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Analog Devices Inc. AD7921AUJ-REEL7
- Part No.:
- AD7921AUJ-REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
AD7921AUJ-REEL7.pdf
- Description:
- IC ADC 12BIT DUAL LP TSOT-23-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,332
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Product details
Overview
AD7921AUJ-REEL7 from Analog Devices is a 12-bit, dual-channel, successive approximation analog-to-digital converter (ADC) operating from a single 2.35 V to 5.25 V supply. It delivers 250 kSPS throughput, 71 dB minimum SNR at 100 kHz input, ±1.5 LSB integral nonlinearity, and channel-to-channel isolation of −90 dB. It is used in portable medical instruments for simultaneous dual-sensor signal digitization with low power and high DC/AC accuracy.
For engineers reviewing the AD7921AUJ-REEL7 datasheet, AD7921AUJ-REEL7 pinout, AD7921AUJ-REEL7 application, or AD7921AUJ-REEL7 equivalent, key selection criteria include its 12-bit resolution with no missing codes, flexible serial clock management up to 5 MHz, internal VDD-referenced conversion, 8-lead TSOT package footprint, and guaranteed −40°C to +85°C operation.
Technical Context
The AD7921AUJ-REEL7 implements a true successive approximation register (SAR) architecture with no pipeline delay, enabling deterministic single-shot conversion timing. Sampling is triggered on the falling edge of CS, and conversion is synchronized to the SCLK signal-requiring exactly 16 clock cycles at 5 MHz for full 12-bit result output.
It integrates a wide-bandwidth track-and-hold amplifier supporting >6 MHz input frequencies, accepts 0 V to VDD single-ended analog inputs on VIN0/VIN1, and uses DIN to select the active channel prior to conversion. The DOUT stream includes a channel identifier bit and two leading zeros, ensuring unambiguous dual-channel data framing in SPI/QSPI/MICROWIRE-compatible interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12 bits - guarantees monotonic transfer function and no missing codes across full temperature range. |
| Throughput Rate | 250 kSPS maximum - enables real-time sampling of audio-band and sensor signals without oversampling penalty. |
| SNR | 71 dB minimum at 100 kHz - supports high-fidelity digitization of precision analog sensors and instrumentation signals. |
| INL | ±1.5 LSB max - ensures accurate end-point linearity for calibrated measurement systems requiring <0.05% full-scale error. |
| Power Dissipation | 6 mW max at 3 V / 250 kSPS - enables battery-powered operation with sub-2 mA supply current during active conversion. |
| Channel Isolation | −90 dB typical - prevents crosstalk between VIN0 and VIN1 in multiplexed dual-signal acquisition (e.g., differential pair or reference/sense). |
| Supply Range | 2.35 V to 5.25 V - allows direct interface with Li-ion, 3.3 V, and 5 V system rails without external regulators. |
Pinout & Package
AD7921AUJ-REEL7 is housed in an 8-lead TSOT package (2.1 mm × 1.6 mm × 0.8 mm), optimized for space-constrained portable designs. Pin numbering follows standard top-view orientation with pin 1 marked by a dot or beveled edge.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DIN (Pin 1) | Serial data input | Selects VIN0 or VIN1 before conversion via third MSB; must be stable before CS falling edge. |
| SCLK (Pin 2) | Serial clock input | Drives both data transfer and internal ADC conversion timing; 5 MHz max rated frequency. |
| CS (Pin 3) | Chip select (active low) | Initiates sampling on falling edge and frames 16-bit serial output; defines conversion window boundary. |
| DOUT (Pin 4) | Serial data output | Outputs 16-bit frame: two leading zeros + channel ID + invalid bit + 12-bit result (MSB first). |
| VDD (Pin 5) | Power supply | Single analog/digital supply rail; also serves as internal reference source for full 0–VDD input range. |
| GND (Pin 6) | Analog ground | Common reference for VIN0/VIN1 and internal circuitry; requires low-impedance connection to system AGND. |
| VIN0 (Pin 7) | Analog input channel 0 | Single-ended input referenced to GND; supports 0–VDD range with 20 pF input capacitance. |
| VIN1 (Pin 8) | Analog input channel 1 | Single-ended input identical to VIN0; channel selection controlled via DIN prior to CS assertion. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | True SAR architecture ensures deterministic 3.2 μs conversion time and immediate data validity-critical for closed-loop control timing. |
| VDD-referenced conversion | Eliminates need for external reference; maximizes dynamic range across all supply voltages from 2.35 V to 5.25 V. |
| Flexible serial clock management | Conversion rate scales linearly with SCLK frequency-enables dynamic power/performance trade-off without firmware change. |
| Ultra-low standby current | 1 μA max in full power-down mode-reduces quiescent consumption by >1000× versus active mode for intermittent sampling. |
| High channel isolation | −90 dB typical crosstalk enables independent dual-channel acquisition without guard-band timing or hardware separation. |
Applications
| Portable Medical Instrumentation | Battery-Powered Data Acquisition |
|---|---|
Use Scenario: Simultaneous acquisition of ECG lead voltage and respiration sensor output in handheld diagnostic device. IC Role / Device Role / Timing Role: Dual-channel SAR ADC digitizing two analog biosignals at 250 kSPS with synchronized sampling and no inter-channel skew. Use Value: Enables compact, low-power design with 12-bit resolution and −90 dB channel isolation-eliminating need for separate ADCs or analog switching. |
Use Scenario: Field-deployable environmental monitor logging temperature and humidity using two analog sensor outputs. IC Role / Device Role / Timing Role: Low-quiescent ADC performing burst-mode sampling every 100 ms, entering 1 μA power-down between conversions. Use Value: Achieves >1-year battery life on coin cell via 6 mW active power and 5 μW power-down dissipation at 3 V. |
| Optical Sensor Interface | Industrial Control Signal Conditioning |
