SY88903V

The SY88903V limiting post amplifier with its high gain and wide bandwidth is ideal for use as a post amplifier in fiber optic receivers with data rates up to 1.25Gbps. Signals as small as 5mVpp can be amplified to drive devices with PECL inputs. The SY88903V generates a chatter-free, Loss--of-Signal (LOS), open-collector TTL output.

The SY88903V is an integrated limiting amplifier intended for high-frequency fiber optic applications. The circuit connects to typical transimpedance amplifiers found within a fiber optics link. The linear signal output from a transimpedance amplifier can contain significant amounts of noise, and may vary in amplitude over time. The SY88903V limiting amplifier quantizes the signal and outputs a voltage-limited waveform.

The /EN pin allows the user to disable the output signal without removing the input signal.The SY88903V incorporates a programmable level detect function to identify when the input signal has been lost.This information can be fed back to the /EN input of the device to maintain stability under loss of signal condition.The sensitivity of the level detection can be adjusted using LOSLVL. The LOSLVL voltage can be set by connecting a resistor divider between VCC and VREF as shown in Figure 3. "Typical Characteristics" show the relationship between input level sensitivity and the voltage set on LOSLVL.