
MSOP
(θ
JA
)
Still-Air ........................................................... 113°C/W
EPAD-MSOP
(θ
JA
)
Still-Air ............................................................. 38°C/W
DC ELECTRICAL CHARACTERISTICS
(3)
V
CC
=+5V
±10%
or +3.3V
±10%;
R
L
= 50Ω to V
CC
–2V; T
A
= –40°C to +85°C; unless otherwise noted.
Symbol
I
CC
Parameter
Power Supply Current
Condition
No output load
V
CC
= 5V
±10%,
V
CC
= 3.3V
±10%
V
IN
= 0.5V
V
IN
= 2.7V
V
IN
= V
CC
GND +2.0
–0.3
20
100
V
CC
±80
V
REF
I
OL
= +2mA
V
OH
= 5.5V
V
CC
0.5
100
V
CC
–1085 V
CC
–955 V
CC
–880
V
CC
–1830 V
CC
–1705 V
CC
–1555
V
CC
–1.38 V
CC
–1.32 V
CC
–1.26
–0.8
2.0
0.8
0.5
Min
Typ
38
35
Max
60
53
Units
mA
mA
mA
µA
µA
V
mV
V
V
µA
mV
mV
V
mA
V
V
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
Notes:
/EN Input LOW Current
/EN Input HIGH Current
Common Mode Range
Differential Output Offset
LOS
LVL
Level
LOS Output LOW Level
LOS Output Leakage
D
OUT
and /D
OUT
Output HIGH Voltage
D
OUT
and /D
OUT
Output LOW Voltage
Reference Supply
V
REF
Output Current
/EN Input HIGH Voltage
/EN Input LOW Voltage
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.
2.
The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.
3.
The device is guaranteed to meet the DC specifications, shown in the table above, after thermal equilibrium has been established. The device is
tested in a socket such that transverse airflow of
≥500lfpm
is maintained.
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
3
Micrel, Inc.
SY88923AV
AC ELECTRICAL CHARACTERISTICS
V
CC
=+5V
±10%
or +3.3V
±10%;
R
L
= 50Ω to V
CC
–2V; T
A
= –40°C to +85°C; unless otherwise noted.
Symbol
V
ID
V
OD
Parameter
Input Voltage Range
Differential Output Voltage Swing
Note 4
V
ID
= 15mV
PP
V
ID
= 5mV
PP
Note 5
Note 5
2
23
–1 pattern
2
23
–1 pattern
V
ID
> 100mV
PP
V
ID
< 100mV
PP
5
2
4.6
115
t
rin
,t
fin
Condition
Min
5
1400
600
0.2
0.1
0.5
0.5
50
8
150
Typ
Max
1800
Units
mV
PP
mV
PP
mV
PP
µs
µs
mV
PP
dB
ps
t
ON
t
OFF
V
SR
HYS
t
r
, t
f
Notes:
LOS Assert Time
LOS Release Time
LOS Sensitivity Range
LOS Hysteresis
Output Rise/Fall Time
4. Input is a 200MHz square wave, t
r
< 300ps.
5. Input is a 200MHz square wave, t
r
< 300ps, 1.8V
PP
.
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
4
Micrel, Inc.
SY88923AV
GENERAL DESCRIPTION
General
The SY88923AV 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
SY88923AV 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.
DESIGN PROCEDURE
Output Termination
The SY88923AV outputs must be terminated with a 50Ω
load to V
CC
– 2V (or Thevenin equivalent).
Layout and PCB Design
Since the SY88923AV 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 SY88923AV 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
can degrade performance.
V
CC
R1
LOS
LVL
0.1µF
0.1µF
R2
D
IN+
V
REF
D
IN—
50Ω
V
REF
0.1µF
Note 1.
50Ω
Figure 3. LOS
LVL
Circuit
LOS
LVL
= V
CC
–1.32V +
R1 + R2
≥
2.6kΩ
R2
×
1.32V
R1 + R2
V
CC
Figure 2. Differential Input Configuration
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
5
Analog electronics
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