The DAC-8221 integrates two identical 12-bit multiplies in one CMOS chipDigital-to-analog converters。 The device is electrically similar to the DAC-8212 with improved microprocessor interface timing performance in a narrow 0.300" DIP package. The monolithic construction provides good DAC-DAC matching and tracking over the entire operating temperature range. The DAC-8221 consists of two thin-film R-2R resistor ladder networks, two 12-bit data latches, one 12-bit input buffer, and control logic. The DAC-8221 operates from a single supply and has a voltage range of +5V to +15V. When the logic levels are 0V and +5V and the supply voltage is +5V, the maximum power consumption is less than 0.5mW. The DAC-8221 is based on an advanced oxide-isolated, silicon-gate CMOS process and is manufactured with PMI's highly stable thin-film resistors. PMI's improved anti-latch-up design eliminates the need for external protection Schottky diodes.
A common 12-bit (TTL/CMOS compatible) input port is used to load a 12-bit wide data word into one of the two DACs. The port's data loading structure is similar to the write cycle of RAM, interfacing directly with most 12-bit systems or wider bus systems. When WR and.CSWhen the line is logic low, the input data registers are transparent. In this way, direct unbuffered data can flow directly to byDAC A/DAC B controls the DAC output selected by the input.