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Analog Devices Inc. AD7872TQ
- Part No.:
- AD7872TQ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
AD7872TQ.pdf
- Description:
- IC ADC 14BIT SAR 16CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,667
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Product details
Overview
AD7872TQ from Analog Devices is a complete monolithic 14-bit successive approximation analog-to-digital converter (ADC) with integrated track-and-hold amplifier, 3 V buried Zener reference, and serial-only digital interface. It operates from ±5 V supplies, accepts ±3 V bipolar analog inputs, delivers 83 kSPS throughput, and achieves 77 dB minimum SNR at 10 kHz - optimized for high-fidelity data acquisition in DSP servo control and spectrum analysis systems.
For engineers reviewing the AD7872TQ datasheet, AD7872TQ pinout, AD7872TQ application, or AD7872TQ equivalent, this page provides verified technical context, real-world interface timing constraints, confirmed serial output behavior (SSTRB/SCLK/SDATA), T-grade temperature range (−55°C to +125°C), and validated alternative options for serial-output 14-bit ADC replacement scenarios.
Technical Context
The AD7872TQ implements a self-contained LC2MOS architecture with laser-trimmed internal 2 MHz clock, eliminating external timing components. Its serial interface uses open-drain SCLK (requiring 2 kΩ pull-up) and active-low SSTRB (4.7 kΩ pull-up), with SDATA valid on SCLK falling edges while SSTRB is low.
All dynamic performance specs - including 77 dB min SNR, −86 dB max THD, and 2 μs track/hold acquisition - are guaranteed across the full −55°C to +125°C operating range. The internal 3 V reference (±40 ppm/°C tempco, 500 μA load capability) feeds both DAC and bipolar bias circuitry, with CREF requiring a mandatory 10 nF AGND decoupling capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit monotonic, no missing codes guaranteed - enables precise amplitude measurement of ±3 V signals at 366 μV LSB step size. |
| Throughput Rate | 83 kSPS maximum - supports real-time sampling of baseband signals up to 41.5 kHz (Nyquist-limited). |
| SNR (10 kHz) | 77 dB minimum over −55°C to +125°C - ensures usable dynamic range for speech synthesis and spectrum analysis applications. |
| Reference Output | 3.00 V ±20 mV, ±40 ppm/°C - stable internal voltage source usable for external circuit biasing with ≤500 μA load. |
| Power Dissipation | 50 mW typical at ±5 V - enables low-thermal-impact operation in sealed industrial enclosures. |
| Conversion Time | 11 μs maximum with internal clock - defines minimum inter-sample interval for deterministic timing-critical control loops. |
| Analog Input Range | ±3 V differential into 15 kΩ - compatible with standard op-amp signal conditioning stages without attenuation or gain scaling. |
Pinout & Package
AD7872TQ is housed in a 16-pin hermetic CERDIP package (package code TQ), with lead finish suitable for high-reliability military/aerospace applications. Pin 1 is CONTROL; pins 7 and 10 are NC; pins 9 and 16 are tied VDD; all digital I/Os are TTL-compatible with defined VOH/VOL and leakage limits.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CONTROL) | Serial clock gating control | Selects SCLK continuity: −5 V = continuous; 0 V = gated off after transmission - determines serial bus timing predictability. |
| 2 (CONVST) | Asynchronous conversion trigger | Rising-edge initiates track-to-hold transition - enables jitter-free sampling synchronized to external timers or PLLs. |
| 3 (CLK) | External clock input / oscillator enable | Tied to VSS to activate internal 2 MHz laser-trimmed oscillator - removes need for external crystal or clock generator. |
| 4 (SSTRB) | Active-low serial framing pulse | Three-state output with 4.7 kΩ pull-up - defines start of 14-bit serial word; must be low during SCLK falling edges for valid SDATA. |
| 5 (SCLK) | Gated serial clock output | Open-drain, requires 2 kΩ pull-up - rising/falling edges clock SDATA bits; frequency derived from internal/external ADC clock. |
| 6 (SDATA) | Three-state serial data output | Valid on SCLK falling edge when SSTRB low - transmits MSB-first twos-complement 14-bit word over single-wire interface. |
| 8 (DGND) | Digital ground return | Separate from AGND - prevents digital switching noise from modulating analog conversion accuracy. |
| 11 (CREF) | Internal reference decoupling node | Must connect 10 nF capacitor to AGND - suppresses reference noise and stabilizes DAC linearity across temperature. |
