SY88923 [MICREL]
2.5Gbps HIGH-SPEED LIMITING POST AMPLIFIER; 2.5Gbps的高速限幅后置放大器
| 型号： | SY88923 |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | 2.5Gbps HIGH-SPEED LIMITING POST AMPLIFIER |
| 文件： | 总8页 (文件大小：100K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
2.5Gbps HIGH-SPEED
LIMITING POST AMPLIFIER
SY88923
DESCRIPTION
FEATURES
■ Up to 2.5Gbps operation
■ Low noise
The SY88923 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 SY88923 generates a chatter-free Loss
of Signal (LOS) open collector TTL output.
■ Chatter-Free LOS generation
■ Open Collector TTL LOS output
■ TTL /EN Input
The SY88923 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.
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. Figure 3 and
Figure 4 show the relationship between input level sensitivity
and the voltage set on LOSLVL. Figure 5 shows the
relationship between input level sensitivity and resistor
divider ratio.
■ Differential PECL inputs for data
■ Single power supply
■ Designed for use with SY88922 and SY88904 or
SY88905
■ Available in a tiny 10-pin (3mm) MSOP
PIN CONFIGURATION
The LOS output is a TTL open collector output that
requires a pull-up resistor for proper operation, Figure 1.
/EN
1
2
3
4
5
10 VCC
DIN
9
8
7
6
DOUT
+5.0V
MSOP
K10-1
/DIN
/DOUT
LOS
SY88923
VREF
2k
LOS
LOSLVL
GND
Figure 1. LOS Output with Desired Rise Time
BLOCK DIAGRAM
APPLICATIONS
■ 1.25Gbps Gigabit Ethernet
■ 531Mbps and 1062Mbps Fibre Channel
■ 622Mbps SONET
D
IN
IN
D
OUT
OUT
■ Gigabit interface converter
■ 2.5Gbps SDH/SONET
Limiting
Amplifer
ECL
Buffer
D
D
V
REF
CC
Enable
EN
V
Level
Detect
GND
LOS
LOSLVL
Rev.: C
Amendment:/1
Issue Date: July 2000
1
Micrel
SY88923
GENERAL DESCRIPTION
PIN NAMES
General
Pin
DIN
/DIN
Type
Data Input
Data Input
Function
Data Input
The SY88923 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 SY88923
limiting amplifier quantizes the signal and outputs a voltage-
limited waveform.
Inverting Data Input
LOS Limit Set
LOS LVL Input
/EN
TTL Input
Output Enable (Active Low)
LOS
TTL Output
(Open Collector)
Loss of Signal Indicator
(Active High)
GND
/DOUT
DOUT
VCC
Ground
Ground
The /EN pin allows the user to disable the output signal
without removing the input signal.
PECL Output
PECL Output
Power Supply
Output
Inverting Data Output
Data Output
Positive Power Supply
VREF
Reference Voltage Output for
LOS Level Set (see Fig. 3)
(1)
ABSOLUTE MAXIMUM RATINGS
Symbol
Rating
Value
0 to +7.0
Unit
V
VCC
Power Supply Voltage
Input Voltage
DIN, /DIN
DOUT, /DOUT
TA
0 to VCC
V
Output Voltage (with 50Ω load)
Operating Temperature Range
Storage Temperature Range
VCC –2.5, VCC +0.3
–40 to +85
V
°C
°C
Tstore
–55 to +125
NOTE:
1. PermanentdevicedamagemayoccurifABSOLUTEMAXIMUMRATINGSareexceeded. Thisisastressratingonlyandfunctionaloperationisnotimplied
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
SY88923
DC ELECTRICAL CHARACTERISTICS
VCC = +5V ±10%, RLOAD = 50Ω to VCC-2V, TA = –40°C to +85°C
TA = –40°C TA = 0°C
Min. Max.
TA = +25°C
TA = +85°C
Symbol
ICC
Parameter
Min.
Max.
35
Min.
—
Typ.
Max.
35
Min.
—
Max.