Use Scenario: Digitizing photodiode current and ambient light reference in optical smoke detector. IC Role / Device Role / Timing Role: High-SNR ADC capturing fast transient pulses with 71 dB SNR at 100 kHz while rejecting supply noise via VDD-referencing. Use Value: Supports reliable detection of rapid smoke-induced signal changes without external op-amp gain stages or reference ICs. |
Use Scenario: Monitoring dual analog feedback signals (motor current + position encoder voltage) in motor drive PCB. IC Role / Device Role / Timing Role: Precision ADC providing synchronized 12-bit samples for real-time current/voltage loop control with <±1.5 LSB INL. Use Value: Ensures closed-loop stability and <0.05% measurement linearity across industrial temperature range (−40°C to +85°C). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7920BRMZ-REEL | 12-bit, single-channel, MSOP-10 package; lacks second analog input and channel-select logic. | Requires external multiplexer for dual-signal support; adds propagation delay and crosstalk risk. | Choose only if board layout permits external mux and timing budget allows added latency. |
| ADS7822U | 12-bit, dual-channel, but uses external reference; 2.7 V–5.25 V supply; 200 kSPS max; SOIC-8 package. | Lower throughput and higher power (12 mW at 5 V); requires external 2.5 V reference for full performance. | Prefer AD7921AUJ-REEL7 when VDD-referencing, 250 kSPS, or TSOT footprint are required. |
Compared with AD7920BRMZ-REEL and ADS7822U, AD7921AUJ-REEL7 uniquely combines integrated dual-channel selection, VDD referencing, 250 kSPS throughput, and ultra-small TSOT packaging-making it optimal for space- and power-constrained dual-signal systems where timing determinism and supply simplicity are critical.
Availability
AD7921AUJ-REEL7 is available at Aetrix Electronics and suitable for battery-powered medical instruments, portable data loggers, optical smoke detectors, and industrial motor control systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.
Supply support for AD7921AUJ-REEL7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD79xx family-including AD7921AUJ-REEL7-is designed specifically for low-power, high-accuracy, multi-channel data acquisition in portable and embedded systems where size, energy efficiency, and DC/AC performance are jointly constrained.
FAQ
What is the maximum sampling rate supported by the AD7921AUJ-REEL7?
The AD7921AUJ-REEL7 supports a maximum throughput rate of 250 kSPS under specified conditions (VDD = 2.35 V to 5.25 V, fSCLK = 5 MHz). This rate is achieved with a fixed 16-cycle SCLK conversion time, and actual achievable rate depends on SCLK frequency and system-level timing margins including tQUIET (30 ns minimum between conversions).
Does the AD7921AUJ-REEL7 require an external voltage reference?
No, the AD7921AUJ-REEL7 uses an internal reference derived from VDD, enabling a full-scale input range of 0 V to VDD. This eliminates the need for external reference components and simplifies design for applications where supply rail stability meets system accuracy requirements.
What package type is used for the AD7921AUJ-REEL7?
The AD7921AUJ-REEL7 is supplied in an 8-lead TSOT (Thin Small Outline Transistor) package measuring 2.1 mm × 1.6 mm × 0.8 mm. This compact, surface-mount package supports high-density PCB layouts typical in portable and wearable electronics.
How is channel selection implemented on the AD7921AUJ-REEL7?
Channel selection on the AD7921AUJ-REEL7 is performed via the DIN pin: the third most significant bit (MSB) of the data written to DIN before the CS falling edge determines whether VIN0 or VIN1 is sampled. This occurs prior to conversion initiation and is validated in the functional block diagram and timing examples.
What is the guaranteed operating temperature range for the AD7921AUJ-REEL7?
The AD7921AUJ-REEL7 is specified for operation across −40°C to +85°C (A Grade), with all electrical parameters-including INL, SNR, and throughput-guaranteed over this full industrial temperature range per the AD7921 specifications table.
AD7921AUJ-REEL7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- SOT-23-8 Thin, TSOT-23-8
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 250k
- Number of Inputs:
- -
- Input Type:
- -
- Data Interface:
- SPI, DSP
- Configuration:
- -
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- -
- Reference Type:
- -
- Voltage - Supply, Analog:
- -
- Voltage - Supply, Digital:
- -
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- TSOT-23-8
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7921AUJ-REEL7 FAQ
1.How can I place an order for AD7921AUJ-REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7921AUJ-REEL7 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD7921AUJ-REEL7 reliable?
The price and inventory of AD7921AUJ-REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7921AUJ-REEL7 is usually 5 days.
3.What payment methods are accepted for AD7921AUJ-REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7921AUJ-REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7921AUJ-REEL7?
AD7921AUJ-REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7921AUJ-REEL7 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD7921AUJ-REEL7?
For technical support, including AD7921AUJ-REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7921AUJ-REEL7 requirements.
6.How does Aetrix verify that AD7921AUJ-REEL7 is sourced from the original manufacturer or authorized distributors?
All AD7921AUJ-REEL7 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7921AUJ-REEL7 meets industry standards.
7.What is the process for return or replacement of AD7921AUJ-REEL7?
All AD7921AUJ-REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with AD7921AUJ-REEL7, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD7921AUJ-REEL7 part is unused and in its original packaging.
Return procedure for AD7921AUJ-REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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