AD568

The AD568 is an ultrahigh-speed, 12-bit digital-to-analog converter(DAC) settling to 0.025% in 35 ns. The monolithic deviceis fabricated using Analog Devices' Complementary Bipolar(CB) Process. This is a proprietary process featuring high-speedNPN and PNP devices on the same chip without the use ofdielectricisolation or multichip hybrid techniques. The high speedof the AD568 is maintained by keeping impedance levels lowenough to minimize the effects of parasitic circuit capacitances.

The DAC consists of 16 current sources configured to deliver a10.24 mA full-scale current. Multiple matched current sourcesand thin-film ladder techniques are combined to produce bitweighting. The DAC's output is a 10.24 mA full scale (FS) forcurrent output applications or a 1.024 V FS unbuffered voltageutput. Additionally, a 10.24 V FS buffered output may be generatedusing an onboard 1 kW span resistor with an external opamp. Bipolar ranges are accomplished by pin strapping.

Laser wafer trimming insures full 12-bit linearity. All grades ofthe AD568 are guaranteed monotonic over their full operatingtemperature range. Furthermore, the output resistance of theDAC is trimmed to 100 ± 1.0%. The gain temperaturecoefficientof the voltage output is 30 ppm/ max (K).