ETC SY88903VKCTR

5V/3.3V 1.25Gbps HIGH-SPEED
LIMITING POST AMPLIFIER
FEATURES
DESCRIPTION
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3.3V and 5V power supply option
Up to 1.5Gbps 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 SY88903V 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 1.5Gbps.
Signals as small as 5mVp-p can be amplified to drive
devices with PECL inputs. The SY88903V generates a
chatter-free Loss of Signal (LOS) open collector TTL
output.
The SY88903V incorporates a programmable 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 condition.
The sensitivity of the level detection can be adjusted using
LOSLVL. The LOSLVL voltage can be set by connecting a
resistor divider between VCC and VREF as shown in Figure
3. Figure 4 and 5 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
9 DOUT
SY88903V
8 /DOUT
LOS
/DIN 3
SY88903V
MSOP
K10-1
VREF 4
7 LOS
LOSLVL 5
6 GND
VCC
2k
Figure 1. LOS Output with Desired Rise Time
APPLICATIONS
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BLOCK DIAGRAM
1.25Gbps Gigabit Ethernet
531Mbps and 1062Mbps Fibre Channel
622Mbps SONET
Gigabit Interface Converter
Digital Video
DIN
DOUT
Limiting
Amplifer
ECL
Buffer
DIN
DOUT
VREF
Enable
VCC
GND
Level
Detect
LOS
LOSLVL
Rev.: A
1
EN
Amendment: /1
Issue Date: July 2000
Micrel
SY88903V
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 SY88903V 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
SY88903V 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
Micrel
SY88903V
DC ELECTRICAL CHARACTERISTICS
VCC = +5V ±10% or +3.3V ±10%; RLOAD = 50Ω to VCC -2V, TA = –40°C to +85°C
TA = –40°C
Symbol
ICC
Parameter
IIL
IIH
TA = +25°C
TA = +85°C
Max.
Min.
Max.
Min.
Typ.
Max.
Min.
Max.
Unit
5V
—
35
—
35
—
25
35
—
40
mA
3.3V
—
20
35
—
40
mA
—
—
–0.3(6)
—
mA
—
20(4)
—
20(4)
µA
—
100(5)
µA
Power Supply
Current(1)
TA = 0°C
Min.
/EN Input LOW Current
35
—
35
—
–0.3(6)
—
–0.3(6)
—
–0.3(6)
—
20(4)
—
20(4)
—
100(5)
—
100(5)
—
—
100(5)
GND +2.0
VCC
GND +2.0
VCC
GND +2.0
—
VCC
GND +2.0
VCC
V
—
±100
—
±100
—
±40
±100
—
±100
mV
VREF
VCC
VREF
VCC
VREF
—
VCC
VREF
VCC
V
—
0.5
—
0.5
—
—
0.5
—
0.5
V
—
250
—
250
—
—
250
—
250
µA
/EN Input HIGH Current
VCMR
Common Mode Range
Voffset
Differential Output Offset
LOSLVL
LOSLVL Level
Level(2)
—
VOL
LOS Output Low
IOH
LOS Output Leakage(3)
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 to +85°C
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
1800 mVp-p
t r, t f
Output Rise/Fall Time
—
—
260
—
—
—
260
—
—
—
170
trin,tfin
260
—
—
—
260
—
ps
VID > 100mVp-p
VID < 100mVp-p
VOD
Differential Output
Voltage Swing(2)
—
200
—
—
—
200
—
—
—
200
700
250
—
—
—
200
—
—
mV
mV
VID = 15mVp-p
VID = 5mVp-p
tOFFL
LOS Release Time(3)
Minimum Input
—
0.5
—
0.5
—
0.1
0.5
—
0.5
µs
tOFFH
LOS Release Time(4)
Maximum 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
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
NOTES:
1. Input referred noise = RMS output noise/low frequency gain.
2. Input is a 622MHz square wave.
Conditions
Input referred,
55MHz
3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p.
4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p.
3
Micrel
SY88903V
DESIGN PROCEDURE
Output Termination
The SY88903V outputs must be terminated with a 50Ω
load to VCC – 2V (or Thevenin equivalent).
The SY88903V 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 SY88903V 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
R1
DIN+
0.1µF
50
DIN–
LOSLVL
50
R2
VREF
VREF
NOTES:
R2 × 1.32V
LOSLVS = VCC -1.32V +
R1 + R2
R1 + R2 ≥ 2.6kΩ
Figure 2. Differential Input Configuration
Figure 3. LOSLVL Circut
PRODUCT ORDERING CODE
Ordering
Code
4
Package
Type
Operating
Range
SY88903VKC
K10-1
Commercial
SY88903VKCTR
K10-1
Commercial
Micrel
SY88903V
10 LEAD MSOP (K10-1)
Rev. 00
MICREL-SYNERGY
TEL
+ 1 (408) 980-9191
FAX
3250 SCOTT BOULEVARD
+ 1 (408) 914-7878
WEB
SANTA CLARA
CA 95054 USA
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.
© 1999 Micrel Incorporated
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