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Texas Instruments ADS8694IDBT
- Part No.:
- ADS8694IDBT
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
ADS8694IDBT.pdf
- Description:
- IC ADC 18BIT SAR 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:122
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Product details
Overview
ADS8694IDBT from Texas Instruments is a 4-channel, 18-bit successive approximation register (SAR) analog-to-digital converter with integrated analog front-end, 500-kSPS aggregate throughput, ±10.24 V bipolar input range support, and on-chip 4.096-V low-drift reference-designed for high-precision industrial data acquisition in protection relays and PLC analog input modules.
For engineers reviewing the ADS8694IDBT datasheet, ADS8694IDBT pinout, ADS8694IDBT application, or ADS8694IDBT equivalent, this page delivers verified specifications, channel-independent programmable gain, 1-MΩ constant input impedance, SPI-compatible daisy-chain interface, and thermal performance validated across –40°C to 125°C.
Technical Context
The ADS8694IDBT implements a true single-supply 5-V architecture with independent software-selectable input ranges per channel (±10.24 V, ±5.12 V, ±2.56 V, 0–10.24 V, 0–5.12 V), each maintaining 1-MΩ resistive input impedance and ±20-V overvoltage protection. Its integrated PGA, 2nd-order LPF, and auto/manual scan multiplexer enable direct sensor interfacing without external signal conditioning.
It features a dedicated auxiliary 16-bit ADC channel (AUX_IN/AUX_GND), ALARM output with per-channel high/low thresholds, and a daisy-chain-capable SPI interface operating up to 18 MHz-supporting synchronized multi-device acquisition while maintaining 93.5-dB SNR and ±0.5-LSB DNL at 500 kSPS.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 18-bit SAR ADC with no missing codes-ensures monotonicity and full-scale fidelity in precision measurement systems. |
| Throughput Rate | 500 kSPS aggregate sampling-supports real-time monitoring of fast transients in power automation and relay protection. |
| Input Ranges | Software-programmable per channel: ±10.24 V, ±5.12 V, ±2.56 V, 0–10.24 V, 0–5.12 V-enables flexible sensor compatibility without hardware reconfiguration. |
| Input Impedance | Constant 1 MΩ across all ranges-eliminates gain error variation due to source impedance mismatch in multi-sensor systems. |
| Overvoltage Protection | ±20 V on all analog inputs-protects against field-wiring faults and transient surges in industrial environments. |
| Reference | On-chip 4.096-V reference with 6–10 ppm/°C drift-reduces system BOM count and improves long-term dc accuracy without external REF. |
| Dynamic Performance | SNR = 93.5 dB, THD = –105 dB at 1 kHz-meets Class A power quality monitoring and IEC 61850-9-2 compliance requirements. |
| Operating Temperature | –40°C to +125°C-qualified for deployment in harsh environments including outdoor substations and motor control cabinets. |
Pinout & Package
TSSOP-38 package (9.7 mm × 4.4 mm) with exposed pad for thermal management; pin-compatible with ADS8698 but with 4 active analog input pairs (AIN_0P/GND through AIN_3P/GND) and NC pins for unused channels.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SDI) | Digital input | SPI serial data input; accepts command and configuration registers during daisy-chain or standalone operation. |
| 2 (RST/PD) | Digital input | Active-low dual-function pin: resets internal logic or places device in ultra-low-power shutdown mode (3 µA). |
| 3 (DAISY) | Digital input | Enables daisy-chain mode; when asserted low, routes SDO of upstream device to SDI of this device for cascaded readout. |
| 4 (REFSEL) | Digital input | Selects reference source: low enables internal 4.096-V reference on REFIO; high disables internal ref and allows external reference injection. |
| 5 (REFIO) | Analog I/O | Internal reference output / external reference input; requires 10–22 µF decoupling to REFGND (pin 6) for stability. |
| 16–23 (AIN_0P to AIN_3P, AIN_0GND to AIN_3GND) | Analog inputs | Four fully differential single-ended input pairs; each pair supports independent range selection and OVP up to ±20 V. |
| 10/11 (AUX_IN/AUX_GND) | Analog inputs | Dedicated 16-bit auxiliary ADC channel for diagnostics, temperature sensing, or auxiliary voltage monitoring. |
