5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface

The MAX1202/MAX1203 are 12-bit data-acquisition systems specifically designed for use in applications with mixed +5V (analog) and +3V (digital) supply voltages. They operate with a single +5V analog supply or dual ±5V analog supplies, and combine an 8-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption.

A 4-wire serial interface connects directly to SPI/MICROWIRE® devices without external logic, and a serial strobe output allows direct connection to TMS320-family digital signal processors. The MAX1202/MAX1203 use either the internal clock or an external serial-interface clock to perform successive approximation analog-to-digital conversions. The serial interface operates at up to 2MHz.

The MAX1202 features an internal 4.096V reference, while the MAX1203 requires an external reference. Both parts have a reference-buffer amplifier that simplifies gain trim. They also have a VL pin that is the power supply for the digital outputs. Output logic levels (3V, 3.3V, or 5V) are determined by the value of the voltage applied to this pin.

These devices provide a hard-wired active-low SHDN pin and two software-selectable power-down modes. Accessing the serial interface automatically powers up the devices. A quick turn-on time enables the MAX1202/MAX1203 to be shut down between conversions, allowing the user to optimize supply currents. By customizing power-down between conversions, supply current can drop below 10µA at reduced sampling rates.

The MAX1202/MAX1203 are available in 20-pin SSOP and PDIP packages, and are specified for the commercial and extended temperature ranges.

Applications

* 5V/3V Mixed-Supply Systems * Battery-Powered Applications * Data Acquisition * High-Accuracy Process Control * Medical Instruments

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

* Operates from Single +5V or Dual ±5V Supplies

* User-Adjustable Output Logic Levels (2.7V to 5.25V)

* Low Power:

* 1.5mA (Operating Mode)

* 2µA (Power-Down Mode)

* Internal Track/Hold, 133kHz Sampling Rate

* Internal 4.096V Reference (MAX1202)

* SPI/MICROWIRE/TMS320-Compatible 4-Wire Serial Interface

* Software-Configurable Unipolar/Bipolar Inputs

* 20-Pin PDIP/SSOP