Page 1
PRELIMINARY INFORMATION
Low Phase Noise Zero Delay Buffer
ICS571
Description
The ICS571 is a high speed, high output drive, low
phase noise Zero Delay Buffer (ZDB) which
integrates ICS’ proprietary analog/digital Phase
Locked Loop (PLL) techniques. ICS introduced
the world standard for these devices in 1992 with
the debut of the AV9170, and updated that with
the ICS570. The ICS571, part of ICS’
ClockBlocks™ family, was designed to operate at
higher frequencies, with faster rise and fall times,
and with lower phase noise. The zero delay feature
means that the rising edge of the input clock aligns
with the rising edges of both outputs, giving the
appearance of no delay through the device. There
are two outputs on the chip, one being a low-skew
divide by two of the other.
The chip is ideal for synchronizing outputs in a
large variety of systems, from personal computers
to data communications to video. By allowing offchip feedback paths, the ICS571 can eliminate the
delay through other devices. The use of dividers in
the feedback path will enable the part to multiply
by more than two.
Features
• Packaged in 8 pin SOIC.
• Can function as low phase noise x2 multiplier.
• Low skew outputs. One is ÷2 of other.
• Input clock frequency up to 160 MHz at 3.3V.
• Phase noise of better than -100 dBc/Hz from
1kHz to 1MHz offset from carrier
• Can recover poor input clock duty cycle.
• Output clock duty cycle of 45/55 at 3.3V.
• High drive strength for >100 MHz outputs.
• Full CMOS clock swings with 25mA drive
capability at TTL levels.
• Advanced, low power CMOS process.
• Operating voltages of 3.0 to 5.5 V.
Block Diagram
ICLK
FBIN
External feedback can come from CLK or CLK/2 (see table on page 2).
MDS 571 B 1 Revision 072899 Printed 11/14/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
Phase
Detector,
Charge
Pump, and
Loop Filter
Voltage
Controlled
Oscillator
÷2
Output
Buffer
Output
Buffer
CLK
CLK/2
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Pin Assignment
PRELIMINARY INFORMATION
ICS571
Low Phase Noise Zero Delay Buffer
ICLK
VDD
GND
CLK/2
1 8
2
3
4
FBIN
7
CLK
6
VDD
5
GND
Feedback Configuration Table and Frequency Ranges (at 3.3V)
Feedback From CLK CLK/2 Input Range
CLK Input clock frequency Input clock frequency/2 20 -160 MHz
CLK/2 2xInput clock frequency Input clock frequency 10 - 80 MHz
Pin Descriptions
Number Name Type Description
1 ICLK CI Reference clock input.
2 VDD P Connect to +3.3V or +5V. Must be same as other VDD.
3 GND P Connect to ground.
4 CLK/2 O Clock output per Table above. Low skew divide by two of pin 7 clock.
5 GND P Connect to ground.
6 VDD P Connect to +3.3V or +5V. Must be same as other VDD.
7 CLK O Clock output per Table above.
8 FBIN CI Feedback clock input. Connect to CLK or CLK/2 per table above.
Key: CI = clock input, I = input, O = output, P = power supply connection
External Components
The ICS571 requires a 0.01 µF decoupling capacitor to be connected between VDD and GND on each
side of the chip (between pins 2 and 3, and also between pins 6 and 5). They must be connected close to
the ICS571 to minimize lead inductance. No external power supply filtering is required for this device.
A 33 Ω terminating resistor can be used next to each output pin.
MDS 571 B 2 Revision 072899 Printed 11/14/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
Page 3
PRELIMINARY INFORMATION
DC CHARACTERISTICS (VDD = 5.0V or 3.3V unless otherwise noted)
AC CHARACTERISTICS (VDD = 5.0V or 3.3V unless otherwise noted)
ICS571
Low Phase Noise Zero Delay Buffer
Electrical Specifications
Parameter Conditions Minimum Typical Maximum Units
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage, VDD Referenced to GND 7 V
Inputs Referenced to GND -0.5 VDD+0.5 V
Clock Output Referenced to GND -0.5 VDD+0.5 V
Ambient Operating Temperature 0 70 °C
Soldering Temperature Max of 10 seconds 260 °C
Storage temperature -65 150 °C
Operating Voltage, VDD 3 5.5 V
Input High Voltage, VIH, ICLK, FBIN Pins 1, 8 VDD/2+1 VDD/2 V
Input Low Voltage, VIL, ICLK, FBIN Pins 1, 8 VDD/2 VDD/2-1 V
Output High Voltage, VOH, CMOS level IOH=-4mA VDD-0.4 V
Output High Voltage, VOH IOH=-25mA 2.4 V
Output Low Voltage, VOL IOL=25mA 0.4 V
IDD Operating Supply Current, 133 in, 133 out No Load, 3.3V 34 mA
IDD Operating Supply Current, 50 in, 100 out No Load, 3.3V 26 mA
Short Circuit Current Each Output ±100 mA
Input Capacitance, ICLK, FBIN 5 pF
Input Frequency, clock input FB from CLK 20 160 MHz
Input Frequency, clock input FB from CLK/2 10 80 MHz
Skew CLK/2 with respect to CLK Note 2 150 500 850 ps
Input clock to output connected to FBIN Note 2 -500 500 ps
Output Clock Rise Time, 5V 0.8 to 2.0V, 15 pF load 0.3 ns
Output Clock Fall Time, 5V 2.0 to 0.8V, 15 pF load 0.4 ns
Output Clock Rise Time, 3.3V 0.8 to 2.0V, 15 pF load 0.45 ns
Output Clock Fall Time, 3.3V 2.0 to 0.8V, 15 pF load 0.55 ns
Output Clock Duty Cycle, 5V at VDD/2 40 52 to 55 60 %
Output Clock Duty Cycle, 3.3V at VDD/2 45 49 to 51 55 %
Absolute Clock Period Jitter, CLK, note 3 Deviation from mean ±80 ps
One Sigma Clock Period Jitter, CLK, note 3 50 ps
Phase Noise, relative to carrier 1kHz offset -105 dBc/Hz
Phase Noise, relative to carrier 100kHz offset -115 dBc/Hz
Notes: 1. Stresses beyond these can permanently damage the device.
2. Assumes clocks with same rise time, measured from rising edges at VDD/2. Measured with 33Ω
termination resistors and 15 pF loads. Applies to both 3.3V and 5V operation.
3. CLK/2 has lower jitter (both absolute and one sigma, in ps) than CLK.
MDS 571 B 3 Revision 072899 Printed 11/14/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
Page 4
PRELIMINARY INFORMATION
Inches
Millimeters
Package Outline and Package Dimensions
E H
ICS571
Low Phase Noise Zero Delay Buffer
8 pin SOIC
Q
Pin 1
e
D
Symbol Min Max Min Max
A 0.055 0.068 1.397 1.7272
b 0.013 0.019 0.330 0.483
D 0.185 0.200 4.699 5.080
h x 45°
A
c
b
L
E 0.150 0.160 3.810 4.064
H 0.225 0.245 5.715 6.223
e
h 0.015 0.381
L 0.016 0.035 0.406 0.889
Q 0.004 0.01 0.102 0.254
MDS 571 B 4 Revision 072899 Printed 11/14/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
Ordering Information
Part/Order Number Marking Package Temperature
ICS571M ICS571M 8 pin SOIC 0 to 70 °C
ICS571MT ICS571M 8 pin SOIC on tape and reel 0 to 70 °C
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS) assumes no responsibility for either its use or for the
infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in
normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements
are not recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any
ICS product for use in life support devices or critical medical instruments.
ClockBlocks is a trademark of ICS
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