8725AM-21LFT

Clock Generators, PLLs, Frequency Synthesizers Overview

The ICS8725AM-21LFT is a differential-to-HSTL zero delay clock generator from the HiPerClockS family. It accepts standard differential inputs including LVPECL, LVDS, HSTL, HCSL, and SSTL. The device features a fully integrated PLL for zero delay buffer, multiplier, or divider configurations with output frequencies ranging from 31.25MHz to 630MHz. It operates on a 3.3V core and 1.8V output supply within a 0°C to 70°C temperature range. Key electrical parameters include a maximum cycle-to-cycle jitter of 35ps, an output skew of 50ps, and a static phase offset of 30ps ± 125ps.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Configurable as zero delay buffer, multiplier, or divider with programmable dividers allowing ratios of 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, and 1:8.
• Accepts multiple differential input levels: LVPECL, LVDS, HSTL, HCSL, and SSTL.
• Provides one differential HSTL output pair and one differential feedback output pair.
• Features a PLL_SEL pin to bypass the PLL for system test and debug purposes.

Clock Generators, PLLs, Frequency Synthesizers Applications

• Zero delay clock regeneration in high-performance networking systems.
• Clock distribution for memory interfaces requiring HSTL compatibility.
• System synchronization where low jitter and precise phase alignment are critical.

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify the package type matches the required PCB footprint, specifically the 20-lead SOIC (M Package). Confirm the suffix 'LF' indicates lead-free compliance and RoHS status. Ensure the ambient operating temperature range of 0°C to 70°C meets the application environment requirements before procurement.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Select this component when a differential-to-HSTL conversion with zero delay buffering is required. Ensure the input source supports the specified voltage swings and common mode ranges for LVDS, LVPECL, or HCSL. Verify that the power supply constraints (3.3V core, 1.8V output) align with the system design. Consider the thermal resistance characteristics if operating near the upper temperature limit.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This part belongs to the ICS8725 series of HiPerClockS solutions manufactured by Integrated Device Technology (IDT), which was later acquired by Renesas Electronics Corporation. The 'AM' designation typically refers to the specific grade or revision within the product line, while 'LFT' denotes the lead-free tape and reel packaging configuration.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

Direct replacements should be sought from the IDT/Renesas HiPerClockS family, such as other variants within the ICS8725 series. Cross-vendor substitutes must match the 20-lead SOIC package, HSTL output levels, and zero-delay functionality. Verify pin compatibility and electrical specifications carefully.

Clock Generators, PLLs, Frequency Synthesizers FAQ

What is the purpose of the PLL_SEL pin?

The PLL_SEL pin allows the user to bypass the internal PLL. When set LOW, the reference clock is routed directly to the internal output dividers, which is useful for system test and debug purposes.

How is the zero delay feature achieved?

Zero delay is achieved by connecting the external feedback outputs (QFB/nQFB) to the feedback inputs (FB_IN/nFB_IN). This creates a loop that forces the output clock to have zero phase difference relative to the input reference clock when the PLL is locked.

What are the supported output frequency ratios?

The device supports output-to-input frequency ratios of 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, and 1:8 through its programmable dividers.