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MCP4921 12-Bit SPI DAC

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by Ray

Single-channel 12-bit voltage-output DAC with SPI and an external reference input.

dac12-bitsinglespiexternal-referencemicrochipsoic-8
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README

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MCP4921

Microchip · Digital-to-Analog Converter · SOIC-8

The MCP4921 is a single-channel, 12-bit voltage-output DAC with an SPI interface. It uses an external reference input with a selectable 1x or 2x output gain and includes a shutdown mode. It suits set-point generation, bias control, and programmable voltage sources, and is the single-channel version of the dual MCP4922.

Pinout

Pin Name Type Function
1 VDD power_in Positive supply voltage input, 2.7V to 5.5V (absolute max 6.5V). Bypass with 0.1 µF to VSS.
2 CS input SPI chip-select (active low). Enables the serial interface; input register writes latch on rising edge.
3 SCK input SPI serial clock input, up to 20 MHz. Data on SDI is sampled on the rising edge.
4 SDI input SPI serial data input. 16-bit command word (config bits + DAC data) shifted in MSB-first.
5 LDAC input Synchronous DAC latch (active low). Falling edge transfers both DAC input registers to the DAC output registers, updating VOUTA and VOUTB simultaneously. Tie low for asynchronous updates.
6 VREF input External voltage reference input for DAC A. Unbuffered range 0 to VDD; buffered range 0.040 V to VDD−0.040 V. Input impedance ~165 kΩ (unbuffered).
7 VSS power_in Ground return / negative supply. Connect to system analog ground.
8 VOUT output DAC channel A buffered analog output. Rail-to-rail, output swing 0.01 V to VDD−0.04 V, short-circuit current ~15 mA typ, slew rate 0.55 V/µs.

Key specifications

Parameter Value
Resolution 12-bit, 1 channel
Output Voltage output (buffered, rail-to-rail)
Reference External (VREF pin), 1x or 2x gain
Interface SPI (up to 20 MHz)
Settling time 4.5 us typ
Supply voltage 2.7 V to 5.5 V
Operating temperature -40 C to 125 C

Ordering variants

Same part, different packaging or reel option.

  • MCP4921-E/P
  • MCP4921I/P
  • MCP4921-E/SL
  • MCP4921I/SL
  • MCP4921-E/ST
  • MCP4921I/ST

CAD (KiCad official)

  • Symbol: mcp4921.kicad_sym
  • Footprint: mcp4921.kicad_mod
  • 3D model: SOIC-8 body from KiCad Package_SO/SOIC-8_3.9x4.9mm_P1.27mm.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip datasheet (48 pp, sha256 8c507a2bce321888, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF