AD678

a FEATURES AC and DC Characterized and Specified (K, B and T Grades) 200k Conversions per Second 1 MHz Full Power Bandwidth 500 kHz Full Linear Bandwidth 72 dB S/N+D (K, B, T Grades) Twos Complement Data Format (Bipolar Mode) Straight Binary Data Format (Unipolar Mode) 10 M⍀ Input Impedance 8-Bit or 16-Bit Bus Interface On-Board Reference and Clock 10 V Unipolar or Bipolar Input Range Commercial, Industrial and Military Temperature Range Grades MIL-STD-883 Compliant Versions Available 12-Bit 200 kSPS Complete Sampling ADC AD678 REFOUT REFIN BIPOFF AIN AGND FUNCTIONAL BLOCK DIAGRAM CS SC OE EOCEN SYNC 12/8 EOC VOLTAGE REF. CONTROL LOGIC 12 12 12-BIT D/A CONVERSION CONVERTER LOGIC AD678 OUTPUT REGISTER SAMPLE/ HOLD GAIN STAGE 4 4-BIT FLASH A/D CONVERTER DB11 DB2 DB1 (R/L) DB0 (HBE) VCC VEE VDD DGND PRODUCT DESCRIPTION The AD678 is a complete, multipurpose 12-bit monolithic analog-to-digital converter, consisting of a sample-hold amplifier (SHA), a microprocessor compatible bus interface, a voltage reference and clock generation circuitry. The AD678 is specified for ac (or “dynamic”) parameters such as S/N+D ratio, THD and IMD which are important in signal processing applications. In addition, the AD678K, B and T grades are fully specified for dc parameters which are important in measurement applications. The AD678 offers a choice of digital interface formats; the 12 data bits can be accessed by a 16-bit bus in a single read operation or by an 8-bit bus in two ...