DATASHEET
LOCO™ PLL CLOCK MULTIPLIER
Description
The ICS501B LOCO
TM
is the most cost effective way to
generate a high-quality clock output from a lower
frequency crystal or clock input. The name LOCO
stands for Low Cost Oscillator, as it is designed to
replace crystal oscillators in most electronic systems.
Using Phase-Locked Loop (PLL) techniques, the
device uses a standard fundamental mode,
inexpensive crystal to produce output clocks up to 15
MHz.
Stored in the chip’s ROM is the ability to generate nine
different multiplication factors, allowing one chip to
output many common frequencies (see table on page
2).
The device also has an output enable pin which
tri-states the clock output when the OE pin is taken low.
This product is intended for clock generation. It has low
output jitter (variation in the output period), but input to
output skew and jitter are not defined or guaranteed.
For applications which require defined input to output
skew, use the ICS570B.
ICS501B
Features
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Packaged as 8 pin SOIC or die
Available in Pb (lead) free package
IDT’s lowest cost PLL clock
Zero ppm multiplication error
Output clock frequencies up to 15 MHz
Extremely low jitter of 25 ps (one sigma)
Compatible with popular CPUs
Duty cycle of 45/55 up to 20 MHz
Nine selectable frequencies
Operating voltage of 3.3 V or 5.5 V
Tri-state output for board level testing
25 mA drive capability at TTL levels
Ideal for oscillator replacement
Industrial temperature version available
Advanced, low-power CMOS process
Block Diagram
VDD
S1:0
X1/ICLK
Crystal or
Clock input
X2
2
Crystal
Oscillator
PLL Clock
Multiplier
Circuitry
and ROM
CLK
Optional crystal capacitors
GND
OE
IDT™ / ICS™
LOCO™ PLL CLOCK MULTIPLIER
1
ICS501B
REV D 120307
ICS501B
LOCO™ PLL CLOCK MULTIPLIER
CLOCK MULTIPLIER
Pin Assignment
Clock Output Table
S1 S0
0
0
M
1
0
M
1
0
M
1
CLK
4X input
5.3125X input
5X input
6.25X input
2X input
3.125X input
6X input
3X input
8X input
Minimum Input
0.5 MHz
1 MHz
0.5 MHz
0.5 MHz
1 MHz
1 MHz
0.5MHz
0.5MHz
0.5MHz
X1/ I CLK
VDD
GND
S1
1
2
3
4
8
7
6
5
X2
OE
S0
CLK
0
0
M
M
M
1
1
1
8 Pi n ( 150 mi l ) SOI C
0 = connect directly to ground
1 = connect directly to VDD
M = leave unconnected (floating)
Pin Descriptions
Pin
Number
1
2
3
4
5
6
7
8
Pin
Name
XI/ICLK
VDD
GND
S1
CLK
S0
OE
X2
Pin
Type
Input
Power
Power
Tri-level Iinput
Output
Tri-level Input
Input
Output
Pin Description
Crystal connection or clock input.
Connect to +3.3 V or +5 V.
Connect to ground.
Select 1 for output clock. Connect to GND or VDD or float.
Clock output per table above.
Select 0 for output clock. Connect to GND or VDD or float.
Output enable. Tri-states CLK output when low. Internal pull-up.
Crystal connection. Leave unconnected for clock input.
IDT™ / ICS™
LOCO™ PLL CLOCK MULTIPLIER
2
ICS501B
REV D 120307
ICS501B
LOCO™ PLL CLOCK MULTIPLIER
CLOCK MULTIPLIER
External Components
Decoupling Capacitor
As with any high-performance mixed-signal IC, the
ICS501B must be isolated from system power supply
noise to perform optimally.
A decoupling capacitor of 0.01µF must be connected
between VDD and the GND. It must be connected close
to the ICS501B to minimize lead inductance. No
external power supply filtering is required for the
ICS501B.
parallel resonant, fundamental mode crystal should be
used. The device crystal connections should include
pads for small capacitors from X1 to ground and from
X2 to ground. These capacitors are used to adjust the
stray capacitance of the board to match the nominally
required crystal load capacitance. Because load
capacitance can only be increased in this trimming
process, it is important to keep stray capacitance to a
minimum by using very short PCB traces (and no vias)
between the crystal and device. Crystal capacitors, if
needed, must be connected from each of the pins X1
and X2 to ground.
