Beyond-the-Rails™ Amplifier Provides Bipolar Output from a Single Positive Supply

The MAX44267 precision, low-noise, low-drift dual opera- tional amplifier offers true-zero output that allows the output to cross zero maximizing the dynamic range of an ADC and increasing resolution. In addition, the input com- mon-mode range extends from +13.5V down to -12V. 

The MAX44267 integrates charge-pump circuitry that generates the negative voltage rail in conjunction with external capacitors. This allows the amplifier to operate from a single +4.5V to +15V power supply, but it is as effective as a normal dual-rail ±4.5V to ±15V amplifier. The architecture eliminates the need for a negative power-supply rail, saving system cost and size.

The MAX44267 is unity-gain stable with a gain-bandwidth product of 5MHz. The device features low offset voltage of 50µV (max), drift of 0.4µV/°C (max), and 200nVP-P noise from 0.1Hz to 10Hz. The low offset and noise specifications and wide input common-mode range make the device ideal for sensor transmitters and interfaces. Varying the external charge pump capacitors enables the charge-pump noise to be minimized.

The MAX44267 is part of a family of signal chain ICs including amplifiers, multiplexers and ADCs. These ICs eliminate the need for a negative supply to the multiplexer, amplifier and ADC, saving space and cost. See the Typical Application Circuit and Table 1 for more information.

The MAX44267 is available in a 14-pin TSSOP package and is specified over the -40°C to +125°C operating temperature range.

Key Features

• True Bipolar Output Greater than ±10V from a Single +15V Supply Eliminates Space and Cost of Negative Power Supply
  • True Zero Output from a Single Supply
• High-Accuracy Sensing Over Temperature
• Low Input VOS: 50µV (max)
• Low 0.4µV/°C (max) of Offset Drift
• 9nV/ Low Input Noise at 1kHz Provides Wide ADC Dynamic Range
• 5MHz Gain-Bandwidth Product Provides Wide Frequency Input Range
• Low 2.4mA (max) Quiescent Current Enables Lower Power Dissipation and Cooler Operation
• Integrated EMI Filter Reduces Sensitivity to Motors and Other High-Frequency Noise Generators
• 14-Pin TSSOP Package with External Charge-Pump Capacitors Enables Noise Optimization