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Analog Devices Inc. AD7871KN
- Part No.:
- AD7871KN
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
AD7871KN.pdf
- Description:
- IC ADC 14BIT SAR 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,168
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Product details
Overview
AD7871KN from Analog Devices is a complete monolithic 14-bit LC2MOS sampling ADC with integrated track-and-hold, 3 V buried Zener reference, and self-contained laser-trimmed internal clock. It delivers 83 kSPS throughput, 80 dB SNR at 10 kHz, 57 ns data access time, and supports ±3 V bipolar analog input on ±5 V supplies - used in high-speed DSP servo control and spectrum analysis systems.
For engineers reviewing the AD7871KN datasheet, AD7871KN pinout, AD7871KN application, or AD7871KN equivalent, key selection considerations include its three configurable output formats (14-bit parallel / dual-byte / serial), internal clock override capability for system synchronization, and verified dynamic performance across commercial temperature range (0°C to +70°C).
Technical Context
The AD7871KN implements a successive approximation register (SAR) architecture with a voltage-output DAC and high-speed comparator, paired with a low-noise track-and-hold amplifier acquiring to 14-bit accuracy in ≤2 μs. Its internal 3 V buried Zener reference is factory trimmed (±0 mV), temperature-compensated (±40 ppm/°C), and provides both DAC reference and bipolar bias.
Control logic enables three distinct interface modes via the 14/8/CLK pin: 14-bit parallel only (+5 V), byte/serial with gated SCLK (0 V), or byte/serial with continuous SCLK (−5 V). The BUSY/INT output signals conversion completion asynchronously, supporting both timer-driven (Mode 1) and microprocessor-controlled (Mode 2) operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - guarantees no missing codes; ideal LSB = 366 µV for ±3 V input range |
| Throughput Rate | 83 kSPS - maximum sustained sampling rate with internal 2 MHz clock |
| SNR @ 10 kHz | 80 dB min - measured including distortion and noise; enables clean digitization of audio-band signals |
| Data Access Time | 57 ns max - defines minimum RD pulse-to-valid-data delay in Mode 1 parallel read |
| Analog Input Range | ±3 V - bipolar full-scale range referenced to AGND; supports direct connection to op-amp outputs |
| Power Dissipation | 50 mW typ - achieved at 83 kSPS with ±5 V supplies; enables thermally constrained embedded designs |
| Reference Output | 3.00 V ±10 mV - stable, low-drift internal Zener source; loadable up to 500 µA |
Pinout & Package
AD7871KN is housed in a 28-pin plastic DIP (PDIP) package with 0.600-inch body width and through-hole mounting. Pin layout follows standard dual-in-line configuration with pin 1 marked by notch or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONVST | Asynchronous convert start | Rising-edge-triggered hold command; independent of CLK timing for jitter-critical sampling |
| CS | Chip select enable | Active-low input enabling data bus drivers and initiating conversion in Mode 2 when CONVST = low |
| RD | Read strobe | Active-low signal enabling three-state data outputs DB0–DB13 during parallel read cycles |
| BUSY/INT | Status output | Open-collector logic-low active indicator of conversion progress or completion |
| CLK | Clock input/control | Accepts external TTL clock or ties to VSS to enable internal 2 MHz oscillator |
| 14/8/CLK | Interface mode selector | Configures output format: +5 V = 14-bit parallel only; 0 V = byte/serial with gated SCLK; −5 V = byte/serial with continuous SCLK |
| VIN | Analog input | Differential-capable input node accepting ±3 V bipolar signals with 15 kΩ typical input resistance |
| REFOUT | Reference output | Provides regulated 3.00 V reference for external circuitry; requires ≤50 pF capacitive load for stability |
| CREF | Reference decoupling | Internal reference bypass point; must connect 10 nF capacitor to AGND per datasheet specification |
| AGND / DGND | Analog/digital ground | Separate ground pins minimize digital switching noise coupling into analog conversion path |
Key Features
| Feature | Design Value |
|---|---|
| Complete monolithic ADC | Integrates track-and-hold, SAR core, 3 V Zener reference, and interface logic - eliminates need for external precision components |
| Three output formats | Hardware-selectable 14-bit parallel, dual-byte (8-bit bus compatible), or serial stream - simplifies integration across 8/16-bit microcontrollers and DSPs |
| Internal clock with override | Factory-laser-trimmed 2 MHz oscillator enables standalone operation; external clock input allows system-level noise synchronization |
| Dynamic performance spec'd | Full AC specs including THD (−86 dB max), IMD (−86 dB max), and SNR (80 dB min) validated for DSP-grade signal fidelity |
| Bipolar/unipolar flexibility | Supports ±3 V bipolar input natively; unipolar operation enabled via REFOUT offsetting - accommodates sensor and industrial signal conditioning |
Applications
| High-Speed Modems | Digital Signal Processing |
|---|---|
Use Scenario: Real-time analog front-end in V.34/V.90 modem chipsets digitizing baseband I/Q signals at >40 kHz. IC Role / Device Role / Timing Role: ADC sampling engine providing synchronized 14-bit digitization with <2 µs acquisition time to preserve signal integrity. Use Value: 80 dB SNR ensures clean spectral representation of narrowband communication channels; internal clock eliminates external timing component count. | Use Scenario: Data acquisition stage in real-time FFT-based spectrum analyzers processing 0–20 kHz analog inputs. IC Role / Device Role / Timing Role: High-fidelity sampling ADC feeding DSP engines; BUSY/INT signal coordinates DMA transfers without CPU polling. Use Value: Verified −86 dB THD and IMD prevent harmonic leakage into adjacent bins; 57 ns access time enables tight loop timing in pipelined architectures. |
| Speech Recognition Systems | DSP Servo Control |
