The MAX1246/MAX1247 12-bit data-acquisition systems combine a 4-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption. The MAX1246 operates from a single +2.7V to +3.6V supply; the MAX1247 operates from a single +2.7V to +5.25V supply. Both devices' analog inputs are software configurable for unipolar/bipolar and single-ended/differential operation.
The 4-wire serial interface connects directly to SPI™/QSPI™ and MICROWIRE™ devices without external logic. A serial strobe output allows direct connection to TMS320-family digital signal processors. The MAX1246/MAX1247 use either the internal clock or an external serial-interface clock to perform successive-approximation analog-to-digital conversions.
The MAX1246 has an internal 2.5V reference, while the MAX1247 requires an external reference. Both parts have a reference-buffer amplifier with a ±1.5% voltage-adjustment range.
These devices provide a hard-wired SHDN-bar pin and a software-selectable power-down, and can be programmed to automatically shut down at the end of a conversion. Accessing the serial interface automatically powers up the MAX1246/MAX1247, and the quick turn-on time allows them to be shut down between all conversions. This technique can cut supply current to under 60µA at reduced sampling rates.
The MAX1246/MAX1247 are available in a 16-pin DIP and a small QSOP that occupies the same board area as an 8-pin SO.
For 8-channel versions of these devices, see the MAX146/MAX147 data sheet.
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