SY88345BLMG

Special Purpose Amplifiers Overview

The SY88345BLMG is a high-sensitivity limiting post amplifier designed for fiber-optic receivers, operating from a single +3.3V power supply across temperatures of –40°C to +85°C. It supports data rates up to 3.2Gbps and amplifies input signals as small as 5mVPP to drive CML inputs. The device features a TTL enable input, an internal 50Ω input termination, and generates a chatter-free open-collector TTL signal-detect output with an internal 4.75kΩ pull-up resistor. A programmable signal-detect level-set pin allows sensitivity adjustment.

Special Purpose Amplifiers Feature Summary

• Generates low-noise CML data outputs suitable for driving devices with CML or AC-coupled CML/PECL inputs.
• Provides a chatter-free open-collector TTL signal-detect output with internal pull-up resistor.
• Features a programmable signal-detect level set pin to adjust input amplitude detection sensitivity.
• Includes an internal 50Ω input termination and a TTL enable input for signal control.

Special Purpose Amplifiers Applications

• APON/BPON, EPON, GPON and GEPON systems
• Gigabit Ethernet interfaces
• 1X and 2X Fibre Channel connections
• SONET/SDH applications including OC-3/12/24/48–STM1/4/8/16

Special Purpose Amplifiers Procurement Notes

Verify the specific package type required for your design, as the SY88345BL series includes both MSOP and QFN options. Confirm that the industrial temperature range (–40°C to +85°C) meets your environmental specifications. Ensure proper PCB layout for the exposed pad ground connection in the QFN package to maintain thermal performance. Check for any lead finish requirements if using older inventory versus Pb-Free recommendations.

Special Purpose Amplifiers Selection Notes

Select this component when interfacing with low-gain transimpedance amplifiers in fiber-optic receivers. It is suitable for multi-rate applications requiring operation from 155Mbps to 3.2Gbps. Consider the internal 50Ω input termination if external matching components are to be minimized. The programmable signal detect feature is advantageous for maintaining output stability during loss-of-signal conditions.

Special Purpose Amplifiers Part Context

This part belongs to the SY88345 family of limiting post amplifiers manufactured by Micrel, now part of Microchip Technology. It is specifically engineered for optical communication markets such as FTTP/FTTH and optical transceivers. The device serves as a critical interface between the TIA and subsequent digital logic, quantizing noisy linear signals into clean CML waveforms.

Special Purpose Amplifiers Replacement Considerations

SY88345BLEY is the equivalent MSOP package version of this component.

Special Purpose Amplifiers FAQ

How is the signal-detect threshold configured?

The signal-detect threshold is set by connecting an external resistor between VCC and the SDLVL pin, which creates a voltage divider to determine the input amplitude at which the SD output asserts.

What is the purpose of the EN input?

The TTL EN input de-asserts the true data output without removing the input signal, allowing for output stability maintenance under loss-of-signal conditions.