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Analog Devices Inc. AD7851KRZ-REEL
- Part No.:
- AD7851KRZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7851KRZ-REEL.pdf
- Description:
- IC ADC 14BIT SAR 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,569
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Product details
Overview
AD7851KRZ-REEL from Analog Devices is a 14-bit, 285 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 ±1 LSB DNL (K grade), and supports dual input ranges (0 V to VREF and ±VREF/2) for precision signal acquisition in high-speed data acquisition systems.
For engineers reviewing the AD7851KRZ-REEL datasheet, AD7851KRZ-REEL pinout, AD7851KRZ-REEL application, or AD7851KRZ-REEL equivalent, this page provides verified technical context, real-world design meaning of specifications, validated pin functions, confirmed alternative parts with documented functional differences, and application-specific implementation guidance - all grounded in the official AD7851 Rev. B datasheet and ordering guide.
Technical Context
The AD7851KRZ-REEL implements a successive approximation register (SAR) architecture with integrated track-and-hold, charge redistribution DAC, and comparator. Its pseudo-differential input stage acquires signals in 3.5 µs (max) and supports two user-selectable voltage ranges via the AMODE pin.
Calibration is performed using on-chip registers: self-calibration corrects offset and gain errors over temperature, while system calibration allows external circuit error correction. The serial interface supports five configurable modes-including master-clock-driven and self-clocked variants-with programmable polarity (POLARITY pin) and synchronization (SYNC).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - delivers 16,384 discrete output codes for high-fidelity digitization of analog sensor or signal chain outputs. |
| Throughput Rate | 285 kSPS - enables real-time sampling of audio-band and control-loop signals up to ~140 kHz Nyquist frequency. |
| Differential Nonlinearity | ±1 LSB max - guarantees monotonicity and absence of code misses across full operating temperature range (0°C to +85°C). |
| Input Voltage Ranges | 0 V to VREF (unipolar) or ±VREF/2 (bipolar) - selectable via AMODE pin; supports both single-ended referenced and centered differential measurements. |
| Reference Source | Internal 4.096 V ±0.5% (REFIN/REFOUT pin) - eliminates need for external reference; supports overdrive with external 4 V–5.25 V sources. |
| Power Dissipation | 60 mW typ (normal mode); 5 µW typ (full power-down) - enables low-power operation in battery-backed or thermally constrained systems. |
| Serial Interface Compatibility | 8051/SPI/QSPI/P - interoperates with common microcontrollers without level-shifting or protocol translation hardware. |
Pinout & Package
The AD7851KRZ-REEL is housed in a 24-lead SOIC package (R-24 footprint, 0.3-inch width), RoHS-compliant (Z suffix), tape-and-reel format (REEL suffix). Pin assignments are identical across PDIP, SOIC, and SSOP variants per datasheet Figure 7 (PINOUT FOR DIP, SOIC, AND SSOP).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONVST | Convert Start Input | Edge-triggered control: rising edge initiates hold-and-convert sequence; required for synchronous sampling timing control. |
| BUSY | Conversion Status Output | Active-high open-drain signal indicates ongoing conversion or calibration; used for polling or interrupt-driven readout. |
| SLEEP | Power-Down Control | Logic low disables internal reference and analog circuitry, reducing current to 10 µA (ext clock off); retains calibration data. |
| REFIN/REFOUT | Reference I/O | Provides 4.096 V internal reference; accepts external 4–5.25 V reference; requires CREF1/CREF2 decoupling capacitors. |
| AIN(+), AIN(–) | Pseudo-Differential Analog Inputs | Support unipolar (0–VREF) or bipolar (±VREF/2) ranges; AIN(–) must be biased appropriately per AMODE setting. |
| AMODE | Analog Range Select | Logic 0 = 0 V to VREF; Logic 1 = –VREF/2 to +VREF/2 - configures transfer function and input biasing requirements. |
| DIN/DOUT/SCLK/SYNC | Serial Interface Signals | Support 3-wire SPI (DIN/DOUT/SCLK), 2-wire 8051 (DIN/SCLK), or self-clocked modes (SCLK output); SYNC enables multi-device synchronization. |
| POLARITY | Interface Clock Polarity | Selects SCLK edge sensitivity: HIGH = data sampled on SCLK↑; LOW = data sampled on SCLK↓ - ensures timing compatibility with host controller. |
Key Features
| Feature | Design Value |
|---|---|
| Single 5 V supply operation | Eliminates dual-rail power design complexity; AVDD and DVDD tied together simplifies PCB layout and reduces BOM count. |
| On-chip self- and system calibration | Enables drift compensation over temperature and time without external calibration hardware; offset/gain registers accessible via serial interface. |
| Pseudo-differential input architecture | Rejects common-mode noise on AIN(+) and AIN(–) while supporting both unipolar and bipolar signal conditioning topologies. |
| Five configurable serial interface modes | Permits direct connection to 8051, ADSP-21xx, TMS320Cxx, and QSPI hosts - avoids glue logic or firmware protocol translation layers. |
| Low-power sleep mode (5 µW typ) | Extends battery life in portable instrumentation; retains calibration state during wake-up, eliminating recalibration overhead. |
Applications
| Digital Signal Processing | Instrumentation & Control Systems |
|---|---|
Use Scenario: Real-time spectral analysis of vibration or acoustic signals in embedded edge nodes. IC Role / Device Role / Timing Role: ADC front-end capturing 14-bit samples at 285 kSPS; synchronized via SYNC to multi-channel acquisition engines. Use Value: 78 dB SNR and 20 MHz full-power bandwidth preserve signal integrity for FFT-based feature extraction without aliasing. |
Use Scenario: Closed-loop motor position feedback in industrial PLC analog I/O modules. IC Role / Device Role / Timing Role: High-accuracy analog input channel converting resolver or LVDT outputs with system calibration for sensor offset drift compensation. Use Value: ±1 LSB DNL and on-chip calibration ensure <1 LSB total unadjusted error over 0°C–85°C, meeting SIL-2 functional safety margin requirements. |
