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Texas Instruments ADS8508IBDWR
- Part No.:
- ADS8508IBDWR
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ADS8508IBDWR.pdf
- Description:
- IC ADC 12BIT SAR 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,486
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Product details
Overview
ADS8508IBDWR from Texas Instruments is a 12-bit, 250-kSPS successive approximation register (SAR) analog-to-digital converter with internal 2.5-V reference, SPI-compatible serial output, and daisy-chain (TAG) capability. It supports six input ranges (±10 V, 0–5 V, etc.), delivers 73-dB SINAD at 45 kHz, ±0.45 LSB max INL/DNL, and operates from a single +5-V supply in industrial temperature range (–40°C to +85°C). It is used in precision data acquisition systems interfacing with DSPs or microcontrollers.
For engineers reviewing the ADS8508IBDWR datasheet, ADS8508IBDWR pinout, ADS8508IBDWR application, or ADS8508IBDWR equivalent, key selection considerations include its 250-kSPS throughput, bipolar zero error drift of ±0.4 ppm/°C, internal/external reference flexibility, SO-20 package compatibility, and TAG-enabled multi-channel synchronization for distributed sensor systems.
Technical Context
The ADS8508IBDWR implements a capacitor-based SAR architecture with integrated sample-and-hold, internal clock generator, and configurable serial interface. Its conversion cycle comprises 1.8 µs acquisition and 2.2 µs conversion, totaling 4 µs per sample, enabling deterministic timing for real-time control loops.
It supports dual clocking modes: internal DATACLK (9 MHz output, 16-pulse burst per conversion) or external DATACLK (0.1–26 MHz), with EXT/INT pin selecting mode. The TAG feature enables hardware-level daisy-chaining of multiple converters on a shared serial bus without software arbitration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12 bits - delivers 1 LSB = 4.88 mV for ±10-V range, sufficient for 0.025% full-scale precision in industrial voltage monitoring. |
| Sampling Rate | 250 kSPS - supports Nyquist-limited signal capture up to 125 kHz, suitable for motor current sensing and vibration analysis. |
| SINAD | 73 dB at 45 kHz - ensures >11.8 effective bits of dynamic resolution for clean spectral analysis in medical or instrumentation applications. |
| INL / DNL | ±0.45 LSB max - guarantees monotonicity and no missing codes across full scale, critical for closed-loop feedback accuracy. |
| Reference | Internal 2.5 V ±0.4% (2.48–2.52 V), 8 ppm/°C drift - eliminates need for external reference unless sub-ppm stability required. |
| Power Dissipation | 70 mW typical at 250 kSPS - enables thermally constrained designs without forced cooling in compact industrial modules. |
| Input Ranges | Six factory-configured ranges: ±10 V, ±5 V, ±3.33 V, 0–4 V, 0–5 V, 0–10 V - simplifies front-end design across diverse sensor outputs. |
Pinout & Package
ADS8508IBDWR is housed in a 20-pin SOIC (SO-20, DW package), 7.5 mm × 12.8 mm body, 1.27 mm pitch, fully specified for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| R1IN | Analog input channel 1 | Main differential input with ±25-V overvoltage protection; referenced to AGND1 for low ground-loop noise. |
| R2IN | Analog input channel 2 | Secondary analog input supporting same six factory-calibrated ranges as R1IN. |
| R3IN | Analog input channel 3 | Third analog input, identical electrical specs and protection as R1IN/R2IN. |
| REF | Reference I/O | Outputs internal 2.5-V reference or accepts external 2.3–2.7-V reference; requires 2.2-µF tantalum bypass to CAP. |
| CAP | Reference buffer capacitor node | Internal reference buffer output; must be decoupled to AGND2 with 2.2-µF tantalum capacitor. |
| CS | Chip select | Active-low enable for serial interface; internally ORed with R/C to trigger conversion or read. |
| R/C | Read/Convert control | Falling edge initiates conversion and hold; rising edge (in external clock mode) triggers data read and SYNC pulse. |
| BUSY | Status output | Active-low open-drain signal indicating active conversion; falls at start, rises after data latched into shift register. |
| DATA | Serial data output | MSB-first SPI-compatible output; level follows TAG input at transmission start; supports daisy-chain via TAG cascading. |
| DATACLK | Data clock I/O | Output in internal mode (9 MHz, 16 pulses); input in external mode (0.1–26 MHz); timing-critical for data validity windows. |
| EXT/INT | Mode select | Low = internal DATACLK generation; high = external DATACLK synchronization - determines clock source and timing constraints. |
| SB/BTC | Data format select | High = straight binary; low = binary two's complement - configures output coding for signed/unsigned processing. |
