AD7111A

a FEATURES Dynamic Range: 88.5 dB Resolution: 0.375 dB On-Chip Data Latches +5 V Operation AD7111A Pin Compatible with AD7524 Low Power APPLICATIONS Audio Attenuators Sonar Systems Function Generators Digitally Controlled AGC System LC2MOS LOGDAC Logarithmic D/A Converter AD7111/AD7111A FUNCTIONAL BLOCK DIAGRAMS VDD VIN R FB AD7111 17-BIT DAC I OUT AGND 17-BIT LATCH DECODE LOGIC The LOGDAC® AD7111/AD7111A are monolithic multiplying D/A converters featuring wide dynamic range in a small package. Both DACs can attenuate an analog input signal over the range 0 dB to 88.5 dB in 0.375 dB steps. They are available in 16-pin DIPs and SOIC packages. The AD7111 is also available in a 20-terminal LCCC package. The degree of attenuation across the DAC is determined by an 8-bit word applied to the onboard decode logic. This 8-bit word is decoded into a 17-bit word which is then applied to a 17-bit R-2R ladder. The very fine step resolution, which is available over the entire dynamic range, is due to the use of this 17-bit DAC. The AD7111/AD7111A are easily interfaced to a standard 8-bit MPU bus via an 8-bit data port and standard microprocessor control lines. The AD7111 WR input is edge triggered and requires a rising edge to load new data to the DAC. The AD7111A WR is level triggered to allow transparent operation of the latches, if required. It should also be noted that the AD7111A is exactly pin and function-compatible with the AD7524, an industry standard 8-bit multiplying DAC....