Texas Instruments ADS8504IBDW

Overview

ADS8504IBDW from Texas Instruments is a 12-bit, 250-kSPS successive-approximation register (SAR) analog-to-digital converter with ±10-V input range, internal 2.5-V reference, full parallel binary 2's complement output, and single +5-V supply operation. It integrates S/H, reference buffer, clock, and three-state drivers for microprocessor interfacing in industrial data acquisition systems.

For engineers reviewing the ADS8504IBDW datasheet, ADS8504IBDW pinout, ADS8504IBDW application, or ADS8504IBDW equivalent, key selection criteria include bipolar zero error drift (±0.4 ppm/°C), INL/DNL (±0.45 LSB max), SINAD (73 dB at 45 kHz), SOIC-28 package compatibility, and support for internal/external reference configurations.

Technical Context

The ADS8504IBDW implements a capacitor-based SAR architecture with integrated sample-and-hold, internal CDAC, and comparator-driven control logic. Its analog front end uses precision resistors to deliver a standard ±10-V input range with 11.5-kΩ input impedance and inherent ±25-V overvoltage protection.

Digital interface relies on dual-control timing via CS and R/C pins, enabling conversion initiation and parallel data readout with BUSY synchronization. The device supports byte-mode (8-bit MSB/LSB) and full-word (12-bit) output formats, with all outputs in high-impedance state when CS is high or R/C is low.

Key Specifications

Pinout & Package

ADS8504IBDW is housed in a 28-pin SOIC (DW) package with gull-wing leads, rated for -40°C to +85°C operation and Θ_JA = 46°C/W thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7804UB, ADS8504IBDW delivers 25× faster throughput and single-supply simplicity; compared with ADS8505IBDW, it trades 4 bits of resolution for lower cost and reduced digital processing load while retaining identical packaging and timing behavior.

Availability

ADS8504IBDW is available at Aetrix Electronics and suitable for industrial process control, medical equipment, and instrumentation applications requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for ADS8504IBDW 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 ADS8504IBDW belongs to TI's precision SAR ADC product line, engineered for high-accuracy, moderate-speed data acquisition in harsh industrial and medical environments where reliability, low drift, and simplified power architecture are critical.

FAQ

What is the maximum sampling rate supported by the ADS8504IBDW?

The ADS8504IBDW supports a maximum sampling rate of 250 kSPS across its full operating temperature range (-40°C to +85°C). This throughput is achieved with a 4-µs conversion cycle (acquisition + conversion), verified under conditions of VANA = VDIG = 5 V and use of the internal reference. Performance remains stable without derating at maximum ambient temperature.

Does the ADS8504IBDW require external calibration components?

The ADS8504IBDW can operate without external calibration components: its internal offset and gain adjustments allow software-based correction, eliminating the need for trim pots or precision resistors. However, hardware calibration using the external resistor network shown in Figure 24(a) achieves tighter specifications-±0.25% FSR full-scale error versus ±2.5% without external components.

Can the ADS8504IBDW use an external reference, and what voltage range is supported?

Yes, the ADS8504IBDW supports an external reference applied to the REF pin (pin 3) within 2.3 V to 2.7 V. When used, the internal 2.5-V reference is bypassed. External reference operation improves full-scale error drift to ±2 ppm/°C (vs. ±7 ppm/°C with internal reference) and maintains ±0.25% FSR accuracy across temperature.

How does the BYTE pin affect data output formatting on the ADS8504IBDW?

The BYTE pin (pin 23) selects between full-word and byte-mode output: when LOW, D11–D4 output the 8 most significant bits; when HIGH, D7–D0 output the 8 least significant bits. This enables 8-bit microcontroller interfacing without external multiplexing. Both modes retain binary 2's complement format and are synchronized to R/C timing.

What is the purpose of the four DZ pins on the ADS8504IBDW?

The four DZ pins (pins 19–22) are dedicated three-state control indicators that go LOW only when CS is LOW and R/C is HIGH-signaling active parallel data output. They provide hardware-level confirmation of bus enable state, simplifying FPGA or CPLD interface logic by eliminating need for internal BUSY decoding to manage output drivers.