The SY88403BL is a low-power limiting post amplifier optimized for copper applications. 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 SY88403BL quantizes these signals and outputs typically 800mVPP voltage-limited waveforms.

The SY88403BL operates from a single +3.3V ±10% power supply, over an industrial temperature range of -40°C to +85°C. With its wide bandwidth and high gain, signals with data rates up to 4.25Gbps and as small as 20mVPP can be amplified to drive devices with CML inputs or AC-coupled PECL inputs.

The SY88403BL incorporates a loss-of-signal (LOS) open-collector TTL output with internal 4.75kΩ pull-up resistor. A programmable loss-of-signal level set pin (LOSLVL) sets the sensitivity of the input amplitude detection. LOS asserts high if the input amplitude falls below the threshold set by LOSLVL and de-asserts low otherwise. LOS can be fed back to the enable bar (/EN) input to maintain output stability under a loss of signal condition. /EN de-asserts the true output signal without removing the input signal. Typically 3.5dB LOS hysteresis is provided to prevent chattering.