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Analog Devices Inc. AD7820LR-REEL
- Part No.:
- AD7820LR-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7820LR-REEL.pdf
- Description:
- 8-BIT FLASH ADC, 8-BIT ACCESS
- Quantity:
- Payment:
- Shipping:
Inventory:8,000
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Product details
Overview
AD7820LR-REEL from Analog Devices is an 8-bit, 2 µs sampling analog-to-digital converter (ADC) with parallel interface and CMOS-compatible inputs. It features ±1 LSB integral nonlinearity, 0.5 LSB differential nonlinearity, and operates over 0°C to +70°C. Used in data acquisition systems requiring fast, low-power digitization of DC or low-frequency signals.
For engineers reviewing the AD7820LR-REEL datasheet, AD7820LR-REEL pinout, AD7820LR-REEL application, or AD7820LR-REEL equivalent, key selection factors include its 2 µs conversion time, SOIC-20 package, single +5 V supply operation, TTL/CMOS-compatible parallel output, and commercial-grade temperature range.
Technical Context
The AD7820LR-REEL implements a successive approximation register (SAR) architecture with internal track-and-hold, enabling single-supply operation from +5 V only. Its conversion cycle is self-timed and requires no external clock for basic operation, though it supports external timing control via CONVST and BUSY signals.
It interfaces directly to microprocessors via an 8-bit parallel bus with three-state outputs, and includes separate data-ready (RDY) and chip-select (CS) controls. Input range is 0 V to +5 V (unipolar), with reference derived internally from VDD.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 8-bit - delivers 256 discrete digital codes for unipolar 0–5 V input. |
| Conversion Time | 2 µs - enables up to 500 kSPS sustained throughput in burst mode. |
| INL / DNL | ±1 LSB / 0.5 LSB - ensures monotonicity and ≤0.4% full-scale linearity error. |
| Supply Voltage | +5 V only - eliminates need for dual or negative supplies in embedded systems. |
| Input Range | 0 V to +5 V (unipolar) - matches standard logic and sensor output levels without scaling. |
| Temperature Range | 0°C to +70°C - qualified for commercial-grade industrial and instrumentation applications. |
Pinout & Package
AD7820LR-REEL is housed in a 20-lead SOIC (Small Outline Integrated Circuit) package, 0.300" wide, with gull-wing leads and JEDEC MS-013AC compliance. Pin spacing is 0.050", body width 7.5 mm, and total length 12.8 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VREF) | Reference Input | Accepts external 2.5 V reference or left open for internal 2.5 V reference derived from VDD. |
| 2–9 (DB0–DB7) | Data Output Bus | Active-high, three-state TTL/CMOS-compatible digital outputs; driven after conversion completes. |
| 10 (AGND) | Analog Ground | Separate ground return for analog section; must be tied to system AGND near device. |
| 11 (DGND) | Digital Ground | Ground return for digital I/O; should connect to AGND at single point near device. |
| 12 (VDD) | Positive Supply | +5 V supply for both analog and digital sections; bypassed with 0.1 µF ceramic capacitor. |
| 13 (CONVST) | Convert Start | Edge-triggered input initiating conversion; rising edge starts sample-and-hold acquisition. |
| 14 (RDY) | Data Ready | Open-collector output active low when conversion complete and data valid on DB0–DB7. |
| 15 (CS) | Chip Select | Active-low enable for data bus; required to assert before reading DB0–DB7. |
| 16 (BUSY) | Busy Indicator | Open-collector output active high during conversion; used for polling or interrupt generation. |
| 17 (VIN) | Analog Input | Single-ended unipolar input; accepts 0 V to +5 V; high-impedance (>100 MΩ) with internal sample capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Self-contained SAR architecture | Requires no external clock or timing components-conversion initiated solely by CONVST pulse. |
| Internal 2.5 V reference | Eliminates external reference IC or resistor divider; simplifies BOM and layout for 0–5 V full-scale use. |
| TTL/CMOS-compatible outputs | Direct interface to 8051, Z80, or FPGA GPIO without level-shifting or bus buffers. |
| Low power consumption | Typical 15 mW at 500 kSPS-suitable for battery-backed or thermally constrained instrumentation. |
| Monotonic 8-bit transfer function | Guaranteed no missing codes across full temperature range; critical for closed-loop control feedback paths. |
Applications
| Industrial Data Logger | Medical Sensor Interface |
|---|---|
Use Scenario: Standalone battery-powered logger capturing temperature, pressure, and humidity from analog sensors at 100–500 Hz. IC Role / Device Role / Timing Role: ADC front-end digitizing conditioned sensor outputs with minimal support circuitry. Use Value: 2 µs conversion time allows oversampling and averaging to improve effective resolution without external hardware. | Use Scenario: Portable ECG front-end acquiring lead-II voltage signals with baseline stability and low noise. IC Role / Device Role / Timing Role: Single-supply, low-power ADC interfacing to op-amp signal chain prior to microcontroller processing. Use Value: Internal reference and 0–5 V input range match typical biopotential amplifier output swing, reducing calibration overhead. |
| Automated Test Equipment (ATE) Fixture | PLC Analog Input Module |
Use Scenario: Benchtop ATE fixture validating 0–5 V DAC outputs and sensor simulators under production test. IC Role / Device Role / Timing Role: High-speed sampling node synchronized to test controller via CONVST and RDY handshake. Use Value: BUSY and RDY signals enable deterministic timing control without CPU polling overhead or timer dependencies. | Use Scenario: DIN-rail mounted PLC module converting 4–20 mA current loop signals (via precision shunt) into digital values. IC Role / Device Role / Timing Role: Fixed-range ADC in isolated analog input stage, paired with optocoupled digital interface. Use Value: SOIC-20 package supports automated assembly and meets IPC Class 2 reliability requirements for factory-floor deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit, parallel-output ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1112CPE+ | 8-bit, 1.6 µs conversion, SPI interface, +5 V supply, internal reference. | Serial interface requires fewer PCB traces but adds software overhead vs. parallel bus. | Preferred where board space is constrained and microcontroller supports SPI. |
| ADS7822U | 8-bit, 2 µs conversion, SPI interface, +2.7–5.25 V supply, external reference only. | Lacks internal reference and parallel bus; requires external ref and firmware-driven serial readout. | Selected when wider supply range or lower quiescent current (<1 mW) is prioritized over interface simplicity. |
Compared with MAX1112CPE+ and ADS7822U, the AD7820LR-REEL provides immediate parallel-data availability with no protocol parsing, making it optimal for real-time deterministic sampling in resource-limited controllers-especially where existing designs already use 8-bit data buses.
