Microchip Technology

The TC7126A is a 3½ digit CMOS analog-to-digital converter (ADC) containing all the active components necessary to construct a 0.05% resolution measurement system. Seven-segment decoders, digit and polarity drivers, voltage reference, and clock circuit are integrated on-chip. The TC7126A directly drives a liquid crystal display (LCD), and includes a backplane driver. A low-cost, high-resolution indicating meter requires only a display, four resistors, and four capacitors. The TC7126A's extremely low power drain and 9V battery operation make it ideal for portable applications. The TC7126A reduces linearity error to less than 1 count. Roll-over error (the difference in readings for equal magnitude but opposite polarity input signals) is below ±1 count. High-impedance differential inputs offer 1 pA leakage current and a 1012 ohm input impedance. The 15 µVp-p noise performance guarantees a great reading, and the auto-zero cycle guarantees a zero display reading with a 0V input. The TC7126A features a precision, low-drift internal voltage reference and is functionally identical to the TC7126. A low-drift external reference is not normally required with the TC7126A.

The TC7129 is a 4-1/2 digit analog-to-digital converter (ADC) that directly drives a multiplexed liquid crystal display (LCD).Fabricated in high-performance, low-power CMOS, the TC7129 ADC is designed specifically for high-resolution, battery-powered digital multimeter applications. The traditional dual-slope method of A/D conversion has been enhanced with a successive integration technique to produce readings accurate to better than 0.005% of full scale, and resolution down to 10µV per count. The TC7129 includes features important to multimeter applications. It detects and indicates low-battery condition. A continuity output drives an annunciator on the display, and can be used with an external driver to sound an audible alarm. Overrange and underrange outputs and a range-change input provide the ability to create auto-ranging instruments. For snapshot readings, the TC7129 includes a latch-and-hold input to freeze the present reading. This combination of features makes the TC7129 the ideal choice for full-featured multimeter and digital measurement applications.

TC72 is a digital temperature sensor capable of reading temperatures from -55°C to +125°C. The sensor features a simple, SPI compatible serial interface that allows communication with a host controller or other peripherals. The TC72 does not require any additional external components. Temperature data is measured from an integrated temperature sensor and converted to a 10 bit digital word with a Sigma Delta Analog to Digital Converter. The temperature resolution is 0.25°C per bit. The TC72 can be used either in a continuous temperature conversion mode or a one-shot conversion mode. The continuous conversion mode measures the temperature approximately every 150 msec and stores the data in the temperature registers. In contrast, the one-shot mode performs a single temperature measurement and returns to the power saving shut down mode. The TC72 features high temperature accuracy, ease-of-use and is therefore the ideal solution for implementing thermal management in a variety of systems. The device also features a shutdown mode for low power operation.

TC74 is a serially accessible digital temperature sensor particularly suited for low cost and small form-factor applications. Temperature data is converted from the on-board thermal sensing element and made available as an 8-bit digital word. Communication with the TC74 is accomplished via a simple 2-wire SMBus/I2C™-compatible serial port. This bus also can be used to implement multi-drop/multi-zone monitoring. The SHDN bit in the CONFIG register can be used to activate the low-power Standby mode. Temperature resolution is 1°C. Conversion rate is a nominal 8 samples/sec. Power consumption in only 200 µA (5 µA Standby). Small size, low installed cost and ease of use make the TC74 an ideal choice for implementing thermal management in a variety of systems.

TC7650 CMOS chopper-stabilized operational amplifier practically removes offset voltage error terms from system error calculations. 5uV maximum VOS specification, for example, represents a 15 times improvement over the industry-standard OP07E. 50 nV/°C off-set drift specification is over 25 times lower than the OP07E. Increased performance eliminates VOS trim procedures, periodic potentiometer adjustment and the reliability problems caused by damaged trimmers. The TC7650 performance advantages are achieved without the additional manufacturing complexity and cost incurred with laser or "zener zap" VOS trim techniques. The TC7650 nulling scheme corrects both DC VOS errors and VOS drift errors with temperature. A nulling amplifier alternately corrects its own VOS errors and the main amplifier VOS error. Offset nulling voltages are stored on two user-supplied external capacitors. The capacitors connect to the internal amplifier VOS null points. The main amplifier input signal is never switched. Switching spikes are not present at the TC7650 output. The 14-pin dual-in-line package (DIP) has an external oscillator input to drive the nulling circuitry for optimum noise performance. Both the 8 and 14-pin DIPs have an output voltage clamp circuit to minimize overload recovery time.

TC7652 is a lower noise version of the TC7650, sacrificing some input specifications (bias current and bandwidth) to achieve a 10x reduction in noise. All the other benefits of the chopper technique are present, i.e., freedom from offset adjust, drift and reliability problems from external trim components. Like the TC7650, the TC7652 requires only two non-critical external caps for storing the chopped null potentials. There are no significant chopping spikes, internal effects or overrange lockup problems.

The TC7660S is a pin-compatible upgrade to the Industry standard TC7660 charge pump voltage converter. It converts a +1.5V to +12V input to a corresponding -1.5V to -12V output using only two low-cost capacitors, eliminating inductors and their associated cost, size and EMI. Added features include an extended supply range to 12V, and a frequency boost pin for higher operating frequency, allowing the use of smaller external capacitors. The on-board oscillator operates at a nominal frequency of 10kHz. Frequency is increased to 45kHz when pin 1 is connected to V+. Operation below 10kHz (for lower supply current applications) is possible by connecting an external capacitor from OSC to ground (with pin 1 open). The TC7660S is available in both 8-pin DIP and 8-pin small outline (SOIC) packages in commercial and extended temperature ranges.

The TC7662A is a pin-compatible upgrade to the Industry standard TC7660 charge pump voltage converter. It converts a +3V to +18V input to a corresponding –3V to –18V output using only two low-cost capacitors, eliminating inductors and their associated cost, size and EMI. In addition to a wider power supply input range (3V to 18V versus 1.5V to 10V for the TC7660), the TC7662A can source output currents as high as 40mA. The on-board oscillator operates at a nominal frequency of 12kHz. Operation be-low 10kHz (for lower supply current applications) is also possible by connecting an external capacitor from OSC to ground. The TC7662A directly is recommended for designs requiring greater output current and/or lower input/output voltage drop. It is available in 8-pin PDIP, and CerDIP packages in commercial and extended temperature ranges.