SY88973VMG-TR

Overview

The SY88973VMG-TR is a low-power limiting post amplifier designed for fiber optic receivers. It operates from a single +3.3V ±10% or +5V ±10% power supply over an industrial temperature range of –40°C to +85°C. The device supports multi-rate operation up to 3.2Gbps with a typical differential voltage gain of 38dB and a 2GHz -3dB bandwidth. It features internally terminated 50Ω CML data inputs and outputs with a typical 800mVPP output swing. An open-collector TTL Loss-of-Signal (LOS) output provides chatter-free detection with typically 4.6dB electrical hysteresis.

Feature Summary

• Integrates a limiting amplifier with high sensitivity to amplify input signals as small as 10mVPP to drive downstream devices.
• Includes a programmable Loss-of-Signal (LOS) detection circuit that asserts based on input amplitude thresholds set by an external resistor.
• Features internally terminated 50Ω differential data inputs and CML outputs suitable for driving standard transmission lines.

Applications

• Fiber optic receivers
• Gigabit Ethernet interfaces
• Fibre Channel links
• SONET/SDH networks

Procurement Notes

Verify the specific ordering suffix 'VMG' corresponds to the MLF-16 package with NiPdAu lead finish, distinct from other variants like VKI or VEY. Confirm the '-TR' suffix indicates tape and reel packaging. Ensure compatibility with the required industrial temperature range and verify RoHS compliance status for the specific batch.

Selection Notes

Select this component when a limiting post amplifier with integrated Loss-of-Signal detection is required. It is suitable for applications needing amplification of small differential signals from transimpedance amplifiers. Consider the internal 50Ω input termination and CML output characteristics for interface matching with upstream TIA and downstream receiver stages.

Part Context

The SY88973V belongs to Micrel's family of 3.3V/5V 3.2Gbps CML low-power limiting post amplifiers. Unlike the SY88843V which uses a Sense Detect (SD) feature, the SY88973V utilizes a TTL LOS output. It is available in 10-pin EPAD-MSOP and 16-pin MLF packages, serving as a signal conditioning stage between optical front-end electronics and digital logic.

Replacement Considerations

SY88973VKI-TR: Same function in 10-pin MSOP package.

FAQ

How is the Loss-of-Signal threshold determined?

The LOS threshold is set by connecting an external resistor between the VCC and LOSLVL pins, creating a voltage divider that defines the input amplitude level at which the LOS output asserts.

What is the purpose of the /EN input?

The /EN input allows feedback from the LOS output to maintain stability. When asserted high, it de-asserts the true data output without removing the input signal, preventing chattering during signal loss.