| 12 (AGND) | Analog ground reference | Low-impedance return for VIN, REFOUT, CREF - routing separation from DGND is mandatory for 80 dB SNR performance. |
| 13 (REFOUT) | 3 V reference output | Supplies up to 500 μA - usable as precision bias for external op-amps but limited to ≤50 pF capacitive load for stability. |
| 14 (VIN) | Bipolar analog input | ±3 V range, 15 kΩ input impedance - accepts directly conditioned sensor outputs without additional level-shifting circuitry. |
| 15 (VSS) | Negative supply rail | −5 V ±5% - powers analog core and track-and-hold; must be decoupled locally with ≥10 μF tantalum + 0.1 μF ceramic. |
Key Features
| Feature | Design Value |
|---|---|
| Complete monolithic ADC | Integrates SAR core, track-and-hold, 3 V Zener reference, and serial interface - eliminates 7+ external components required by discrete solutions. |
| LC2MOS process | Enables ±5 V dual-supply operation with low power (50 mW) and high noise immunity - critical for ruggedized industrial control environments. |
| Twos-complement coding | Direct bipolar signal representation - simplifies DSP firmware by removing offset subtraction and sign-extension logic. |
| Self-contained clock | Laser-trimmed 2 MHz internal oscillator - guarantees timing accuracy without external crystal, reducing BOM cost and board space. |
| T-grade qualification | Specified from −55°C to +125°C - meets MIL-STD-883 requirements for extended-temperature avionics and downhole instrumentation. |
Applications
| DSP Servo Control | Spectrum Analysis |
|---|---|
|
Use Scenario: Real-time position feedback loop in motor drives where encoder signals are conditioned and digitized at 50–100 kHz. IC Role / Device Role / Timing Role: ADC front-end capturing analog current/voltage waveforms with deterministic 11 μs conversion latency. Use Value: 77 dB SNR preserves harmonic content for accurate field-oriented control algorithms; T-grade operation sustains reliability in hot engine compartments. |
Use Scenario: Baseband signal capture in RF test equipment analyzing spectral purity of communication transmitters. IC Role / Device Role / Timing Role: High-fidelity digitizer feeding FFT engines with minimal quantization noise floor elevation. Use Value: 83 kSPS throughput and −86 dB THD enable resolution of spurious tones ≥86 dB below carrier - meeting IEEE 1057 compliance thresholds. |
| Speech Recognition | Digital Signal Processing |
|
Use Scenario: Voice capture subsystem in secure military radios operating across desert and arctic climates. IC Role / Device Role / Timing Role: Analog front-end converting microphone preamp output into 14-bit twos-complement stream for feature extraction. Use Value: Integrated 3 V reference eliminates external voltage source drift; T-grade spec ensures consistent SNR across −55°C to +125°C ambient. |
Use Scenario: Data acquisition node in programmable logic controller (PLC) monitoring analog sensor inputs in factory automation. IC Role / Device Role / Timing Role: Standalone ADC interfacing to microcontroller via minimal 3-wire serial bus (SSTRB/SCLK/SDATA). Use Value: Serial-only interface reduces PCB trace count vs parallel alternatives; CERDIP package withstands reflow and thermal cycling in industrial assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial-output 14-bit ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8320UB | 16-bit resolution, SPI interface, 100 kSPS, single +5 V supply - higher resolution but no internal reference or bipolar input support. | Requires external reference and level-shifting for ±3 V inputs - increases component count and calibration complexity. | Choose ADS8320UB only if 16-bit resolution is mandatory and system can accommodate external reference design. |
| MAX1167BCAP+ | 14-bit, serial SPI, 250 kSPS, internal reference, ±5 V supplies - faster but rated only to +85°C (not T-grade). | Lacks extended temperature qualification - unsuitable for aerospace or downhole applications requiring −55°C operation. | Select MAX1167BCAP+ for commercial/industrial systems where speed >83 kSPS is needed and temperature range is ≤+85°C. |
Compared with ADS8320UB and MAX1167BCAP+, the AD7872TQ uniquely combines T-grade temperature range, integrated bipolar ±3 V input handling, self-contained 3 V reference, and proven LC2MOS robustness - making it the sole option qualified for mission-critical extended-temperature embedded data acquisition.
