ADV476KN80E

Digital To Analog Converters Overview

The ADV476KN80E is a CMOS monolithic 256x18 color palette RAM-DAC designed for VGA and Personal System/2 graphics. It integrates a 256-entry lookup table, pixel mask register, and triple 6-bit video D/A converters. The device supports pipelined operation at clock rates up to 66 MHz, enabling simultaneous display of 256 colors from a 262,144-color palette. Key electrical parameters include a supply voltage (VCC) range of 4.5 V to 5.5 V, maximum supply current of 220 mA at 66 MHz, and glitch impulse energy of 75 pV-sec. Integral nonlinearity is guaranteed within ±0.5 LSB, ensuring monotonic performance. The component operates within an ambient temperature range of 0°C to +70°C.

Digital To Analog Converters Feature Summary

• 256x18 Color Palette RAM with asynchronous MPU interface for direct access without affecting video data
• Triple 6-bit DACs generating RS-343A/RS-170 compatible RGB outputs capable of driving doubly terminated 75 Ω cables
• 66 MHz pipelined operation with standard video refresh rates of 35 MHz, 50 MHz, and 66 MHz
• Pixel Read Mask Register allows bitwise logical ANDing of input pixel stream for special effects

Digital To Analog Converters Applications

• High Resolution Color Graphics
• CAE/CAD/CAM Applications
• Image Processing
• Instrumentation
• Desktop Publishing

Digital To Analog Converters Procurement Notes

Verify the specific speed grade suffix (N35, N50, or N66) required for the target system clock frequency, as the base model ADV476KN80E indicates a 66 MHz version but ordering guides list distinct part numbers for each speed bin. Confirm package availability in 28-pin DIP format. Check for obsolete status and lead times due to end-of-life classification.

Digital To Analog Converters Selection Notes

Select the appropriate speed variant based on the system's pixel clock requirements: ADV476KN35 for 35 MHz, ADV476KN50 for 50 MHz, or ADV476KN66 for 66 MHz. Ensure the design accommodates the 220 mA maximum supply current at peak clock speeds. Verify that the external reference current circuit provides the necessary IREF (typically 8.88 mA for RS-343A levels) to achieve correct full-scale output voltages across the 37.5 Ω load.

Digital To Analog Converters Part Context

The ADV476 series serves as a pin-compatible and software-compatible replacement for INMOS 171/176 components. It is designed specifically for legacy VGA and Personal System/2 color graphics systems. The KN80E designation corresponds to the 66 MHz speed grade within the 28-pin plastic DIP package family, offering high-speed pipelined data conversion for real-time video generation.

Digital To Analog Converters Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. The ADV476 is marked as OBSOLETE. Designers should evaluate modern RAM-DAC alternatives or FPGA-based solutions for new designs, as direct pin-for-pin replacements may require schematic modifications.