SY88903

1.25Gbps HIGH-SPEED LIMITING POST AMPLIFIER SY88903 FEATURES s s s s s s s s s Up to 1.25Gbps operation Low noise Chatter-Free LOS Generation Open Collector TTL LOS Output TTL /EN Input Differential PECL inputs for data Single power supply Designed for use with SY88902 and SY88904 Available in a tiny 10-pin (3mm) MSOP DESCRIPTION The SY88903 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 5mVp-p can be amplified to drive devices with PECL inputs. The SY88903 generates a chatter-free Loss of Signal (LOS) open collector TTL output. The SY88903 incorporates a programmble 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 conditions. Using LOSLVL pin the sensitivity of the level detect can be adjusted. The LOS LVL voltage can be set by connecting a resistor divider between VCC and VREF, Figure 3. Figure 4 shows the relationship between input level sensitivity and the voltage set on LOSLVL. Figure 5 shows the relationship between input level sensitivity and resistor divider ratio. The LOS output is a TTL open collector output that requires pull-up resistor for proper operation, Figure 1. +5V PIN CONFIGURATION /EN 1 DIN 2 /DIN 3 VREF 4 LOSLVL 5 MSOP K10-1 10 VCC 9 DOUT 8 /DOUT 7 LOS 6 GND SY88903 2k LOS APPLICATIONS s s s s ...