Texas Instruments ADC0804LCWM/NOPB

Overview

ADC0804LCWM/NOPB from Texas Instruments is an 8-bit successive approximation analog-to-digital converter (ADC) with differential analog inputs, on-chip clock generator, and tri-state parallel output interface. It operates from a single 5-V supply, delivers ±1 LSB total unadjusted error at 640 kHz clock, and supports microprocessor bus interfacing without external logic - used in embedded sensor data acquisition systems requiring ratiometric or fixed-reference conversion.

For engineers reviewing the ADC0804LCWM/NOPB datasheet, ADC0804LCWM/NOPB pinout, ADC0804LCWM/NOPB application, or ADC0804LCWM/NOPB equivalent, key selection criteria include its 100 µs conversion time, 20-pin SOIC package, differential input architecture for common-mode rejection, and compatibility with 8080-family microprocessors via CS/RD/WR control signals.

Technical Context

The ADC0804LCWM/NOPB implements a differential potentiometric ladder architecture with successive approximation register (SAR) logic, enabling 8-bit resolution through 64 internal clock cycles per conversion. Its analog front-end supports differential voltage inputs (VIN(+) and VIN(−)) referenced to VREF/2, allowing offset adjustment and full-scale encoding of sub-5-V spans.

Digital control uses active-low CS, RD, and WR signals compliant with TTL/MOS voltage levels; tri-state output latches drive microprocessor data buses directly. Internal clock generation is enabled via external RC network on CLK R and CLK IN pins, or bypassed for external clock injection at up to 1.46 MHz.

Key Specifications

Pinout & Package

ADC0804LCWM/NOPB is housed in a 20-pin small-outline integrated circuit (SOIC) package with 12.80 mm × 7.50 mm body size and standard 0.050-inch lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit ADC applications.

Compared with ADC0804LCN/NOPB, ADC0804LCWM/NOPB trades larger board footprint for improved thermal performance and manufacturability; versus ADC0809CCN/NOPB, it sacrifices channel count for reduced system-level timing dependencies and lower firmware burden in basic sensing roles.

Availability

ADC0804LCWM/NOPB is available at Aetrix Electronics and suitable for industrial process controllers, legacy microprocessor interfaces, standalone data loggers, and temperature monitoring systems requiring stable component supply and long-term production continuity.

Supply support for ADC0804LCWM/NOPB 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

ADC0804LCWM/NOPB belongs to TI's legacy precision data converter portfolio, designed specifically for cost-sensitive, microprocessor-integrated analog acquisition in commercial-grade embedded systems.

FAQ

What is the maximum clock frequency supported by ADC0804LCWM/NOPB?

The ADC0804LCWM/NOPB supports clock frequencies from 100 kHz to 1460 kHz. However, accuracy is guaranteed only at 640 kHz per the datasheet specification. Operating above this frequency may degrade total unadjusted error beyond ±1 LSB due to timing margin reduction in the successive approximation logic.

Does ADC0804LCWM/NOPB require external zero or full-scale calibration?

No, ADC0804LCWM/NOPB requires no zero adjust - factory trimming ensures zero code at 0 V differential input. Full-scale adjustment is optional and achieved by tuning the VREF/2 voltage; the device supports ratiometric operation where full-scale tracks VCC, eliminating need for precision reference sources in many applications.

How does the differential input architecture of ADC0804LCWM/NOPB improve measurement accuracy?

The differential inputs (VIN(+) and VIN(−)) of ADC0804LCWM/NOPB provide inherent common-mode noise rejection - measured DC common-mode error is ±1/16 LSB. This allows accurate digitization of small signals superimposed on noisy grounds or floating sensor outputs, such as bridge-based pressure transducers or thermocouple amplifiers.

Can ADC0804LCWM/NOPB operate without an external microprocessor?

Yes, ADC0804LCWM/NOPB can operate as a stand-alone ADC. By tying INTR to WR and holding CS low, it enters free-running mode - automatically initiating conversions and asserting INTR upon completion. External logic (e.g., flip-flop or microcontroller GPIO) can then latch data on the rising edge of INTR or respond to its falling edge.

What is the purpose of separate A GND and D GND pins on ADC0804LCWM/NOPB?

A GND and D GND on ADC0804LCWM/NOPB isolate analog and digital return paths to prevent digital switching noise from modulating the analog reference ladder. They must be connected at a single point - typically at the power supply filter capacitor - to maintain ±1 LSB accuracy and avoid ground-loop-induced errors in high-resolution measurements.