Texas Instruments ADS8508IBDWRG4

Overview

ADS8508IBDWRG4 from Texas Instruments is a 12-bit, 250-kSPS serial CMOS sampling analog-to-digital converter (ADC) with SAR architecture, internal 2.5-V reference, ±0.45 LSB max INL/DNL, and SPI-compatible daisy-chain serial interface. It operates from a single +5-V supply, supports six input ranges (±10 V, 0–5 V, etc.), and delivers 73-dB SINAD at 45 kHz - used in industrial process control and precision data acquisition systems.

For engineers reviewing the ADS8508IBDWRG4 datasheet, ADS8508IBDWRG4 pinout, ADS8508IBDWRG4 application, or ADS8508IBDWRG4 equivalent, key selection factors include its 250-kHz throughput, bipolar zero error drift of ±0.4 ppm/°C, internal/external reference flexibility, 20-pin SOIC package, and compatibility with DSP interfaces requiring SYNC pulse synchronization.

Technical Context

The ADS8508IBDWRG4 implements a capacitor-based successive approximation register (SAR) core with integrated sample-and-hold, reference buffer, and serial output logic. Its conversion cycle comprises 1.8-µs acquisition and 2.2-µs conversion, achieving full 12-bit accuracy within 4 µs at 250 kSPS across –40°C to +85°C.

It supports dual clocking modes via EXT/INT: internal DATACLK (9 MHz output, 16 pulses per conversion) or external DATACLK (0.1–26 MHz), with BUSY signaling and optional SYNC pulse for deterministic timing alignment to host processors. The TAG pin enables daisy-chaining of multiple converters on a shared serial bus.

Key Specifications

Pinout & Package

ADS8508IBDWRG4 is housed in a 20-pin SOIC (DW) package with standard 0.3-inch body width and 0.050-inch lead pitch. Thermal resistance Θ_JA = 75°C/W supports operation up to +85°C ambient with minimal heatsinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS8508IBDWRG4, ADS8509IBDWR trades speed for resolution while maintaining pin and software compatibility, whereas ADS7808UB requires interface redesign and sacrifices serial features - making ADS8508IBDWRG4 optimal for new 12-bit, 250-kSPS serial DAQ designs.

Availability

ADS8508IBDWRG4 is available at Aetrix Electronics and suitable for industrial process control, medical equipment, and precision instrumentation requiring stable component supply and long-term production continuity.

Supply support for ADS8508IBDWRG4 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 converters and industrial-grade ICs.

The ADS8508IBDWRG4 belongs to TI's precision SAR ADC product line, designed specifically for high-accuracy, medium-speed data acquisition in harsh industrial and medical environments where reliability and parametric consistency are critical.

FAQ

What is the maximum sampling rate of the ADS8508IBDWRG4?

The ADS8508IBDWRG4 achieves a guaranteed 250-kSPS sampling rate across its full industrial temperature range (–40°C to +85°C). This is supported by a 4-µs total conversion cycle (1.8 µs acquisition + 2.2 µs conversion), confirmed in the Electrical Characteristics table under "Throughput rate" with min/typ/max values of 250 kHz. Performance remains stable under 5-V supply conditions with internal reference enabled.

Does the ADS8508IBDWRG4 require an external reference?

No, the ADS8508IBDWRG4 includes a factory-trimmed internal 2.5-V reference (2.48–2.52 V, ±0.4%) with 8 ppm/°C drift, sufficient for most industrial applications. An external reference (2.3–2.7 V) may be used via the REF pin to achieve tighter drift (±2 ppm/°C) or match system-level reference domains - but it is not required. The internal reference must be bypassed with a 2.2-µF tantalum capacitor on CAP.

How does the TAG daisy-chain feature work on the ADS8508IBDWRG4?

The TAG pin on the ADS8508IBDWRG4 enables cascading multiple converters on a single serial bus: DATA output of one device connects to TAG input of the next. In external clock mode, each device shifts its 16-bit result onto the shared DATA line sequentially, with NULL bits (determined by TAG state) separating words. This eliminates additional SPI chip selects and simplifies multi-channel synchronization in modular DAQ systems.

What are the absolute maximum ratings for analog inputs on the ADS8508IBDWRG4?

The ADS8508IBDWRG4 analog inputs (R1IN, R2IN, R3IN) tolerate up to ±25 V continuously, as specified in the Absolute Maximum Ratings table. This overvoltage protection allows direct connection to industrial sensors and transducers without external clamping circuitry - provided the input signal remains referenced to AGND1 and is driven by a low-impedance source per Figure 27 recommendations.

Can the ADS8508IBDWRG4 operate with separate analog and digital supplies?

No - the ADS8508IBDWRG4 requires a single +5-V supply applied to both VANA and VDIG pins, with VDIG ≤ VANA strictly enforced. The datasheet specifies VANA = VDIG = 5 V (±5%) for all electrical characteristics, and violating the VDIG ≤ VANA condition risks latch-up or parametric degradation. Decoupling requires 0.1-µF ceramic + 10-µF tantalum per supply pin, connected directly to respective ground planes (AGND2 and DGND).