| TAG | Daisy-chain input | Accepts serial data from upstream converter in cascaded configuration; forms NULL bit separator between words. |
| SYNC | Synchronization pulse | Output pulse generated on first external DATACLK edge during read state - aligns multi-converter reads in discontinuous clock mode. |
| PWRD | Power-down control | Active-high input that halts conversions and reduces power to 50 µW while preserving last result in shift register. |
| AGND1 / AGND2 | Analog grounds | Separate analog return paths: AGND1 for inputs, AGND2 for REF/CAP - minimizes coupling between signal and reference paths. |
| DGND | Digital ground | Dedicated digital return; must be connected to AGND at single point to avoid ground loops. |
| VANA | Analog supply | +5 V ±5% analog rail; powers core ADC, sample-and-hold, and reference; must be ≥ VDIG. |
| VDIG | Digital supply | +5 V ±5% digital rail; powers interface logic; must be ≤ VANA to prevent backfeeding. |
Key Features
| Feature | Design Value |
|---|---|
| SPI-compatible serial interface with TAG daisy-chain | Enables synchronous readout of up to N ADS8508IBDWR devices on one serial bus, reducing GPIO count and PCB routing complexity in multi-channel DAQ. |
| Factory-calibrated six-input-range support | Eliminates external gain/offset trimming for ±10 V, ±5 V, ±3.33 V, 0–4 V, 0–5 V, and 0–10 V ranges - accelerates system bring-up and improves production yield. |
| Internal 2.5-V reference with 8 ppm/°C drift | Provides stable, low-noise reference without external components; drift spec ensures <0.1 mV zero-error shift over full industrial temperature range. |
| Discontinuous external DATACLK mode | Allows safe, high-speed data read (up to 26 MHz) only during sampling period - avoids timing conflicts with internal conversion clock and guarantees data integrity. |
| ±25-V analog input overvoltage protection | Protects R1IN/R2IN/R3IN pins against transient surges common in industrial field wiring, reducing need for external TVS or clamping networks. |
Applications
| Industrial Process Monitoring | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Continuous voltage/current measurement from PLC analog I/O modules feeding real-time SCADA dashboards. IC Role / Device Role / Timing Role: Primary 12-bit ADC digitizing 4–20 mA loop signals and ±10 V sensor outputs at 250 kSPS with deterministic 4-µs cycle time. Use Value: ±0.45 LSB linearity and 73-dB SINAD ensure accurate representation of process variables under EMI-rich plant-floor conditions. | Use Scenario: Front-end signal conditioning in portable ECG or EEG units acquiring biopotential waveforms. IC Role / Device Role / Timing Role: High-fidelity analog digitizer capturing low-amplitude, low-frequency bio-signals with minimal harmonic distortion. Use Value: –95 dB THD and 73-dB SINAD at 45 kHz preserve waveform fidelity critical for arrhythmia detection algorithms. |
| Test & Measurement Instrumentation | DSP-Based Motor Control |
Use Scenario: Modular data logger capturing transient events (e.g., surge testing, switch bounce) across multiple channels. IC Role / Device Role / Timing Role: Synchronized multi-channel sampling node using TAG daisy-chain to align timestamps across 4+ ADS8508IBDWR units. Use Value: Hardware SYNC pulse and deterministic 5-ns aperture delay enable sub-microsecond inter-channel skew control. | Use Scenario: Real-time current/voltage feedback in servo drives using TI C2000 microcontrollers. IC Role / Device Role / Timing Role: Precision ADC interfaced directly to C2000's SPI port, delivering sampled values within fixed 4-µs latency for field-oriented control loops. Use Value: Internal clock mode provides jitter-free data delivery synchronized to PWM cycles, improving torque ripple suppression. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8509IBDWR | 16-bit resolution, same SO-20 package, 250-kSPS, higher 86-dB SINAD, 100-mW power | Required where >12-bit dynamic range is needed (e.g., high-resolution audio test, precision metrology) | Select ADS8509IBDWR when ENOB > 12.5 bits is mandatory; note increased power and layout sensitivity to noise. |
| ADS7808UB | 12-bit, 10-kSPS max, SO-20, no TAG, no internal reference, 5-V-only supply | Suitable for low-speed, cost-sensitive applications where daisy-chain and reference integration are unnecessary | Choose ADS7808UB only for legacy designs or ultra-low-power standby scenarios; lacks ADS8508IBDWR's speed, features, and flexibility. |
Compared with ADS8509IBDWR, ADS8508IBDWR trades 4-bit resolution for lower power and simpler interface; compared with ADS7808UB, it adds 25× speed, integrated reference, and hardware synchronization-making it optimal for modern industrial DAQ requiring balance of precision, throughput, and system integration.
