SY898535L
Precision Differential 3.3V, Low Skew, 1:4
LVCMOS/LVTTL -to-LVPECL Fanout Buffer
General Description
The SY898535L is a 3.3V, low skew, 1:4 LVCMOS/LVTTL-
to-LVPECL fanout buffer with two selectable single ended
clock inputs. The CLK0 and CLK1 accept LVCMOS or
LVTTL input levels and translate them to 3.3V LVPECL
levels. To eliminate runt pulses on the outputs during
asynchronous assertion/de-assertion of the clock enable
pin, the clock enable is synchronized with the input signal.
The SY898535L operates from a 3.3V ±5% supply and is
guaranteed over the full industrial temperature range of
–40°C to +85°C. The SY898535L is part of Micrel’s high-
speed, Precision Edge
®
product line.
Datasheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
Provides four differential 3.3V LVPECL copies
Selects between single-ended CLK0 or CLK1 input
CLK0 and CLK1 accept LVCMOS or LVTTL input levels
Guaranteed AC performance over temperature and
supply voltage:
235MHz Maximum output frequency
<1.9ns Propagation delay (In-to-Q)
<30ps Output skew
<250ps Part-to-part skew
Additive phase jitter, RMS: 0.09ps (typical)
•
3.3V ±5% supply voltage
•
–40°C to +85°C industrial temperature operating range
•
Available in a 20-pin TSSOP package
Functional Block Diagram
Applications
•
•
•
•
Gigabit Ethernet
10Gigabit Ethernet
SONET/SDH
PCI
Markets
•
•
•
•
LAN/WAN
Enterprise servers
ATE
Test and measurement
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
June 2011
M9999-062211-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY898535L
Ordering Information
(1)
Part Number
SY898535LKY
SY898535LKYTR
(2)
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= 25°C, DC Electricals Only.
2. Tape and Reel.
Package Type
K4-20-1
K4-20-1
Operating Range
Industrial
Industrial
Package Marking
898535L with Pb-Free Bar-Line Indicator
898535L with Pb-Free Bar-Line Indicator
Truth Table
Inputs
CLK_EN
0
0
1
1
CLK_SEL
0
1
0
1
Selected Source
CLK0
CLK1
CLK0
CLK1
Q0 :Q3
Disabled : LOW
Disabled : LOW
Enabled
Enabled
Outputs
/Q0:/Q3
Disabled : HIGH
Disabled : HIGH
Enabled
Enabled
June 2011
2
M9999-062211-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY898535L
Pin Configuration
20-Pin TSSOP (K4-20-1)
Pin Description
Pin Number
1
Pin Name
V
EE
Pin Function
Ground.
Single-Ended Input: This TTL/CMOS input disables and enables the Q0-Q3 outputs. It is
internally connected to a 51kΩ pull-up resistor and will default to a logic HIGH state if left open.
When disabled, Q goes LOW and /Q goes HIGH. CLK_EN being synchronous, outputs will be
enabled/disabled following a rising and a falling edge of the input clock. V
TH
= is approximately
1.5V.
Single-Ended Input: This single-ended TTL/CMOS-compatible input selects the input to the
multiplexer. If HIGH, selects CLK1 input. When LOW, it selects CLK0 input. Note that this input
is internally connected to a 51kΩ pull-down resistor and will default to logic LOW state if left
open. V
TH
= is approximately 1.5V.
Single-Ended Input: This LVCMOS or LVTTL signal is the input signal to the device. It is
internally connected to a 51kΩ pull-down resistor and will default to a logic LOW state if left
open. This input is selected when CLK_SEL is set to logic LOW.
Single-Ended Input: This LVCMOS or LVTTL signal is the input signal to the device. It is
internally connected to a 51kΩ pull-down resistor and will default to a logic LOW state if left
open. This input is selected when CLK_SEL is set to logic HIGH.
Unused Pins
Positive Power Supply Pins: Bypass with 0.1µF||0.01µF low ESR capacitors as close to the V
CC
pins as possible.
LVPECL Differential Output Pairs: Differential buffered output copies the selected input signal.
The output swing is typically 800mV. Unused output pairs may be left floating with no impact on
jitter. These differential LVPECL outputs are a logic function of the CLK0 and CLK1 inputs. See
“Truth Table” below.
