General Description
The TC3401 is a low cost, low power analog-to-digital converter based on Microchip’s Sigma-Delta technology. It will perform 16-bit conversions (15-bit plus sign) at up to eight per second. The TC3401 is optimized for use as a microcontroller peripheral in low cost, battery operated systems. A voltage reference is included, or an external reference can be used. A VDD monitor with a reset generator provides Power-on Reset and Brown out protection while an extra threshold detector is suitable for use as an early warning Power Fail detector, or as a Wake-up Timer.
The TC3401’s 2-wire microPort™ digital interface is used for starting conversions and for reading out the data. Driving the SCLK line low starts a conversion. After the conversion starts, each additional falling edge (up to six) detected on SCLK for t4 seconds reduces the A/D resolution by one bit and cuts conversion time in half. After a conversion is completed, clocking the SCLK line puts the MSB through LSB of the resulting data word onto the SDAT line, much like a shift register. The part automatically sleeps when not performing a data conversion.
The TC3401 is available in a 16-Pin PDIP and a 16-Pin QSOP package.

Features
• 16-bit Resolution at Eight Conversions Per
   Second, Adjustable Down to 10-bit Resolution at
   512 Conversions Per Second
• 1.8V – 5.5V Operation, Low Power Operating
   300µA; Sleep: 50µA
• microPort™ Serial Bus Requires only two
   Interface Lines
• Uses Internal or External Reference
• Automatically Enters Sleep Mode when not in use
• True Differential Inputs with Built-In Multiplexer
   Provide Ratiometric Conversions
• Early Warning Power Fail Detector, also suitable as
   Wake-Up Timer Operational in Shutdown Mode
• VDD Monitor and Reset Generator Operational in
   Shutdown Mode
  
Applications
• Consumer Electronics, Thermostats, CO
   Monitors, Humidity Meters, Security Sensors
• Embedded Systems, Data Loggers,
   Portable Equipment
• Medical Instruments