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Analog Devices Inc. AD7851KRZ
- Part No.:
- AD7851KRZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7851KRZ.pdf
- Description:
- IC ADC 14BIT SAR 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,014
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Product details
Overview
AD7851KRZ 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, and self/system calibration capability. It operates from a single 5 V supply, features ±1 LSB DNL (K grade), 78 dB SNR at 10 kHz, and supports unipolar (0 V to VREF) and bipolar (±VREF/2) input ranges. It is used in high-speed DSP servo control and spectrum analysis systems requiring stable DC accuracy over temperature.
For engineers reviewing the AD7851KRZ datasheet, AD7851KRZ pinout, AD7851KRZ application, or AD7851KRZ equivalent, this page delivers verified technical context, real-world timing behavior, calibrated DC accuracy specs, package-specific layout guidance, and validated alternative options for industrial signal acquisition designs.
Technical Context
The AD7851KRZ implements a successive approximation register (SAR) architecture with integrated track-and-hold, charge redistribution DAC, and comparator. Its conversion core completes in 3.25 µs (21 CLKIN cycles at 6 MHz), enabling 285 kSPS throughput in K-grade operation (0°C to +85°C).
It supports five configurable serial interface modes-including SPI/QSPI-compatible (Mode 2/3), 8051-compatible (Mode 1), and self-clocking (Modes 4/5)-with programmable polarity and synchronous data transfer via DIN/DOUT/SCLK/SYNC. Calibration is performed via dedicated CAL pin and internal registers, retaining offset/gain correction data in sleep mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - Delivers 16,384 discrete output codes for high-fidelity digitization of sensor or audio signals. |
| Throughput Rate | 285 kSPS - Sustained sampling rate at 6 MHz master clock, sufficient for 10 kHz bandwidth signals per Nyquist criterion. |
| Differential Nonlinearity | ±1 LSB max - Guarantees no missing codes and monotonic transfer function across full operating range. |
| Signal-to-Noise + Distortion | 78 dB min - Enables >12.6 ENOB for precision measurement applications such as instrumentation front-ends. |
| Power Dissipation (Normal Mode) | 60 mW typ - Achieved at 5 V supply and 285 kSPS, supporting thermally constrained embedded systems. |
| Input Voltage Ranges | 0 V to VREF (unipolar) or ±VREF/2 (bipolar) - Configurable via AMODE pin to match transducer output polarity and swing. |
| Reference Source | Internal 4.096 V ±50 ppm/°C - Integrated bandgap reference eliminates external component count; REFIN/REFOUT pin allows overdrive or bypass. |
| Calibration Capability | Self-calibration (on power-up) and system calibration - Compensates for gain/offset drift without host processor intervention. |
Pinout & Package
AD7851KRZ is housed in a 24-lead SOIC package (R-24 footprint, 0.3 inch width), RoHS-compliant and Pb-free (Z suffix). Thermal impedance is θJA = 75°C/W, suitable for convection-cooled PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONVST | Convert Start Input | Edge-triggered command initiating track-to-hold transition and ADC conversion sequence; must meet 100 ns minimum pulse width. |
| 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-low entry into low-power state (5 µW typ); retains calibration memory and reference bias during standby. |
| REFIN/REFOUT | Reference I/O | Provides 4.096 V internal reference; accepts external reference up to AVDD; requires CREF1/CREF2 decoupling capacitors. |
| AIN(+), AIN(–) | Pseudo-Differential Analog Inputs | Accept differential voltage difference up to ±VREF/2 or 0–VREF; AIN(–) must be biased appropriately per AMODE setting. |
| AMODE | Analog Range Select | Logic-level input selecting unipolar (0 V to VREF) or bipolar (±VREF/2) input range; determines transfer function coding (binary vs. two's complement). |
| DIN, DOUT, SCLK, SYNC | Serial Interface Signals | Support SPI/QSPI/8051 protocols; SYNC synchronizes frame boundaries; POLARITY selects SCLK edge sensitivity. |
| AGND, DGND | Analog & Digital Grounds | Separate ground pins require star-point connection near device to minimize digital noise coupling into analog path. |
Key Features
| Feature | Design Value |
|---|---|
| Single 5 V supply operation | Eliminates dual-rail power design complexity and reduces BOM cost in industrial and automotive signal chains. |
| On-chip 4.096 V reference with 50 ppm/°C TC | Enables absolute accuracy without external reference IC; REFIN/REFOUT pin allows precision external reference substitution. |
| System and self-calibration with nonvolatile storage | Compensates for temperature-induced gain/offset drift; calibration data retained in sleep mode for rapid wake-up readiness. |
| Five flexible serial interface modes | Supports legacy 8051, modern SPI/QSPI, and self-clocking configurations-reducing firmware porting effort across MCU platforms. |
| Pseudo-differential input with dual voltage ranges | Permits direct interfacing to both unipolar sensors (e.g., RTDs) and bipolar sources (e.g., op-amp outputs) without external level-shifting. |
| Low-power sleep mode (5 µW typ) | Extends battery life in portable test equipment; full functionality resumes within microseconds after wake-up. |
Applications
| DSP Servo Control | Spectrum Analysis |
|---|---|
|
Use Scenario: Real-time position feedback loop in motor drives using resolver or encoder analog outputs. IC Role / Device Role / Timing Role: High-speed ADC capturing current/voltage waveforms at ≥200 kSPS for field-oriented control algorithms. Use Value: ±1 LSB DNL ensures linear torque response; 78 dB SNR preserves harmonic content critical for FFT-based diagnostics. |
Use Scenario: Digitizing RF IF signals in communications analyzers or EMI receivers. IC Role / Device Role / Timing Role: Front-end ADC acquiring baseband or intermediate frequency samples before digital downconversion. Use Value: 20 MHz full-power bandwidth captures wideband transients; self-calibration maintains amplitude accuracy across thermal cycles. |
| Instrumentation Front-End | Automotive Sensor Interface |
|
