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Hi,
I'm using CY7C1618KV18 DDR II device.
The minimal clock frequency is defined in the datasheet to 119Mhz (K & C max clock cycle time = 8.4ns).
Is it safe to use slower clock frequency, e.g 80Mhz? What is the lowest supported frequency?
Thanks,
Gil
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Hi Gil,
When you operate the DDR II device at frequecies below 120 MHz the PLL has to be disabled by tying DOFF# to GND. PLL is bypassed by strapping the DOFF # signal LOW. In this mode, the read latency for QDR-II/II+/DDR-II/II+ devices is 1.0 clock cycle and the timings are
guaranteed by design but not tested.
So to answer your question it is safe to operate at slow clock frequency. There is as such no limit to lowest supported frequency, as it is not a tested parameter. Hence i cannot provide you a fixed number for this.
Thanks,
Pradipta.