SY88913

Micrel, Inc. 1.25Gbps HIGH-SPEED LIMITING POST AMPLIFIER Not recommended for new designs SY88913 SY88913 FEATURES ■ Up to 1.25Gbps operation ■ Low noise ■ Chatter-Free /LOS Generation ■ PECL /LOS Output ■ TTL /EN Input ■ Differential PECL inputs for data ■ /EN input is TTL with internal 27K pull-up ■ Single power supply ■ Designed for use with SY88902 and SY88904 ■ Available in a tiny 10-pin (3mm x3 mm) MSOP APPLICATIONS ■ 1.25Gbps Gigabit Ethernet ■ 531Mbps and 1062Mbps Fibre Channel ■ 622Mbps SONET ■ Gigabit Interface Converter DESCRIPTION The SY88913 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 SY88913 generates a chatter-free PECL Loss of Signal (/LOS). The SY88913 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 LOSLVL voltage can be set by connecting a resistor divider between VCC and VREF, Figure 2. Figure 3 shows the relationship between input level sensitivity and the voltage set on LOSLVL. Figure 4 shows the relationship between input level sensitivity and resistor divider ratio. BLOCK DIAGRAM DIN DIN VREF VCC GND LOSLVL Limiting A...