| 35 (ALARM) | Digital output | Open-drain active-high alarm flag indicating any channel exceeds user-configured high/low threshold limits. |
| 36–38 (SDO, SCLK, CS) | Digital I/O | SPI interface signals supporting 18-MHz clock rate; CS falling edge initiates conversion sequence and frame sync. |
Key Features
| Feature | Design Value |
|---|---|
| Channel-independent programmable input ranges | Each of four analog inputs supports ±10.24 V, ±5.12 V, ±2.56 V, 0–10.24 V, or 0–5.12 V via software-enabling mixed-sensor systems on one IC. |
| Integrated analog front-end per channel | Combines OVP, PGA, and 2nd-order LPF-removes need for external protection, gain, and anti-alias filtering components. |
| 1-MΩ constant input impedance | Maintains identical loading across all input ranges-prevents measurement error drift when switching ranges or sensors. |
| On-chip 4.096-V reference with low drift | 6–10 ppm/°C drift and 4.095–4.097 V tolerance-delivers stable full-scale calibration without external reference IC or trimming. |
| Daisy-chain SPI interface | Supports synchronous readout of multiple ADS8694/ADS8698 devices using single SCLK/CS-reduces host GPIO count and simplifies PCB routing. |
| Auxiliary 16-bit ADC channel | Dedicated AUX_IN/AUX_GND inputs with 87–89 dB SNR-provides independent diagnostic path without consuming main channel resources. |
Applications
| Power Automation Monitoring | Protection Relay Input Stage |
|---|---|
Use Scenario: Real-time acquisition of phase voltages and currents in medium-voltage switchgear for fault detection and waveform analysis. IC Role / Device Role / Timing Role: Primary 18-bit ADC capturing synchronized 50/60-Hz waveforms at 500 kSPS with ±10.24 V range and ±20 V OVP. Use Value: Enables IEC 61850-9-2-compliant sampled value streams with <±1.5 LSB INL and 93.5 dB SNR for accurate RMS and harmonic calculation. | Use Scenario: High-reliability analog input for overcurrent, overvoltage, and differential protection algorithms in digital relays. IC Role / Device Role / Timing Role: Channel-isolated ADC with per-channel alarm thresholds triggering immediate trip decisions upon threshold violation. Use Value: ALARM pin provides hardware-level fast response (<1 µs latency) independent of host processor, meeting ANSI C37.90 surge immunity and timing requirements. |
| PLC Analog Input Module | Industrial Data Logger |
Use Scenario: Modular 4-channel analog input card for programmable logic controllers handling mixed sensor types (RTD, 4–20 mA, ±10 V). IC Role / Device Role / Timing Role: Single-chip solution providing four independently configurable inputs with 1-MΩ impedance and software-selectable ranges. Use Value: Eliminates external multiplexers, op-amps, and reference ICs-reducing bill-of-materials cost by >30% and board area by 45% versus discrete implementations. | Use Scenario: Battery-powered remote sensor node logging temperature, pressure, and vibration in oil & gas or renewable energy sites. IC Role / Device Role / Timing Role: Low-power ADC (65 mW active, 4.5 mA standby) with auxiliary channel monitoring battery voltage and internal die temperature. Use Value: Integrated 16-bit AUX ADC and STDBY mode extend field deployment life beyond 5 years on primary lithium thionyl chloride cells. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8698IPWR | 8-channel version in same TSSOP-38 package; shares identical specs except for additional AIN_4P/GND through AIN_7P/GND pins. | Requires full 8-channel acquisition; not pin-compatible due to NC pin mapping differences on ADS8694-specific pins (12–15, 24–27). | Select ADS8698IPWR only if system requires ≥8 analog inputs and layout accommodates full pin utilization. |
| AD7606BSTZ | 8-channel, 16-bit SAR ADC with parallel/serial interface; ±10 V input range, 270 kSPS, external reference required. | Lacks integrated OVP, PGA, and software-programmable ranges; requires external protection and gain circuitry. | Choose AD7606BSTZ only when legacy parallel interface is mandatory or when lower resolution (16-bit) suffices and external reference is already present. |
Compared with ADS8698IPWR, the ADS8694IDBT reduces channel count and eliminates unused pins-lowering system cost and simplifying layout-while retaining identical precision, OVP, and reference integration. Versus AD7606BSTZ, it delivers higher resolution, built-in signal conditioning, and simpler power architecture at the expense of parallel interface support.
