link to page 10 AD1580 The AD1580 is ideal for creating the reference level to use with 12-bit 3.3V multiplying DACs, such as the AD7943, AD7945, and AD7948. In the single-supply bias mode (see Figure 26), the impedance VDDRBFC1 seen looking into the IOUT2 terminal changes with DAC code. If IOUT1 the AD1580 drives I V OUT2 and AGND directly, less than 0.2 LSBs REFVINDACIA1OUT2VOUT of additional linearity error results. The buffer amp eliminates any linearity degradation that could result from variations in AD7943/AGNDA1: OP295AD7945/AD822 the reference level. OP2283AD7948DGND3.3V41.2kΩA1AD1580 026 SIGNAL GROUND 00700- Figure 26. Single-Supply System Rev. F | Page 10 of 12 Document Outline Features Applications General Description Pin Configurations Revision History Specifications Absolute Maximum Ratings ESD Caution Typical Performance Characteristics Theory of Operation Applying the AD1580 Temperature Performance Voltage Output Nonlinearity vs. Temperature Reverse Voltage Hysteresis Output Impedance vs. Frequency Noise Performance and Reduction Turn-On Time Transient Response Precision Micropower Low Dropout Reference Using the AD1580 with 3 V Data Converters Outline Dimensions Ordering Guide Package Branding Information