LTC1272

The LTC1272 is a 3ms, 12-bit, successive approximation sampling A/D converter. It has the same pinout as the industry standard AD7572 and offers faster conversion time, on-chip sample-and-hold, and single supply operation. It uses LTBiCMOSTM switched-capacitor technology to combine a high speed 12-bit ADC with a fast, accurate sample-and-hold and a precision reference.

The LTC1272 operates with a single 5V supply but can also accept the 5V/15V supplies required by the AD7572 (Pin 23, the negative supply pin of the AD7572, is not connected on the LTC1272). The LTC1272 has the same 0V to 5V input range as the AD7572 but, to achieve single supply operation, it provides a 2.42V reference output instead of the 5.25V of the AD7572. It plugs in for the AD7572 if the reference capacitor polarity is reversed and a 1ms sampleand- hold acquisition time is allowed between conversions.

The output data can be read as a 12-bit word or as two 8-bit bytes. This allows easy interface to both 8-bit and higher processors. The LTC1272 can be used with a crystal or an external clock and comes in speed grades of 3s and 8s.