IDT59910A

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 (CY7B9910 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.