DESCRIPTION
The LTC®1400 is a complete 400ksps, 12-bit A/D converter which draws only 75mW from 5V or ±5V supplies. This easy-to-use device comes complete with a 200ns sample-and-hold and a precision reference. Unipolar and bipolar conversion modes add to the flexibility of the ADC. The LTC1400 has two power saving modes: Nap and Sleep. In Nap mode, it consumes only 6mW of power and can wake up and convert immediately. In the Sleep mode, it consumes 30μW of power typically. Upon power-up from Sleep mode, a reference ready (REFRDY) signal is available in the serial data word to indicate that the reference has settled and the chip is ready to convert.
The LTC1400 converts 0V to 4.096V unipolar inputs from a single 5V supply and ±2.048V bipolar inputs from ±5V supplies. Maximum DC specs include ±1LSB INL, ±1LSB DNL and 45ppm/°C drift over temperature. Guaranteed AC performance includes 70dB S/(N + D) and –76dB THD at an input frequency of 100kHz, over temperature.
The 3-wire serial port allows compact and efficient data transfer to a wide range of microprocessors, microcontrollers and DSPs.

FEATURES
■ Complete 12-Bit ADC in SO-8
■ Single Supply 5V or ±5V Operation
■ Sample Rate: 400ksps
■ Power Dissipation: 75mW (Typ)
■ 72dB S/(N + D) and –80dB THD at Nyquist
■ No Missing Codes over Temperature
■ Nap Mode with Instant Wake-Up: 6mW
■ Sleep Mode: 30μW
■ High Impedance Analog Input
■ Input Range (1mV/LSB): 0V to 4.096V or ±2.048V
■ Internal Reference Can Be Overdriven Externally
■ 3-Wire Interface to DSPs and Processors (SPI and MICROWIRETM Compatible)

APPLICATIONS
■ High Speed Data Acquisition
■ Digital Signal Processing
■ Multiplexed Data Acquisition Systems
■ Audio and Telecom Processing
■ Digital Radio
■ Spectrum Analysis
■ Low Power and Battery-Operated Systems
■ Handheld or Portable Instruments