**The AD7228LPZ: A Comprehensive Technical Overview of the 8-BIT DAC with Output Amplifiers**

The AD7228LPZ from Analog Devices represents a highly integrated, monolithic solution for digital-to-analog conversion, combining an 8-bit DAC, output amplifiers, and interface logic into a single package. This device is engineered for applications requiring multiple precision voltage outputs, offering a compact and reliable alternative to discrete designs.

At its core, the AD7228LPZ features **four 8-bit voltage-mode digital-to-analog converters**. Each DAC is constructed from an R-2R ladder network, a architecture renowned for its inherent monotonicity. This design ensures the analog output consistently increases or decreases with changes in the digital input code, a critical characteristic for control and calibration applications. The digital interface is designed for straightforward connection to most microprocessors, with **separate data latches for each DAC channel**. This allows all four DACs to be updated simultaneously using a single load command after their individual input registers have been loaded sequentially, simplifying software control.

A defining feature of the AD7228LPZ is the inclusion of **four dedicated, precision output buffer amplifiers**. Each DAC is paired with its own amplifier, capable of sourcing up to 5 mA of output current. These amplifiers eliminate the need for external components to achieve a usable voltage output, thereby reducing board space, component count, and overall system cost. The output amplifiers are configured to provide a voltage range programmable via two reference input pins. By applying different reference voltages to the VREFHI and VREFLO pins, the **full-scale output range can be adjusted** to suit various system requirements, including unipolar (e.g., 0 V to +5 V) and bipolar (e.g., -5 V to +5 V) operation.

Housed in a 20-lead PDIP package, the AD7228LPZ is specified for operation across the industrial temperature range. Its performance is characterized by **low gain error and high output drive capability**, making it suitable for a wide array of applications. These include automated test equipment (ATE), process control, programmable power supplies, and digital-controlled gain and offset adjustment. The device operates from a single +12 V to +15 V power supply and a -5 V to -15 V supply for the output amplifiers, ensuring flexibility in different system power environments.

**ICGOODFIND:** The AD7228LPZ integrates four complete 8-bit DAC channels with output amplifiers in one IC, offering designers a compact, monolithic solution for multi-channel analog output. Its microprocessor-compatible interface, simultaneous update capability, and flexible output ranging make it a versatile and reliable choice for precision digital control systems.

**Keywords:** 8-Bit DAC, Output Amplifier, Monotonic, Simultaneous Update, Programmable Output Range.