AD8804AR

Overview

The AD8804AR is a 12-channel, 8-bit digital-to-analog converter (DAC) from Analog Devices. It features individually programmable voltage outputs controlled via a 3-wire SPI-compatible serial interface. The device includes a dedicated VREFL pin for independent zero-scale voltage setting, optimizing resolution for limited control ranges. Operating on a single +3 V to +5 V supply, it consumes only 10 μA in normal mode and enters a low-power shutdown state with <55 mW dissipation while retaining latch settings. Key static accuracy parameters include ±1/4 LSB DNL and ±1/2 LSB INL.

Feature Summary

• 12-Channel 8-Bit Resolution: Provides independent digitally controllable voltage outputs replacing mechanical trimmers.
• Independent Zero-Scale Setting: Unique VREFL pin allows separate adjustment of the bottom end of the potentiometer divider.
• Low Power Consumption: Operates at 10 μA supply current; shutdown mode reduces reference input current to 10 μA.
• Serial Interface: Compatible with standard 3-wire SPI protocols using CS, CLK, and SDI pins.

Applications

• Automatic Adjustment and Trimmer Replacement
• Video and Audio Equipment Gain and Offset Adjustment
• Portable and Battery Operated Equipment

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm package type (SOIC-20) and temperature range (-40°C to +85°C). Check for ESD sensitivity precautions during handling. Ensure supply voltage matches specifications (+3 V to +5 V). Validate serial interface timing requirements against microcontroller capabilities.

Selection Notes

Select the AD8804AR over the AD8802AR when independent zero-scale voltage adjustment is required via the VREFL pin. The AD8804 optimizes resolution for devices with limited allowable voltage control ranges. Ensure the application requires 12 channels and 8-bit precision. Verify that the 3-wire serial interface aligns with the system's microcontroller architecture.

Part Context

The AD8804AR belongs to the AD8802/AD8804 family of TrimDACs. It shares the same core architecture and performance characteristics as the AD8802 but adds the VREFL pin for enhanced flexibility. Both parts are designed to replace mechanical potentiometers in DC voltage adjustment applications.

Replacement Considerations

The AD8802AR is a functional substitute if the VREFL pin is not utilized and the application does not require independent zero-scale setting. Both components share identical pinouts except for Pin 11 (VREFL vs. GND) and Pin 1 (VREFH vs. VREF).

FAQ

What is the function of the VREFL pin on the AD8804?

The VREFL pin provides an independent low-side reference input, allowing users to set a separate zero-scale voltage. This feature helps maximize resolution for applications with limited voltage control ranges.

How does the power shutdown mode affect the DAC outputs?

In shutdown mode, the DAC structure enters a zero-power consumption state, reducing supply current to leakage levels. However, the DAC latch settings are maintained, and outputs return to their previous voltages upon returning to normal operation.

What is the settling time for the AD8804?

The typical settling time to within ±1/2 LSB error band is 0.6 μs.