ADC / DAC
IC (Mixed)
The bridges between the analog world and digital logic. An ADC measures a voltage into a number; a DAC turns a number back into a voltage. Resolution, speed and the reference determine everything.
Schematic symbol
Integrated circuit (DIP)
How adc / dac appears in a circuit diagram.
Types & variants
Key specs
Resolution
bitsStep count: 10-bit = 1024 steps; 16-bit = 65,536.
Sample rate
S/sConversions per second — bandwidth of what you can capture.
Reference
VFull-scale is set by Vref; its noise/drift limits real accuracy.
ENOB / INL
bits / LSBReal-world accuracy vs the headline bits.
Markings
IC part number on package (ADS1115, MCP3008, MCP4725, PCM5102...).
Standard values
Hobby staples: ADS1115 (16-bit I2C ADC), MCP3008 (8-ch SPI ADC), MCP4725 (12-bit I2C DAC).
How to choose
Resolution from the smallest change you must detect, speed from signal bandwidth (sample ≥ 2×, practically 5–10×), then interface (I2C easy, SPI fast). A clean reference matters more than extra bits.
Pinout & package
DIP/SOIC/QFN. Power, GND, reference, analog in/out, and an I2C/SPI digital side. Keep analog and digital grounds tidy.
Example circuits
- ADS1115 reading a load-cell amplifier
- MCP4725 generating a control voltage
- Audio DAC (PCM5102) on a Raspberry Pi
Common failures
Latch-up or dead inputs from over-voltage on analog pins; 'noisy readings' that are really reference or grounding problems, not a bad chip.
How to test
ADC: feed a known voltage from a divider, read the code, compute back. DAC: command half-scale, meter the output ≈ Vref/2. Check supply and reference pins first when readings wander.
Substitutes
Your MCU's built-in 10–12-bit ADC/DAC covers casual uses; move to an external converter for more bits, channels or isolation.