SY88953ALMG

Overview

The SY88953ALMG is a high-speed limiting post amplifier designed for fiber-optic receivers, operating from a single +3.3V supply across an industrial temperature range of –40°C to +85°C. It supports data rates up to 10.7Gbps with input sensitivity as low as 5mVPP and delivers a typical output swing of 700mVPP with 25ps edge rates. The device features 28dB voltage gain, on-chip 50Ω I/O termination, and TTL signal-detect outputs (SD and /SD) with programmable thresholds via the SDLVL pin. Packaged in a compact 3mm x 3mm 16-pin QFN, it consumes approximately 62mA.

Feature Summary

• Provides high-gain amplification and quantization of noisy transimpedance amplifier signals into clean CML level waveforms.
• Generates chatter-free TTL signal-detect outputs with internal pull-up resistors and programmable hysteresis to prevent false triggering.
• Includes adjustable DC threshold pins to correct pulse-width distortion and maintain signal integrity at high speeds.
• Integrates on-chip 50Ω input and output termination to simplify board layout and reduce external component requirements.

Applications

• OC-192 SDH/SONET systems
• 10G Ethernet and Fibre Channel receivers
• XFP optical transceivers
• Proprietary links operating up to 10.7Gbps

Procurement Notes

Verify that the specific ordering suffix matches the required package type, such as tape and reel versus standard tube packaging. Confirm the lead finish specifications align with your assembly process requirements. Ensure the industrial temperature rating meets your environmental constraints. Cross-reference the manufacturer part number against current distributor listings to confirm availability status and revision levels before finalizing procurement plans.

Selection Notes

Select this component when interfacing directly with transimpedance amplifiers requiring high sensitivity and fast edge rates. The integrated signal-detect functionality simplifies loss-of-signal detection logic without external comparators. Consider the thermal resistance characteristics of the QFN package for adequate heat dissipation in dense layouts. Verify that the CML output compatibility matches the downstream receiver inputs to ensure proper signal transmission.

Part Context

This device belongs to the Micrel/SY88953 family of high-speed limiting amplifiers. It serves as a post-amplifier stage following the initial photodetection and transimpedance conversion phases in optical communication chains. The design focuses on maintaining signal fidelity while providing robust amplitude detection capabilities essential for reliable data recovery in high-bandwidth fiber optic networks.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.

FAQ

How is the signal detect threshold configured?

The signal detect threshold is set by connecting an external resistor between the VCC supply and the SDLVL pin, which creates a voltage divider to define the input amplitude sensitivity.

What is the purpose of the VTHP and VTHN pins?

These pins allow for DC threshold adjustment to correct pulse-width distortion by forcing an offset at the respective inputs, ensuring accurate duty cycle control.

How does the device handle loss of signal conditions?

The complementary /SD output can be fed back to the /EN input to deassert the true data output, maintaining stability during loss-of-signal events without removing the input signal.