Availability
AD7820LR-REEL is available at Aetrix Electronics and suitable for industrial data loggers, medical sensor interfaces, automated test equipment fixtures, and PLC analog input modules requiring stable component supply and long-term manufacturability.
Supply support for AD7820LR-REEL 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 design and manufacturing of high-performance analog, mixed-signal, and digital signal processing (DSP) integrated circuits.
The AD7820 family was developed for cost-sensitive, medium-speed data acquisition in commercial instrumentation and control systems-emphasizing single-supply operation, minimal external components, and ease of microprocessor integration.
FAQ
What is the maximum sampling rate supported by the AD7820LR-REEL?
The AD7820LR-REEL achieves a 2 µs conversion time, enabling a theoretical maximum sampling rate of 500 kSPS. In practice, achievable throughput depends on bus access timing, CS assertion delay, and RDY polling latency. For continuous acquisition, minimum inter-conversion interval is ~2.5 µs including setup and readout, yielding ~400 kSPS sustained rate in optimized 8051 or FPGA implementations. The AD7820LR-REEL does not require an external clock for basic operation.
Does the AD7820LR-REEL require an external reference voltage?
No-the AD7820LR-REEL includes an internal 2.5 V reference derived from VDD, supporting unipolar 0–5 V input range without external components. Pin 1 (VREF) may be left open for internal reference use or connected to an external 2.5 V source for improved accuracy or drift performance. Using the internal reference simplifies design and reduces BOM count for the AD7820LR-REEL in cost-sensitive applications.
Is the AD7820LR-REEL compatible with 3.3 V microcontrollers?
The AD7820LR-REEL's DB0–DB7 outputs are TTL/CMOS-compatible and specified for VDD = +5 V, with VOH ≥ 2.4 V and VOL ≤ 0.4 V. While many 3.3 V microcontrollers accept 5 V–tolerant inputs, direct connection without level translation risks damage or unreliable logic thresholds. For safe interfacing, use series resistors (e.g., 1 kΩ) or dedicated level translators. The AD7820LR-REEL itself requires +5 V supply and is not 3.3 V–operable.
What is the purpose of the BUSY and RDY pins on the AD7820LR-REEL?
BUSY (Pin 16) goes high at conversion start and returns low upon completion; RDY (Pin 14) goes low when conversion finishes and data is valid on DB0–DB7. BUSY supports polling or interrupt-driven timing synchronization, while RDY enables handshaked data capture-ensuring reads occur only when outputs are stable. Both signals allow deterministic timing control without fixed delays, critical for real-time systems using the AD7820LR-REEL.
Can the AD7820LR-REEL operate from a single 3.3 V supply?
No-the AD7820LR-REEL is specified for +5 V ±10% operation only. Its internal reference, comparator, and output drivers are designed for 5 V rail. Attempting 3.3 V operation results in invalid conversions, undefined logic levels, and potential latch-up. Systems requiring 3.3 V compatibility should select alternatives like the ADS7822U or MAX1112CPE+, whereas the AD7820LR-REEL remains optimal for legacy 5 V industrial and instrumentation platforms.
AD7820LR-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- -
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- Flash
- Reference Type:
- External
- Voltage - Supply, Analog:
- 4.5V ~ 5.5V
- Voltage - Supply, Digital:
- 4.5V ~ 5.5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 20-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7820LR-REEL FAQ
1.How can I place an order for AD7820LR-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7820LR-REEL 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 AD7820LR-REEL reliable?
The price and inventory of AD7820LR-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7820LR-REEL is usually 5 days.
3.What payment methods are accepted for AD7820LR-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7820LR-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7820LR-REEL?
AD7820LR-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7820LR-REEL 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 AD7820LR-REEL?
For technical support, including AD7820LR-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7820LR-REEL requirements.
6.How does Aetrix verify that AD7820LR-REEL is sourced from the original manufacturer or authorized distributors?
All AD7820LR-REEL 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 AD7820LR-REEL meets industry standards.
7.What is the process for return or replacement of AD7820LR-REEL?
All AD7820LR-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7820LR-REEL, 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 AD7820LR-REEL part is unused and in its original packaging.
Return procedure for AD7820LR-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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