Low Skew, 1-to-4,
Differential-to-LVDS Fanout Buffer
General Description
The ICS8543I is a low skew, high performance 1-to-4 Differen-
tial-to-LVDS Clock Fanout Buffer. Utilizing Low Voltage Differential
Signaling (LVDS) the ICS8543I provides a low power, low noise, so-
lution for distributing clock signals over controlled impedances of
100. The ICS8543I has two selectable clock inputs. The CLK,
nCLK pair can accept most standard differential input levels. The
PCLK, nPCLK pair can accept LVPECL, CML, or SSTL input levels.
The clock enable is internally synchronized to eliminate runt pulses
on the outputs during asynchronous assertion/deassertion of the
clock enable pin.
Guaranteed output and part-to-part skew characteristics make the
ICS8543I ideal for those applications demanding well defined perfor-
mance and repeatability.
ICS8543I
DATA SHEET
Features
•
•
•
•
•
•
•
•
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•
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Four differential LVDS output pairs
Selectable differential CLK/nCLK or LVPECL clock inputs
CLK/nCLK pair can accept the following differential input levels:
LVPECL, LVDS, LVHSTL, SSTL, HCSL
PCLK/nPCLK pair can accept the following differential input
levels: LVPECL, CML, SSTL
Maximum output frequency: 650MHz
Translates any single-ended input signals to LVDS levels with
resistor bias on nCLK input
Additive phase Jitter, RMS: 0.164ps (typical)
Output skew: 40ps (maximum)
Part-to-part skew: 600ps (maximum)
Propagation delay: 2.6ns (maximum)
Full 3.3Vsupply mode
-40°C to 85°C ambient operating temperature
Available in lead-free packages
Block Diagram
CLK_EN
Pullup
D
Q
CLK
Pulldown
nCLK
Pullup
PCLK
Pulldown
nPCLK
Pullup
CLK_SEL
Pulldown
LE
Pin Assignment
GND
CLK_EN
CLK_SEL
CLK
nCLK
PCLK
nPCLK
OE
GND
V
DD
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
Q0
nQ0
V
DD
Q1
nQ1
Q2
nQ2
GND
Q3
nQ3
0
0
1
1
Q0
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
ICS8543I
20-Lead TSSOP
6.5mm x 4.4mm x 0.925
mm
OE
Pullup
package body
G Package
Top View
ICS8543BGI REVISION E NOVEMBER 15, 2012
1
©2012 Integrated Device Technology, Inc.
ICS8543I Data Sheet
LOW SKEW, 1-to-4, DIFFERENTIAL-TO-LVDS FANOUT BUFFER
Table 1. Pin Descriptions
Number
1, 9, 13
2
Name
GND
CLK_EN
Power
Input
Pullup
Type
Description
Power supply ground.
Synchronizing clock enable. When HIGH, clock outputs follows clock input.
When LOW, Qx outputs are forced low, nQx outputs are forced high.
LVCMOS / LVTTL interface levels.
Clock select input. When HIGH, selects PCLK/nPCLK inputs.
When LOW, selects CLK/nCLK inputs. LVCMOS / LVTTL interface levels.
Non-inverting differential clock input.
Inverting differential clock input.
Non-inverting differential LVPECL clock input.
Inverting differential LVPECL clock input.
Output enable. Controls enabling and disabling of outputs Q0/nQ0 through
Q3/nQ3. LVCMOS/LVTTL interface levels.
Positive supply pins.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
3
4
5
6
7
8
10, 18
11, 12
14, 15
16, 17
19, 20
CLK_SEL
CLK
nCLK
PCLK
nPCLK
OE
V
DD
nQ3, Q3
nQ2, Q2
nQ1, Q1
nQ0, Q0
Input
Input
Input
Input
Input
Input
Power
Output
Output
Output
Output
Pulldown
Pulldown
Pullup
Pulldown
Pullup
Pullup
NOTE:
Pullup and Pulldown
refer to internal input resistors. See Table 2,
Pin Characteristics,
for typical values.
