The **AD7247KNZ** from Analog Devices is a monolithic, dual 12-bit voltage-output digital-to-analog converter (DAC) that has established itself as a reliable solution for a wide range of digital-to-analog conversion needs. Integrating two complete DACs, output amplifiers, and a precision reference onto a single chip, it offers a compact and highly functional solution for systems requiring multiple analog output channels.
**Architecture and Key Features**
At its core, the AD7247KNZ utilizes a **latch-free, inverted R-2R ladder architecture** for each DAC. This design is chosen for its inherent monotonicity, a critical characteristic ensuring the output voltage always increases for an increasing digital code. Each DAC is paired with a single output amplifier capable of sourcing or sinking up to 5 mA.
A significant feature of this IC is its **on-chip, buried Zener diode voltage reference**. This precision 2.5 V reference provides excellent stability and low temperature drift, which is crucial for maintaining overall system accuracy over time and varying environmental conditions. The reference is shared between the two DACs and can also be used externally, adding to the device's flexibility.
The digital interface is designed for straightforward connection to most microprocessors. It features **double-buffered input logic**, comprising an input register and a DAC register. This allows for simultaneous updating of both DAC outputs from a single 16-bit word, a vital function for applications like motion control where coordinated movement is required. The interface supports data widths of 12, 13, 14, or 16 bits, providing compatibility with various bus architectures.
**Performance Specifications**
The AD7247KNZ delivers robust performance with a **typical settling time of 10 μs to ±0.5 LSB** for a full-scale step, enabling it to handle dynamic signal generation effectively. It operates over a standard supply voltage range of ±12 V or ±15 V, accommodating industrial-level designs. Key performance metrics include:
* **Resolution:** 12 Bits
* **Integral Nonlinearity (INL):** ±1 LSB max
* **Differential Nonlinearity (DNL):** ±0.5 LSB max
* **Power Consumption:** 165 mW typical
**Application Guide**
The integration and feature set of the AD7247KNZ make it suitable for numerous applications:
1. **Process Control and Automation:** Its dual-channel output and simultaneous update capability are ideal for driving setpoints in control loops or providing bias and control signals to various actuators and drives.
2. **Automated Test Equipment (ATE):** The device can be used to generate precise analog stimuli for testing electronic circuits and components. The dual channels allow for generating differential signals or controlling two independent test parameters.
3. **Digital Control Systems:** It serves as a fundamental component in systems where a digital controller must interface with the analog world, such as in motor control, programmable power supplies, and industrial robotics.
4. **Waveform Generation:** While not the fastest DAC available, it is perfectly capable of generating lower-frequency waveforms, ramps, and other function shapes under microprocessor control.
When designing with the AD7247KNZ, careful attention must be paid to **power supply decoupling and grounding** to achieve optimal performance. Bypass capacitors (typically 0.1 μF ceramic) should be placed as close as possible to the power supply pins. For the best DC accuracy, it is recommended to use a dedicated analog ground plane. The output amplifiers are stable with capacitive loads up to 100 pF; for larger capacitive loads, a small series resistor may be required to maintain stability.
ICGOOODFIND: The AD7247KNZ stands out as a highly integrated, precise, and versatile dual 12-bit DAC. Its combination of **monotonicity, a stable on-chip reference, and simultaneous update capability** makes it an excellent choice for designers seeking a reliable and space-efficient solution for multi-channel analog output systems in industrial and instrumentation applications.
**Keywords:**
1. **Digital-to-Analog Converter (DAC)**
2. **Monotonicity**
3. **On-Chip Reference**
4. **Simultaneous Update**
5. **Settling Time**
