Texas Instruments ADS8515IBDB

Overview

ADS8515IBDB from Texas Instruments is a 16-bit, 250-kSPS successive approximation register (SAR) analog-to-digital converter with ±10 V input range, internal 4.096 V reference, and full parallel 16-bit twos-complement output. It operates from a single +5 V analog supply and supports flexible I/O voltage (1.65–5.25 V), delivering 90 dB min SNR at 20 kHz for high-fidelity industrial data acquisition.

For engineers reviewing the ADS8515IBDB datasheet, ADS8515IBDB pinout, ADS8515IBDB application, or ADS8515IBDB equivalent, key selection criteria include its SSOP-28 package, ±2 LSB max INL, 100 mW typical power dissipation at full throughput, and compatibility with external 3.9–4.2 V references for precision scaling.

Technical Context

The ADS8515IBDB integrates a capacitor-based SAR architecture with on-chip sample-and-hold, comparator, CDAC, and three-state parallel drivers. Its control logic accepts asynchronous R/C and CS inputs to initiate conversion and enable data output, supporting both full-word and byte-read modes via the BYTE pin.

It uses precision internal resistors to establish the standard ±10 V input range (8.885 kΩ impedance, 75 pF capacitance) and includes dedicated REF and CAP pins for internal reference buffering with 2.2 µF tantalum decoupling. The device achieves 16-bit no-missing-code performance across –40°C to +85°C with <2 ms conversion time and 4 ms minimum inter-conversion interval.

Key Specifications

Pinout & Package

ADS8515IBDB is housed in a 28-pin SSOP (DB) package with exposed pad not electrically connected. Pin spacing is 0.65 mm, body width 5.3 mm, and total footprint 10.2 × 5.3 mm - suitable for automated SMT assembly and industrial-grade reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with ADS8515IBDB, ADS8505IBDB trades throughput and AC performance for lower cost and power, while ADS8686SIPWR adds integrated signal conditioning and serial interface at the expense of pin compatibility and analog supply simplicity.

Availability

ADS8515IBDB is available at Aetrix Electronics and suitable for industrial process control, data acquisition systems, and medical equipment requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for ADS8515IBDB 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 IC design.

The ADS8515IBDB belongs to TI's high-accuracy SAR ADC product line, engineered for applications demanding 16-bit resolution, low power, and robust operation in harsh industrial environments without external support components.

FAQ

What is the maximum sampling rate supported by the ADS8515IBDB?

The ADS8515IBDB is specified for continuous operation at 250 kSPS across its full industrial temperature range (–40°C to +85°C). This throughput is achieved with a 4 µs conversion cycle time and requires ≥4 ms between consecutive conversions to ensure complete signal acquisition. At this rate, the device delivers 90 dB minimum SNR at 20 kHz input frequency, making it suitable for high-fidelity industrial and medical signal capture. The ADS8515IBDB maintains 16-bit no-missing-code performance at full speed.

Does the ADS8515IBDB require an external reference voltage?

No, the ADS8515IBDB includes an internal 4.096 V reference with ±0.2% initial accuracy (4.076–4.116 V) and 8 ppm/°C typical drift, sufficient for most industrial applications. However, it also supports external references from 3.9 V to 4.2 V applied to the REF pin, which can improve full-scale accuracy and reduce temperature-induced gain error - especially when using the external reference option, full-scale error drift drops to ±2 ppm/°C. The ADS8515IBDB's CAP pin must still be decoupled with a 2.2 µF capacitor regardless of reference source.

How does the BYTE pin function on the ADS8515IBDB?

The BYTE pin (pin 23) on the ADS8515IBDB controls 8-bit data access mode: when LOW, pins D8–D15 output the most significant byte (MSB); when HIGH, pins D0–D7 output the least significant byte (LSB). This enables microcontrollers with 8-bit data buses to read the full 16-bit result in two cycles without external latching. Valid data appear on the selected byte bus within 1.2 ms after R/C goes high, and the ADS8515IBDB retains previous conversion data for up to 2 ms during new conversion initiation - allowing safe byte reads even during active sampling.

What are the absolute maximum ratings for analog input voltage on the ADS8515IBDB?

The ADS8515IBDB specifies an absolute maximum analog input voltage (VIN) of ±25 V - exceeding its rated ±10 V operating range. This overvoltage tolerance is enabled by internal precision resistor networks that limit current into the front-end circuitry. However, operation beyond ±10 V will saturate the ADC output and may cause temporary performance degradation until the input returns within range. For reliable 16-bit accuracy, the ADS8515IBDB must be operated strictly within ±10 V, with proper decoupling and grounding per the layout guidelines in the datasheet.

Can the ADS8515IBDB operate with separate analog and digital supplies?

Yes, the ADS8515IBDB supports independent analog (VANA, pin 27) and digital (VDIG, pin 28) supplies. VANA accepts 4.75–5.25 V, while VDIG accepts 1.65–5.25 V - allowing use of isolated or filtered rails to minimize digital noise coupling. However, both supplies must power on before any voltage is applied to VIN to prevent latch-up. TI recommends tying VANA and VDIG together at the board level unless stringent noise isolation is required, as 90% of the device's power is consumed by analog circuitry, and the ADS8515IBDB is optimized for single-supply operation.