Overview
The AD5678BRUZ-1REEL7, produced by Analog Devices Inc., is a low power, octal, buffered voltage-output Digital-to-Analog Converter (DAC). This device integrates four 12-bit DACs and four 16-bit DACs within a single package, making it highly versatile for various applications. It operates from a single supply voltage ranging from 2.7 V to 5.5 V and is guaranteed monotonic by design. The AD5678 features an on-chip reference with an internal gain of 2, and the AD5678-1 model specifically includes a 1.25 V reference, resulting in a full-scale output of 2.5 V. The device also includes a power-on reset circuit and multiple power-down modes to minimize current consumption.
Key Specifications
| Parameter | Min | Typ | Max | Unit | Conditions/Comments |
|---|---|---|---|---|---|
| VDD | 2.7 | - | 5.5 | V | All digital inputs at 0 or VDD, DAC active, excludes load current |
| IDD (Normal Mode) | 1.3 | 1.8 | 2.6 | mA | Internal reference off, VDD = 4.5 V to 5.5 V |
| IDD (All Power-Down Modes) | 0.4 | - | 1 | μA | VDD = 4.5 V to 5.5 V, VIH = VDD and VIL = GND |
| Output Voltage Range | 0 | - | VDD | V | - |
| DC Output Impedance | 0.5 | - | - | Ω | - |
| Reference Input Voltage | 0 | - | VDD | V | ±1% for specified performance |
| Reference Current | 20 | - | 55 | μA | VREF = VDD = 3.6 V (per DAC channel) |
| Reference Output Impedance | 7.5 | - | - | kΩ | - |
Key Features
- Octal DAC Configuration: Includes four 12-bit DACs and four 16-bit DACs in a single package.
- On-Chip Reference: Features an on-chip reference with an internal gain of 2, and models like AD5678-1 have a 1.25 V reference.
- Power-On Reset and Power-Down Modes: Ensures DAC output powers up to 0 V and includes multiple power-down modes to reduce current consumption.
- LDAC and CLR Functions: Allows simultaneous update of all DAC outputs and asynchronous clearing of DACs to a software-selectable code.
- Rail-to-Rail Operation: The on-chip precision output amplifier enables rail-to-rail output swing.
- Versatile Interface: Utilizes a 3-wire serial interface compatible with standard SPI, QSPI, MICROWIRE, and DSP interface standards.
Applications
- Process Control: Suitable for precise control in industrial processes.
- Data Acquisition Systems: Ideal for systems requiring high accuracy and multiple channel control.
- Portable Battery-Powered Instruments: Low power consumption makes it suitable for battery-powered devices.
- Digital Gain and Offset Adjustment: Useful in applications requiring dynamic adjustment of gain and offset.
- Programmable Voltage and Current Sources: Can be used to create programmable sources for various applications.
- Programmable Attenuators: Suitable for applications requiring adjustable attenuation.
Q & A
- What is the voltage supply range for the AD5678?
The AD5678 operates from a single supply voltage ranging from 2.7 V to 5.5 V.
- How many DACs are included in the AD5678, and what are their resolutions?
The AD5678 includes four 12-bit DACs and four 16-bit DACs.
- What is the purpose of the on-chip reference in the AD5678?
The on-chip reference has an internal gain of 2 and can be used to set the full-scale output voltage. For example, the AD5678-1 has a 1.25 V reference, resulting in a full-scale output of 2.5 V.
- What are the power-down modes available in the AD5678?
The AD5678 features multiple power-down modes that reduce the current consumption to as low as 400 nA at 5 V.
- How does the LDAC function work in the AD5678?
The LDAC function allows the simultaneous update of all DAC outputs, and users can select which DAC channels to update simultaneously.
- What is the purpose of the CLR function in the AD5678?
The CLR function clears all DACs to a software-selectable code—0 V, midscale, or full scale—via an asynchronous operation.
- What interface standards is the AD5678 compatible with?
The AD5678 is compatible with standard SPI, QSPI, MICROWIRE, and DSP interface standards.
- What is the output impedance of the AD5678?
The DC output impedance of the AD5678 is 0.5 Ω.
- What are some common applications of the AD5678?
Common applications include process control, data acquisition systems, portable battery-powered instruments, digital gain and offset adjustment, programmable voltage and current sources, and programmable attenuators.
- How does the power-on reset circuit work in the AD5678?
The power-on reset circuit ensures that the DAC output powers up to 0 V and remains at this level until a valid write takes place.