| Speech Recognition & Synthesis | Automotive Sensor Interface |
Use Scenario: Voice capture in automotive infotainment or smart home voice assistants. IC Role / Device Role / Timing Role: Audio ADC sampling microphone preamp output; configured in bipolar mode for AC-coupled inputs with zero-crossing detection. Use Value: –86 dB THD and 78 dB SNR support wide dynamic range speech processing; low 60 mW power enables always-on listening without thermal throttling. |
Use Scenario: Engine knock sensing or exhaust gas oxygen (EGO) signal digitization in engine control units (ECUs). IC Role / Device Role / Timing Role: High-speed analog input for transient combustion event detection; uses AMODE to select 0–VREF range for ratiometric sensor interfacing. Use Value: 3.5 µs acquisition time captures fast pressure transients; 125°C-rated K-grade operation ensures reliability under hood temperature extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 14-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7851ARZ-REEL | A-grade variant: ±2 LSB DNL, rated –40°C to +85°C, 333 kSPS throughput. | Preferred where wider temperature range or higher speed is required; not suitable for 125°C ambient. | Select AD7851ARZ-REEL if system operates below 0°C or requires >285 kSPS sampling. |
| ADS8325IPW | Texas Instruments 16-bit, 100 kSPS SAR ADC; SPI-only interface; no on-chip reference; external REFIO required. | Higher resolution but lower speed; lacks self-calibration and dual-range input; requires external reference design. | Choose ADS8325IPW only when 16-bit resolution outweighs need for calibration autonomy and input flexibility. |
Compared with AD7851KRZ-REEL, the AD7851ARZ-REEL offers higher speed and extended cold-temperature operation but sacrifices DNL performance, while the ADS8325IPW trades calibration convenience and input versatility for increased resolution - making AD7851KRZ-REEL optimal for cost-sensitive, thermally demanding, or calibration-critical 14-bit applications.
Availability
AD7851KRZ-REEL is available at Aetrix Electronics and suitable for digital signal processing, instrumentation and control systems, speech recognition, and automotive sensor interface applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AD7851KRZ-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, founded in 1965 and headquartered in Wilmington, MA.
The AD7851 belongs to Analog Devices' precision SAR ADC product line, designed specifically for high-speed, high-accuracy data acquisition in industrial, automotive, and communications systems where calibration stability and interface flexibility are critical.
FAQ
What is the maximum operating temperature for the AD7851KRZ-REEL?
The AD7851KRZ-REEL is specified for operation from 0°C to +85°C, with guaranteed performance up to +125°C at reduced throughput (238 kSPS). This K-grade rating makes it suitable for under-hood automotive and industrial environments where ambient temperatures exceed standard commercial ranges but do not reach the –40°C lower limit of the A-grade variants.
Does the AD7851KRZ-REEL require external reference components?
Yes, the AD7851KRZ-REEL requires two external capacitors: a 0.1 µF ceramic + 470 nF tantalum pair on CREF1, and a 0.01 µF ceramic capacitor on CREF2. These stabilize the internal 4.096 V reference and charge redistribution DAC. No external voltage reference IC is needed unless overriding the internal reference via the REFIN/REFOUT pin.
How does the AMODE pin affect analog input configuration in the AD7851KRZ-REEL?
The AMODE pin selects between two input ranges: logic low configures unipolar mode (0 V to VREF), requiring AIN(–) ≥ AGND and AIN(+) ≥ AIN(–); logic high enables bipolar mode (±VREF/2), requiring AIN(–) biased to VREF/2 and AIN(+) ≥ 0 V. This determines transfer function, coding (straight binary vs. two's complement), and external biasing network design.
Can the AD7851KRZ-REEL perform calibration without host processor intervention?
Yes, the AD7851KRZ-REEL supports automatic self-calibration on power-up and can execute full system calibration autonomously via the CAL pin. When CAL is pulsed high, the device performs offset and gain calibration using internal DACs and reference - no serial commands or host timing control are required for basic calibration sequences.
What serial interface modes does the AD7851KRZ-REEL support, and how are they selected?
The AD7851KRZ-REEL supports five serial interface modes selected by SM1/SM2 pin states and POLARITY pin level. Modes include 2-wire 8051 (SM1=0, SM2=0), 3-wire SPI/QSPI (SM1=1, SM2=0), QSPI with separate SYNC (SM1=1, SM2=1), and two self-clocked variants (SM1=0, SM2=1). Mode selection is hardware-configured at power-on and cannot be changed dynamically.
AD7851KRZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 285k
- 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:
- 0°C ~ 125°C
- Supplier Device Package:
- 24-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7851KRZ-REEL FAQ
1.How can I place an order for AD7851KRZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7851KRZ-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 AD7851KRZ-REEL reliable?
The price and inventory of AD7851KRZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7851KRZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7851KRZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7851KRZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7851KRZ-REEL?
AD7851KRZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7851KRZ-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 AD7851KRZ-REEL?
For technical support, including AD7851KRZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7851KRZ-REEL requirements.
6.How does Aetrix verify that AD7851KRZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7851KRZ-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 AD7851KRZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7851KRZ-REEL?
All AD7851KRZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7851KRZ-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 AD7851KRZ-REEL part is unused and in its original packaging.
Return procedure for AD7851KRZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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