AD7628

a FEATURES On-Chip Latches for Both DACs +12 V to +15 V Operation DACs Matched to 1% Four Quadrant Multiplication TTL/CMOS Compatible from +12 V to +15 V Latch Free (Protection Schottkys not Required) APPLICATIONS Disk Drives Programmable Filters X-Y Graphics Gain/Attenuation CMOS Dual 8-Bit Buffered Multiplying DAC AD7628 FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD7628 is a monolithic dual 8-bit digital/analog converter featuring excellent DAC-to-DAC matching. It is available in small 0.3" wide 20-pin DIPs and in 20-terminal surface mount packages. Separate on-chip latches are provided for each DAC to allow easy microprocessor interface. Data is transferred into either of the two DAC data latches via a common 8-bit TTL/CMOS compatible input port. Control input DAC A/DAC B determines which DAC is to be loaded. The AD7628’s load cycle is similar to the write cycle of a random access memory, and the device is bus compatible with most 8-bit microprocessors, including 6502, 6809, 8085, Z80. The device operates from a +12 V to +15 V power supply and is TTL-compatible over this range. Power dissipation is a low 20 mW. Both DACs offer excellent four quadrant multiplication characteristics with a separate reference input and feedback resistor for each DAC. 1. DAC to DAC matching: since both of the AD7628 DACs are fabricated at the same time on the same chip, precise matching and tracking between DAC A and DAC B is inherent. The AD7628’s matched CMOS DA...