Availability
ADS8694IDBT is available at Aetrix Electronics and suitable for power automation monitoring, protection relay input stages, and PLC analog input modules requiring stable component supply, long-term lifecycle assurance, and industrial-grade temperature qualification.
Supply support for ADS8694IDBT 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of leadership in precision data converters and industrial interface solutions.
The ADS869x product line was designed specifically for high-reliability industrial data acquisition-integrating signal conditioning, protection, and conversion into a single IC to simplify design of protection relays, PLCs, and power quality analyzers.
FAQ
What input voltage ranges does the ADS8694IDBT support per channel?
The ADS8694IDBT supports five software-programmable input ranges per channel: ±10.24 V, ±5.12 V, ±2.56 V, 0–10.24 V, and 0–5.12 V. Each range is selected independently via configuration registers, and all maintain a constant 1-MΩ input impedance and ±20-V overvoltage protection. The ADS8694IDBT achieves this using an integrated PGA and front-end architecture that scales full-scale codes without external components.
Does the ADS8694IDBT require an external reference voltage?
No, the ADS8694IDBT includes a factory-trimmed 4.096-V internal reference with 6–10 ppm/°C temperature drift and 4.095–4.097 V tolerance at 25°C. It can be enabled via the REFSEL pin (pin 4) driving REFIO (pin 5) as an output. An external reference is optional and only needed if tighter initial accuracy or custom voltage is required-the ADS8694IDBT remains fully functional with its internal reference.
How does the daisy-chain SPI interface work on the ADS8694IDBT?
The ADS8694IDBT supports daisy-chain operation via the DAISY pin (pin 3). When DAISY is pulled low, the device routes the SDO output of the upstream device in the chain to its own SDI input (pin 1), enabling cascaded readout using a single SPI bus. This allows synchronous acquisition and readout of multiple ADS8694IDBT or ADS8698 devices without additional chip-select lines or host GPIO overhead.
What is the purpose of the AUX_IN and AUX_GND pins on the ADS8694IDBT?
The AUX_IN (pin 10) and AUX_GND (pin 11) pins connect to a dedicated 16-bit auxiliary ADC channel inside the ADS8694IDBT. This channel operates independently of the four main channels and supports 0–VREF input range with 87–89 dB SNR. It is commonly used for monitoring auxiliary signals such as supply voltage, die temperature, or sensor bias-freeing main channels for critical measurements.
Can the ADS8694IDBT operate with a digital supply below 3.3 V?
Yes, the ADS8694IDBT supports digital supply voltages from 1.65 V to 5.25 V on DVDD (pin 34), enabling direct interface with low-voltage microcontrollers and FPGAs. Logic levels scale accordingly: VIH = 0.7 × DVDD (DVDD > 2.1 V) and VOL = 0.2 × DVDD. Performance specifications-including 500-kSPS throughput and 93.5-dB SNR-are guaranteed across the full DVDD range when AVDD = 5 V and operating conditions are met.
ADS8694IDBT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 18
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 4
- Input Type:
- Single Ended
- Data Interface:
- SPI
- Configuration:
- PGA-MUX-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:
- 1.65V ~ 5.25V
- Features:
- PGA
- Operating Temperature:
- -40°C ~ 125°C
- Supplier Device Package:
- 38-TSSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
ADS8694IDBT FAQ
1.How can I place an order for ADS8694IDBT through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS8694IDBT 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 ADS8694IDBT reliable?
The price and inventory of ADS8694IDBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS8694IDBT is usually 5 days.
3.What payment methods are accepted for ADS8694IDBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS8694IDBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS8694IDBT?
ADS8694IDBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS8694IDBT 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 ADS8694IDBT?
For technical support, including ADS8694IDBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS8694IDBT requirements.
6.How does Aetrix verify that ADS8694IDBT is sourced from the original manufacturer or authorized distributors?
All ADS8694IDBT 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 ADS8694IDBT meets industry standards.
7.What is the process for return or replacement of ADS8694IDBT?
All ADS8694IDBT units undergo pre-shipment inspection (PSI). If there is an issue with ADS8694IDBT, 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 ADS8694IDBT part is unused and in its original packaging.
Return procedure for ADS8694IDBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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