CY2276A-21

Features:

• Mixed 2.5V and 3.3V operation
• Single-chip clock solution to meet requirements of Pentium ® and Pentium® II motherboards
-Multiple CPU clocks at 2.5V supporting single and dual-processor systems
-Seven synchronous PCI clocks
-Multiple 2.5V IOAPIC clocks at 14.318 MHz
-Multiple 3.3V SDRAM clocks
-Multiple 3.3V USB and I/O clocks
-Multiple 3.3V Ref. clocks at 14.318 MHz
• I²C™ Serial Configuration Interface
• Factory-EPROM programmable output drive and slew rate for EMI customization
• Factory-EPROM programmable clock frequencies for custom configurations
• High drive, low skew, and low jitter outputs
• Available in space-saving 56-pin SSOP package


Pinout




Specifications

(Above which the useful life may be impaired. For user guidelines,
not tested.)
Supply Voltage ..................................................0.5 to +7.0V
Input Voltage .............................................. 0.5V to V_DD+0.5
Storage Temperature (Non-Condensing) ... ..65 to +150
Max. Soldering Temperature (10 sec) ......................... +260
Junction Temperature ................................................. +150
Package Power Dissipation .............................................. 1W
Static Discharge Voltage ........................................... >2000V
(per MIL-STD-883, Method 3015, like V_DD pins tied together)


Description

The CY2276A-21 andCY2276A-31 are single-chip clock generators for Pentium or Pentium II systems designed with the Intel® 82440LX or similar chipset. They differ in the number of outputs available from each device, as shown in the Selector Guide.

The CY2276A-21 is ideal for four-SDRAM module or server applications that require sixteen SDRAM clocks, and do not require the ability to stop CPU clocks. The CY2276A-31 is ideal for single-processor or dual-processor desktop systems, which require an extra CPU clock.

All CY2276A-21 outputs are designed for low EMI emissions.

Controlled rise and fall times, unique output driver circuits and factory-EPROM programmable output drive and slew-rate enable optimal configurations for EMI control.