Texas Instruments ADC0802LCWM/NOPB

Overview

ADC0802LCWM/NOPB from Texas Instruments is an 8-bit successive approximation analog-to-digital converter (ADC) designed for µP-compatible interfacing without external logic. It features ±1/2 LSB total unadjusted error, 100 µs conversion time at 640 kHz clock, and differential analog inputs enabling common-mode rejection. It operates from a single 5-V supply and supports stand-alone or microprocessor-based data acquisition in industrial sensor monitoring systems.

For engineers reviewing the ADC0802LCWM/NOPB datasheet, ADC0802LCWM/NOPB pinout, ADC0802LCWM/NOPB application, or ADC0802LCWM/NOPB equivalent, key selection considerations include its unadjusted accuracy grade, internal clock generator with RC timing, tri-state output latching for direct 8080 bus connection, and SOIC-20 package suitability for space-constrained embedded designs.

Technical Context

The ADC0802LCWM/NOPB implements a differential potentiometric ladder architecture with successive approximation register (SAR) logic, requiring exactly 64 clock cycles per conversion. Its control interface uses active-low CS, RD, and WR signals compliant with both MOS and TTL voltage levels, allowing seamless integration with 8080-family microprocessors as memory-mapped or I/O-mapped peripherals.

It supports two primary operating modes: single-conversion triggered by WR pulse, and free-running mode enabled by tying INTR to WR with CS grounded. The internal clock generator accepts RC components on CLK R (Pin 19) and CLK IN (Pin 4), while the VREF/2 input (Pin 9) sets full-scale span via an on-chip resistor divider-2.2 kΩ per leg for ADC0802LCWM/NOPB-enabling ratiometric operation or fixed 2.5-V reference scaling.

Key Specifications

Pinout & Package

ADC0802LCWM/NOPB is housed in a 20-pin Small Outline Integrated Circuit (SOIC) package measuring 12.80 mm × 7.50 mm, optimized for surface-mount assembly and thermal performance (R_θJA = 63.8 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADC0804LCN/NOPB, ADC0802LCWM/NOPB offers tighter ±1/2 LSB error in a smaller SOIC package but lacks DIP compatibility; versus ADC0808CCN/NOPB, it provides simpler single-input operation with integrated clocking, eliminating external timing components at the cost of channel count flexibility.

Availability

ADC0802LCWM/NOPB is available at Aetrix Electronics and suitable for industrial sensor interfaces, embedded data loggers, legacy microprocessor upgrades, and standalone test instrumentation requiring stable component supply across long-lifecycle programs.

Supply support for ADC0802LCWM/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 personal electronics markets.

ADC0802LCWM/NOPB belongs to the ADC080x family of 8-bit µP-compatible successive approximation ADCs, engineered for low-cost, low-complexity data acquisition in resource-constrained embedded systems without external interface logic.

FAQ

What is the maximum clock frequency supported by ADC0802LCWM/NOPB?

The ADC0802LCWM/NOPB supports a clock frequency range of 100 kHz to 1460 kHz, with optimal accuracy specified at 640 kHz. At higher frequencies, AC performance degrades due to reduced internal timing margins; at lower frequencies, duty cycle constraints relax but minimum high/low times must remain ≥275 ns per datasheet Section 6.7.

Does ADC0802LCWM/NOPB require external zero or full-scale calibration?

No, ADC0802LCWM/NOPB requires no zero adjust - factory-trimmed offset ensures correct 00000000 output at analog ground. Full-scale adjustment is optional via the VREF/2 pin and is only needed if precise span matching is required; the device operates accurately without it using default internal resistor values.

Can ADC0802LCWM/NOPB operate with a 3.3-V microprocessor interface?

ADC0802LCWM/NOPB logic inputs meet both MOS and TTL voltage-level specifications, but its VCC must be 4.5–5.5 V. While input thresholds allow recognition of 3.3-V logic highs (≥2.0 V) and lows (≤0.8 V), the 5-V supply means level-shifting is required for bidirectional data bus interfacing to avoid damaging the 3.3-V µP's outputs.

What is the purpose of separate A GND and D GND pins on ADC0802LCWM/NOPB?

The ADC0802LCWM/NOPB uses separate analog (Pin 8) and digital (Pin 10) ground pins to isolate noise-sensitive analog circuitry from switching digital currents. Both must be connected to the same system ground point with low-impedance traces - splitting grounds or routing them separately degrades accuracy and increases offset drift.

How does the internal clock generator work in ADC0802LCWM/NOPB?

The ADC0802LCWM/NOPB internal clock generator uses an RC network: CLK R (Pin 19) connects to an external resistor, and CLK IN (Pin 4) connects to an external capacitor. The Schmitt-triggered CLK IN input shapes the oscillation waveform, producing a clock frequency determined by R×C - enabling self-timed conversion without external clock sources.