MAXIM MX7224KN+

The MX7224 is a precision voltage-output CMOS digital-to-analog converter (DAC) which includes an output amplifier on chip. Only an external reference source is required for operation and the fully specified accuracy is achieved with no external trims. The MX7224 contains an 8-bit digital-to-analog converter that operates in the voltage output mode. The output voltage is of the same polarity as the external reference voltage thus allowing single supply operation. A DAC switch pair arrangement on the Mx7224 allows a reference voltage range from +2V to +12.5V. The DAC consists of a stable thin-film resistor R-2R ladder and eight NMOS single pole, double-throw switches. The input impedance at the V_REF pin is code dependent and varies from 8kΩ minimum to infinity. The lowest input impedance occurs when the DAC is loaded with the digital code 01010101. Capacitance at the reference terminal is also code dependent and typically varies from 25pF to 50pF. The V_OUT pin can be considered as a digitally programmable voltage source. The DAC's voltage output is buffered by a unity-gain CMOS voltage follower that slews at greater than 2.5V/μs. This amplifier is capable of driving a 2kΩ load to +10V. When driving a 2kΩ load in parallel with 100pF with full-scale transitions (0V to +10V or +10V to 0V), the output settles to 1/2 LSB in less than 5μs.

• Double buffered interface logic is included to allow simultaneous updating in systems which have several DAC channels in operation.
• Control is provided by CS, WR, and LDAC (Load DAC) inputs.
• A RESET input is provided which acts as a zero override.
• All logic inputs are compatible with TTL and 5V CMOS logic levels.
• Specified performance is guaranteed for reference inputs ranging from +2V to +12.5V when using dual supplies.
• With a +10V reference the performance is also specified for single supply operation.
• The DAC output can drive +10V into a 2kΩ load.

• Automatic Calibration
• Motion Control
• Digital Attenuators
• Function Generators