Availability
AD7872TQ is available at Aetrix Electronics and suitable for DSP servo control, spectrum analysis, speech recognition, and digital signal processing applications requiring stable component supply under extended temperature conditions and long-term obsolescence management.
Supply support for AD7872TQ 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 AD7872TQ belongs to Analog Devices' legacy high-speed precision ADC product line, designed specifically for demanding data acquisition in military, aerospace, and industrial systems where extended temperature operation and integrated reference stability are non-negotiable.
FAQ
What is the guaranteed SNR performance of the AD7872TQ across its full operating temperature range?
The AD7872TQ guarantees a minimum 77 dB signal-to-noise ratio at 10 kHz input frequency over its entire −55°C to +125°C operating range (T version). This value is measured with ±3 V full-scale sine wave input and includes distortion and noise components per the Rev. F datasheet Table 1. No derating is required - the 77 dB spec applies identically at temperature extremes.
Does the AD7872TQ require an external clock source, or does it include an internal oscillator?
The AD7872TQ includes a self-contained, laser-trimmed internal 2 MHz oscillator. Connecting Pin 3 (CLK) to VSS activates this oscillator - eliminating the need for external crystals, clock generators, or timing components. External clocks may still be applied to CLK if system-level synchronization is required, but they are not mandatory for basic operation.
How is the serial data format structured on the AD7872TQ's SDATA output?
The AD7872TQ outputs a 14-bit twos-complement word MSB-first on SDATA. Data is valid on the falling edge of SCLK while SSTRB is asserted low. Each serial transmission consists of exactly 14 clock cycles; SSTRB goes low before the first SCLK falling edge and returns high after the 14th bit. The CONTROL pin (Pin 1) determines whether SCLK runs continuously (−5 V) or is gated (0 V).
What decoupling is required on the CREF and REFOUT pins of the AD7872TQ?
Pin 11 (CREF) requires a 10 nF capacitor connected directly to AGND - this is mandatory for reference stability and SNR performance. Pin 13 (REFOUT) may drive external circuitry up to 500 μA, but its capacitive load must not exceed 50 pF. For external use, Analog Devices specifies a series 200 Ω resistor followed by parallel 10 μF tantalum + 0.1 μF ceramic decoupling to AGND.
Is the AD7872TQ pin-compatible with the AD7871 series, and can they share the same PCB layout?
No - the AD7872TQ (16-pin CERDIP) is not pin-compatible with any AD7871 variant (28-pin PDIP/PLCC/CERDIP). Their pin counts, functions, and package footprints differ fundamentally: AD7872TQ uses dedicated SSTRB/SCLK/SDATA pins for serial output, while AD7871 provides parallel DB0–DB13 plus mode-select 14/8/CLK. Separate PCB layouts are required.
AD7872TQ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-CDIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- -55°C ~ 125°C
- Supplier Device Package:
- 16-CERDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD7872TQ FAQ
1.How can I place an order for AD7872TQ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7872TQ 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 AD7872TQ reliable?
The price and inventory of AD7872TQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7872TQ is usually 5 days.
3.What payment methods are accepted for AD7872TQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7872TQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7872TQ?
AD7872TQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7872TQ 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 AD7872TQ?
For technical support, including AD7872TQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7872TQ requirements.
6.How does Aetrix verify that AD7872TQ is sourced from the original manufacturer or authorized distributors?
All AD7872TQ 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 AD7872TQ meets industry standards.
7.What is the process for return or replacement of AD7872TQ?
All AD7872TQ units undergo pre-shipment inspection (PSI). If there is an issue with AD7872TQ, 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 AD7872TQ part is unused and in its original packaging.
Return procedure for AD7872TQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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