LD120 Datasheet | Siliconix

FEATURES 0.005% +1 Count Accuracy © +R2a0n0g.e0s m V and +2.000V ¢ Auto-Polarit - Auto Zero ' y @ Over and Under Range Outputs BENEFITS © High System Performance __@ SPirnogglrea Rmemsiinstgor ®© SENaiuslnilgilslye OIRunettfee Orfrffeascneectdes DESCRIPTION APPLICATIONS e High Accuracy Digital VPoalntemlet Meertserasnd - e Su Daiyn Pgsdit Dta Taelthmaes Src Aamcloqemusiestietrion a : ® Scientific Instrumentation The LD120 and LD121A form a precision 4 1/2 digit A/D converter system for use in display and microprocessor based data acquisition applications. Based on Siliconix’s “Quantized Feedback” technique, intrinsic features include auto-polarity, auto-zero, and ratiometric operation. Except for a stable reference, no critical ponents are required to achieve rated performance. The technique used offers superior linearity, normal mode rejection, and stability due to the simultaneous integration of the unknown input and the reference voltages. Unlike other conversion techniques, the integrator output voltage never represents more than 100 counts. Thus, critical, high resolution performance is not required of either the integrator or the parator. The LD120 analog processor is fabricated with a unique PMOS/Bipolar process. It contains all the necessary amplifiers, MOSFET switches, and switch driver circuits for the system. The reference voltage input is fully buffered in LD120 to eliminate the reference switch resistance as a source of error. All the amplifiers are internally pensated, The LD120 directly interfaces the LD121A digital processor with no additional active ponents required. The LD121A synchronous processor contains all the digital circuitry for the quantized feedback system. Device outputs supply two overrange signals, underrange, sign and 4% digits of multiplexed BCD data. (All outputs are TTL patible). Overrange is also indicated by blinking digit strobes above 20,000 counts. An input is provided to inhibit this feature at user option. Microprocessor...