TC815

The TC815 is a 3-1/2 digit integrating analog-to-digital converter with triplex LCD display drive and automaticranging. A display hold function is on-chip. Input voltage/ ohm attenuators ranging from 1 to 1/10,000 areautomatically selected. Five full scale ranges are provided. The CMOS TC815 contains all the logic and analog switches needed to manufacture an autoranging instrument for ohms and voltage measurements. User selected 20mA and 200mA current ranges are available. Full scale range and decimal point LCD annunciators are automatically set in auto-range operation. Auto-range operation is available during ohms (high and low power ohms) and voltage (AC and DC) measurements, eliminating expensive range switches in hand-held DMM designs. The auto-range feature may be bypassed allowing decimal point selection and input attenuator selection control through a single line input. Expensive rotary switches are not required. During Manual mode operation, resolution is extended

The TC815 includes an AC to DC converter for AC measurements. Only external diodes/resistors/ capacitors are required.

A complete LCD annunciator set describes the TC815 meter function and measurement range during ohms, voltage and current operation. AC measurements are indicated as well as auto-range operation. A low battery detection circuit also sets the low battery display annunciator. The triplex LCD display drive levels may be set and temperature compensation applied via the VDISP pin. With HOLD low, the display is not updated. A HOLD mode LCD annunciator is activated. The "low ohms" measurement option allows in-circuit resistance measurements by preventing semiconductor junctions from being forward biased.