Table 2. Pin Characteristics
Symbol
C
IN
R
PULLUP
R
PULLDOWN
Parameter
Input Capacitance
Input Pullup Resistor
Input Pulldown Resistor
Test Conditions
Minimum
Typical
4
51
51
Maximum
Units
pF
k
k
ICS8543BGI REVISION E NOVEMBER 15, 2012
2
©2012 Integrated Device Technology, Inc.
ICS8543I Data Sheet
LOW SKEW, 1-to-4, DIFFERENTIAL-TO-LVDS FANOUT BUFFER
Function Tables
Table 3A. Control Input Function Table
Inputs
OE
0
1
1
1
1
CLK_EN
X
0
0
1
1
CLK_SEL
X
0
1
0
1
CLK/nCLK
PCLK/nPCLK
CLK/nCLK
PCLK/nPCLK
Selected Source
Q0:Q3
Hi-Z
Disabled; Low
Disabled; Low
Enabled
Enabled
Outputs
nQ0:nQ3
Hi-Z
Disabled; High
Disabled; High
Enabled
Enabled
After CLK_EN switches, the clock outputs are disabled or enabled following a rising and falling input clock edge as shown in Figure 1.
In the active mode, the state of the outputs are a function of the CLK/nCLK and PCLK/nPCLK inputs as described in Table 3B.
Disabled
nCLK, nPCLK
CLK, PCLK
Enabled
CLK_EN
nQ0:nQ3
Q0:Q3
Figure 1. CLK_EN Timing Diagram
Table 3B. Clock Input Function Table
Inputs
CLK or PCLK
0
1
0
1
Biased; NOTE 1
Biased; NOTE 1
nCLK or nPCLK
1
0
Biased; NOTE 1
Biased; NOTE 1
0
1
Q[0:3]
LOW
HIGH
LOW
HIGH
HIGH
LOW
Outputs
nQ[0:3]
HIGH
LOW
HIGH
LOW
LOW
HIGH
Input to Output Mode
Differential to Differential
Differential to Differential
Single-Ended to Differential
Single-Ended to Differential
Single-Ended to Differential
Single-Ended to Differential
Polarity
Non-Inverting
Non-Inverting
Non-Inverting
Non-Inverting
Inverting
Inverting
NOTE 1: Please refer to the Application Information section,
Wiring the Differential Input to Accept Single-Ended Levels.
ICS8543BGI REVISION E NOVEMBER 15, 2012
3
©2012 Integrated Device Technology, Inc.
ICS8543I Data Sheet
LOW SKEW, 1-to-4, DIFFERENTIAL-TO-LVDS FANOUT BUFFER
Absolute Maximum Ratings
NOTE: Stresses beyond those listed under
Absolute Maximum Ratings
may cause permanent damage to the device. These ratings are stress
specifications only. Functional operation of product at these conditions or any conditions beyond those listed in the
DC Characteristics or AC
Characteristics
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability.
Item
Supply Voltage, V
DD
Inputs, V
I
Outputs, I
O
Continuos Current
Surge Current
Package Thermal Impedance,
JA
Storage Temperature, T
STG
Rating
4.6V
-0.5V to V
DD
+ 0.5V
10mA
15mA
73.2C/W (0 lfpm)
-65C to 150C
DC Electrical Characteristics
Table 4A. Power Supply DC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
V
DD
I
DD
Parameter
Positive Supply Voltage
Power Supply Current
Test Conditions
Minimum
3.135
Typical
3.3
Maximum
3.465
50
Units
V
mA
Table 4B. LVCMOS/LVTTL DC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
V
IH
V
IL
I
IH
Parameter
Input High Voltage
Input Low Voltage
OE, CLK_EN
Input High Current
CLK_SEL
OE, CLK_EN
I
IL
Input Low Current
CLK_SEL
V
DD
= V
IN
= 3.465V
V
DD
= V
IN
= 3.465V
V
DD
= 3.465V, V
IN
= 0V
V
DD
= 3.465V, V
IN
= 0V
-150
-5
Test Conditions
Minimum
2
-0.3
Typical
Maximum
V
DD
+ 0.3
0.8
5
150
Units
V
V
µA
µA
µA
µA
Table 4C. Differential DC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
I
IH
Parameter
CLK
Input High Current
nCLK
CLK
I
IL
V
PP
V
CMR
Input Low Current
nCLK
Peak-to-Peak Voltage; NOTE 1
Common Mode Input Voltage;
NOTE 1, 2
Test Conditions
V
DD
= V
IN
= 3.465V
V
DD
= V
IN
= 3.465V
V
DD
= 3.465V, V
IN
= 0V
V
DD
= 3.465V, V
IN
= 0V
-5
-150
0.15
0.5
1.3
V
DD
– 0.85
Minimum
Typical
Maximum
150
5
Units
µA
µA
µA
µA
V
V
NOTE 1: V
IL
should not be less than -0.3V.
