The DAC813 is a complete monolithic 12-bit digital-to-analog converter with a flexible digital interface. It includes a precision + 10V reference, interface control logic, double-buffered latches, and a 12-bit D/A converter with voltage output op amps. Fast current switching and laser-trimmed thin-film resistors provide high-precision, fast D/A converters. Double-buffered latches facilitate the digital interface. The input latch consists of an 8-bit byte and a 4-bit nibble, allowing connection to an 8-bit (right-justified format) or 16-bit data bus. Design the input gating logic so that the last nibble or byte to be loaded can be loaded while data is being transferred to the D/A latch, saving computer instructions. The reset control allows the DAC813 D/A latch to asynchronously reset the D/A output to bipolar zero, a feature useful for power-on reset, recalibration, or system reinitialization in the event of a system failure. The DAC813 is specified for ±1/2LSB maximum linearity error (J, A grade) and ±1/4LSB (K grade). It is available in 28-pin 0.3" wide plastic DIP and 28-pin plastic SOIC packages.

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The DAC813 accepts true binary input codes. The DAC813 can be connected by the user to any of the following codes: USB (Unipolar Standard Binary), BOB (Bipolar Offset Binary) or, using the MSB line on the external inverter, BTC (Two's Complement). See Table 1.

Linearity error

The tolerance error used in the D/A converter specification for Burr-Brown is the analog output drawn from a deviation between the endpoints of a straight line (inputs drawn between all "1"s and all "0s"). The specified DAC813 linearity error is ±1/4LSB (max) at +25°C grade K, and ±1/2LSB (max) for ? grades.

Differential Linearity Error

Differential Linearity Error (DLE) is the deviation from a 1LSB output change from an adjacent state. A DLE specification of 1/2LSB means that the output step size can range from 1/2LSB to 3/2LSB when the input changes from one state to the next. Monotonicity requires the DLE to be less than 1LSB over the temperature range of interest.

Monotonicity

D/A converters are monotonic if the output either increases or stays the same to increase the digital input. All grades of the DAC813 are monotonic over their specified temperature range.

Drift Gain drift is a measure of the change in the full-scale range (FSR) output over the temperature range of specifications. Yield drift is expressed as parts per million per degree Celsius (PPM/°C). Data input 000 (hex) for unipolar offset drift measurements. The D/A is configured as a unipolar output. Unipolar offset drift is expressed in parts per million of full scale per degree Celsius of range (FSR ppm/°C). Bipolar Zero Drift Measurement 800 's data input (hex). The D/A is configured as a bipolar output. Bipolar zero drift is expressed in parts per million of full scale degrees Celsius (ppm FSR/°C of manufacture).

Settling time is the total time (including transition time) for the output to settle within the error band around its final value after a change in the input. Three settling times are specified as ±0.012% of full scale range (FSR): 2 for a maximum full-scale range change of 20V and 10V, and one for a 1LSB change. The 1LSB change is measured in major carry (7FF (hex) to 800 (hex) and 800 (hex) to 7FF (hex)), input transcription learned these worst Situation stabilization time occurs.

The reference supply to the DAC813 includes an on-chip +10V reference. This voltage (pin 6) has a tolerance of ±50mV. VREF OUT must be connected to V at REF through a gain adjustment resistor with a nominal value of 500Ω. This connection can be adjusted to zero gain error by making an optional 1kΩ trimmer resistor. The reference output can be used to drive an external load, sourcing at least 5mA. This current should be constant, otherwise the gain of the converter will vary.

Power Supply Sensitivity Power supply sensitivity is a measure of the effect of a power supply change on the D/A converter output. This is the change in output change defined as ppm per percent FSR or +VCC or -vCC FSR/% in ppm relative to the nominal voltage. Typical power supply rejection versus power supply ripple frequency is shown on page 5 of the first performance curve.

The DAC813 is a complete single integrated circuit chip 12-bit D/A converter. The chip contains a 12-bit D/A converter, voltage reference, output amplifier and microcomputer-compatible input logic as shown in Figure 1.

Figure II