1:5 Differential-to-LVDS Zero Delay
Clock Generator
ICS8745B
DATA SHEET
General Description
The ICS8745B is a highly versatile 1:5 LVDS Clock
Generator and a member of the HiPerClockS™ family
HiPerClockS™
of High Performance Clock Solutions from IDT. The
ICS8745B has a fully integrated PLL and can be
configured as zero delay buffer, multiplier or divider,
and has an output frequency range of 31.25MHz to 700MHz. The
Reference Divider, Feedback Divider and Output Divider are each
programmable, thereby allowing for the following output-to-input
frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8. The external
feedback allows the device to achieve “zero delay” between the input
clock and the output clocks. The PLL_SEL pin can be used to
bypass the PLL for system test and debug purposes. In bypass
mode, the reference clock is routed around the PLL and into the
internal output dividers.
Features
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Five differential LVDS outputs designed to meet
or exceed the requirements of ANSI TIA/EIA-644
Selectable differential clock inputs
CLKx, nCLKx pairs can accept the following differential
input levels: LVPECL, LVDS, LVHSTL, HCSL, SSTL
Output frequency range: 31.25MHz to 700MHz
Input frequency range: 31.25MHz to 700MHz
VCO range: 250MHz to 700MHz
External feedback for “zero delay” clock regeneration
with configurable frequencies
Programmable dividers allow for the following output-to-input
frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8
Cycle-to-cycle jitter: 30ps (maximum)
Output skew: 35ps (maximum)
Static phase offset: 25ps ± 125ps
Full 3.3V supply voltage
0°C to 70°C ambient operating temperature
Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
ICS
Block Diagram
Q0
nQ0
PLL_SEL
Pullup
Pin Assignment
PLL_SEL
SEL3
V
DDA
CLK0
Pulldown
nCLK0
Pullup
CLK1
Pulldown
nCLK1
Pullup
CLK_SEL
Pulldown
FB_IN
Pulldown
nFB_IN
Pullup
÷1, ÷2, ÷4, ÷8,
÷16, ÷32
,
÷64
0
Q1
nQ1
0
Q2
nQ2
Q3
nQ3
Q4
nQ4
SEL0
SEL1
CLK0
nCLK0
CLK1
nCLK1
CLK_SEL
MR
1
2
3
4
5
6
7
8
32 31 30 29 28 27 26 25
24
23
22
21
20
19
18
17
9
V
DD
GND
V
DDO
Q4
nQ4
V
DD
Q3
nQ3
V
DDO
Q2
nQ2
GND
Q1
nQ1
1
1
PLL
8:1, 4:1, 2:1, 1:1,
1:2, 1:4, 1:8
10 11 12 13 14 15 16
nFB_IN
FB_IN
SEL2
GND
V
DDO
nQ0
Q0
SEL0
Pulldown
SEL1
Pulldown
SEL2
Pulldown
SEL3
Pulldown
MR
Pulldown
ICS8745B
32-Lead LQFP 7mm x 7mm x 1.4mm
package body
Top View
ICS8745BY REVISION D JUNE 29, 2009
1
©2009 Integrated Device Technology, Inc.
ICS8745B Data Sheet
1:5 DIFFERENTIAL-TO-LVDS ZERO DELAY CLOCK GENERATOR
Table 1. Pin Descriptions
Number
1, 2,
12, 29
3
4
5
6
7
Name
SEL0, SEL1,
SEL2 SEL3
CLK0
nCLK0
CLK1
nCLK1
CLK_SEL
Input
Input
Input
Input
Input
Input
Type
Pulldown
Pulldown
Pullup
Pulldown
Pullup
Pulldown
Description
Determines output divider values in Table 3. LVCMOS / LVTTL interface levels.
Non-inverting differential clock input.
Inverting differential clock input.
Non-inverting differential clock input.
Inverting differential clock input.
Clock select input. When HIGH, selects CLK1,nCLK1. When LOW, selects CLK0,
nCLK0. LVCMOS / LVTTL interface levels.
Active HIGH Master Reset. When logic HIGH, the internal dividers are reset
causing the true outputs Qx to go low and the inverted outputs nQx to go high.
When logic LOW, the internal dividers and the outputs are enabled.
LVCMOS / LVTTL interface levels.
Core supply pins.
Pullup
Pulldown
Inverting differential feedback input to phase detector for regenerating clocks with
“Zero Delay.”
Non-inverted differential feedback input to phase detector for regenerating clocks
with “Zero Delay.”
Power supply ground.
Differential output pair. LVDS interface levels.
Output 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.
Analog supply pin.
Pullup
PLL select. Selects between the PLL and reference clock as the input to the
dividers. When LOW, selects reference clock. LVCMOS/LVTTL interface levels.
8
MR
Input
Pulldown
9, 32
10
11
13, 19, 25
14, 15
16, 22, 28
17, 18
20, 21
23, 24
26, 27
30
31
V
DD
FBIN
FBIN
GND
nQ0/Q0
V
DDO
nQ1/Q1
nQ2/Q2
nQ3/Q3
nQ4/Q4
V
DDA
PLL_SEL
Power
Input
Input
Power
Output
Power
Output
Output
Output
Output
Power
Input
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
Ω
k
Ω
ICS8745BY REVISION D JUNE 29, 2009
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©2009 Integrated Device Technology, Inc.
ICS8745B Data Sheet
1:5 DIFFERENTIAL-TO-LVDS ZERO DELAY CLOCK GENERATOR
Function Tables
Table 3A. Control Input Function Table
Inputs
Outputs
PLL_SEL = 1
PLL Enable Mode
Reference Frequency Range (MHz)*
250 - 700
125 - 350
62.5 - 175
31.25 - 87.5
250 - 700
125 - 350
62.5 - 175
250 - 700
125 - 350
250 - 700
125 - 350
62.5 - 175
31.25 - 87.5
62.5 - 175
31.25 - 87.5
31.25 - 87.5
Q[0:4], nQ[0:4]
÷1
÷1
÷1
÷1
÷2
÷2
÷2
÷4
÷4
÷8
x2
x2
x2
x4
x4
x8
SEL3
0z
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
SEL2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
SEL1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
SEL0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
*NOTE: VCO frequency range for all configurations above is 250MHz to 700MHz.
ICS8745BY REVISION D JUNE 29, 2009
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©2009 Integrated Device Technology, Inc.
ICS8745B Data Sheet
1:5 DIFFERENTIAL-TO-LVDS ZERO DELAY CLOCK GENERATOR
Table 3B. PLL Bypass Function Table
Inputs
Outputs
PLL_SEL = 0
PLL Bypass Mode
SEL1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
SEL0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Q[0:4], nQ[0:4]
÷4
÷4
÷4
÷8
÷8
÷8
÷16
÷16
÷32
÷64
÷2
÷2
÷4
÷1
÷2
÷1
SEL3
0z
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
SEL2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
ICS8745BY REVISION D JUNE 29, 2009
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©2009 Integrated Device Technology, Inc.
ICS8745B Data Sheet
1:5 DIFFERENTIAL-TO-LVDS ZERO DELAY CLOCK GENERATOR
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,
θ
JA
Storage Temperature, T
STG
Rating
4.6V
-0.5V to V
DD
+ 0.5V
10mA
15mA
47.9°C/W (0 lfpm)
-65°C to 150°C
DC Electrical Characteristics
Table 4A. LVDS Power Supply DC Characteristics,
V
DD
= V
DDO
= 3.3V ± 5%, T
A
= -0°C to 70°C
Symbol
V
DD
V
DDA
V
DDO
I
DD
I
DDA
I
DDO
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
Test Conditions
Minimum
3.135
3.135
3.135
Typical
3.3
3.3
3.3
Maximum
3.465
3.465
3.465
125
17
59
Units
V
V
V
mA
mA
mA
Table 4B. LVCMOS/LVTTL DC Characteristics,
V
DD
= V
DDO
= 3.3V ± 5%, T
A
= 0°C to 70°C
Symbol
V
IH
V
IL
I
IH
Parameter
Input High Voltage
Input Low Voltage
CLK_SEL,
SEL[0:3], MR
PLL_SEL
CLK_SEL,
SEL[0:3], MR
PLL_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
-5
-150
Test Conditions
Minimum
2
-0.3
Typical
Maximum
V
DD
+ 0.3
0.8
150
5
Units
V
V
µA
µA
µA
µA
Input High Current
I
IL
Input Low Current
ICS8745BY REVISION D JUNE 29, 2009
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©2009 Integrated Device Technology, Inc.
