SY88973BL
3.3V 3.2Gbps CML Low Power Limiting Post
Amplifier with TTL LOS
General Description
The SY88973BL low-power, limiting post amplifier is
designed for use in fiber optic receivers. The device connects
to typical transimpedance amplifiers (TIAs). The linear signal
output from TIAs can contain significant amounts of noise
and may vary in amplitude over time. The SY88973BL
quantizes these signals and outputs typically 800mV
PP
voltage-limited waveforms.
The SY88973BL operates from a single +3.3V ±10% power
supply, over an industrial temperature range of –40°C to
+85°C. With its wide bandwidth and high gain, signals with
data rates up to 3.2Gbps and as small as 10mV
PP
can be
amplified to drive devices with CML inputs or AC-coupled
PECL inputs.
The SY88973BL incorporates a loss-of-signal (LOS), open-
collector TTL output with external 4.75kΩ
to 10kΩ pull-up
resistor to fully comply with SFP MSA. A programmable, loss-
of-signal level-set pin (LOSLVL) sets the sensitivity of the
input amplitude detection. LOS asserts high if the input
amplitude falls below the threshold sets by LOSLVL and de-
asserts low otherwise. LOS can be fed back to the enable
(/EN) input to maintain output stability under a loss-of-signal
condition. /EN de-asserts the true output signal without
removing the input signal. Typically, 4.6dB LOS hysteresis is
provided to prevent chattering.
Please see Micrel’s website at www.micrel.com for a
complete selection of optical module ICs.
All support documentation can be found on Micrel’s web site
at:
www.micrel.com.
Features
•
•
•
•
•
Multi-rate up to 3.2Gbps operation
Wide gain-bandwidth product
38dB differential gain
2GHz 3dB bandwidth
Low noise 50Ω
CML data outputs
– 800mV
PP
output swing
– 60ps edge rates
– 5ps
RMS
typ. random jitter
– 15ps
PP
typ. deterministic jitter
•
Chatter-free, Loss-of-Signal (LOS) output
– No internal pull-up resistor− fully compliant with
SFP MSA
– 4.6dB electrical hysteresis
– OC-TTL output
•
Programmable LOS sensitivity using single external
resistor
•
Internal 50Ω
data input termination
•
TTL /EN input allows feedback from LOS
•
Wide operating range:
– Single 3.3V ±10%
–
–40°C to +85°C industrial temperature range
•
Available in a tiny 3mm x 3mm 16-pin QFN package
Applications
•
1.25Gbps and 2.5Gbps Gigabit Ethernet
•
1.062Mbps and 2.125Gbps Fibre Channel
•
155Mbps, 622Gbps, 1.25Gbps, and 2.5Gbps
SONET/SDH
•
Gigabit interface converter (GBIC)
•
Small form factor (SFF) and small form factor pluggable
(SFP) transceivers
•
Parallel 10G Ethernet
•
High-gain line driver and line receiver
Typical Performance
Markets
•
Telecom/datacom
•
Optical transceiver
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2007
M9999-020207-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88973BL
Typical Application Circuit
Ordering Information
(1)
Part Number
SY88973BLMG
(3)
Package
Type
QFN-16
(2, 3)
Operating
Range
Industrial
Industrial
Package Marking
973B with
Pb-Free bar-line indicator
973B with
Pb-Free bar-line indicator
Lead
Finish
Pb-Free
Matte-Sn
Pb-Free
Matte-Sn
SY88973BLMGTR
Notes:
QFN-16
1. Contact factory for die availability. Dice are guaranteed at TA = 25°C, DC Electricals only.
2. Tape and Reel.
3. Pb-Free package is recommended for new designs.
February 2007
2
M9999-020207-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88973BL
Pin Configuration
16-pin QFN
Pin Description
Pin Number
(QFN)
15
1, 4
6
14
Pin Name
/EN
DIN, /DIN
REF
LOSLVL
Input: Default is
maximum
sensitivity
Ground
Open Collector TTL
Output
Differential CML
Output
Power Supply
Type
TTL Input: Default
is high.