Availability
ADS8508IBDWR is available at Aetrix Electronics and suitable for industrial process control, medical diagnostic equipment, and test & measurement instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for ADS8508IBDWR 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, embedded processing, and high-reliability ICs for industrial, automotive, and communications markets.
The ADS8508IBDWR belongs to TI's precision data acquisition portfolio, designed specifically for high-speed, multi-channel, industrial-grade analog digitization with minimal external components and robust noise immunity.
FAQ
What is the maximum guaranteed sampling rate for ADS8508IBDWR across its full operating temperature range?
The ADS8508IBDWR is fully specified for 250 kSPS throughput over the industrial temperature range of –40°C to +85°C. This rate is maintained with 4-µs total cycle time (1.8 µs acquisition + 2.2 µs conversion), and all AC/DC performance parameters-including SINAD, INL, and DNL-are guaranteed at this rate under worst-case thermal and supply conditions.
Does ADS8508IBDWR require external resistors to support its six input ranges?
ADS8508IBDWR includes internal precision resistors calibrated at factory for its six input ranges (±10 V, 0–5 V, etc.). External resistors shown in Figures 28–29 are optional trim components; omitting them yields larger but still-specified gain/offset errors. The ADS8508IBDWR functions correctly without them, though software calibration may be needed for highest accuracy.
Can ADS8508IBDWR operate with an external reference, and what are the voltage and current requirements?
Yes, ADS8508IBDWR accepts an external reference from 2.3 V to 2.7 V applied to the REF pin, drawing up to 100 µA. The internal 2.5-V reference is disabled when external voltage is present. External reference must drive a 4-kΩ internal load; TI recommends low-output-impedance buffers (e.g., REF5025) for optimal linearity and drift performance.
How does the TAG daisy-chain feature work in ADS8508IBDWR, and what is the timing constraint for reliable multi-converter operation?
The TAG feature allows serial cascading: DATA of converter N connects to TAG of converter N+1. In external clock mode, each converter shifts its 12-bit word plus one NULL bit (from upstream TAG), requiring 13 clocks per device. To avoid violating td11 (1 µs), all data must be read during the sampling period-not mid-conversion-ensuring reliable alignment across ADS8508IBDWR units.
Is ADS8508IBDWR pin-compatible with other members of the ADS85xx family, and which ones?
Yes, ADS8508IBDWR is pin-compatible with ADS7808 (low-speed variant) and ADS8509/ADS7809 (16-bit variants) in the SO-20 (DW) package. Pin assignments for R1IN, R2IN, R3IN, REF, CAP, CS, R/C, BUSY, DATA, DATACLK, EXT/INT, SB/BTC, TAG, SYNC, PWRD, AGND1/2, DGND, VANA, and VDIG are identical-enabling drop-in upgrades or mixed-resolution channel designs.
ADS8508IBDWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 250k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI
- Configuration:
- 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:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 20-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
ADS8508IBDWR FAQ
1.How can I place an order for ADS8508IBDWR through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS8508IBDWR 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 ADS8508IBDWR reliable?
The price and inventory of ADS8508IBDWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS8508IBDWR is usually 5 days.
3.What payment methods are accepted for ADS8508IBDWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS8508IBDWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS8508IBDWR?
ADS8508IBDWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS8508IBDWR 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 ADS8508IBDWR?
For technical support, including ADS8508IBDWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS8508IBDWR requirements.
6.How does Aetrix verify that ADS8508IBDWR is sourced from the original manufacturer or authorized distributors?
All ADS8508IBDWR 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 ADS8508IBDWR meets industry standards.
7.What is the process for return or replacement of ADS8508IBDWR?
All ADS8508IBDWR units undergo pre-shipment inspection (PSI). If there is an issue with ADS8508IBDWR, 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 ADS8508IBDWR part is unused and in its original packaging.
Return procedure for ADS8508IBDWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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