ATA00501S2C

The ATA00501S2C may be operated from a positive supply as low as+4.5 V and as high as+ 6.0 V. Below+4.5 V, bandwidth, overload and sensitivity will degrade, while at+6.0 V,bandwidth, overload and sensitivity improve (see"Bandwidth vs. Temperature" curves). Use of surface mount, low inductance power supply bypass capacitors(>=56pF) are essential for good high frequency and low noise performance. The power supply bypass capacitors should be mounted on or connected to a good low inductance ground plane.

Features of the ATA00501S2C are:(1)single +5 volt supply; (2)automatic gain control; (3)excellent sensitivity; (4)0 dBm optical overload; (5)surface mountpackage.Since the gain stages of the transimpedance amplifier have an open loop bandwidth in excess of 1.0 GHz, it is essential to maintain good high frequency layout practices. To prevent oscillations, a low inductance RF ground plane should be made available for power supply bypassing.

The absolute maximum ratings of the ATA00501S2C can be summarized as:(1)operating voltage range:4.5 to 6.0V; (2)supply current:45mA; (3)operating temperature:-40 to +85; (4)bandwidth -3dB:50MHz.It is important to select an external AGC capacitor of high quality and appropriate size. The ATA00501 S2C has an on-chip 70 KW resistor with a shunt 4 pF capacitor to ground. Without external capacitance the chip will provide an AGC time constant of 280 nS. For the best performance in a typical 51 Mb/s SONET receiver, a minimum AGC capacitor of 56pF is recommended. This will provide the minimum amount of protection against pattern sensitivity and pulse width distortion on repetitive data sequences during high average optical power conditions. The AGC function of the IC can be disabled by grounding pin 6, CACC.  Conservative design practices should be followed when selecting an AGC capacitor, since unit to unit variability of the internal time constant and various data conditions can lead to data errors if the chosen value is too small.