Differential Data
Input
Pin Function
Enable: De-asserts true data output when high. Incorporates 25k
Ω pull
-up to
VCC.
Differential data input. Each pin internally terminates to REF through 50
Ω.
Reference Voltage: Bypass with 0.01µF low ESR capacitor from REF to VCC
to stabilize LOSLVL and REF.
Loss-of-Signal Level Set: A resistor from this pin to VCC sets the threshold for
the data input amplitude at which the LOS output will be asserted.
Device ground. Exposed pad must be soldered (or equivalent) to the same
potential as the ground pins.
Loss-of-Signal: asserts high when the data input amplitude falls below the
threshold set by LOSLVL. For proper operation, connect an external 4.75k
Ω
to 10kΩ pull-up resistor between this pin and Vcc.
Differential data output.
Positive power supply. Bypass with 0.1µF|| 0.01µF low ESR capacitors.
0.01µF capacitors should be as close as possible to VCC pins.
2, 3, 10, 11
Exposed Pad
7
GND
LOS
9, 12
5, 8, 13, 16
DOUT,
/DOUT
VCC
February 2007
3
M9999-020207-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88973BL
Functional Block Diagram
February 2007
4
M9999-020207-A
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY88973BL
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
) ........................................... 0V to 4.0V
/EN, LOSLVL Voltage ........................................... 0V to V
CC
REF Current ................................................................ ±1mA
LOS Current ................................................................ ±5mA
DOUT, /DOUT Current .............................................. ±25mA
DIN, /DIN Current ...................................................... ±10mA
Lead Temperature (soldering, 20sec.) ....................... 260°C
Storage Temperature (T
s
) ......................... –65°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
CC
)................................. +3.0V to +3.6V
Ambient Temperature (T
A
) ....................... –40°C to +85°C
Junction Temperature (T
J
) ..................... –40°C to +120°C
Package Thermal Resistance
QFN
θ
JA
(Still-Air) ................................................. 61°C/W
ψ
JB
.............................................................. 38°C/W
DC Electrical Characteristics
V
CC
= 3.0V to 3.6V; T
A
= –40°C to +85°C, typical values at V
CC
= 3.3V, T
A
= 25°C.
Symbol
I
CC
V
REF
V
LOSLVL
V
OH
V
OL
V
OFFSET
Z
O
Z
I
Parameter
Power Supply Current
REF Voltage
LOSLVL Voltage Range
Output HIGH Voltage
Output LOW Voltage
Differential Output Offset
Single-Ended Output Impedance
Single-Ended Input Impedance
Note 6
Note 6
Note 6
40
40
50
50
V
REF
V
CC
–0.020
V
CC
–0.475
V
CC
–0.005
V
CC
–0.400
Condition
Note 4
Note 5
Min
Typ
28
45
V
CC
–1.3
V
CC
V
CC
V
CC
–0.350
±80
60
60
Max
42
62
Units
mA
mA
V
V
V
V
mV
Ω
Ω
TTL DC Electrical Characteristics
V
CC
= 3.0V to 3.6V; T
A
= –40°C to +85°C.
Symbol
I
OH
V
OL
V
IH
V
IL
I
IH
I
IL
Notes:
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 Rating 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. Thermal performance assumes the use of 4-layer PCB. Exposed pad must be soldered (or equivalent) to the device's most negative potential on the
PCB.
4. Excludes current of CML output stage. See “Detailed Description.”
5. Total device current with no output load.
6. Output levels are based on a 50Ω
to V
CC
load impedance. If the load impedance is different, the output level will be changed. Amplifier is in limiting
mode.
Parameter
LOS Output Leakage
LOS Output LOW Level
/EN Input HIGH Voltage
/EN Input LOW Voltage
/EN Input HIGH Current
/EN Input LOW Current
Condition
V
OH
= 3.6V
Sinking 2mA
Min
Typ
Max
100
0.5
Units
uA
V
V
V
µA
µA
uA
2.0
0.8
V
IN
= 2.7V
V
IN
= V
CC
V
IN
= 0.5V
–300
20
100
February 2007
5
M9999-020207-A
hbwhelp@micrel.com
or (408) 955-1690
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