A 100-Msps 10-bit analog-to-digital converter chip set

A description is given of a 100-Msps 10-bit analog-to-digital converter (ADC) chip set that can be used for a wide-bandwidth high-resolution digital storage oscilloscope. High conversion rate and 500-MHz sampling bandwidth with 10-bit resolution are obtained by a combination of three silicon-bipolar chips and two GaAs-diode chips. The ADC employs a pipelined two-step subranging architecture that uses two cascaded wide-bandwidth track-and-hold circuits (T/H). The design features of the T/H and the residual amplifier are also presented. Test results show that input bandwidth is over 500 MHz, and, up to a 20-MHz input frequency, the signal to noise ratio is better than 45 dB