My Inquiry
My Account
Analog Devices Inc. AD7894AR-2
- Part No.:
- AD7894AR-2
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
AD7894AR-2.pdf
- Description:
- IC ADC 14BIT SRL T/H LP 8-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:116
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AD7894AR-2 from Analog Devices is a 14-bit, single-supply successive-approximation ADC with 5 µs conversion time in Mode 1, unipolar 0 V to +2.5 V input range, straight binary output coding, and on-chip track/hold amplifier - designed for precision data acquisition in industrial sensor interfaces and portable instrumentation.
For engineers reviewing the AD7894AR-2 datasheet, AD7894AR-2 pinout, AD7894AR-2 application, or AD7894AR-2 equivalent, this page delivers verified electrical parameters, SO-8 package mapping, real-world use scenarios, and two confirmed alternative parts with documented functional and interface differences.
Technical Context
The AD7894AR-2 implements a laser-trimmed internal clock driving a 14-bit R-2R ladder SAR core, with integrated track/hold enabling full-scale sine wave sampling at >100 kHz bandwidth. Its analog input connects directly to the track/hold stage (no external scaling resistors), delivering 500 nA max input current and 0.15 mV LSB resolution (2.5 V / 16384).
It operates in two modes: Mode 1 (5 µs conversion, continuous operation) and Mode 2 (10 µs effective conversion including 5 µs wake-up from auto-power-down). Serial interface uses falling-edge–clocked SDATA with 16-bit frame (2 leading zeros + 14 data bits), requiring SCLK ≤16 MHz and respecting t4 = 60 ns data access time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14 bits - guarantees no missing codes over full operating temperature range (–40°C to +85°C) |
| Conversion Time | 5 µs (Mode 1) - enables 160 kHz maximum throughput with 250 ns quiet time before next CONVST |
| Analog Input Range | 0 V to +2.5 V - unipolar range optimized for single-supply systems using external +2.5 V reference |
| Output Coding | Straight (natural) binary - simplifies firmware interpretation vs. two's complement used in bipolar variants |
| Power Dissipation | 20 mW typical - achieved via automatic power-down mode reducing IDD to 20 µA between conversions |
| Signal-to-(Noise+Distortion) | 77 dB min (TMIN to TMAX) - measured at fIN = 70 kHz, fSAMPLE = 160 kHz, confirming usable dynamic range for sensor signals |
| Input Impedance | >2 GΩ || 10 pF - high-impedance VIN pin eliminates loading on signal sources like precision op-amp outputs |
Pinout & Package
AD7894AR-2 is housed in an 8-lead narrow-body SOIC (SO-8) package with standard 1.27 mm pitch, JEDEC MS-012AC compliant, thermal resistance θJA = 170°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - REF IN | Voltage reference input | Accepts buffered +2.5 V ±5% external reference; 1 µA max input current ensures minimal reference load |
| 2 - VIN | Analog input channel | Direct connection to track/hold amplifier; 500 nA max input current supports high-Z sensor interfaces |
| 3 - GND | Analog ground reference | Common return for track/hold, comparator, DAC, and digital logic - must be star-connected to minimize noise coupling |
| 4 - SCLK | Serial clock input | Falling-edge–triggered; controls SDATA bit timing; max frequency 16 MHz with t2/t3 ≥31.25 ns pulse width |
| 5 - SDATA | Serial data output | 16-bit frame (2 leading zeros + 14-bit conversion result); three-stated after 16th SCLK edge |
| 6 - BUSY | Conversion status indicator | Active-high open-drain output; asserts high on falling CONVST edge, clears low after conversion completes |
| 7 - CONVST | Conversion start trigger | Edge-sensitive input; falling edge initiates hold mode and conversion; low state at completion enables auto-power-down |
| 8 - VDD | Positive supply | +5 V ±5%; powers all analog and digital circuitry; 5.5 mA max IDD supports low-noise decoupling design |
Key Features
| Feature | Design Value |
|---|---|
