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Analog Devices Inc. AD7851ARSZ-REEL
- Part No.:
- AD7851ARSZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
AD7851ARSZ-REEL.pdf
- Description:
- IC ADC 14BIT SAR 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,899
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Product details
Overview
AD7851ARSZ-REEL from Analog Devices is a 14-bit, 333 kSPS serial analog-to-digital converter (ADC) with pseudo-differential input, on-chip 4.096 V reference, self/system calibration, and flexible SPI/QSPI/8051-compatible serial interface. It operates from a single 5 V supply, delivers ±2 LSB integral nonlinearity (A grade), and supports dual input ranges (0 V to VREF and ±VREF/2) for precision data acquisition in high-speed control loops.
For engineers reviewing the AD7851ARSZ-REEL datasheet, AD7851ARSZ-REEL pinout, AD7851ARSZ-REEL application, or AD7851ARSZ-REEL equivalent, this page provides verified technical context, real-world design meaning of key specs, validated SOIC-24 pin functions, confirmed alternatives for system-level trade-offs, and supply-chain support for industrial embedded and DSP applications.
Technical Context
The AD7851ARSZ-REEL implements a successive approximation register (SAR) architecture with integrated track-and-hold, charge redistribution DAC, and comparator. Its conversion cycle requires 19.5 master clock cycles (max 3.25 µs at 6 MHz CLKIN), and acquisition time is 0.33 µs - enabling full-scale signal capture up to 20 MHz bandwidth.
Calibration is performed via dedicated on-chip registers: self-calibration adjusts offset and gain using internal DACs, while system calibration allows external reference and sensor path correction. The serial interface supports five modes including self-clocked (SCLK output) and externally clocked (SCLK input) configurations with programmable polarity and phase.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - delivers 16,384 discrete digital codes for high-fidelity signal digitization in spectrum analysis and servo feedback. |
| Throughput Rate | 333 kSPS (A grade, –40°C to +85°C) - enables real-time sampling of 10 kHz sine waves with >77 dB SNR for speech synthesis systems. |
| Integral Nonlinearity | ±2 LSB max - ensures monotonic transfer function and no missing codes across full temperature range, critical for closed-loop control accuracy. |
| Analog Input Ranges | 0 V to VREF (unipolar) or ±VREF/2 (bipolar) - selectable via AMODE pin; supports both single-ended referenced and differential-sensed signals without external level-shifting. |
| Power Dissipation | 60 mW typ (normal mode), 5 µW typ (sleep mode) - allows battery-powered instrumentation to maintain calibration memory while minimizing idle current. |
| Reference | Internal 4.096 V ±0.5% (REFIN/REFOUT pin) - eliminates need for external precision reference; supports external overdrive from 4 V to AVDD for system-level voltage scaling. |
| Serial Interface | SPI/QSPI/8051-compatible with 5 configurable modes - permits direct connection to ADSP-21xx, TMS320C2x, and 8XC51 microcontrollers without glue logic. |
Pinout & Package
AD7851ARSZ-REEL is housed in a 24-lead SOIC package (body width 0.3 inch, JEDEC MS-013AA), RoHS-compliant (Z suffix), tape-and-reel format (REEL). Pin layout matches AD7851AR and AD7851AR-REEL variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONVST | Convert Start input | Edge-triggered control: falling edge initiates hold mode and starts conversion; must be held high between conversions to avoid retriggering. |
| BUSY | Conversion status output | Active-high open-drain signal indicating active conversion or calibration; used for handshaking in interrupt-driven firmware. |
| SLEEP | Power-down control | Logic 0 disables internal reference, analog circuitry, and digital core while retaining calibration memory; wake-up time <1 µs after SLEEP = 1. |
| REFIN/REFOUT | Reference I/O | Provides 4.096 V internal reference; accepts external reference from 4 V to AVDD; requires CREF1 (0.1 µF) and CREF2 (0.01 µF) bypass capacitors to AGND. |
| AIN(+), AIN(–) | Pseudo-differential analog inputs | Support unipolar (0 V to VREF) or bipolar (±VREF/2) ranges selected by AMODE; AIN(–) must be biased ≥0 V; input leakage ≤±1 µA. |
