Integrated
Circuit
Systems, Inc.
AV9172
Low Skew Output Buffer
General Description
The
AV9172
is designed to generate low skew clocks for
clock distribution in high-performance PCs and workstations.
It uses phase-locked loop technology to align the phase and
frequency of the output clocks with an input reference clock.
Because the input to output skew is guaranteed to ±500ps, the
part acts as a “zero delay” buffer.
The
AV9172
has six configurable outputs. The
AV9172-01
version has one output that runs at the same phase and
frequency as the reference clock. A second output runs at the
same frequency as the reference, but can either be in phase or
180° out of phase from the input clock. Two outputs are
provided that are at twice the reference frequency and in
phase with the reference clock. The final outputs can be
programmed to be replicas of the 2x clocks or non-overlapping
two phase clocks at twice the reference frequency. The
AV9172-01
and
AV9172-03
operates with input clocks
from 10 MHz to 50 MHz while producing outputs from
10 MHz to 100 MHz. The
AV9172-07
operates with input
clocks from 20 to 100 MHz.
The use of a phase-locked loop (PLL) allows the output
clocks to run at multiples of the input clock. This permits
routing of a lower speed clock and local generation of a
required high speed clock. Synchronization of the phase
relationship between the input clock and the output clocks is
accomplished when one output clock is connected to the
input pin FBIN. The PLL circuitry matches rising edges of the
input clock and output clocks.
Features
AV9172-07
input is 66 MHz with 66 and 33 MHz
output buffers
• AV9172-01
is pin compatible with Gazelle GA1210E
• ±250ps skew (max) between outputs
• ±500ps skew (max) between input and outputs
• Input frequency range from 10 MHz to 50 MHz
(-01, -03) and from 20 MHz to 100 MHz (-07)
• Output frequency range from 10 MHz to 100 MHz
(-01, -03, -07)
• Special mode for two-phase clock generation
• Inputs and outputs are fully TTL-compatible
• CMOS process results in low power supply current
• High drive, 25mA outputs
• Low cost
• 16-pin SOIC (150-mil) or 16-pin PDIP package
The
AV9172
is fabricated using CMOS technology which
results in much lower power consumption and cost compared
with the gallium arsenide-based GA1210E. The typical
operating current for the
AV9172
is 50mA versus 120mA for
the GA1210E.
ICS offers several versions of the
AV9172.
The different
devices are shown below:
PART
AV9172-01
AV9172-03
AV9172-07
DESCRIPTION
Second source of GA1210E
Clock doubler and buffer
Clock buffer for 66 MHz input
•
Block Diagram
AV9172RevB060297P
ICS reserves the right to make changes in the device data identified in this publication
without further notice. ICS advises its customers to obtain the latest version of all
device data to verify that any information being relied upon by the customer is current
and accurate.
AV9172
Pin Configuration
Functionality Table for AV9172-01
CLKIN input frequency range 10 to 50 MHz.
EN2
0
0
1
1
INV#
0
1
0
1
Q0
1X
1X
1X
1X
Q1
1X#
1X
1X#
1X
Q2
2X
2X
2X
2X
Q3
2X
2X
2X
2X
Q4
2X
2X
∅
1
∅
1
Q5
2X
2X
∅
2
∅
2
16-Pin SOIC or 16-Pin PDIP
Notes:
1. 1X designates that the output is a replica of CLKIN.
2. 2X designates that the output is twice the frequency of
CLKIN, and in phase.
3. 1X# means that the output is at the same frequency and
180°C out of phase (inverted) from CLKIN.
4. Ø1 will produce a ¼ duty cycle clock of CLKIN.
5. Ø2 will produce a ¼ duty cycle clock delayed 180° from
CLKIN.
Pin Description for AV9172-01
PIN NUMBER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PIN NAME
GND
GND
INV#
EN
FBIN
CLKIN
VDD
VDD
GND
Q0
Q1
Q2
Q3
Q4
Q5
VDD
TYPE
-
-
Input
Input
Input
Input
-
-
-
Output
Output
Output
Output
Output
Output
-
DESCRIPTION
GROUND.
GROUND.
INV# Inverts Q1 when low. (-01 [divisor select -03, -07])
EN converts Q4 and Q5 to phase clocks when high.
FEEDBACK INPUT from output Q0.
INPUT for reference clock.
Power supply (+5V).
Power supply (+5V).
GROUND.
Q0 phase and frequency same as input (1X). Feed back to pin 5.
Q1
Q2
Q3
Q4
Q5
is a 1x clock in phase or 180° out of phase with input.
twice the frequency of Q0 (2x).
twice the frequency of Q0 (2x).
is either a 2X clock or a two-phase clock - see configuration table.
is either a 2X clock or a two-phase clock - see configuration table.
Power supply (+5V).
2
AV9172
Timing Diagrams for AV9172-01
3
AV9172
Pin Configuration
Functionality Table for AV9172-03
CLKIN Input Frequency=X, input range is 10 to 50 MHz.
EN2
0
1
0
1
INV#
0
0
1
1
Q0
2X
2X
2X
2X
Q1
2X
2X
2X
2X
Q2
2X
2X
2X
2X
Q3
2X
2X
1X
1X
Q4
2X
2X
1X
1X
Q5
2X
1X
2X
1X
Example Table for AV9172-03
16-Pin SOIC or 16-Pin PDIP
(33 MHz input, all frequencies in MHz.)
EN2
0
1
0
1
INV#
0
0
1
1
Q0
66
66
66
66
Q1
66
66
66
66
Q2
66
66
66
66
Q3
66
66
33
33
Q4
66
66
33
33
Q5
66
33
66
33
Timing Diagram for AV9172-03
Note: The phase alignment between the 1X clock outputs and
reference clocks input will be either at a 0 or 180 degrees
offset if the 2X clock is used as the feedback signal (con-
nected to the FBIN pin). Which relationship occurs is totally
random and has the potential to change any time the device has
its VDD supply cycled off or the devices input clock
removed.
4
AV9172
Pin Configuration
Functionality Table for AV9172-07
CLKIN Input Frequency=X, input range is 20 to 100 MHz.
EN2
0
1
0
1
INV#
0
0
1
1
Q0
1X
1X
1X
1X
Q1
1X
1X
1X
1X
Q2
1X
1X
1X
1X
Q3
1X
1X
0.5X
0.5X
Q4
1X
1X
0.5X
0.5X
Q5
1X
0.5X
1X
0.5X
Example Table for AV9172-07
(66 MHz input, all frequencies in MHz.)
16-Pin SOIC or 16-Pin PDIP
EN2
0
1
0
1
INV#
0
0
1
1
Q0
66
66
66
66
Q1
66
66
66
66
Q2
66
66
66
66
Q3
66
66
33
33
Q4
66
66
33
33
Q5
66
33
66
33
Timing Diagram for AV9172-07
Absolute Maximum Ratings
VDD referenced to GND . . . . . . . . . . . . . . . . . . . . . . 7V
Operating temperature under bias. . . . . . . . . . . . . . . . 0°C to +70°C
Storage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Voltage on I/O pins referenced to GND. . . . . . . . . . . GND -0.5V to VDD +0.5V
Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Watts
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating
only and 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 may affect product
reliability.
5