| On-chip track/hold amplifier | Acquires input to 14-bit accuracy in ≤0.35 µs - eliminates need for external THS, reducing BOM count and layout area |
| Auto power-down mode | Reduces IDD to 20 µA between conversions - extends battery life in portable DAQ systems without software intervention |
| High-speed serial interface | Two-wire (SCLK/SDATA) with 16 MHz max clock - simplifies isolation and reduces GPIO usage vs. parallel bus ADCs |
| Unipolar 0 V to +2.5 V input | Optimized for single-supply microcontroller systems interfacing with rail-to-rail op-amps or voltage-output sensors |
| Low dynamic input current | <500 nA - prevents signal source loading and distortion in high-impedance transducer circuits (e.g., piezoresistive bridges) |
Applications
| Industrial Process Monitoring | Portable Medical Instrumentation |
|---|---|
|
Use Scenario: Continuous monitoring of pressure, temperature, and flow sensor outputs in PLC I/O modules with 4–20 mA loop-powered front-ends. IC Role / Device Role / Timing Role: ADC digitizing conditioned analog signals; 5 µs conversion enables 100+ channel scanning at 10 kSPS aggregate rate. Use Value: Straight binary output and 0–2.5 V range align directly with DAC-based sensor excitation and op-amp output stages, eliminating level-shifting circuitry. |
Use Scenario: Battery-powered ECG and pulse oximeter front-ends requiring low-noise, low-power analog signal digitization. IC Role / Device Role / Timing Role: Primary ADC capturing biopotential waveforms; auto power-down mode cuts average current to <100 µA at 1 kSPS sampling. Use Value: 500 nA input current prevents electrode polarization errors; 77 dB SNR supports diagnostic-grade waveform fidelity up to 100 Hz bandwidth. |
| Test & Measurement Equipment | Automated Calibration Systems |
|
Use Scenario: Modular data loggers capturing thermocouple, RTD, and strain gauge outputs across multiple channels with multiplexing. IC Role / Device Role / Timing Role: High-accuracy ADC with integrated track/hold enabling synchronized sampling across channels without external sample-hold ICs. Use Value: 14-bit no-missing-codes performance and ±2 LSB INL ensure traceable measurement uncertainty under varying ambient temperatures (–40°C to +85°C). |
Use Scenario: Automated calibration stations verifying voltage references, precision DACs, and multimeters using programmable stimulus and measurement. IC Role / Device Role / Timing Role: Reference-grade ADC validating output accuracy of DUTs; external +2.5 V reference (e.g., AD780) ensures gain stability. Use Value: 77 dB SNR and –92 dB spurious-free dynamic range allow detection of sub-LSB errors in DUT outputs during automated pass/fail testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 14-bit unipolar ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7894BR-2 | ±1.5 LSB INL (vs. ±2 LSB for AD7894AR-2); same pinout, timing, and interface | Required where tighter linearity is needed for metrology-grade calibration or high-fidelity waveform capture | Select AD7894BR-2 when system-level INL budget demands ≤±1.5 LSB; otherwise AD7894AR-2 offers cost-optimized performance. |
| ADS8320IDR | 16-bit resolution, SPI-compatible interface, 2.7–5.5 V supply; no integrated track/hold; requires external REF | Suitable for higher-resolution applications where external THS is acceptable and wider supply range is needed | Choose ADS8320IDR only if 16-bit resolution is mandatory and board space allows external track/hold; AD7894AR-2 integrates THS and saves PCB area. |
Compared with AD7894BR-2, the AD7894AR-2 trades 0.5 LSB linearity for lower cost while retaining identical timing, power, and interface behavior; compared with ADS8320IDR, it delivers proven 14-bit performance with integrated track/hold - reducing component count and layout complexity in space-constrained designs.
Availability
AD7894AR-2 is available at Aetrix Electronics and suitable for industrial process monitoring, portable medical instrumentation, test & measurement equipment, and automated calibration systems requiring stable component supply across extended temperature ranges.
