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Texas Instruments ADS8684IDBT
- Part No.:
- ADS8684IDBT
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
ADS8684IDBT.pdf
- Description:
- IC ADC 16BIT SAR 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:211
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Product details
Overview
ADS8684IDBT from Texas Instruments is a 16-bit, 4-channel, single-supply SAR analog-to-digital converter with integrated analog front-end, ±10.24 V bipolar input range support, 500-kSPS aggregate throughput, and on-chip 4.096-V reference - designed for high-precision industrial data acquisition in PLC analog input modules and protection relays.
For engineers reviewing the ADS8684IDBT datasheet, ADS8684IDBT pinout, ADS8684IDBT application, or ADS8684IDBT equivalent, key selection criteria include channel-independent programmable input ranges (±10.24 V / ±5.12 V / ±2.56 V), 1-MΩ constant resistive input impedance, ±20-V input overvoltage protection, and SPI-compatible daisy-chain interface capability.
Technical Context
The ADS8684IDBT implements a successive approximation register (SAR) ADC core with per-channel programmable gain amplifier (PGA), 4-channel single-ended multiplexer, and integrated 2nd-order low-pass filter per channel. It operates from a single 5-V analog supply while supporting independent software-selectable bipolar and unipolar input ranges.
Its analog front-end includes overvoltage protection circuitry rated to ±20 V (with AVDD = 5 V), a 4.096-V internal reference with 6–10 ppm/°C drift, and auxiliary input channel (AUX_IN/AUX_GND) with 16-bit resolution and dedicated 16-bit conversion path - all synchronized under a unified 500-kSPS aggregate sampling rate.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit - delivers 65,536 discrete output codes for high dynamic range measurement |
| Sampling Rate | 500 kSPS aggregate - supports real-time monitoring of up to four channels at 125 kSPS each |
| Input Range | ±10.24 V, ±5.12 V, ±2.56 V (bipolar); 0–10.24 V, 0–5.12 V (unipolar) - configurable per channel via SPI registers |
| INL / DNL | ±0.75 LSB / ±0.5 LSB - ensures monotonicity and <0.001% full-scale linearity error |
| SNR / THD | 92 dB / –102 dB - enables accurate 15.7 ENOB measurement of low-distortion signals at 1 kHz |
| Input Impedance | 1 MΩ constant - eliminates loading effects across all input ranges and simplifies sensor interfacing |
| OVP Rating | ±20 V - protects against transients without external clamping, reducing BOM count in harsh environments |
Pinout & Package
TSSOP-38 package (9.7 mm × 4.4 mm) with exposed thermal pad; RoHS-compliant, industrial-grade plastic body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN_0P to AIN_3P | Analog input (positive) | Four single-ended analog inputs; each paired with corresponding AIN_nGND for differential referencing |
| AIN_0GND to AIN_3GND | Analog input (negative) | Channel-specific ground references; decoupled individually to minimize crosstalk |
| CS, SCLK, SDI, SDO | SPI interface signals | Standard 4-wire SPI with daisy-chain support via DAISY pin; compatible with 1.65–5.25-V I/O hosts |
| REFSEL, REFIO, REFCAP, REFGND | Reference subsystem | Enables internal 4.096-V reference (REFSEL = low) or external reference (REFSEL = high); REFCAP requires 10–22 µF decoupling |
| RST/PD | Reset / Power-down control | Active-low dual-function pin: hard reset (pulse <100 ns) or entry into low-power standby mode (hold >1 µs) |
| AUX_IN / AUX_GND | Auxiliary analog input | Dedicated 16-bit input path bypassing main MUX; used for system calibration or auxiliary sensor monitoring |
Key Features
| Feature | Design Value |
|---|---|
| Per-channel input range programming | Software-selectable bipolar/unipolar ranges enable mixed-signal acquisition without external signal conditioning |
| Integrated OVP (±20 V) | Eliminates need for external TVS diodes or op-amp clamp circuits in industrial field wiring applications |
| Constant 1-MΩ input impedance | Removes gain dependency on input range selection - simplifies anti-alias filter design and calibration |
| Daisy-chain SPI interface | Reduces host GPIO count when cascading multiple ADS8684IDBT units for scalable multi-channel systems |
| Industrial temperature range | –40°C to +125°C operation supports deployment in motor control cabinets and outdoor substations |
Applications
| Power Automation | Protection Relays |
|---|---|
Use Scenario: Monitoring AC voltage/current waveforms in medium-voltage switchgear for real-time RMS, harmonic, and fault detection. IC Role / Device Role / Timing Role: Primary 16-bit data acquisition engine capturing synchronized samples across 4 analog inputs at 125 kSPS per channel. Use Value: ±10.24 V input range directly interfaces with CT/PT signal conditioners; 92 dB SNR ensures accurate harmonic analysis up to 50th order. | Use Scenario: Detecting overcurrent, earth-fault, and differential anomalies in substation feeder protection schemes. IC Role / Device Role / Timing Role: High-reliability analog input subsystem providing time-aligned samples to FPGA-based protection logic. Use Value: ±20 V OVP withstands lightning-induced surges on current transformer secondaries; 1-MΩ input impedance prevents CT saturation during fault conditions. |
| PLC Analog Input Modules | Industrial Process Monitoring |
Use Scenario: Converting 4–20 mA, ±10 V, or thermocouple signals from factory floor sensors into digital values for controller ingestion. IC Role / Device Role / Timing Role: Integrated front-end ADC eliminating external op-amps, references, and protection components per channel. Use Value: Channel-independent range selection allows mixed sensor types (RTD, strain gauge, voltage) on same module; SPI daisy-chain reduces backplane routing complexity. | Use Scenario: Continuous logging of temperature, pressure, and flow in chemical reactor control loops requiring long-term dc stability. IC Role / Device Role / Timing Role: Precision dc-coupled measurement node with low drift gain/offset errors (<±0.05% FSR, ±1 ppm/°C). Use Value: On-chip 4.096-V reference (6–10 ppm/°C drift) and matched PGA trimming ensure <0.1% total unadjusted error over –40°C to 125°C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 16-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8688IPWR | 8-channel variant in same TSSOP-38 package; identical specs except for additional AIN_4P–AIN_7P/GND pins | Requires PCB redesign to route extra analog inputs; suitable only when >4 channels needed | Select ADS8684IDBT for cost-optimized 4-channel systems where board space and BOM count are constrained |
| AD7606BSTZ | 8-channel, 16-bit, 200-kSPS simultaneous sampling; uses parallel interface and external reference; no integrated OVP | Lacks ±20 V OVP and per-channel range programming; requires external protection and signal conditioning | Choose ADS8684IDBT when field-wiring surge immunity, software-configurable ranges, and SPI simplicity outweigh need for simultaneous sampling |
Compared with ADS8688IPWR, ADS8684IDBT saves board area and component count for 4-channel designs; versus AD7606BSTZ, it trades simultaneous sampling for integrated protection, lower power (65 mW vs. 100 mW), and simplified digital interface - making it optimal for cost-sensitive, modular industrial I/O.
