Features: • Compatible with 386, 486 and Pentium CPUs
• 45/55 Duty cycle
• Runs up to 66 MHz at 3.3V
• Single pin can slow clock to 8 MHz (on -42 and -43)
• Single pin can stop the CPU clock glitch-free (on -43)
• Very low jitter, ±250ps for Pentium frequencies
• 1X and 2X CPU clocks skew controlled to ±250ps (-42 only)
• Smooth transitions between all CPU frequencies
• Slow frequency ramp at power-on avoids CPU lock-up
• 16-pin PDIP or 150-mil skinny SOIC packages
• 0.8mm CMOS technologyApplicationComputer motherboards: The AV9154A-ST replaces crystals and oscillators, saving board space, component cost, part count and inventory costs. It produces a switchable CPU clock and up to four fixed clocks to drive floppy disk, communications, super I/O, Bus, and/or keyboard devices. The small package and 3.3V operation is perfect for handheld computers.
Pinout
SpecificationsVDD referenced to GND ........................................................................... 7.0 V
Voltage on I/O pins referenced to GND ................. GND - 0.5 V to VDD + 0.5 V
Operating Temperature under bias .............................................. 0 to +70 ºC
Power Dissipation ................................................................................... 0.5 W
Storage Temperature ............................................................... -40 to +150 ºC
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stess
specifications only and functional operation of the device at these or any other conditions above those listed in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
product reliability.Description.The AV9154A is a 0.8mm version of the industry leading AV9154. Like the AV9154, the AV9154A is a low-cost frequency generator designed for general purpose PC and disk drive applications. However, because the AV9154A uses 0.8mm technology and the latest phaselocked loop architecture, it offers performance advantages that enable the device to be sold into Pentium™ systems.
The AV9154A guarantees a 45/55 duty cycle over all frequencies. In addition, a worst case jitter of ±250ps is specified at Pentium frequencies.
The CPU clock offers the unique feature of smooth, glitch-free transitions from one frequency to the next, making this the ideal device to use when slowing the CPU speed. The AV9154A makes a gradual transition between frequencies so that it obeys the Intel cycle-to-cycle timing specifications for 486 and Pentium systems. The AV9154A-42 and AV9154A-43 devices offer features specifically for green PCs. The AV9154A-42 and -43 have a single pin that, when pulled low, will smoothly slow the 2XCPU clock to 8 MHz. This is ideal for dynamic DX microprocessors. The AV9154A-43 not only has the slow clock feature, but also offers a glitch-free stop clock for static SX microprocessors. The STOPCLK# pin, when pulled low, enables the 2XCPU clock to go low only after completing its last full cycle. The clock continues to run internally, and will be output again on the first full cycle immediately following stop clock disable.
The simultaneous 2X and 1X CPU clocks offer controlled skew to within 500ps of each other (-42 only).
ICS has been shipping motherboard frequency generators since April 1990, and is the leader in the area of multiple output clocks on a single chip. Consult ICS for all your clock generation needs.
AV9154A Data Sheet
