+2.7V, Low-Power, 8-Channel, Serial 12-Bit ADCs

 

Part Number	Replacement	Explanation

Description

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The MAX146/MAX147 12-bit data-acquisition systems combine an 8-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption. The MAX146 operates from a single +2.7V to +3.6V supply; the MAX147 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 MAX146/MAX147 use either the internal clock or an external serial-interface clock to perform successive-approximation analog-to-digital conversions.

The MAX146 has an internal 2.5V reference, while the MAX147 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 MAX146/MAX147, 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 MAX146/MAX147 are available in 20-pin DIP and SSOP packages.

For 4-channel versions of these devices, see the MAX1246/MAX1247 data sheet.

MAX146, MAX147: Typical Operating Circuit Enlarge+

Key Features

• 8-Channel Single-Ended or 4-Channel Differential Inputs
• Single-Supply Operation
  • +2.7V to +3.6V (MAX146)
  • +2.7V to +5.25V (MAX147)
• Internal 2.5V Reference (MAX146)
• Low Power
  • 1.2mA (133ksps, 3V supply)
  • 54µA (1ksps, 3V supply)
  • 1µA (power-down mode)
• SPI/QSPI/MICROWIRE/TMS320-Compatible 4-Wire Serial Interface
• Software-Configurable Unipolar or Bipolar Inputs
• 20-Pin DIP/SSOP Packages

Applications/Uses

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