Unit
mA
mA
µA
Power Supply Current(1)
/EN Input LOW Current
/EN Input HIGH Current
—
35
—
—
21
—
35
—
IIL
–0.3(8)
–0.3(8)
—
–0.3(8)
—
–0.3(8)
IIH
—
—
20(5)
100(6)
—
—
20(5)
100(6)
—
—
—
—
20(5)
100(6)
—
—
20(5)
100(6)
VCMR
Voffset
LOSLVL
VOL
Common Mode Range
Differential Output Offset
LOSLVL Level(2)
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
±100
VCC
V
mV
V
±100
VCC
—
VREF
—
±100
VCC
—
VREF
—
±100
VCC
—
VREF
—
VREF
—
—
LOS Output Low Level(3)
LOS Output Leakage(4)
0.5
0.5
—
0.5
0.5
V
IOH
—
250
—
250
—
—
250
—
250
uA
VOH
DOUT and /DOUT
HIGH Output
V
V
CC–1085
V
CC–880
V
CC–1025
V
CC–880
V
CC–1025
V
CC–955
V
CC–880
V
V
CC–1025
VCC–880 mV
VOL
DOUT and /DOUT
LOW Output
CC–1830
V
CC–1555 VCC–1810 VCC–1620
VCC–1810
V
CC–1705 VCC–1620
CC–1810 VCC–1620 mV
VREF
VIH
Reference Supply(7)
V
CC–2.625 VCC–2.325 VCC–2.625 VCC–2.325 VCC–2.625 VCC–2.475 VCC–2.325 VCC–2.625 VCC–2.325
V
V
V
/EN Input HIGH Voltage
/EN Input LOW Voltage
2.0
—
—
2.0
—
—
2.0
—
—
—
—
2.0
—
—
VIL
0.8
0.8
0.8
0.8
NOTES:
5. VIN = 2.7.
6. VIN =VCC.
1. No output load.
2. 223-1 pattern.
3. IOL = + 2mA.
4. VOH = 5.5V.
7. IREF must be limited within –0.8mA (source) and 0.4mA (sink).
8. VIN = 0.5V.
AC ELECTRICAL CHARACTERISTICS
VCC = +5V ±10%, RLOAD = 50Ω to VCC - 2V, TA = –40°C to +85°C
TA = –40°C TA = 0°C
Min. Max. Min. Max. Min. Typ. Max. Min. Max. Unit
TA = +25°C
TA = +85°C
Symbol
Parameter
Conditions
PSRR
Power Supply(1)
Rejection Ratio
—
—
—
—
—
35
—
—
—
dB
Input referred,
55MHz
VID
tr, tf
Input Voltage Range
Output Rise/Fall Time
5
1800
5
1800
5
—
1800
5
1800 mVp-p
—
—
175
—
—
—
175
—
—
—
—
trin,tfin
175
—
—
—
175
—
ps
VID > 100mVp-p
VID < 100mVp-p
VOD
Differential Output
Voltage Swing(2)
—
—
—
—
—
—
—
—
—
—
600
200
—
—
—
—
—
—
mV
mV
VID = 15mVp-p
VID = 5mVp-p
tOFFL
tOFFH
LOS Release Time(3)
Minimum Input
—
0.5
—
0.5
—
0.1
0.5
—
0.5
0.5
0.5
µs
µs
µs
LOS Release Time(4)
Maximum Input
—
0.5
—
0.5
—
0.1
0.5
—
tONL
VSR
LOS Assert Time(3)
LOS Sensitivity Range
LOS Hysteresis
—
5
0.5
50
8
—
5
0.5
50
8
—
5
0.2
—
0.5
50
8
—
5
50 mVp-p 223-1 pattern
dB
HYS
2
2
2
4.6
2
8
NOTES:
3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p.
4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p.
1. Input referred noise = RMS output noise/low frequency gain.
2. Input is a 622MHz square wave.
3
Micrel
SY88923
DESIGN PROCEDURE
PERFORMANCE CURVE
Output Termination
LOS Assert and Deassert Levels
vs LOSLVL
The SY88923 outputs must be terminated with a 50Ω
load to VCC – 2V (or thevenin equivalent).
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
Layout and PCB Design
Deassert
Since the SY88923 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 power
supply.
The SY88923 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.
Assert
LOSLVL (V)
0.1µF
Figure 4. 223-1 Pattern
DIN+
0.1µF
50Ω
D
IN–
50Ω
VREF
0.1µF
LOS Assert and Deassert Levels
vs Resistor Divide
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
Figure 2. Differential Input Configuration
Deassert
Assert
V
CC
R1
LOSLVL
R2
Resistor Divider R2 / (R1 + R2)
Figure 5. 223-1 Pattern
V
REF
NOTE:
Resistor Divider = R2/ (R1 + R2)
R1 + R2 ≥ 5kΩ
Figure 3. LOSLVL Circut
4
Micrel
SY88923
APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION
GBIC Terminal
200Ω
200Ω
68Ω
68Ω
200Ω
200Ω
68Ω
68Ω
REXT
24Ω
Laserdiode
20kΩ
BLM21A102S
0.1µF
130Ω
82Ω
Photodiode
1000pF
130Ω
82Ω
PRODUCT ORDERING CODE
Ordering
Code
Package
Type
Operating
Range
SY88923KC
K10-1
Commercial
5
Micrel
SY88923
10 LEAD MSOP (K10-1)
Rev. 00
6
Micrel
SY88923
7
Micrel
SY88923
MICREL-SYNERGY 3250 SCOTT BOULEVARD SANTA CLARA CA 95054 USA
TEL + 1 (408) 980-9191 FAX + 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
8
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