analog w devices low cost general purpose digital to analog converter features low cost 12 bit resolution %lsb linearity :t30ppmfc tc 20ppm/% power supply rejection programmable output ranges small size - 2" x 2" x 0.4" general description the dac-12qz is a low-cost/high performance 12-bit digital- to-analog converter designed for general purpose oem applica- tions. the completely self-contained module includes weighted resistor networks, monolithic /ldac current switches, tempera- ture compensated reference and an externally programmable output amplifier. performance specifications include lhlsb linearity error, 5/ls settling time for full scale conversion, 30ppm/ c temperature coefficient and 20ppm/% power sup- ply rejection. /ldac design this outstanding cost/performance ratio has been achieved by utilizing the popular ad550 /ldac current switches. the use of monolithic quad current switches offers close inherent matching of switch characteristics and excellent temperature tracking as well as reasonably fast conversion speed. a hybrid resistor assembly of matched precision resistors and a thick film network is used in conjunction with the /ldac switches. resistors provided include not only the weighting resistors but also the inter-quad attenuators, amplifier feedback resistors, etc. to assure close temperature tracking. input coding the internal /ldac switches of the binary and bcd models are driven directly by complementary input codes without need of a strobe. the complementary codes for each model are: model -f.s. zero +f.s. dac-12qubin 111111111111 000000000000 111111111111 011111111111"000000000000 dac-12qz!bcd 111111111111 011001100110 111111111111 10to 11111111 011001100110 output programming , the scale factor is programmed by connecting external jumpers between module pins. with either model, the user can select anyone of five output ranges, including bipolar outputs. the choices are: unipolar 0 to +5v, 0 to + lov bipolar :t2.5v, :t5v, :tlov the externai jumpers at the module pins determine the output amplifier feedback resistance, allowing use of one 5k resistor, or both, either in series to provide lok, or parallel to provide 2.5k. offset of exactly one-half full scale for bipolar applica- tions is provided by connecting another jumper to the sum- ming junction of the output amplifier. to maintain constant load on the reference zener, the bipolar offset output should be grounded when using the module in a unipolar mode. block diagram dac-12qz 28 zero adj z7 sum jet 20 out zs ref z410v 23 20v 2z gain adj 81t 20 81t39 bit 410 bit' n bit 0 12 bit 713 bit 014 21 b'polar 0 1 2one 0 19 n e 1b bit 12 17 bit n 10 bit 10 15 bit 9 noh pins shown as having no connections ine i are deleted. dia converters 375 obsolete
specifica tiuns (typical @+25c and rated supply voltages, unless otherwise noted) outline dimensions and pin connections dimensions shown in inches and (mm). resolution digital inputs '0' e <+0.8v '1' +2v |
