Texas Instruments ADS7804P

Overview

ADS7804P from Texas Instruments is a 12-bit successive approximation register (SAR) analog-to-digital converter with integrated sample-and-hold, internal 2.5V reference, parallel 12-bit two's complement output, ±10V input range, and 100kHz sampling rate-designed for industrial data acquisition systems requiring high DC accuracy and low power in single +5V operation.

For engineers reviewing the ADS7804P datasheet, ADS7804P pinout, ADS7804P application, or ADS7804P equivalent, this device serves as a complete, self-contained ADC solution for precision bipolar signal digitization in PLC I/O modules, test equipment front-ends, and embedded instrumentation where ±0.9 LSB INL, 70dB SINAD at 45kHz, and DIP-28 industrial temperature support are critical selection criteria.

Technical Context

The ADS7804P implements a capacitor-based SAR architecture with on-chip S/H, clock generator, and three-state parallel bus drivers. Its control logic uses CS and R/C inputs to initiate conversion and enable output, with BUSY signaling completion. The internal 2.5V reference (±0.02V tolerance, 8ppm/°C drift) feeds a buffered CAP pin requiring a 2.2µF tantalum capacitor.

Analog input path includes laser-trimmed resistive scaling for ±10V full-scale range and inherent ±25V overvoltage protection. Input impedance is 23kΩ with 35pF capacitance; acquisition time is 2µs and conversion time is 8µs, enabling full 10µs cycle time at 100kHz throughput.

Key Specifications

Pinout & Package

ADS7804P is housed in a 28-pin plastic DIP (0.3" width, NT package), fully specified for –40°C to +85°C operation. Pin spacing follows JEDEC MS-001 standard with 0.1" row pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7804UB and ADS7805P, the ADS7804P offers the optimal balance of through-hole manufacturability, industrial temperature support, and cost-effective 12-bit performance-making it ideal for volume industrial I/O modules where ±0.9 LSB INL and 100kHz sampling meet system requirements without over-specifying resolution or package type.

Availability

ADS7804P is available at Aetrix Electronics and suitable for programmable logic controller (PLC) analog input modules, automated test equipment (ATE) front-ends, and industrial data loggers requiring stable component supply across extended product lifecycles.

Supply support for ADS7804P 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 ADS7804P belongs to TI's legacy high-accuracy SAR ADC family, engineered specifically for industrial data acquisition where robustness, single-supply operation, and guaranteed DC specifications over temperature are essential.

FAQ

What is the guaranteed INL specification for ADS7804P across its operating temperature range?

The ADS7804P guarantees ±0.9 LSB integral nonlinearity over the full industrial temperature range of –40°C to +85°C. This specification is measured using the internal 2.5V reference and reflects worst-case deviation from ideal transfer function across all codes, ensuring monotonic behavior and <0.05% full-scale error in precision measurement applications.

Can ADS7804P operate with an external reference, and what voltage range is supported?

Yes, ADS7804P supports external reference operation via the REF pin (pin 3), accepting voltages from 2.3V to 2.7V. When an external reference is applied, the internal 2.5V reference is bypassed. Using a higher reference voltage increases full-scale range and LSB size, which can improve SNR-though linearity remains specified only within the 2.3–2.7V window.

Is ADS7804P pin-compatible with any higher-resolution alternatives in the same package?

Yes, ADS7804P is pin-compatible with the 16-bit ADS7805P in the 28-pin DIP package. Both share identical pin assignments, control interface (CS, R/C, BUSY, BYTE), and parallel data bus structure-enabling direct PCB replacement for resolution upgrades without layout modification, though ADS7805P operates at 50kHz max sampling rate.

What decoupling is required for the CAP and REF pins of ADS7804P?

ADS7804P requires a 2.2µF tantalum capacitor placed as close as possible between CAP (pin 4) and AGND2 (pin 5), and another 2.2µF tantalum capacitor between REF (pin 3) and AGND2. These capacitors stabilize the internal reference buffer and CDAC switching currents; using smaller values risks oscillation or insufficient charge delivery, degrading linearity and noise performance.

Does ADS7804P include overvoltage protection on its analog input, and what is the rating?

Yes, ADS7804P features built-in ±25V overvoltage protection on the VIN pin (pin 1), guaranteed indefinitely under normal operating conditions. This protection arises from its internal resistive front-end network and eliminates the need for external TVS diodes or clamping circuits in industrial environments where wiring faults or transients may occur.