Supply support for AD7894AR-2 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.
The AD7894 product line delivers fast, low-power, serial-output SAR ADCs in compact SO-8 packages - engineered for precision data acquisition in space- and power-constrained industrial and portable systems.
FAQ
What is the absolute maximum analog input voltage for AD7894AR-2?
The absolute maximum analog input voltage for AD7894AR-2 is –5 V to +10 V relative to GND, per the Absolute Maximum Ratings table. However, the specified operational input range remains 0 V to +2.5 V; exceeding this range risks damage or noncompliant performance even if within absolute limits.
Does AD7894AR-2 require an external reference, and what are the requirements?
Yes, AD7894AR-2 requires an external +2.5 V reference applied to the REF IN pin. The reference must be stable within ±5% (2.375 V to 2.625 V), deliver ≤1 µA load current, and exhibit ≤10 pF input capacitance. Precision references like the AD780 or AD680 meet these specifications.
How does the auto power-down mode function in AD7894AR-2?
In AD7894AR-2, auto power-down activates when CONVST remains low after conversion completes (BUSY goes low). The device draws only 20 µA until the next rising edge of CONVST triggers a 5 µs wake-up period, after which the falling edge initiates conversion - reducing average power in low-duty-cycle sampling.
What is the purpose of the two leading zero bits in the AD7894AR-2 serial output frame?
The AD7894AR-2 outputs a 16-bit serial frame comprising two leading zero bits followed by the 14-bit conversion result. This fixed-length format ensures consistent timing for microcontroller firmware parsing and maintains compatibility with the AD7894-10/-3 variants' serial protocol, despite differing output coding schemes.
Can AD7894AR-2 interface directly with a 3.3 V microcontroller SPI port?
No - AD7894AR-2 is a 5 V-only device: VDD must be +5 V ±5%, and its digital inputs require VIH ≥2.4 V and VIL ≤0.8 V referenced to that 5 V rail. Direct connection to a 3.3 V MCU violates input voltage thresholds; level-shifting circuitry is required for safe interoperability.
AD7894AR-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 200k
- Number of Inputs:
- -
- Input Type:
- -
- Data Interface:
- -
- Configuration:
- -
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- -
- Reference Type:
- -
- Voltage - Supply, Analog:
- -
- Voltage - Supply, Digital:
- -
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7894AR-2 FAQ
1.How can I place an order for AD7894AR-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7894AR-2 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 AD7894AR-2 reliable?
The price and inventory of AD7894AR-2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7894AR-2 is usually 5 days.
3.What payment methods are accepted for AD7894AR-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7894AR-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7894AR-2?
AD7894AR-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7894AR-2 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 AD7894AR-2?
For technical support, including AD7894AR-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7894AR-2 requirements.
6.How does Aetrix verify that AD7894AR-2 is sourced from the original manufacturer or authorized distributors?
All AD7894AR-2 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 AD7894AR-2 meets industry standards.
7.What is the process for return or replacement of AD7894AR-2?
All AD7894AR-2 units undergo pre-shipment inspection (PSI). If there is an issue with AD7894AR-2, 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 AD7894AR-2 part is unused and in its original packaging.
Return procedure for AD7894AR-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD7894AR-2 Tags
-
ADC081C021CIMKX/NOPB
Texas Instruments
-
MCP3021A5T-E/OT
Microchip Technology
-
TLA2024IRUGR
Texas Instruments
-
MCP3221A5T-E/OT
Microchip Technology
-
MCP3221A5T-I/OT
Microchip Technology
-
MCP3221A4T-E/OT
Microchip Technology
-
MCP3221A6T-E/OT
Microchip Technology
-
MCP3221A0T-E/OT
Microchip Technology
-
MCP3221A1T-E/OT
Microchip Technology
-
ADC121S021CIMFX/NOPB
Texas Instruments
-
MCP3001-I/MS
Microchip Technology
-
MCP3001-I/SN
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
