Document
Integrated Circuit Systems, Inc.
AV9170
Clock Synchronizer and Multiplier
General Description
The AV9170 generates an output clock which is synchronized to a given continuous input clock with zero delay (±1ns at 5V VDD). Using ICSs proprietary phase-locked loop (PLL) analog CMOS technology, the AV9170 is useful for regenerating clocks in high speed systems where skew is a major concern. By the use of the two select pins, multiples or divisions of the input clock can be generated with zero delay (see Tables 2 and 3). The standard versions produce two outputs, where CLK2 is always a divide by two version of CLK1. The AV9170 is also useful to recover poor duty cycle clocks. A 50 MHz signal with a 20/80% duty cycle, for example, can be regenerated to the 48/52% typical of the part. The AV9170 allows the user to control the PLL feedback, making it possible, with an additional 74F240 octal buffer (or other such device that offers controlled skew outputs), to synchronize up to 8 output clocks with zero delay compared to the input (see Figure 1). Application notes for the AV9170 are available. Please consult ICS.
Features
On-chip Phase-Locked Loop for clocks synchronization Synchronizes frequencies up to 107 MHz (output) @ 5.0V ±1ns skew (max) between input & output clocks @ 5.0V Can recover poor duty cycle clocks CLK1 to CLK2 skew controlled to within ±1ns @ 5.0V 3.0 - 5.5V supply range Low power CMOS technology Small 8-pin DIP or SOIC package On chip loop filter AV9170-01, -04 for output clocks 20-107 MHz @ 5.0V, 20 - 66.7 MHz @ 3.3V AV9170-02, -05 for output clocks 5-26.75 MHz @ 5.0V, 5 - 16.7 MHz @ 3.3V
Block Diagram
AV 9170 Rev E 9/24/99
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.
AV9170
Pin Configuration
8-Pin DIP or SOIC
Pin Descriptions
PIN NUMBER 1 2 3 4 5 6 7 8 PIN NAME FBIN IN GND FS0 FS1 CLK1 VDD CLK TYPE Input Input — Input Input Output — Output DESCRIPTION FEEDBACK INPUT INPUT for reference clock GROUND FREQUENCY SELECT 0 FREQUENCY SELECT 1 CLOCK output 1 (See Tables 1, 2, 3, 4, 5 for values) Power Supply CLOCK output 2 (See Tables 1, 2, 3, 4, 5 for values)
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AV9170
Using the AV9170
The AV9170 has the following characteristics: 1. Rising edges at IN and FBIN are lined up. Falling edges are not synchronized. 2. The relationship between the frequencies at FBIN and IN with CLK1 feedback is shown in Table 1 below.
Eliminate High Speed Clock Routing Problems
The AV9170 makes it possible to route lower speed clocks over long distances on the PC board and to place an AV9170 next to the device requiring a higher speed clock. The multiplied output can then be used to produce a phase locked, higher speed output clock.
Functionality (Table 1:)
FS1 0 0 1 1 FS0 0 1 0 1 fFBIN (-01, -02) fFBIN (-04, -05) 2 • f IN 3 • f IN 4 • f IN 5 • f IN f IN 6 • f IN 8 • f IN 10 • f IN
Compensate for Propagation Delays
Including an AV9170 in a timing loop allows the use of PALs, gate arrays, etc., with loose timing specifications. The AV9170 compensates for the delay through the PAL and synchronizes the output to the input reference clock.
Operating Frequency Range
The AV9170 is offered in versions optimized for operation in two frequency ranges. The -01 and -04 cover high frequencies, 20 to 100 MHz.* The -02 and -05 operate from 5 to 25 MHz.* The AV9170 can be supplied with custom multiplication factors and operating ranges. Consult ICS for details.
3. The frequency of CLK2 is half the CLK1 frequency. 4. The CLK1 frequency ranges are: VDD = 5V AV9170-01, -04 AV9170-02, -05 20 < fCLK1 < 5 < fCLK1 < 107 MHz* 26.75 MHz* VDD = 3.3V < 66.7 < 16.7
3.3V VDD Operation
The AV9170 does operate at both 5.0V and 3.3V system conditions. Please note the Electrical Characteristic specifications at 3.3V include a limited output frequency (66.6 MHz max.) and a wider skew of FBIN to CLK1. For 3.3V±5% (3.15V min.), this skew is -5.0 to 0 ns. At 3.3V±10% (3.0V min.), the skew is widened to -8 ns to 0 ns and should be accounted for in system design. *At 3.3V, the maximum CLK1 frequency is 66.7 MHz for -01, -04 and 16.7 MHz for -02, -05.
The AV9170 will only operate correctly within these frequency ranges.
Figure 1: Application of AV9170 for Multiple Outputs
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AV9170
Using CLK2 Feedback
Connecting CLK2 to FBIN as shown in Figure 2 will cause all of the rising edges to be aligned (Figure 4).
Using CLK1 Feedback
With CLK1 connected to FBIN as shown in Figure 3, the input and CLK1 output will be aligned on the rising edge, but CLK2 can be either rising or falling (Figure 5). Consult ICS if the CLK1 frequency is desired to be higher than 107 MHz.
Figure 2:
Figure 3:
For CLK2 frequencies 10 - 53.5 MHz* (-01) For CLK2 frequencies 2.5 - 13.37 MHz (-02) *Maximum 33.3 MHz @ 3.3V (-01.