SY89825UHI

Clock Buffers, Drivers Overview

The SY89825UHI is a high-performance bus clock driver and translator manufactured by Microchip Technology, originally designed by Micrel. It features one differential input multiplexed between LVDS and LVPECL, providing 22 differential LVPECL output pairs. The device operates on a single supply voltage ranging from 2.37V to 3.6V. Key electrical specifications include a maximum toggle frequency of 2 GHz, a maximum channel-to-channel skew of 35 ps, and a total jitter of 10 ps peak-to-peak. The LVDS input includes an internal 100Ω termination. It is housed in a 64-pin exposed pad TQFP package.

Clock Buffers, Drivers Feature Summary

• Multiplexed Input: Selectable LVDS or LVPECL input via CLK_SEL pin; LVDS input includes integrated 100Ω termination.
• High Fanout: Provides 22 differential LVPECL outputs with low pin-to-pin skew (max 35 ps).
• Synchronous Output Enable: OE pin synchronizes with the clock signal to prevent runt pulses during enable/disable transitions.
• Low Voltage Operation: Designed for 2.5V and 3.3V applications with guaranteed AC parameters over the full voltage range.

Clock Buffers, Drivers Applications

• High-performance PCs
• Workstations
• Parallel processor-based systems
• High-performance computing
• Communications

Clock Buffers, Drivers Procurement Notes

The SY89825UHI is marked as obsolete and no longer manufactured. Verification should confirm component authenticity and physical condition upon receipt. Solderability and lead finish (Sn-Pb) must be inspected against storage guidelines. Designers are advised to utilize the recommended Pb-free replacement part for new designs due to RoHS compliance requirements.

Clock Buffers, Drivers Selection Notes

Select this component when a single-chip solution is required to distribute a clock signal to up to 22 destinations with precise alignment. It is suitable for environments requiring low skew (<35 ps) and operation at frequencies up to 2 GHz. Ensure the design accommodates the 64-TQFP package dimensions and thermal dissipation requirements, particularly regarding the exposed pad connection to ground.

Clock Buffers, Drivers Part Context

This device belongs to the Precision Edge® series of clock drivers. Originally developed by Micrel, Inc., the product line was acquired by Microchip Technology. The SY89825U family is engineered for low-voltage, high-speed clock distribution where minimizing part-to-part skew and reducing board space compared to multi-device solutions are critical design constraints.

Clock Buffers, Drivers Replacement Considerations

The SY89825UHY is listed as a direct replacement. The primary difference is the lead finish: the UHI uses Sn-Pb, while the UHY utilizes Matte-Sn and includes a Pb-Free bar-line indicator. Pinouts and functionality remain identical, facilitating drop-in substitution for existing assemblies.

Clock Buffers, Drivers FAQ

How is the input source selected?

The input source is selected using the CLK_SEL pin. When CLK_SEL is Low, the LVDS inputs are active; when High, the LVPECL inputs are active.

What is the purpose of the synchronous Output Enable?

The OE pin is synchronized with the clock signal to ensure outputs are only enabled or disabled when they are already in the LOW state, preventing the generation of runt clock pulses.

Does the LVDS input require external termination?

No, the LVDS input includes an internal 100Ω termination between the LVDS_CLK and /LVDS_CLK pins.