Features and Benefits
- Easy Drive
- Greatly reduced input kickback
- Input current reduced to 0.5 μA/MSPS
- Enhanced acquisition phase, ≥77% of cycle time at 1 MSPS
- First conversion accurate, no latency or pipeline delay
- Input span compression for single-supply operation
- Fast conversion allows low SPI clock rates
- Input overvoltage clamp protection sinks up to 50 mA
- SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface
- Greatly reduced input kickback
- High performance
- Differential analog input range: ±VREF, VREF from 2.4 V to 5.1 V
- Throughput: 1.8 MSPS/1 MSPS/500 kSPS options
- INL: ±3.1 ppm maximum
- Guaranteed 20-bit, no missing codes
- SNR: 100.5 dB at fIN = 1 kHz, VREF = 5 V
- THD: −123 dB at fIN = 1 kHz, −100 dB at fIN = 100 kHz
- SINAD: 89 dB at fIN = 900 kHz (see Figure 17 in the data sheet)
- Oversampled dynamic range
- 104 dB for OSR = 2
- 131 dB for OSR = 1024
- Low power
- Single 1.8 V supply operation with 1.71 V to 5.5 V logic interface
- 2.7 mW at 500 kSPS (VDD only)
- 83 μW at 10 kSPS, 15 mW at 1.8 MSPS (total power)
- 10-lead packages: 3 mm × 3 mm LFCSP, 3 mm × 4.90 mm MSOP
- Guaranteed operation: −40°C to +125°C
The AD4021 is a high accuracy, high speed, low power, 20-bit, Easy Drive, precision successive approximation register (SAR) analog-to-digital (ADC) that operates from a single power supply, VDD. The reference voltage, VREF, is applied externally and can be set independent of the supply voltage. The AD4021 power scales linearly with throughput.
Easy Drive features reduce both signal chain complexity and power consumption while enabling higher channel density. The reduced input current, particularly in high-Z mode, coupled with a long signal acquisition phase, eliminates the need for a dedicated ADC driver. Easy Drive broadens the range of companion circuitry that is capable of driving these ADCs (see Figure 2 in the data sheet).
Input span compression eliminates the need to provide a negative supply to the ADC driver amplifier while preserving access to the full ADC code range. The input overvoltage clamp protects the ADC inputs against overvoltage events, minimizing disturbances on the reference pin, and eliminating the need for external protection diodes.
Fast device throughput up to 1 MSPS allows users to accurately capture high frequency signals and to implement oversampling techniques to alleviate the challenges associated with antialias filter designs. Decreased serial peripheral interface (SPI) clock rate requirements reduce digital input/output power consumption, broadens digital host options, and simplifies the task of sending data across digital isolation. The SPI-compatible serial user interface is compatible with 1.8 V, 2.5 V, 3 V, and 5 V logic by using the separate VIO logic supply.
- Automatic test equipment
- Machine automation
- Medical equipment
- Battery-powered equipment
- Precision data acquisition systems
- Instrumentation and control systems
Markets and Technologies
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
The AD4000/AD4001/AD4002/AD4003/AD4020 family of evaluation boards enable quick, simplified evaluation of the AD4000 family of 16-/18-/20-bit, precision successive approx-imation register (SAR) analog-to-digital converters (ADCs). The AD4000/AD4001/AD4002/AD4003/AD4020 are low power, 16-bit/18-bit/20-bit, precision SAR ADCs that offer high performance with throughputs up to 2 MSPS (1.8 MSPS for the AD4020). The evaluation board demonstrates the performance of the AD4000/AD4001/AD4002/AD4003/AD4020 family of ADCs and provides a simplified interface for a variety of system applications.
The EVAL-AD4000FMCZ/EVAL-AD4001FMCZ/EVAL-AD4002FMCZ/EVAL-AD4003FMCZ/EVAL-AD4020FMCZ evaluation boards, accessible from the EVAL-AD400x-FMCZ product page, are ideal for use with the Analog Devices, Inc., high speed system demonstration platform (SDP-H1). These evaluation boards interface to the SDP-H1 board via a field-programmable gate array (FPGA) mezzanine card (FMC) low pin count (LPC) connector.
On-board components include a high precision buffered band gap 5.0 V reference (ADR4550), a reference buffer (ADA4807-1), a common-mode buffer (ADA4807-1), a signal conditioning circuit with two op amps (ADA4807-1), and a power supply to derive the necessary voltage levels to supply all voltage needs.
The EVAL-AD4000FMCZ, EVAL-AD4001FMCZ, EVAL-AD4002FMCZ, EVAL-AD4003FMCZ, and EVAL-AD4020FMCZ are populated with the AD4000, AD4001, AD4002, AD4003, and AD4020, respectively. However, these boards can be used to evaluate the performance of the AD4004, AD4005, AD4006, AD4007, AD4008, AD4010, AD4011, AD4021, and AD4022 by limiting the sample rate in the evaluation software to the maximum sample rate of the specific ADC. For example, the AD4000 on the EVAL-AD4000FMCZ can be used to evaluate the performance of the AD4004 if the sample rate is limited to 1 MSPS. See the data sheet of each product for the corresponding evaluation board.
Full descriptions of these products are available in their respective data sheets, which must be consulted when using the corresponding evaluation board. Table 7 shows the models of the AD4000/AD4001/AD4002/AD4003/AD4020 evaluation boards.
Features & Benefits
- Fully featured evaluation board for 10-lead precision ADCs
- Versatile analog signal conditioning circuitry
- On-board reference, reference buffers, and ADC drivers
- PC software for control and data analysis of time and frequency domain
- System demonstration platform-compatible (SDP-H1)
Software & Systems Requirements
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
Precision ADC Driver Tool
The Precision ADC Driver Tool is a web application that simulates the performance of precision ADC and driver combinations. Potential issues with driver selection, kickback settling, and distortion are flagged, and design tradeoffs can be quickly evaluated. Simulations and calculations include system noise, distortion, and settling of the ADC input
AD4021 Companion Parts
Recommended Driver Amplifiers
- For low input bias current, low noise applications: ADA4610-1.
- For high frequency, low noise, low distortion applications: ADA4897-1, ADA4932-1.
- For precision, low power, low distortion applications: ADA4807-1, ADA4940-1.
- For precision, lowest power applications: ADA4096-2, ADA4692-2, ADA4077-1, ADA4084-1.
Recommended External Voltage References
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.