SAR A/D converter for rapid sampling

The LTC2320-16 from Linear Technology is a 16-bit 1.5Msample/s per channel, no latency successive approximation register (SAR) A/D converter with eight simultaneously sampling channels supporting a rail-to-rail input common mode range. According to the company, the LTC2320-16 samples three times faster and offers the lowest power dissipation of any octal SAR A/D converter on the market.

The LTC2320-16 features a flexible analogue front end that accepts fully differential, unipolar or bipolar analogue input signals, as well as arbitrary input signals. The device maintains an 82dB signal-to-noise ratio and high common mode rejection ratio of 102dB up to the Nyquist frequency. The wide input bandwidth is said to allow the digitisation of input signals up to the Nyquist frequency of 750kHz.

The converter integrates a precision bandgap reference with low drift and guaranteed 20ppm/°C maximum temperature coefficient into a small 55mm² QFN-52 package, saving space. The internal reference can be overdriven by up to four separate external references for each pair of two channels, to best suit the input range of the application.

The LTC2320-16 leads a family of 16-, 14- and 12-bit SAR A/D converters with single, dual, quad and octal options sampling at up to 5Msample/s/channel. The family accepts 8.192VP-P to 10VP-P true differential inputs that requires no configuration for input signal type.

The family offers 3.3V or 5V supply options and CMOS or LVDS high speed SPI-compatible serial interface options, suitable for a range of high speed and space-constrained applications, including industrial, medical devices, communications systems and battery-operated systems.

Additional features:

•±2LSB INL

•82dB SNR at fIN = 500kHz

•–90dB THD at fIN = 500kHz

•Temperatures ranging from –40 to 125°C

•2.048V or 4.096V internal reference

•1.8V to 2.5V I/O voltages

•Power dissipation 20mW/channel

Author
Peggy Lee