SY89853U
Precision Low-Power Dual 2:1 LVPECL MUX
with Internal Termination
General Description
The SY89853U features two, low jitter 2:1 differential
multiplexers with 100K LVPECL (800mV) compatible
outputs, capable of handling clocks up to 2.5GHz and
data streams up to 2.5Gbps.
The SY89853U differential inputs include Micrel’s
unique, 3-input termination architecture that allows
users to interface to any differential signal (AC- or DC-
Coupled) as small as 100mV without any level shifting
or termination resistors networks in the signal path. The
result is a clean, stub-free, low jitter interface solution.
The differential 800mV LVPECL outputs have fast
rise/fall times guaranteed to be less than 180ps.
The SY89853U operates from a 2.5V ±5% or a 3.3V
±10% supply, and is guaranteed over the full industrial
temperature range (–40°C to +85°C). For applications
that require higher performance, consider the
SY58026U. The SY89853U is part of Micrel's Precision
®
Edge product family.
All support documentation can be found on Micrel’s web
site at
www.micrel.com.
Precision Edge
®
Features
•
Dual 2:1 MUX, each channel selects from inputs
•
Unique, patent-pending input isolation design
minimizes crosstalk
•
Low power 210mW (V
CC
= 2.5V)
•
Guaranteed AC performance over temperature and
voltage:
- DC-to->2.5Gbps data rate throughput
- <360ps IN-to-Q t
pd
- <180ps t
r
/t
f
times
•
Ultra-low jitter design:
- <1ps
RMS
random jitter
- <10ps
PP
deterministic jitter
- <10ps
PP
total jitter (clock)
- <0.7ps
RMS
crosstalk-induced jitter
•
Unique, patent-pending 50Ω
input termination and
VT pin accepts DC- and AC-coupled inputs (CML,
LVDS, PECL)
•
800mV LVPECL output swing
•
Power supply 2.5V ±5% or 3.3V ±10%
•
–40°C to +85°C temperature range
•
Available in 32-pin (5mm x 5mm) QFN package
Applications
•
•
•
•
Data communication systems
All SONET OC-3 to OC-48 applications
All Fibre Channel applications
All GigE applications
Markets
•
•
•
•
United States Patent No. RE44,134
Precision Edge is a registered trademark of Micrel, Inc
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
LAN/WAN communication
Enterprise servers
ATE
Test and measurement
August 2007
M9999-082907-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY89853U
Functional Block Diagram
Truth Table
SEL
0
1
Q
IN0 Input Select
IN1 Input Select
August 2007
2
M9999-082907-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY89853U
Ordering Information
(1)
Part Number
SY89853UMG
SY89853UMGTR
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= 25ºC, DC Electricals only.
2. Tape and Reel.
(2)
Package
Type
QFN-32
QFN-32
Operating
Range
Industrial
Industrial
Package Marking
SY89853U with Pb-Free bar-line indicator
SY89853U with Pb-Free bar-line indicator
Lead Finish
NiPdAu Pb-Free
NiPdAu Pb-Free
Pin Configuration
32-Pin QFN
Pin Description
Pin Number
25, 28,
29, 32
1, 4
5, 8
Pin Name
INA0, /INA0,
INA1, /INA1,
INB0, /INB0,
INB1, /INB1
Pin Function
Differential Inputs: These input pairs are the differential signal inputs to the device. Inputs
accept AC- or DC-coupled signals as small as 100mV. Each pin of a pair internally
terminates to a VT pin through 50Ω.
Note that these inputs will default to an indeterminate
state if left open. Connecting one input to VCC and the complementary input-to-GND
through 1kΩ
resistor can terminate unused differential input pairs. The VT pin is to
be left
open in this configuration. Please refer to the “Input Interface Applications” section for more
details.
Positive power supply. Bypass with 0.1µF//0.01µF low ESR capacitors. The 0.01µF
capacitor should be as close to VCC pin as possible.
Not connected.
Bank A and Bank B Input Channel Select (TTL/CMOS): These TTL/CMOS-compatible
inputs select the inputs to the multiplexers. These inputs are internally connected to a
25kΩ
pull-up
resistor and will default to logic HIGH state if left open.
Differential Outputs: These LVPECL output pairs are the outputs of the device. They are a
logic function of the INA0, INA1, INB0, INB1 and SELA and SELB inputs. Please refer to
the “Truth Table” below for details.
Input Termination Center-Tap: Each side of the differential input pair terminates to a VT
pin. The VTA0, VTA1, VTB0, VTB1 pins provide a center-tap to a termination network for
maximum interface flexibility. See “Input Interface Applications” section for details.
