SY89874AUMG

Overview

The SY89874AUMG is a low-skew, low-jitter clock buffer and programmable divider manufactured by Microchip Technology. It accepts high-speed differential or single-ended inputs (LVTTL, LVCMOS, CML, PECL, LVDS, HSTL) and provides two LVPECL outputs. The device features an integrated programmable divider with ratios of 1, 2, 4, 8, and 16, selectable via S0-S2 pins. Key electrical parameters include a maximum output frequency of 2.5 GHz, propagation delay of 450–760 ps, within-device skew of <15 ps, total jitter <10 ps peak-to-peak, and cycle-to-cycle jitter <1 ps RMS. It operates on a 2.375V to 3.63V supply in a 16-pin QFN package.

Feature Summary

• Integrated Programmable Clock Divider: Supports divide-by-1, 2, 4, 8, and 16 ratios for frequency translation.
• Low-Jitter Performance: Guarantees <10 ps peak-to-peak total jitter and <1 ps RMS cycle-to-cycle jitter.
• Flexible Input Interface: Accepts LVTTL, LVCMOS, CML, PECL, LVDS, and HSTL signals via unique internal termination and VT pin.
• High-Speed Operation: Delivers up to 2.5 GHz output frequency with <15 ps within-device skew.

Applications

• SONET/SDH Line Cards
• Transponders
• High-End Multiprocessor Sensors

Procurement Notes

Verify the ordering suffix 'UMG' corresponds to the 16-Lead 3 mm x 3 mm QFN package, -40°C to +85°C temperature range, and NiPdAu lead-free finish. Confirm packing quantity requirements; standard tubes contain 110 units, while tape and reel options are available as SY89874AUMG-TR with 1,000 units per reel. Ensure compatibility with RoHS3 standards.

Selection Notes

Select the SY89874AUMG when a 1:2 fanout with programmable division is required for frequencies up to 2.5 GHz. Use this part for AC-coupled or DC-coupled applications supporting multiple logic standards. For wider differential input voltage ranges suitable for low-offset signals, consider the SY89874U variant instead. Ensure power supply decoupling with 0.1 μF and 0.01 μF capacitors near VCC pins.

Part Context

This component belongs to the Precision Edge® series of clock drivers and distributors from Microchip Technology. It is functionally related to the SY89874AU base model but specifies the specific package and environmental ratings in its full part number. It serves as a frequency translator and buffer in high-speed digital systems requiring precise timing distribution.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material. Designers should verify pin compatibility and electrical specifications if considering alternative vendors or family members like the SY89874U for different input range requirements.

FAQ

How is the divide ratio selected?

The divide ratio (1, 2, 4, 8, or 16) is selected using the S0, S1, and S2 pins. These pins accept LVTTL/CMOS logic levels and have internal 25 kΩ pull-up resistors. Leaving them unconnected results in a divide-by-16 mode.

What is the function of the VT pin?

The VT pin provides access to the internal termination network. For CML or LVDS inputs, it should be left floating. For other logic standards, it connects to specific termination circuits to ensure proper signal integrity for both DC and AC coupling.

How does the /RESET pin operate?

The /RESET pin asynchronously resets the divider in divide modes (2, 4, 8, 16). In pass-through mode (divide by 1), it acts as a synchronous enable/disable function, turning outputs off on the next falling edge of the input clock.

Can unused LVPECL outputs be left floating?

Yes, unused PECL outputs may be left floating without impacting jitter performance. However, if terminating unused I/O for balance, specific resistor networks (e.g., R3=1kΩ, R4=1.6kΩ for 3.3V) are recommended.