| DIN, DOUT, SCLK, SYNC | Serial interface signals | 3-wire (DIN/DOUT/SCLK) or 2-wire (DIN/SCLK) operation; SYNC controls frame synchronization; POLARITY selects SCLK edge sensitivity. |
| AMODE | Analog range select | Logic 0 → 0 V to VREF range; Logic 1 → ±VREF/2 centered range; determines transfer function coding (straight binary vs. two's complement). |
| CAL | Calibration trigger | Pulse initiates on-chip self-calibration sequence (typ. 41.7 ms at 6 MHz); BUSY remains high until completion; retains calibration data in sleep mode. |
Key Features
| Feature | Design Value |
|---|---|
| Single 5 V supply operation | Eliminates dual-rail power design complexity; AVDD and DVDD internally decoupled but require separate 0.1 µF ceramic bypasses to AGND/DGND. |
| On-chip 4.096 V reference | Reduces BOM count and layout area; reference output stable to ±50 ppm/°C; supports external override for system-level gain trimming. |
| System and self-calibration | Enables field recalibration without test equipment; offset/gain calibration registers are readable/writable; full self-cal takes 41.7 ms (6 MHz CLKIN). |
| Pseudo-differential input architecture | Rejects common-mode noise on AIN(+) and AIN(–); allows DC-biased AC signals (e.g., audio, vibration sensors) without transformer coupling. |
| Five serial interface modes | Mode 2 (3-wire SPI) and Mode 4 (self-clocked) are most commonly used; supports daisy-chaining multiple AD7851 devices via shared SCLK/SYNC. |
Applications
| Digital Signal Processing | Speech Recognition |
|---|---|
|
Use Scenario: Real-time spectral analysis of sensor outputs in motor control systems using FFT-based algorithms. IC Role / Device Role / Timing Role: ADC front-end capturing 10 kHz–20 kHz band-limited signals at 333 kSPS with <0.33 µs acquisition time. Use Value: 14-bit resolution and 77 dB SNR preserve harmonic content for accurate frequency bin detection in predictive maintenance firmware. |
Use Scenario: Digitizing microphone output in voice-controlled industrial HMIs operating at ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Unipolar-mode ADC converting 0–4.096 V audio envelope signals with automatic power-down between voice bursts. Use Value: 5 µW sleep mode power and retained calibration memory enable multi-year battery life in portable diagnostic tools. |
| Spectrum Analysis Equipment | DSP Servo Control |
|
Use Scenario: High-resolution frequency-domain measurement in portable RF analyzers requiring low THD and spurious-free response. IC Role / Device Role / Timing Role: Bipolar-input ADC sampling at 285 kSPS with ±VREF/2 range to capture AC-coupled IF signals centered at VREF/2. Use Value: –86 dB THD and –87 dB spurious noise floor ensure clean baseband reconstruction for 12-bit effective resolution in narrowband filters. |
Use Scenario: Closed-loop position feedback in CNC motion controllers where encoder interpolation demands sub-LSB linearity stability. IC Role / Device Role / Timing Role: System-calibrated ADC measuring analog resolver outputs with on-the-fly gain/offset correction via writable calibration registers. Use Value: ±2 LSB INL guarantee and read/write calibration memory allow factory-trimmed linearity to be maintained across thermal cycling and aging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7852ARSZ-REEL | 12-bit resolution, 333 kSPS, same SOIC-24 package and pinout; lacks internal reference and system calibration registers. | Lower cost for applications where 12-bit ENOB suffices and external reference + calibration logic are acceptable. | Select when BOM cost reduction outweighs need for on-chip reference and field recalibration capability. |
| ADS8325IPW | 16-bit, 100 kSPS, SPI-only interface, no internal reference; requires external 4.096 V reference and external op-amp driver. | Higher resolution for precision instrumentation, but lower throughput and higher system-level component count. | Select when 16-bit resolution is mandatory and 100 kSPS sampling meets control loop timing requirements. |
Compared with AD7851ARSZ-REEL, AD7852ARSZ-REEL trades 2 bits of resolution and calibration features for lower unit cost and identical footprint, while ADS8325IPW offers +2 bits at half the speed and increased external component burden - making AD7851ARSZ-REEL optimal for 14-bit, 333 kSPS, self-contained applications.
