12-BIT PLUS SIGN, SELF-CALIBRATING A/D CONVERTERS FROM NATIONAL FEATURE SERIAL I/O
- Serial I/O (MICROWIRE(tm), SPI, and QSPI Compatible)
- Analog Input Sample/Hold Function
- Power-Down Mode
- Self-Calibrating Architecture
SANTA CLARA, Calif., August 14, 1995 -- Targeting cost-conscious data conversion applications such as pen-input Personal Digital Assistants (PDAs), National Semiconductor has developed a set of three 12-bit plus sign, self-calibrating analog-to- digital (A/D) converters with serial I/O and a configurable input multiplexer. Strengthening National's line of products that shape information, the ADC12130, ADC12132, and ADC12138 all feature self-calibrating architecture that minimizes linearity, zero and full-scale errors. In addition, an on-board sample-and-hold circuit reduces the need for external components, minimizing cost and space. Power consumption for all three ADCs is a low 33mW (max) for a conversion time of 8.8micros (max).
The devices contain a software-programmable multiplexer which simplifies configuration and printed circuit board design. Data word length is also software-programmable. Design is further simplified through the use of a variety of serial interface protocols. These protocols include MICROWIRE(tm), SPI and QSPI.
The ADC12132 has a two-channel multiplexer while the ADC12138 has an eight-channel multiplexer. All differential multiplexer outputs and A/D inputs are available on separate pins. The ADC12130 has a two-channel multiplexer with multiplexer outputs and A/D inputs internally connected.
The analog inputs can be configured to operate in various combinations of single-ended, differential, or pseudo-differential modes. A fully differential unipolar analog input range (0V to +5V) can be accommodated with a single +5V supply. In the differential modes, valid outputs are obtained even when the negative inputs are greater than the positive inputs because of the 12-bit plus sign output data format.
A95002DA
Lit.# 101021-001
