400ksps/300ksps, Single-Supply, Low-Power, 8-Channel, Serial 12-Bit ADCs with Internal Reference

The MAX1280/MAX1281 12-bit ADCs combine an 8-channel analog-input multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption. The MAX1280 operates from a single +4.5V to +5.5V supply; the MAX1281 operates from a single +2.7V to +3.6V supply. Both devices' analog inputs are software configurable for unipolar/bipolar and single-ended/pseudo-differential operation.

The 4-wire serial interface connects directly to SPI™/QSPI™/MICROWIRE™ devices without external logic. A serial strobe output allows direct connection to TMS320-family digital signal processors. The MAX1280/MAX1281 use an external serial-interface clock to perform successive-approximation analog-to-digital conversions. Both parts feature an internal +2.5V reference and a reference-buffer amplifier with a ±1.5% voltage-adjustment range. An external reference with a 1V to VDD1 range may also be used.

The MAX1280/MAX1281 provide a hard-wired active-low SHDN pin and four software-selectable power modes (normal operation, reduced power, fast power-down, and full power-down). These devices can be programmed to automatically shut down at the end of a conversion or to operate with reduced power. When using the power-down modes, accessing the serial interface automatically powers up the devices, and the quick turn-on time allows them to be powered down between all conversions. This technique can cut supply current to under 100µA at reduced sampling rates.

The MAX1280/MAX1281 are available in 20-pin TSSOP packages. These devices are higher-speed versions of the MAX146/MAX147 (for more information, see the respective data sheet).

Applications

* Battery-Powered Applications * Data Acquisition * Medical Instruments * Pen Digitizers * Portable Data Logging * Process Control

* 8-Channel Single-Ended or 4-Channel Pseudo-Differential Inputs

* Internal Multiplexer and Track/Hold

* Single-Supply Operation

* +4.5V to +5.5V (MAX1280)

* +2.7V to +3.6V (MAX1281)

* Internal +2.5V Reference

* 400ksps Sampling Rate (MAX1280)

* Low Power 2.5mA (400ksps)

* 1.3mA (Reduced-Power Mode)

* 0.9mA (Fast Power-Down Mode)

* 2µA (Full Power-Down)

* SPI/QSPI/MICROWIRE/TMS320-Compatible

* 4-Wire Serial Interface

* Software-Configurable Unipolar or Bipolar Inputs

* 20-Pin TSSOP Package