Availability
AD7851ARSZ-REEL is available at Aetrix Electronics and suitable for digital signal processing, speech recognition, and DSP servo control applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for AD7851ARSZ-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 high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide.
The AD7851 belongs to Analog Devices' precision SAR ADC product line, engineered for high-speed, low-power, and self-calibrating data acquisition in industrial automation, test equipment, and real-time control systems.
FAQ
What is the maximum input frequency supported by the AD7851ARSZ-REEL?
The AD7851ARSZ-REEL has a full power bandwidth of 20 MHz - meaning it can accurately digitize full-scale sine wave inputs up to 20 MHz before the amplitude drops by 3 dB. This is enabled by its 0.33 µs track-and-hold acquisition time and 333 kSPS throughput, making it suitable for intermediate-frequency sampling in communication receivers and ultrasonic sensing front-ends.
Does the AD7851ARSZ-REEL require external reference components?
Yes, the AD7851ARSZ-REEL requires two external capacitors on the reference pins: a 0.1 µF ceramic disc in parallel with a 470 nF tantalum capacitor on CREF1, and a 0.01 µF ceramic capacitor on CREF2 - both connected to AGND. These stabilize the internal 4.096 V reference and suppress switching noise during conversion. No external voltage reference IC is needed unless overriding the internal reference.
How does the AMODE pin affect the AD7851ARSZ-REEL's output coding?
The AMODE pin directly controls both input range and output coding format: when AMODE = 0, the device uses unipolar input (0 V to VREF) and outputs straight binary code; when AMODE = 1, it uses bipolar input (±VREF/2) and outputs two's complement code. This mapping is fixed per pin state and cannot be changed via software register writes.
Can the AD7851ARSZ-REEL perform calibration while powered in sleep mode?
No - calibration (both self- and system-) requires the device to be in normal operating mode with SLEEP = 1 and AVDD/DVDD powered. The SLEEP pin must be high to enable internal reference, analog circuitry, and digital controller operation. Attempting CAL pulse with SLEEP = 0 will not initiate calibration and may cause undefined behavior.
What is the purpose of the SYNC pin on the AD7851ARSZ-REEL?
The SYNC pin serves as a frame synchronization signal for multi-device configurations: in Mode 2 and Mode 3, it defines the start of each serial data frame; in Mode 4 and Mode 5, it acts as an output enabling daisy-chained readout. When used as input, SYNC must meet strict setup/hold timing relative to SCLK (±0.4 tSCLK for continuous clocking), ensuring deterministic data alignment across multiple AD7851ARSZ-REEL units.
AD7851ARSZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 333k
- Number of Inputs:
- 1
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Supplier Device Package:
- 24-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7851ARSZ-REEL FAQ
1.How can I place an order for AD7851ARSZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7851ARSZ-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 AD7851ARSZ-REEL reliable?
The price and inventory of AD7851ARSZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7851ARSZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7851ARSZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7851ARSZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7851ARSZ-REEL?
AD7851ARSZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7851ARSZ-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 AD7851ARSZ-REEL?
For technical support, including AD7851ARSZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7851ARSZ-REEL requirements.
6.How does Aetrix verify that AD7851ARSZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7851ARSZ-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 AD7851ARSZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7851ARSZ-REEL?
All AD7851ARSZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7851ARSZ-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 AD7851ARSZ-REEL part is unused and in its original packaging.
Return procedure for AD7851ARSZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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