MAX1249

19-1072; Rev 2; 5/98 +2.7V to +5.25V, Low-Power, 4-Channel, Serial 10-Bit ADCs in QSOP-16 _______________General Description The MAX1248/MAX1249 10-bit data-acquisition systems combine a 4-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption. They operate from a single +2.7V to +5.25V supply, and their 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 MAX1248/MAX1249 use either the internal clock or an external serial-interface clock to perform successiveapproximation analog-to-digital conversions. The MAX1248 has an internal 2.5V reference, while the MAX1249 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 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 MAX1248/MAX1249, 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 MAX1248/MAX1249 are available in a 16-pin DIP and a very small QSOP that occupies the same boa...