Use Scenario: Front-end digitizer in embedded voice recognition units capturing microphone signals with minimal quantization noise. IC Role / Device Role / Timing Role: Low-power 14-bit ADC operating from ±5 V rails; REFOUT supplies bias for electret mic preamp stages. Use Value: 50 mW typical power dissipation extends battery life; twos-complement coding simplifies signed arithmetic in feature extraction algorithms. | Use Scenario: Position/velocity feedback digitization in closed-loop motor controllers requiring precise analog sensing at 50–100 kHz update rates. IC Role / Device Role / Timing Role: High-throughput ADC interfacing directly to TMS320Cxx or ADSP-21xx DSPs via parallel bus with CS/RD handshaking. Use Value: 83 kSPS throughput meets Nyquist requirements for 40 kHz servo bandwidth; bipolar input accepts differential encoder or current-sense outputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 14-bit sampling ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7871JRZ | Same die, 28-pin SOIC package; higher thermal resistance; rated for same 0°C to +70°C range | Preferred for surface-mount production; requires PCB rework for through-hole legacy designs | Select AD7871JRZ when automated assembly and board space constraints outweigh through-hole serviceability needs. |
| ADS8320U | 16-bit SAR ADC; 100 kSPS; SPI interface only; no internal reference; requires external 2.5 V reference | Higher resolution but lacks bipolar input support and integrated reference; demands additional support circuitry | Choose ADS8320U only if 16-bit resolution is mandatory and system can accommodate external reference and SPI-only interface. |
Compared with AD7871KN, AD7871JRZ offers identical electrical performance in a space-saving SOIC package but sacrifices through-hole serviceability, while ADS8320U trades integrated simplicity and bipolar capability for higher resolution and SPI compatibility - making AD7871KN optimal for cost-sensitive, mixed-signal DSP systems needing plug-and-play analog front-ends.
Availability
AD7871KN is available at Aetrix Electronics and suitable for high-speed modems, DSP servo control, and spectrum analysis applications requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for AD7871KN 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 AD7871KN belongs to Analog Devices' precision data acquisition product line, engineered for demanding real-time signal digitization in communications, instrumentation, and industrial control systems where dynamic performance and integration are critical.
FAQ
What is the operating temperature range specified for the AD7871KN?
The AD7871KN is rated for the commercial temperature range of 0°C to +70°C, as confirmed in the Rev. F datasheet under Absolute Maximum Ratings and Specifications tables. This K-version designation aligns with J- and K-versions sharing identical thermal specifications, and the device is tested across this full range for all DC accuracy and dynamic parameters including SNR, THD, and INL.
Does the AD7871KN require an external clock to operate?
No, the AD7871KN does not require an external clock. It features a self-contained, laser-trimmed internal oscillator nominally set to 2 MHz, enabling fully autonomous operation. The CLK pin may be tied to VSS to activate this internal clock; alternatively, an external TTL-compatible clock can be applied to override it for system-level noise reduction or precise timing alignment.
How is the data output format selected on the AD7871KN?
The AD7871KN data output format is selected via the 14/8/CLK pin: applying +5 V configures 14-bit parallel output only; 0 V enables both dual-byte and serial formats with gated SCLK; −5 V enables both formats with continuous SCLK. This hardware-selectable interface eliminates firmware configuration overhead and supports direct connection to 8-bit or 16-bit microprocessor buses without glue logic.
What is the purpose of the CREF pin on the AD7871KN?
The CREF pin on the AD7871KN is the dedicated decoupling point for the internal 3 V buried Zener reference. Per the datasheet, a 10 nF capacitor must be connected between CREF and AGND to minimize reference noise and ensure stable operation. This bypassing is mandatory for achieving specified dynamic performance, including the 80 dB SNR and low THD figures.
Can the AD7871KN interface directly with an 8-bit microcontroller data bus?
Yes, the AD7871KN supports direct 8-bit microcontroller interfacing via its byte-mode output. When the 14/8/CLK pin is set to 0 V or −5 V, the HBEN pin controls upper/lower byte selection on DB7–DB0, allowing sequential reading of 14-bit data across two 8-bit cycles. This eliminates the need for external latches or data-width translators in legacy 8-bit system designs.
AD7871KN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-DIP (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 83k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI, Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- Internal
- Voltage - Supply, Analog:
- ±5V
- Voltage - Supply, Digital:
- ±5V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 28-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD7871KN FAQ
1.How can I place an order for AD7871KN through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7871KN 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 AD7871KN reliable?
The price and inventory of AD7871KN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7871KN is usually 5 days.
3.What payment methods are accepted for AD7871KN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7871KN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7871KN?
AD7871KN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7871KN 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 AD7871KN?
For technical support, including AD7871KN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7871KN requirements.
6.How does Aetrix verify that AD7871KN is sourced from the original manufacturer or authorized distributors?
All AD7871KN 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 AD7871KN meets industry standards.
7.What is the process for return or replacement of AD7871KN?
All AD7871KN units undergo pre-shipment inspection (PSI). If there is an issue with AD7871KN, 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 AD7871KN part is unused and in its original packaging.
Return procedure for AD7871KN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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