NOTE 2: Common mode input voltage is defined as V
IH
.
ICS8543BGI REVISION E NOVEMBER 15, 2012
4
©2012 Integrated Device Technology, Inc.
ICS8543I Data Sheet
LOW SKEW, 1-to-4, DIFFERENTIAL-TO-LVDS FANOUT BUFFER
Table 4D. LVPECL DC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
I
IH
Parameter
PCLK
Input High Current
nPCLK
PCLK
I
IL
V
PP
V
CMR
Input Low Current
nPCLK
Peak-to-Peak Voltage; NOTE 1
Common Mode Input Voltage;
NOTE 1, 2
Test Conditions
V
DD
= V
IN
= 3.465V
V
DD
= V
IN
= 3.465V
V
DD
= 3.465V, V
IN
= 0V
V
DD
= 3.465V, V
IN
= 0V
-5
-150
0.3
1.5
1
V
DD
Minimum
Typical
Maximum
150
5
Units
µA
µA
µA
µA
V
V
NOTE 1: V
IL
should not be less than -0.3V.
NOTE 2: Common mode input voltage is defined as V
IH
.
Table 4E. LVDS DC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Symbol
V
OD
V
OD
V
OS
V
OS
I
Oz
I
OFF
I
OSD
I
OS
V
OH
V
OL
Parameter
Differential Output Voltage
V
OD
Magnitude Change
Offset Voltage
V
OS
Magnitude Change
High Impedance Leakage
Power Off Leakage
Differential Output Short Circuit
Current
Output Short Circuit Current
Output Voltage High
Output Voltage Low
0.9
-10
-20
±1
-3.5
-3.5
1.34
1.06
1.125
Test Conditions
Minimum
200
Typical
280
0
1.25
5
Maximum
360
40
1.375
25
+10
+20
-5
-5
1.6
Units
mV
mV
V
mV
µA
µA
mA
mA
V
V
AC Electrical Characteristics
Table 5. AC Characteristics,
V
DD
= 3.3V ± 5%, T
A
= -40°C to 85°C
Parameter
f
MAX
tjit
t
PD
tsk(o)
tsk(pp)
t
R
/ t
F
odc
Symbol
Maximum Output Frequency
Buffer Additive Phase Jitter, RMS;
refer to Additive Phase Jitter Section
Propagation Delay; NOTE 1
Output Skew; NOTE 2, 4
Part-to-Part Skew; NOTE 3, 4
Output Rise/Fall Time
Output Duty Cycle
odc
20% to 80% @ 50MHz
150
45
50
153.6MHz, Integration
Range: 12kHz – 20MHz
ƒ
650MHz
1.5
0.164
2.6
40
600
450
55
Test Conditions
Minimum
Typical
Maximum
650
Units
MHz
ps
ns
ps
ps
ps
%
All parameters measured at 500MHz unless noted otherwise.
NOTE 1: Measured from the differential input crossing point to the differential output crossing point.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions.
Measured at the differential output crosspoints.
NOTE 3: 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 crosspoints.
NOTE 4: This parameter is defined in accordance with JEDEC Standard 65.
ICS8543BGI REVISION E NOVEMBER 15, 2012
5
©2012 Integrated Device Technology, Inc.
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