a FEATURES Eight 8-Bit DACs with Output Amplifiers Operates with Single +5 V, +12 V or +15 V or Dual Supplies P Compatible (95 ns WR Pulse) No User Trims Required Skinny 24-Pin DlPs, SOIC, and 28-Terminal Surface Mount Packages
LC2MOS Octal 8-Bit DAC AD7228A FUNCTIONAL BLOCK DIAGRAM
The AD7228A contains eight 8-bit voltage-mode digital-toanalog converters, with output buffer amplifiers and interface logic on a single monolithic chip. No external trims are required to achieve full specified performance for the part. Separate on-chip latches are provided for each of the eight D/A converters. Data is transferred into the data latches through a common 8-bit TTL/CMOS (5 V) compatible input port. Address inputs A0, A1 and A2 determine which latch is loaded when WR goes low. The control logic is speed compatible with most 8-bit microprocessors. Specified performance is guaranteed for input reference voltages from +2 to +10 V when using dual supplies. The part is also specified for single supply +15 V operation using a reference of +10 V and single supply +5 V operation using a reference of +1.23 V. Each output buffer amplifier is capable of developing +10 V across a 2 kΩ load. The AD7228A is fabricated on an all ion-implanted, highspeed, Linear Compatible CMOS (LC2MOS) process which has been specifically developed to integrate high-speed digital logic circuits and precision analog circuits on the same chip.
1. Eight DACs and Amplifiers in Small Package The single-chip design of eight 8-bit DACs and amplifiers allows a dramatic reduction in board space requirements and offers increased reliability in systems using multiple converters. Its pinout is aimed at optimizing board layout with all analog inputs and outputs at one side of the package and all digital inputs at the other. 2. Single or Dual Supply Operation The voltage-mode configuration of the DACs allows single supply operation of the AD7228A. The part can also be operated with dual supplies giving enhanced performance for some parameters. 3. Microprocessor Compatibility The AD7228A has a common 8-bit data bus with individual DAC latches, providing a versatile control architecture for simple interface to microprocessors. All latch enable signals are level triggered and speed compatible with most high performance 8-bit microprocessors.
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