IDT59910A

NOTE:
1. Stresses beyond those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolutemaximum- rated conditions for extended periods may affect device reliability.

The IDT59910A is a high fanout phase lock loop clock driver intended for high performance computing and data-communications applications. The IDT59910A has eight zero delay TTL outputs.

The IDT59910A maintains Cypress CY7B9910 compatibility while providing two additional features: Synchronous Output Enable (GND/sOE), and Positive/Negative Edge Synchronization (V_CCQ/PE). When the GND/ sOE pin is held low, all the outputs are synchronously enabled (CY7B9910 compatibility). However, if GND/sOE is held high, all the outputs except Q2 and Q3 are synchronously disabled.

Furthermore, when the VCCQ/PE is held high, all the outputs are synchronized with the positive edge of the REF clock input (IDT59910A compatibility). When VCCQ/PE is held low, all the outputs are synchronized with the negative edge of REF.

The FB signal is compared with the input REF signal at the phase detector in order to drive the VCO. Phase differences cause the VCO of the PLL to adjust upwards or downwards accordingly.

An internal loop filter moderates the response of the VCO to the phase detector. The loop filter transfer function has been chosen to provide minimal jitter (or frequency variation) while still providing accurate responses to input frequency changes.