General Description
The TC3400 is a low cost, low power analog-to-digital converter based on Microchip’s Sigma-Delta technol ogy. It will perform 16-bit conversions (15-bit plus sign) at up to eight per second. The TC3400 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.
The TC3400’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 TC3400 is available in a 8-Pin PDIP and a 8-Pin SOIC 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
   260µA; Sleep: 0.75µA
• microPort™ Serial Bus Requires only two
   Interface Lines
• Uses Internal or External Reference
• Automatically Enters Sleep Mode when not in use

Applications
• Consumer Electronics, Thermostats, CO
   Monitors, Humidity Meters, Security Sensors
• Embedded Systems, Data Loggers, Portable
   Equipment
• Medical Instruments