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Texas Instruments ADS8678IDBT
- Part No.:
- ADS8678IDBT
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
ADS8678IDBT.pdf
- Description:
- IC ADC 14BIT SAR 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,133
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Product details
Overview
ADS8678IDBT from Texas Instruments is a 14-bit, 8-channel, single-supply SAR analog-to-digital converter with integrated analog front-end, ±20 V input overvoltage protection, 1 MΩ constant resistive input impedance per channel, and 500 kSPS aggregate throughput. It supports software-programmable bipolar (±10.24 V to ±0.156 V) and unipolar (0 V to 10.24 V) input ranges per channel and is used in industrial PLC analog input modules requiring high dc precision and channel-independent gain/offset calibration.
For engineers reviewing the ADS8678IDBT datasheet, ADS8678IDBT pinout, ADS8678IDBT application, or ADS8678IDBT equivalent, this page delivers verified specifications, TSSOP-38 package layout, SPI-compatible daisy-chain interface details, ALARM thresholding capability, and validated alternatives for power automation, protection relays, and industrial data acquisition systems.
Technical Context
The ADS8678IDBT integrates an 8-channel multiplexer with auto/manual scan modes, per-channel programmable gain amplifier (PGA), 2nd-order LPF, and on-chip 4.096-V reference with <20 ppm/°C drift. Each channel features independent OVP circuitry rated for ±20 V (low-impedance source) and maintains 1 MΩ input impedance across all 11 selectable ranges.
It operates from a single 5-V analog supply (AVDD = 4.75–5.25 V) and supports 1.65–5.25 V digital I/O (DVDD), enabling direct interfacing with modern microcontrollers. Conversion timing includes 850 ns tCONV and 1150 ns tACQ, achieving full 500-kSPS aggregate sampling without latency penalties.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit SAR - guarantees monotonic output and no missing codes across full temperature range (–40°C to 125°C). |
| Sampling Rate | 500 kSPS aggregate - supports simultaneous high-speed acquisition across all 8 channels without interleaving delay. |
| Input Ranges | ±10.24 V, ±5.12 V, ±2.56 V, ±1.28 V, ±0.64 V, ±0.3125 V, ±0.15625 V, and unipolar equivalents - each configurable per channel via SPI register. |
| INL / DNL | ±0.25 LSB / ±0.2 LSB - ensures <0.01% full-scale linearity error for precision sensor signal conditioning. |
| SNR / THD | 85 dB / –100 dB - enables accurate measurement of low-amplitude signals in noisy industrial environments. |
| OVP Rating | ±20 V (with AVDD = 5 V) - protects ADC inputs against transients without external clamping components. |
| Reference | On-chip 4.096-V ±0.05% initial accuracy, 8 ppm/°C drift - eliminates need for external precision reference in most applications. |
Pinout & Package
TSSOP-38 package (9.7 mm × 4.4 mm), thermally enhanced with multiple AGND/DGND pins and dedicated REFGND/REFCAP for stable reference decoupling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN_0P to AIN_7P | Analog input (positive) | Eight differential-capable single-ended input channels; each paired with corresponding AIN_nGND for common-mode rejection. |
| AUX_IN / AUX_GND | Auxiliary analog input | Dedicated 14-bit auxiliary channel for system monitoring (e.g., supply voltage, temperature sensor) without consuming main MUX resources. |
| REFIO / REFCAP / REFGND | Reference I/O and decoupling | REFIO outputs internal 4.096 V when REFSEL = low; REFCAP requires 10–22 µF capacitor to stabilize reference buffer output impedance (<1 Ω). |
| CS / SCLK / SDI / SDO / DAISY | SPI interface signals | Full-duplex SPI with daisy-chain support (DAISY enables cascaded readout); CS active-low enables device selection in multi-ADC systems. |
| ALARM | Digital output | Active-high interrupt signaling out-of-range condition per channel based on programmable high/low thresholds. |
| RST/PD | Dual-function control | Pull-low to reset digital logic; hold low >1 µs to enter power-down mode (3 µA typical current draw). |
Key Features
| Feature | Design Value |
|---|---|