2
CLK_EN
3
CLK_SEL
4
CLK0
6
5, 7, 8, 9
10, 13, 18
20, 19
17, 16
15, 14
12, 11
CLK1
NC
VCC
Q0, /Q0
Q1, /Q1
Q2, /Q2
Q3, /Q3
June 2011
3
M9999-062211-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY898535L
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
).................................... –0.5V to +4.6V
Input Voltage (V
IN
) ..................................–0.5V to V
CC
+0.5V
LVPECL Output Current (I
OUT
) .............................................
Continuous............................................................50mA
Surge ..................................................................100mA
Lead Temperature (soldering, 20 sec.).................... +260°C
Storage Temperature (T
s
) ........................... –65°C to 150°C
Operating Ratings
(2)
Supply Voltage (V
CC
)............................ +3.135V to +3.465V
Ambient Temperature (T
A
) ...........................-40°C to +85°C
(3)
Package Thermal Resistance
TSSOP (θ
JA
)
Still-Air......................................................73.2°C/W
Power Supply DC Electrical Characteristics
(4)
V
CC
= 3.3V ±5%; T
A
= -40°C to +85°C, unless otherwise stated.
Symbol
V
CC
I
EE
Parameter
Power Supply
Power Supply Current
No load, max V
CC
Condition
Min
3.135
Typ
3.3
Max
3.465
55
Units
V
mA
LVCMOS/LVTTL DC Electrical Characteristics
(4)
V
CC
= 3.3V ±5%; T
A
= -40°C to +85°C, unless otherwise stated.
Symbol
V
IH
V
IL
I
IH
I
IL
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
CLK0, CLK1
CLK_EN, CLK_SEL
CLK0, CLK1
CLK_EN, CLK_SEL
CLK0, CLK1, CLK_SEL
CLK_EN
CLK0, CLK1, CLK_SEL
CLK_EN
V
IN
= V
CC
= 3.465V
V
IN
= V
CC
= 3.465V
V
IN
= 0V, V
CC
= 3.465V
V
IN
= 0V, V
CC
= 3.465V
-5
-150
Condition
Min
2
2
-0.3
-0.3
Typ
Max
V
CC
+ 0.3V
V
CC
+ 0.3V
1.3
0.8
150
5
Units
V
V
V
V
µA
µA
µA
µA
LVPECL DC Electrical Characteristics
(4)
V
CC
= 3.3V ±5%; T
A
= -40°C to +85°C, unless otherwise stated.
Symbol
V
OH
V
OL
V
SWING
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.
θ
JA
value is 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.
50Ω to V
CC
-2V terminated outputs.
Parameter
Output High Voltage
Output Low Voltage
(5)
(5)
Condition
Min
V
CC
- 1.4
V
CC
– 2.0
0.6
Typ
Max
V
CC
– 0.9
V
CC
- 1.7
1.0
Units
V
V
V
Peak-to-Peak Output Voltage
Swing
June 2011
4
M9999-062211-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY898535L
AC Electrical Characteristics
(6)
V
CC
= 3.3V ±5%; R
L
= 50Ω to V
CC
-2V; T
A
= -40°C to +85°C, unless otherwise stated.
Symbol
f
MAX
t
PD
t
SKEW
t
JITTER
t
r,
t
f
odc
Notes:
6.
7.
8.
9.
High-frequency AC-parameters are guaranteed by design and characterization.
Measured from V
CC
/2 of the input to the differential output crossing point.
Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at the output differential cross points.
Defined as skew between outputs on different devices operating at the same supply voltages and with equal load conditions. Using the same type
of inputs on each device, the outputs are measured at the differential cross points.
Parameter
Maximum Operating Frequency
Propagation Delay
(7)
Output-to-Output Skew
(8)
Part-to-Part Skew
(9)
(10)
Condition
f
≤
266MHz
Min
1.0
Typ
Max
235
1.4
Units
MHz
ns
ps
ps
ps
RMS
ps
%
11
0.09
20% to 80% @ 50MHz
300
48
50
30
250
700
52
Additive Phase Jitter
Output Duty Cycle
Output Rise/Fall Time
10. Driving only one input clock.
June 2011
5
M9999-062211-B
hbwhelp@micrel.com
or (408) 955-1690
微控制器 MCU
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