Reference Voltages: These reference voltage outputs are equivalent to V
CC
-1.2V. They are
used for AC-coupled inputs. Connect VREF-AC directly to the VT pin and bypass with
0.01
µ
F low ESR capacitor to V
CC
. See
“
Input Interface Applications
”
section. Maximum
sink/source current is
±
1.5mA.
Ground: Ground pins and exposed pad must be connected to the same ground plane.
10, 13, 16, 17,
20, 23
14, 19
18
15
22, 21
12, 11
26, 30
2, 6
27
31
3
7
9, 24
VCC
NC
SELA,
SELB
QA, /QA,
QB, /QB
VTA0, VTA1
VTB0, VTB1
VREF-ACA0,
VREF-ACA1,
VREF-ACB0,
VREF-ACB1
GND,
Exposed Pad
August 2007
3
M9999-082907-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY89853U
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
) ............................ –0.5V to +4.0V
Input Voltage (V
IN
) ....................................–0.5V to V
CC
LVPECL Output Current (I
OUT
)
Continuous ................................................. ±50mA
Surge ....................................................... ±100mA
Termination Current
Source or Sink Current on V
T
.................... ±50mA
Input Current
Source or Sink Current on IN, /IN .............. ±50mA
Current (V
REF-AC
)
Source or Sink Current on V
REF-AC
............... ±2mA
Lead Temperature (soldering, 20sec.) ............... 260°C
Storage Temperature (T
s
) .................–65°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
CC
) ..................... +2.375V to +2.625V
..................................................... +3.0V to +3.6V
Ambient Temperature (T
A
) .................... –40°C to +85°C
(3)
Package Thermal Resistance
QFN (θ
JA
)
Still-Air ......................................................35°C/W
500lfpm ....................................................28°C/W
QFN (ψ
JB
)
Junction-to-Board .....................................16°C/W
DC Electrical Characteristics
(4)
T
A
= –40°C to +85°C, unless otherwise noted.
Symbol
V
CC
I
CC
R
IN
R
DIFF_IN
V
IH
V
IL
V
IN
V
DIFF_IN
V
T_IN
V
REF-AC
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 ratings 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. Package thermal resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB.
θ
JA
and
ψ
JB
values are determined for a 4-layer board in still-air, unless otherwise stated.
4. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.
5. V
IH
(min) not lower than 1.2V.
Parameter
Power Supply
Power Supply Current
Input Resistance
(IN-to-VT)
Differential Input Resistance
(IN-to-/IN)
Input High Voltage
(IN, /IN)
Input Low Voltage
(IN, /IN)
Input Voltage Swing
(IN-to-/IN)
Differential Input Voltage Swing
|IN
- /IN|
Maximum Input Voltage
(IN-to-V
T
)
Output Reference Voltage
Condition
V
CC
= 2.5V
V
CC
= 3.3V
No load, max. V
CC
.
Min
2.375
3.0
45
90
Typ
2.5
3.3
65
50
100
Max
2.625
3.6
85
55
110
V
CC
V
IH
– 0.1
1.7
Units
V
V
mA
Ω
Ω
V
V
V
V
Note 5
V
CC
– 1.6
0
See Figure 1a.
See Figure 1b.
0.1
0.2
1.28
V
CC
– 1.3
V
CC
– 1.2
V
CC
– 1.1
V
V
August 2007
4
M9999-082907-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY89853U
LVPECL Outputs DC Electrical Characteristics
(5)
V
CC
= 2.5V ±5% or 3.3V ±10%; R
L
= 50Ω
to V
CC
–2V; T
A
= –40°C to +85°C, unless otherwise noted.
Symbol
V
OH
V
OL
V
OUT
V
DIFF-OUT
Parameter
Output High Voltage
(Q, /Q)
Output Low Voltage
(Q, /Q)
Output Voltage Swing
(Q, /Q)
Differential Output Voltage Swing
(Q, /Q)
See Figure 1a.
See Figure 1b.
Condition
Min
V
CC
–1.145
V
CC
–1.945
400
800
800
1600
Typ
Max
V
CC
–0.895
V
CC
–1.695
Units
V
V
mV
mV
LVTTL/CMOS DC Electrical Characteristics
(5)
V
CC
= 2.5V ±5% or 3.3V ±10%; T
A
= –40°C to +85°C, unless otherwise noted.
Symbol
V
IH
V
IL
I
IH
I
IL
Notes:
5. The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
Condition
Min
2.0
Typ
Max
0.8
Units
V
V
µA
µA
V
IN
= V
CC
V
IN
= 0.5V
–300
75
August 2007
5
M9999-082907-C
hbwhelp@micrel.com
or (408) 955-1690
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