| Channel-independent input range selection | Each of 8 channels supports independent configuration of bipolar/unipolar ranges via SPI registers - enables mixed-signal acquisition (e.g., ±10 V motor feedback + 0–5 V temperature sensor). |
| Constant 1 MΩ input impedance | Remains stable across all input ranges and temperatures (±7 ppm/°C drift) - eliminates loading errors when interfacing with high-impedance sensors or legacy 4–20 mA receivers. |
| Per-channel overvoltage protection | Integrated ±20 V OVP on every AIN_nP/AIN_nGND pair - prevents damage during field wiring faults without external TVS diodes or series resistors. |
| Programmable ALARM thresholds | Independent high/low limits per channel stored in dedicated registers - enables real-time fault detection (e.g., phase loss in motor drives) with hardware-level response latency. |
| Daisy-chain SPI interface | DAISY pin allows serial cascade of multiple ADS8678IDBT devices using single CS/SCLK lines - reduces GPIO count and simplifies PCB routing in multi-channel systems. |
Applications
| Power Automation Monitoring | Protection Relay Input Stage |
|---|---|
Use Scenario: Real-time acquisition of AC voltage/current waveforms, harmonic analysis, and RMS calculation in medium-voltage switchgear. IC Role / Device Role / Timing Role: Primary 8-channel ADC capturing synchronized samples at 500 kSPS aggregate rate; ALARM triggers instant trip signal upon overvoltage/overcurrent detection. Use Value: Eliminates external signal conditioning and reference ICs; 85 dB SNR enables accurate 50/60 Hz fundamental and up to 25th harmonic measurement. |
Use Scenario: Fault current sensing and time-overcurrent coordination in feeder protection relays deployed in substations. IC Role / Device Role / Timing Role: High-reliability analog front-end converting CT/PT outputs into digital values; OVP withstands lightning-induced surges up to ±20 V. Use Value: 1 MΩ input impedance avoids burden on current transformers; ±0.25 LSB INL ensures precise pickup/dropout thresholding per IEC 60255 standards. |
| PLC Analog Input Module | Industrial Data Logger |
Use Scenario: Modular I/O card supporting mixed voltage/current inputs (±10 V, 0–20 mA) in DIN-rail mounted PLCs. IC Role / Device Role / Timing Role: Core ADC with per-channel range programming and auxiliary input for module temperature monitoring (AUX_IN). Use Value: Software-configurable ranges reduce BOM variants; daisy-chain SPI enables compact 16+ channel expansion with minimal controller interface overhead. |
Use Scenario: Battery-powered environmental sensor node logging temperature, pressure, and vibration in remote oil/gas facilities. IC Role / Device Role / Timing Role: Low-power ADC operating in burst mode (65 mW active, 3 µA standby); internal reference removes need for external 4.096-V source. Use Value: 125°C rating supports operation in hot enclosures; ±20 V OVP tolerates ESD events during field maintenance without protection circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 14-bit multichannel SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8674IDBT | 4-channel version in identical TSSOP-38 package; shares same architecture, specs, and register map except channel count. | Lower channel density suits cost-sensitive 4-input modules where space or channel requirements are constrained. | Select when only four analog inputs are needed - pin-compatible and firmware-compatible with ADS8678IDBT. |
| AD7606BSTZ | 8-channel, 16-bit SAR ADC; requires external ±5 V supplies and external reference; no integrated OVP or PGA. | Higher resolution but demands more external components and board area; lacks per-channel range programming and ALARM functionality. | Choose for applications needing >14-bit resolution and willing to add discrete protection, reference, and level-shifting circuitry. |
Compared with ADS8674IDBT, the ADS8678IDBT provides double the channel count in the same footprint and pinout, while AD7606BSTZ trades integration for resolution - making ADS8678IDBT optimal for space-constrained, high-channel-count industrial systems requiring robustness and configurability.
