描述 Description

General Description
The DAC1208 and the DAC1230 series are 12-bit multiply ing D to A converters designed to interface directly with a wide variety of microprocessors (8080, 8048, 8085, Z-80, etc.). Double buffering input registers and associated control lines allow these DACs to appear as a two-byte ‘‘stack’’ in the system’s memory or I/O space with no additional in terfacing logic required.
The DAC1208 series provides all 12 input lines to allow single buffering for maximum throughput when used with 16-bit processors. These input lines can also be externally configured to permit an 8-bit data interface. The DAC1230 series can be used with an 8-bit data bus directly as it internally formulates the 12-bit DAC data from its 8 input lines. All of these DACs accept left-justified data from the processor.
The analog section is a precision silicon-chromium (Si-Cr) R-2R ladder network and twelve CMOS current switches.
An inverted R-2R ladder structure is used with the binary weighted currents switched between the IOUT1 and IOUT2 maintaining a constant current in each ladder leg independent of the switch state. Special circuitry provides TTL logic input voltage level compatibility.
The DAC1208 series and DAC1230 series are the 12-bit members of a family of microprocessor compatible DACs (MICRO-DACsTM). For applications requiring other resolutions, the DAC1000 series for 10-bit and DAC0830 series for 8-bit are available alternatives.

特性 Features

■ Linearity specified with zero and full-scale adjust only
■ Direct interface to all popular microprocessors
■ Double-buffered, single-buffered or flow through digital data inputs
■ Logic inputs which meet TTL voltage level specs (1.4V logic threshold)
■ Works with g10V reference—full 4-quadrant multiplication
■ Operates stand-alone (without mP) if desired
■ All parts guaranteed 12-bit monotonic
■ DAC1230 series is pin compatible with the DAC0830 series 8-bit MICRO-DACs