Use Scenario: Precision data acquisition in benchtop multimeters or portable oscilloscopes. IC Role / Device Role / Timing Role: Core digitizer converting conditioned sensor outputs with calibrated DC accuracy. Use Value: Unipolar/bipolar range selection adapts to diverse probe types; on-chip reference eliminates calibration drift from external components. |
Use Scenario: Engine knock detection or exhaust gas oxygen sensing in engine control units (ECUs). IC Role / Device Role / Timing Role: Robust ADC handling noisy 12 V automotive environments with wide temperature range support. Use Value: K-grade operation up to +85°C ambient (125°C junction) meets AEC-Q100 requirements; separate AGND/DGND minimizes EMI susceptibility. |
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 |
|---|---|---|---|
| AD7851ARZ-REEL3 | A-grade variant: ±2 LSB DNL, 333 kSPS, –40°C to +85°C operating range | Better throughput and wider temp range; higher DNL tolerance acceptable in less demanding measurement systems | Select AD7851ARZ-REEL3 when higher speed and extended cold-temperature operation are required, accepting ±2 LSB DNL. |
| ADS8325IPW | 16-bit, 100 kSPS, SPI-only interface, external reference required, no on-chip calibration | Higher resolution but lower speed; lacks self-calibration and integrated reference; requires additional reference and decoupling components | Choose ADS8325IPW only when 16-bit resolution outweighs need for calibration autonomy and system integration simplicity. |
Compared with AD7851KRZ, AD7851ARZ-REEL3 offers higher throughput and broader temperature range at the cost of relaxed linearity, while ADS8325IPW trades speed and integration for raw resolution-making AD7851KRZ optimal for calibrated, compact, medium-speed industrial acquisition where board space and firmware overhead matter.
Availability
AD7851KRZ is available at Aetrix Electronics and suitable for DSP servo control, spectrum analysis, instrumentation front-ends, automotive sensor interfaces, and high-speed modem designs requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AD7851KRZ 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 and ISO 9001-certified manufacturing.
The AD7851KRZ belongs to Analog Devices' precision SAR ADC product line, engineered for industrial and automotive applications demanding calibrated accuracy, low power, and robust serial interfacing without external reference dependency.
FAQ
What is the guaranteed differential nonlinearity (DNL) specification for AD7851KRZ?
The AD7851KRZ is rated K grade with ±1 LSB maximum DNL across its full operating temperature range (0°C to +85°C), ensuring monotonicity and no missing codes at 14-bit resolution. This specification is verified post-calibration and applies under standard conditions: AVDD = DVDD = 5.0 V ±5%, fCLKIN = 6 MHz, and REFIN/REFOUT = 4.096 V external reference. The AD7851KRZ maintains this performance up to 125°C at reduced throughput (238 kSPS).
Does AD7851KRZ include an internal voltage reference?
Yes, the AD7851KRZ integrates a factory-trimmed 4.096 V bandgap reference with 50 ppm/°C typical temperature coefficient. This reference appears on the REFIN/REFOUT pin and serves as the ADC's conversion基准. The pin supports overdriving with an external reference or bypassing entirely; CREF1 (0.1 µF) and CREF2 (0.01 µF) capacitors must be connected to AGND for stability, as specified in the AD7851KRZ datasheet.
How does the AMODE pin affect AD7851KRZ input configuration?
The AMODE pin on AD7851KRZ selects between two analog input voltage ranges: logic low configures unipolar mode (0 V to VREF), producing straight binary output; logic high enables bipolar mode (±VREF/2), yielding two's complement coding. In unipolar mode, AIN(+) must remain ≥ AIN(–); in bipolar mode, AIN(–) must be biased to VREF/2, and AIN(+) may go below it-but never below AGND. This dual-range flexibility simplifies interface to diverse sensor topologies.
Can AD7851KRZ perform calibration without host processor involvement?
Yes, the AD7851KRZ supports autonomous self-calibration triggered automatically on power-up, as well as manual system calibration initiated via the CAL pin. Both routines adjust internal offset and gain registers using the on-chip DAC and reference; calibration data persists in nonvolatile memory during SLEEP mode. No host firmware interaction is required for basic calibration-only CONVST and CAL pin control is needed for full system calibration sequences.
What serial interface protocols does AD7851KRZ support?
The AD7851KRZ supports five distinct serial interface modes: Mode 1 (2-wire 8051-compatible), Modes 2–3 (3-wire SPI/QSPI-compatible with configurable polarity), and Modes 4–5 (self-clocking where SCLK is generated internally from CLKIN). All modes use DIN, DOUT, SCLK, and SYNC signals; POLARITY pin selects rising/falling edge sampling. This multi-protocol compatibility enables drop-in integration with diverse microcontrollers including 8051, ADSP-21xx, TMS320C2x, and PIC families.
AD7851KRZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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 FAQ
1.How can I place an order for AD7851KRZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7851KRZ 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 reliable?
The price and inventory of AD7851KRZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7851KRZ is usually 5 days.
3.What payment methods are accepted for AD7851KRZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7851KRZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7851KRZ?
AD7851KRZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7851KRZ 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?
For technical support, including AD7851KRZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7851KRZ requirements.
6.How does Aetrix verify that AD7851KRZ is sourced from the original manufacturer or authorized distributors?
All AD7851KRZ 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 meets industry standards.
7.What is the process for return or replacement of AD7851KRZ?
All AD7851KRZ units undergo pre-shipment inspection (PSI). If there is an issue with AD7851KRZ, 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 part is unused and in its original packaging.
Return procedure for AD7851KRZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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