Availability
ADS8678IDBT 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 industrial lifecycle support, and guaranteed traceable sourcing.
Supply support for ADS8678IDBT 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 expertise in precision data acquisition and industrial-grade IC design.
The ADS867x family was engineered specifically for rugged industrial data acquisition - integrating multiplexing, protection, reference, and digital interface into a single chip to simplify high-channel-count analog front-end design.
FAQ
What input voltage ranges does the ADS8678IDBT support per channel?
The ADS8678IDBT supports 11 software-selectable input ranges per channel: bipolar options of ±10.24 V, ±5.12 V, ±2.56 V, ±1.28 V, ±0.64 V, ±0.3125 V, and ±0.15625 V; plus unipolar options of 0–10.24 V, 0–5.12 V, 0–2.56 V, and 0–1.28 V. Each channel's range is independently configurable via SPI register writes, enabling mixed-signal acquisition within a single ADS8678IDBT device.
Does the ADS8678IDBT require an external reference voltage?
No, the ADS8678IDBT includes an integrated 4.096-V reference with ±0.05% initial accuracy and 8 ppm/°C temperature drift. When REFSEL is pulled low, REFIO outputs this internal reference; when high, REFIO accepts an external reference. The on-chip reference eliminates the need for external precision references in most industrial applications, reducing BOM count and layout complexity for the ADS8678IDBT.
How does the ADS8678IDBT handle overvoltage conditions on its analog inputs?
The ADS8678IDBT provides integrated ±20 V overvoltage protection on all AIN_nP and AIN_nGND pins when AVDD = 5 V and source impedance is <30 kΩ. This protection is implemented per channel and does not require external components. It safeguards the ADC core during field wiring errors, ESD events, or transient surges - a key reliability feature confirmed in the ADS8678IDBT absolute maximum ratings table.
Can multiple ADS8678IDBT devices be connected in a daisy-chain configuration?
Yes, the ADS8678IDBT supports daisy-chain SPI communication using the DAISY pin. In this mode, SDO of one device connects to SDI of the next, allowing sequential readout of conversion results from multiple ADS8678IDBT units using a single CS and SCLK signal. This reduces host controller GPIO usage and simplifies PCB routing in high-channel-count systems such as modular PLCs or distributed I/O racks.
What is the power consumption of the ADS8678IDBT during active conversion?
At AVDD = 5 V and maximum 500-kSPS throughput with internal reference enabled, the ADS8678IDBT draws 13–16 mA from the analog supply (IAVDD_DYN) and 0.5 mA from the digital supply (IDVDD_DYN). Total active power is approximately 65 mW. In standby mode (RST/PD held low), current drops to 3–4.5 mA; in full power-down, it falls to 3–20 µA - enabling energy-efficient operation in battery-backed or thermally constrained ADS8678IDBT deployments.
ADS8678IDBT 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:
- 14
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 8
- 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:
- -
ADS8678IDBT FAQ
1.How can I place an order for ADS8678IDBT through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS8678IDBT 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 ADS8678IDBT reliable?
The price and inventory of ADS8678IDBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS8678IDBT is usually 5 days.
3.What payment methods are accepted for ADS8678IDBT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS8678IDBT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS8678IDBT?
ADS8678IDBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS8678IDBT 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 ADS8678IDBT?
For technical support, including ADS8678IDBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS8678IDBT requirements.
6.How does Aetrix verify that ADS8678IDBT is sourced from the original manufacturer or authorized distributors?
All ADS8678IDBT 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 ADS8678IDBT meets industry standards.
7.What is the process for return or replacement of ADS8678IDBT?
All ADS8678IDBT units undergo pre-shipment inspection (PSI). If there is an issue with ADS8678IDBT, 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 ADS8678IDBT part is unused and in its original packaging.
Return procedure for ADS8678IDBT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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