MICREL SY88923VKCTR

5V/3.3V 2.5Gbps HIGH-SPEED
LIMITING POST AMPLIFIER
DESCRIPTION
FEATURES
■
■
■
■
■
■
■
■
■
3.3V and 5V power supply options
Up to 2.5Gbps operation
Low noise
Chatter-Free LOS Generation
Open Collector TTL LOS Output
TTL /EN Input
Differential PECL inputs for data
Single power supply
Designed for use with (Micrel-Synergy laser diode
driver and controller)
■ Available in a tiny 10-pin (3mm) MSOP
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 5mVp-p 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
LOSLVL. This information can be fed back to the EN input
of the device to maintain stability under loss of signal
condition. Using LOSLVL pin, the sensitivity of the level
detection can be adjusted. The LOSLVL voltage can be set
by connecting a resistor divider between VCC and VREF
show in Figure 3. Figure 4, 5, 6, and 7 show the relationship
between input level sensitivity and the voltage set on
LOSLVL.
The LOS output is a TTL open collector output that
requires a pull-up resistor for proper operation, Figure 1.
PIN CONFIGURATION
/EN 1
10 VCC
DIN 2
/DIN 3
SY88923V
9 DOUT
MSOP
K10-1
VCC
8 /DOUT
VREF 4
7 LOS
LOSLVL 5
6 GND
SY88923V
2k
LOS
Figure 1. LOS Output with Desired Rise Time
BLOCK DIAGRAM
APPLICATIONS
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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
DIN
DOUT
Limiting
Amplifer
ECL
Buffer
/DIN
/DOUT
VREF
Enable
/EN
VCC
GND
Level
Detect
LOS
LOSLVL
Rev.: B
1
Amendment: /0
Issue Date: August 2000
SY88923V
Micrel
PIN NAMES
GENERAL DESCRIPTION
Pin
Type
DIN
Data Input
Data Input
/DIN
Data Input
Inverting Data Input
LOSLVL
Input
LOS Limit Set
/EN
TTL Input
Output Enable (Active Low)
LOS
TTL Output
(Open Collector)
Loss of Signal Indicator
(Active High)
GND
Ground
Ground
/DOUT
PECL Output
Inverting Data Output
DOUT
PECL Output
Data Output
VCC
Power Supply
Positive Power Supply
VREF
Output
Reference Voltage Output for
LOS Level Set (see Fig. 3)
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 transimpedance 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.
Function
ABSOLUTE MAXIMUM RATINGS(1)
Symbol
Rating
Value
Unit
VCC
Power Supply Voltage
0 to +7.0
V
DIN, /DIN
Input Voltage
0 to VCC
V
DOUT, /DOUT
Output Voltage (with 50Ω load)
VCC –2.5 to VCC +0.3
V
/EN
Input Voltage
0 to VCC
V
LOSLVL
Input Voltage
0 to VCC
V
VREF
Output Voltage
VCC –2.0 to VCC
V
TA
Operating Temperature Range
–40 to +85
°C
Tstore
Storage Temperature Range
–55 to +125
°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.
2
SY88923V
Micrel
DC ELECTRICAL CHARACTERISTICS
VCC = +5V ±10% or +3.3V ±10%, RLOAD = 50Ω to VCC –2V
TA = –40°C
Symbol
Parameter
ICC
Power Supply
Current(1)
IIL
/EN Input LOW Current
/EN Input HIGH Current
VCMR
Common Mode Range
Voffset
Differential Output Offset
LOSLVL
LOSLVL Level
VOL
LOS Output Low
TA = +25°C
TA = +85°C
Min.
Max.
Min.
Max.
Min.
Typ.
Max.
Min.
Max.
Unit
—
—
40
40
—
—
40
40
—
—
30
28
40
40
—
—
45
45
mA
–0.3(6)
—
–0.3(6)
—
–0.3(6)
—
—
–0.3(6)
—
mA
—
—
20(4)
—
—
µA
100(5)
—
—
20(4)
100(5)
—
—
20(4)
100(5)
—
—
20(4)
100(5)
GND +2.0
VCC
GND +2.0
VCC
GND +2.0
—
VCC
GND +2.0
VCC
V
—
±100
—
±100
—
±17
±100
—
±100
mV
VREF
VCC
VREF
VCC
VREF
—
VCC
VREF
VCC
V
—
0.5
—
0.5
—
—
0.5
—
0.5
V
—
100
—
100
—
—
100
—
100
uA
5V
3.3V
IIH
TA = 0°C
Level(2)
Leakage(3)
IOH
LOS Output
VOH
DOUT and /DOUT
HIGH Output
VCC –1085 VCC –880 VCC –1025 VCC –880 VCC –1025 VCC –955 VCC –880 VCC –1025 VCC –880
mV
VOL
DOUT and /DOUT
LOW Output
VCC –1830 VCC –1555 VCC –1810 VCC –1620 VCC –1810 VCC –1705 VCC –1620 VCC –1810 VCC –1620
mV
VREF
Reference Supply
VCC –1.38 VCC –1.26 VCC –1.38 VCC –1.26 VCC –1.38 VCC –1.32 VCC –1.26 VCC –1.38 VCC –1.26
V
IREF
VREF Output Current
–0.8
0.5
–0.8
0.5
–0.8
—
0.5
–0.8
0.5
mA
VIH
/EN Input HIGH Voltage
2.0
—
2.0
—
2.0
—
—
2.0
—
V
VIL
/EN Input LOW Voltage
—
0.8
—
0.8
—
—
0.8
—
0.8
V
NOTES:
1. No output load
2. IOL = + 2mA
3. VOH = 5.5V
4. VIN = 2.7V
5. VIN = VCC
6. VIN = 0.5V
AC ELECTRICAL CHARACTERISTICS
VCC = +5V ±10% or +3.3V ±10%, RLOAD = 50Ω to VCC –2V
TA = –40°C
Symbol
Parameter
TA = 0°C
TA = +25°C
TA = +85°C
Min.
