The SY88903AL, burst mode, high-sensitivity limiting post amplifier is designed for use in fiber-optic receivers, specially optimized for passive optical networks (PONs). The device connects to typical transimpedance amplifiers (TIAs). The linear signal output from TIAs can contain significant amounts of noise and may vary in amplitude over time. The SY88903AL quantizes these signals and outputs PECL level waveforms. The SY88903AL operates from a single +3.3V power supply, over temperatures ranging from -40°C to +85°C. Signals with data rates from 622Mbps up to 1.25Gbps, and as small as 5mVPP, can be amplified to drive devices with PECL inputs. The SY88903AL generates a Loss-of-Signal (LOS) open-collector TTL output. A programmable Loss-of-Signal level set pin (LOS LVL) sets the sensitivity of the input amplitude detection. LOS asserts high if the input amplitude falls below the threshold set by LOS LVL and de-asserts low otherwise. The enable bar input (/EN) de-asserts the true output signal without removing the input signal. The LOS output can be fed back to the /EN input to maintain output stability under a loss-of-signal condition. Typically, 3.4dB LOS hysteresis is provided to prevent chattering.

• Single 3.3V power supply
• Fast LOS release/assert (<500ns) time for PON applications
• 622Mbps to 1.25Gbps operation
• Low-noise PECL data outputs
• High gain LOS
• Chatter-free Open-Collector TTL signal detect (LOS) output with internal 4.75kΩ pull-up resistor
• TTL /EN input
• Programmable LOS level set (LOS LVL)
• Available in a tiny 10-pin MSOP package