Availability
ADS8684IDBT is available at Aetrix Electronics and suitable for power automation, protection relay, and PLC analog input module applications requiring stable component supply, long lifecycle support, and industrial-grade reliability.
Supply support for ADS8684IDBT 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 deep expertise in precision data converters and industrial signal chain solutions.
The ADS8684IDBT belongs to TI's ADS868x family of integrated SAR ADCs - engineered specifically for ruggedized industrial data acquisition where input protection, software flexibility, and single-supply operation are critical.
FAQ
What input voltage ranges does the ADS8684IDBT support?
The ADS8684IDBT supports bipolar input ranges of ±10.24 V, ±5.12 V, and ±2.56 V, plus unipolar ranges of 0–10.24 V and 0–5.12 V. Each of its four analog input channels can be independently programmed to any of these ranges via SPI register writes - enabling mixed-signal acquisition without external hardware reconfiguration. The ADS8684IDBT maintains a constant 1-MΩ input impedance across all ranges.
Does the ADS8684IDBT require an external reference voltage?
No, the ADS8684IDBT includes an integrated 4.096-V reference with 6–10 ppm/°C temperature drift and low output impedance (0.5–1 Ω). When REFSEL is pulled low, the device enables the internal reference and drives REFIO as an output. An external reference may be used by pulling REFSEL high and applying 4.046–4.146 V to REFIO - but the ADS8684IDBT performs optimally with its trimmed internal reference for most industrial applications.
How does the ADS8684IDBT handle overvoltage conditions on its analog inputs?
Each analog input pair (AIN_nP/AIN_nGND) on the ADS8684IDBT features integrated overvoltage protection rated to ±20 V when AVDD = 5 V and source impedance is <30 kΩ. This protection operates independently per channel and does not require external components. The ADS8684IDBT continues normal conversion during transient overvoltages within this rating, preventing latch-up or damage in noisy industrial environments.
Can multiple ADS8684IDBT devices be connected in a daisy-chain configuration?
Yes, the ADS8684IDBT supports SPI daisy-chaining using the DAISY pin. When configured in daisy-chain mode, the SDO of one ADS8684IDBT connects to the SDI of the next, allowing a single SPI bus to control and read from multiple devices with minimal GPIO usage. The ADS8684IDBT's CS and timing parameters (e.g., tD_CKCS, tDZ_CSDO) are fully specified for reliable multi-device operation at up to 17 MHz SCLK.
What is the power consumption of the ADS8684IDBT during active conversion?
At AVDD = 5 V, DVDD = 3.3 V, and 500-kSPS aggregate throughput with internal reference enabled, the ADS8684IDBT draws 8.5–11.5 mA from AVDD and 0.5 mA from DVDD - totaling approximately 65 mW. In standby mode (RST/PD held low), analog supply current drops to 3–4.5 mA; in power-down mode, DVDD current falls to 3–20 µA. These low-power states make the ADS8684IDBT suitable for energy-conscious industrial edge nodes.
ADS8684IDBT 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:
- 16
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 4
- Input Type:
- Differential, 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:
- External, 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:
- -
ADS8684IDBT FAQ
1.How can I place an order for ADS8684IDBT through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS8684IDBT 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 ADS8684IDBT reliable?
The price and inventory of ADS8684IDBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS8684IDBT is usually 5 days.
3.What payment methods are accepted for ADS8684IDBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS8684IDBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS8684IDBT?
ADS8684IDBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS8684IDBT 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 ADS8684IDBT?
For technical support, including ADS8684IDBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS8684IDBT requirements.
6.How does Aetrix verify that ADS8684IDBT is sourced from the original manufacturer or authorized distributors?
All ADS8684IDBT 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 ADS8684IDBT meets industry standards.
7.What is the process for return or replacement of ADS8684IDBT?
All ADS8684IDBT units undergo pre-shipment inspection (PSI). If there is an issue with ADS8684IDBT, 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 ADS8684IDBT part is unused and in its original packaging.
Return procedure for ADS8684IDBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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