Max.
Min.
Max.
Min.
Typ.
Max.
Min.
Max.
Unit
PSRR
Power Supply(1)
Rejection Ratio
—
—
—
—
—
35
—
—
—
dB
VID
Input Voltage Range
5
1800
5
1800
5
—
1800
5
VOD
Differential Output
Voltage Swing(2)
—
—
—
—
—
—
—
—
—
—
700
300
—
—
—
—
—
—
mV
mV
tOFFL
LOS Release Time(3)
Minimum Input
—
0.5
—
0.5
—
0.1
0.5
—
0.5
µs
tONL
LOS Assert Time(3)
—
0.5
—
0.5
—
0.2
0.5
—
0.5
µs
Conditions
Input referred,
55MHz
1800 mVp-p
VID = 15mVp-p
VID = 5mVp-p
tOFFH
LOS Release
Maximum Input
—
0.5
—
0.5
—
0.1
0.5
—
0.5
µs
VSR
LOS Sensitivity Range
5
50
5
50
5
—
50
5
50
mVp-p
223-1 pattern
HYS
LOS Hysteresis
2
8
2
8
2
4.6
8
2
8
dB
223-1 pattern
tr, tf
Output Rise/Fall Time
—
—
175
—
—
—
175
—
—
—
150
trin,tfin
175
—
—
—
175
—
ps
VID > 100mVp-p
VID < 100mVp-p
Time(4)
3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p.
4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p.
NOTES:
1. Input referred noise = RMS output noise/low frequency gain.
2. Input is a 622MHz square wave.
3
SY88923V
Micrel
DESIGN PROCEDURE
Output Termination
The SY88923V outputs must be terminated with a 50Ω
load to VCC – 2V (or Thevenin equivalent).
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
can degrade performance.
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.
VCC
0.1µF
DIN+
R1
0.1µF
50Ω
DIN–
LOSLVL
50Ω
R2
VREF
VREF
0.1µF
Figure 2. Differential Input Configuration
Figure 3. LOSLVL Circuit
NOTES:
R2 × 1.32V
LOSLVL = VCC -1.32V +
R1 + R2
R1 + R2 ≥ 2.6kΩ
PRODUCT ORDERING CODE
Ordering
Code
4
Package
Type
Operating
Range
SY88923VKC
K10-1
Commercial
SY88923VKCTR
K10-1
Commercial
SY88923V
Micrel
PERFORMANCE CURVE
LOS Assert and Deassert
Levels vs LOSLVL
LOS Assert and Deassert
Levels vs LOSLVL
100
3.3V
TA = 25°C
2.5Gbps
Pattern 223-1
90
80
70
60
INPUT LEVEL (mVp-p)
INPUT LEVEL (mVp-p)
100
50
40
30
20
10
0
0
70
60
50
40
30
20
10
0
-0.2 -0.4 -0.6 -0.8 -1.0 -1.2
LOSLVL = VCC – V (V)
5.0V
TA = 25°C
2.5Gbps
Pattern 223-1
90
80
0
Figure 4.
Figure 5.
LOS Assert and Deassert
Levels vs LOSLVL
LOS Assert and Deassert
Levels vs LOSLVL
100
3.3V
TA = 25°C
2.5Gbps
Pattern 27-1
90
80
70
60
50
INPUT LEVEL (mVp-p)
INPUT LEVEL (mVp-p)
100
40
30
20
10
0
-0.2 -0.4 -0.6 -0.8 -1.0 -1.2
LOSLVL = VCC – V (V)
0
70
60
50
40
30
20
10
0
-0.2 -0.4 -0.6 -0.8 -1.0 -1.2
LOSLVL = VCC – V (V)
Figure 6.
5.0V
TA = 25°C
2.5Gbps
Pattern 27-1
90
80
0
-0.2 -0.4 -0.6 -0.8 -1.0 -1.2
LOSLVL = VCC – V (V)
Figure 7.
5
SY88923V
Micrel
10 LEAD MSOP (K10-1)
Rev. 00
6
SY88923V
Micrel
7
SY88923V
Micrel
MICREL-SYNERGY
TEL
+ 1 (408) 980-9191
FAX
3250 SCOTT BOULEVARD SANTA CLARA CA 95054 USA
+ 1 (408) 914-7878
WEB
http://www.synergysemi.com http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 2000 Micrel Incorporated
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