NATIONAL SEMICONDUCTOR INTRODUCES THE FIRST ON-CHIP 16-BIT SINGLE-SLOPE ANALOG TO DIGITAL CONVERTER ON A MICROCONTROLLER

Applications Formerly Requiring Multi-Chip Solutions Now Can Be Implemented With A Single Microcontroller

May 12, 1997 -- National Semiconductor Corporation® today announced the COP8ACC, a family of low-cost microcontrollers that offer up to 16-bit ADC performance with an integrated analog function block dedicated for high resolution, single-slope Analog-to-Digital conversion. As a complete system on a chip, the COP8ACC saves designers printed-circuit-board (PCB) space, manufacturing and passive component costs, while increasing reliability and reducing costs for applications such as battery chargers, data acquisition systems, personal electronics and medical equipment.

"Merging data-acquisition with this level of resolution, flexibility and integration on a microcontroller is unprecedented in the industry," said Bob Martin, senior applications engineer at National Semiconductor. "The COP8ACC will allow engineers to design high performance data acquisitions systems while maintaining the low price, small real-estate, and minimal power requirements demanded by embedded applications."

The resolution of the ADC block is programmable through an external capacitor, offering the designer the flexibility of choosing the optimal balance between conversion time and resolution. Nominal performance is achieved at a resolution of 12 bits, which offers +/-2 LSB accuracy at a conversion rate of 410 ms at 10 MHz clock frequency. The analog function block also integrates the 6 channel MUX and the on-chip voltage reference specified at 2.5V ± 3.2% @ Vcc = 5.0V.

Typical characteristics of the analog function block at 10 Mhz, T= 25(long-f)C:

Resolution              Conversion Time         Accuracy
12 bits                 410µs                           +-2.0 LSB
10 bits                 100µs                           +-1.5 LSB
8 bits                  26µs                            +-1.0 LSB

Today's market standard for a microcontroller with integrated ADCis 8-bit successive approximation. The unique combination of analog functions on the COP8ACC allows for higher resolution analog-to-digital conversion of up to 16 bits and up to 6 input channels at a much lower cost," said Ralph Detert, senior technical marketing engineer at National Semiconductor. "The capture timer associated with the analog function block is clocked directly from the external clock frequency as opposed to the instruction cycle clock. This allows for faster conversion times."

The COP8ACC also provides excellent EMI performance by achieving up to 20dB reduction ("Quiet Design") in EMI transmissions in comparison to designs which do not incorporate this circuitry. National's patented EMI reduction technology offers low EMI circuitry, gradual turn-on drivers (GTOs) and internal Icc smoothing filters, to help circumvent many of the EMI issues influencing embedded control designs.

For applications requiring higher-resolution A/D conversion without the need for very high speed, the COP8ACC's on-chip ADC is ideal.

These applications, which formerly required an external ADC, include battery chargers, personal electronics, appliances, portable medical equipment, portable test equipment, data acquisition systems, security and energy management.

The COP8ACC comes with 4k bytes of ROM and 128 bytes RAM. A16-bit timer associated with two auto reload/capture registers and two dedicated pins can be configured for true PWM, external event counting or time/frequency measurements. Up to four pins have high current sink capabilities allowing to directly drive regular LEDs with a minimum of 15mA. For applications demanding high safety standards, the device offers a Watchdog/clock monitor block, software trap interrupt, high ESD immunity and reduced EMI emissions. In addition, the COP8ACC features Multi-Input Wake-Up and "MicroWire Plus" serial interface. The part is packaged in a 20-pin and 28-pin small outline (so) package as well as a 28-pin dual-in-line package. The COP8ACC is also available in a one-time programmable (OTP) package, allowing systems designers the ability to get applications to market quickly at a fraction of the cost.

The COP8ACC family also provides the first time designer an easy introduction to developing with microcontrollers. User friendly development tools range from a free software simulator, a low cost Evaluation and Programming Unit ($99.00), a mid-ranged Debug Module ($699), or a full featured iceMASTER 400 ($2990) for in-circuit emulation. Software development tools have been enhanced to take advantage of the new features that can be found on this device including the C Compiler ($795) and the free COP8 Assembler/Linker/Librarian. The combination of this wide variety of tools allows the designer to pick and choose the right tool, at the price they can afford.

Price and Availability
The COP8ACC family is available in both masked ROM and One time programmable solutions. Packaging options include a 20 & 28-SO and a 28-DIP. In thousand piece quantities, prices start at $2.05. For more information on the COP8ACC, visit our website at http://www.national.com/pf/CO/COP8ACC5.html

National Semiconductor Corporation, a Fortune 500 company, produces system on a chip silicon solutions for the information highway, based on its leadership in analog and mixed signal technologies. National is headquartered in Santa Clara, California, and focuses on the communications, personal systems and consumer markets. In March 1997 National sold its Fairchild Semiconductor businesses and now has 12,300 employees worldwide with annual sales of approximately $2.0 billion.