Overview
The AD7821KR is a high-speed, 8-bit analog-to-digital converter (ADC) manufactured by Analog Devices Inc. This component is designed to offer improved performance over its predecessor, the AD7820, with a faster conversion time and higher signal bandwidth. The AD7821KR features a conversion time of 660 ns and supports both unipolar and bipolar input ranges. It is fabricated using Analog Devices’ Linear Compatible CMOS (LC2MOS) process, combining precision bipolar circuits with low power CMOS logic. This ADC is suitable for applications requiring high-speed data conversion and precision, making it ideal for various industrial and embedded systems.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Resolution | 8-bit | |
| Conversion Time | 660 ns (WR-RD mode), 700 ns (RD mode) | ns |
| Sample Rate | 1 MHz | |
| Input Range | Unipolar and Bipolar | |
| Reference Input | Ratiometric | |
| Operating Temperature | –40°C to +85°C | °C |
| Power Supply | ±5 V or single +5 V | V |
| Power Dissipation | 50 mW | mW |
| Package Type | 20-Lead DIP, SOIC, 20-Terminal Surface-Mount |
Key Features
- Fast Conversion Time: The AD7821KR features a conversion time of 660 ns in the WR-RD mode and 700 ns in the RD mode, making it suitable for high-speed applications.
- Built-In Track-and-Hold: This ADC includes a built-in track-and-hold function, allowing it to digitize full-scale signals up to 100 kHz without an external track-and-hold circuit.
- No External Clock Required: The half-flash conversion technique eliminates the need for an external clock signal, simplifying system design.
- Low Power Dissipation: The AD7821KR has a low power dissipation of 50 mW, making it energy-efficient for various applications.
- Microprocessor Compatibility: The ADC is designed with standard microprocessor control signals (CS, RD, WR, RDY, INT) and latched, three-state data outputs, enabling easy integration with high-speed data buses).
- Overflow Output: An overflow output (OFL) is provided for cascading devices to achieve higher resolution).
Applications
- Industrial Automation: The AD7821KR is suitable for high-speed data acquisition in industrial automation systems, where precision and speed are critical).
- Embedded Systems: Its compatibility with microprocessors and low power consumption make it an ideal choice for embedded systems requiring fast and accurate analog-to-digital conversion).
- Medical Devices: The ADC’s high accuracy and fast conversion time make it suitable for medical devices that require precise and rapid data acquisition).
- Aerospace and Defense: The AD7821KR’s robust performance over a wide temperature range and its ability to handle bipolar inputs make it a viable option for aerospace and defense applications).
Q & A
- What is the resolution of the AD7821KR ADC?
The AD7821KR has an 8-bit resolution).
- What is the conversion time of the AD7821KR?
The conversion time is 660 ns in the WR-RD mode and 700 ns in the RD mode).
- Does the AD7821KR require an external clock signal?
No, the AD7821KR does not require an external clock signal due to its half-flash conversion technique).
- What are the operating temperature ranges for the AD7821KR?
The operating temperature range is –40°C to +85°C).
- What types of input ranges does the AD7821KR support?
The AD7821KR supports both unipolar and bipolar input ranges).
- What is the power dissipation of the AD7821KR?
The power dissipation is 50 mW).
- What package types are available for the AD7821KR?
The AD7821KR is available in 20-Lead DIP, SOIC, and 20-Terminal Surface-Mount packages).
- Does the AD7821KR have a built-in track-and-hold function?
Yes, the AD7821KR has a built-in track-and-hold function capable of digitizing full-scale signals up to 100 kHz).
- Is the AD7821KR compatible with microprocessors?
Yes, the AD7821KR is designed with standard microprocessor control signals and latched, three-state data outputs).
- What is the purpose of the overflow output (OFL) in the AD7821KR?
The overflow output (OFL) is provided for cascading devices to achieve higher resolution).
