Overview

Description

The IDT9248-39 generates all clocks required for high speed RISC or CISC microprocessor systems such as Intel PentiumPro or Cyrix. Eight different reference frequency multiplying factors are externally selectable with smooth frequency transitions.

Features

  • 3.3V outputs: SDRAM, PCI, REF, 48/24MHz
  • 2.5V outputs: CPU, IOAPIC
  • 20 ohm CPU clock output impedance
  • 20 ohm PCI clock output impedance
  • Skew from CPU (earlier) to PCI clock - 1.5 to 4 ns, center 2.6 ns.
  • No external load cap for CL=18pF crystals
  • ±175 ps CPU clock skew
  • 250ps (cycle to cycle) CPU jitter
  • Smooth frequency switch, with selections from 66.8 to 150 MHz CPU.
  • I2C interface for programming
  • 3ms power up clock stable time
  • Clock duty cycle 45-55%.
  • 48 pin 300 mil SSOP package
  • 3.3V operation, 5V tolerant inputs (with series R)

Comparison

Applications

Documentation

Type Title Date
Datasheet PDF 324 KB
End Of Life Notice PDF 606 KB
End Of Life Notice PDF 599 KB
Product Change Notice PDF 35 KB
Product Change Notice PDF 484 KB
Product Change Notice PDF 361 KB
6 items

Design & Development

Models