TC826

1 TC826 A/D CONVERTER WITH BAR GRAPH DISPLAY OUTPUT FEATURES s s s s s s s s s s s s s s s s Bipolar A/D Conversion 2.5% Resolution Direct LCD Display Drive ‘Thermometer’ Bar or Dot Display 40 Data Segments Plus Zero Overrange Plus Polarity Indication Precision On–Chip Reference ................ 35ppm/°C Differential Analog Input Low Input Leakage .......................................... 10pA Display Flashes on Overrange Display Hold Mode Auto–Zero Cycle Eliminates Zero Adjust Potentiometer 9V Battery Operation Low Power Consumption ............................ 1.1mW 20mV to 2.0 V Full–Scale Operation Non–Multiplexed LCD Drive for Maximum Viewing Angle 2 3 4 5 6 7 Temperature 0°C to +70°C GENERAL DESCRIPTION In many applications a graphical display is preferred over a digital display. Knowing a process or system operates, for example, within design limits is more valuable than a direct system variable readout. A bar or moving dot display supplies information precisely without requiring further interpretation by the viewer. The TC826 is a complete analog–to–digital converter with direct liquid crystal (LCD) display drive. The 40 LCD data segments plus zero driver give a 2.5% resolution bar display. Full–scale differential input voltage range extends from 20mV to 2V. The TC826 sensitivity is 500µv. A low drift 35 ppm/°C internal reference, LCD backplane oscillator and driver, input polarity LCD driver, and overrange LCD driver make designs simple and low cost. The CMOS desi...