#14, M1S: Four-channel DAC


Function: Four-channel DAC

Form factor: M1S

Category: Output module

Special needs: ---

Power requirements: 5V/20mA, 15V/4mA, -15V/4mA (the aggregated consumption through Tibbit #12 is 56mA, measurements were made with no loads on the DAC outputs)

Mates with: #19, #20, #21 (limited use)

See also: #13



This DAC Tibbit is based on the MCP4728 12-bit DAC with I2C interface. All four channels of this DAC are used by the Tibbit. The analog front end of the module allows you to output signals in the -10V to +10V range (respective to the system ground).

The MCP4728 DAC IC has a 12-bit resolution. The Tibbit #14 has the effective resolution of around 9~10 bits. This reduction is caused by the system noise and other factors that affect the measurement quality.

Combine this Tibbit with #20 (nine terminal blocks) or #19 (DB9M connector). It's not common but possible to use the latter for wiring into the DAC outputs. The Tibbit #21 (four terminal blocks) can also be used but you will have to steal the ground elsewhere, as #21 doesn't have its own ground line and the DAC outputs voltages with respect to the system ground.  


There are two red, one yellow, and one green LED. The red LEDs are connected to the SCL and LDAC lines, the yellow LED — to the SDA line, and the green LED — to the -BUSY line.

Sample project

The use of this Tibbit is illustrated by a Tibbo BASIC test project. Yo can find it here: https://github.com/tibbotech/CA-Test-Tibbits-13-14.