The value (in pF) of these crystal caps should equal (C
L
-12 pF)*2. In this equation, C
L
= crystal load capacitance
in pF. Example: For a crystal with a 16 pF load
capacitance, each crystal capacitor would be 8 pF
[(16-12) x 2] = 8.
Series Termination Resistor
A 33Ω terminating resistor can be used next to the CLK
pin for trace lengths over one inch.
Crystal Load Capacitors
The total on-chip capacitance is approximately 12 pF. A
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS501B. These ratings,
which are standard values for IDT commercially rated parts, are stress ratings only. Functional operation of
the device at these or any other conditions above those indicated in the operational sections of the
specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can
affect product reliability. Electrical parameters are guaranteed only over the recommended operating
temperature range.
Item
Supply Voltage, VDD
All Inputs and Outputs
Ambient Operating Temperature
Storage Temperature
Soldering Temperature
7V
Rating
-0.5 V to VDD+0.5 V
-40 to +85° C
-65 to +150° C
260° C
Recommended Operation Conditions
Parameter
Ambient Operating Temperature
Power Supply Voltage (measured in respect to GND)
Min.
0
+3.14
Typ.
Max.
+70
+5.25
Units
°
C
V
IDT™ / ICS™
LOCO™ PLL CLOCK MULTIPLIER
3
ICS501B
REV D 120307
ICS501B
LOCO™ PLL CLOCK MULTIPLIER
CLOCK MULTIPLIER
DC Electrical Characteristics
VDD=5.0 V ±5%
, Ambient temperature 0 to +70° C, unless stated otherwise
Parameter
Operating Voltage
Input High Voltage, ICLK only
Input Low Voltage, ICLK only
Input High Voltage
Input Low Voltage
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
IDD Operating Supply Current
Short Circuit Current
On-Chip Pull-up Resistor
Input Capacitance, S1, S0, and OE
Nominal Output Impedance
Symbol
VDD
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
OH
V
OL
Conditions
ICLK (pin 1)
ICLK (pin 1)
OE (pin 7)
OE (pin 7)
S0, S1
S0, S1
I
OH
= -25 mA
I
OL
= 25 mA
No load
CLK output
Pin 7
Pins 4, 6, 7
Min.
3.14
(VDD/2)+1
Typ.
Max.
5.25
(VDD/2)-1
Units
V
V
V
V
V
V
V
V
V
mA
mA
kΩ
pF
Ω
2.0
0.8
VDD-0.5
0.5
2.4
0.4
20
+70
270
4
20
IDT™ / ICS™
LOCO™ PLL CLOCK MULTIPLIER
4
ICS501B
REV D 120307
ICS501B
LOCO™ PLL CLOCK MULTIPLIER
CLOCK MULTIPLIER
AC Electrical Characteristics
VDD = 5.0 V ±5%,
Ambient Temperature 0 to +70° C, unless stated otherwise
Parameter
Input Frequency, crystal input
Input Frequency, clock input
Output Frequency, VDD = 5.0 V ±5%
Output Frequency, VDD = 3.3 V ±5%
Output Clock Rise Time
Output Clock Fall Time
Output Clock Duty Cycle
PLL Bandwidth
Output Enable Time, OE high to
output on
Output Disable Time, OE low to
tri-state
Absolute Clock Period Jitter
One Sigma Clock Period Jitter
Note 1: Measured with 15 pF load.
Symbol
F
IN
F
IN
F
OUT
F
OUT
t
OR
t
OF
t
OD
Conditions
Min.
0.5
Typ.
Max.
7.5
7.5
15
15
15
15
Units
MHz
MHz
MHz
MHz
MHz
MHz
ns
ns
0° C to +70° C
-40° C to +85° C
0° C to +70° C
-40° C to +85° C
0.8 to 2.0 V, Note 1
2.0 to 8.0 V, Note 1
1.5 V, up to 25 MHz
4
4
4
4
1
1
45
10
50
50
49-51
55
%
kHz
ns
ns
ps
ps
t
ja
t
js
Deviation from
mean, Note 1
Note 1
+70
25
IDT™ / ICS™
LOCO™ PLL CLOCK MULTIPLIER
5
ICS501B
REV D 120307
Embedded System
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