Texas Instruments OPA847

Wideband Ultra-Low Noise Voltage Feedback Operational Amplifier with Shutdown

The OPA847 combines very high gain bandwidth and large signal performance with an ultra-low input noise voltage (0.85nV/Hz\) while using only 18mA supply current. Where power savings is critical, the OPA847 also includes an optional power shutdown pin that, when pulled low, disables the amplifier and decreases the supply current to < 1% of the powered-up value. This optional feature may be left disconnected to ensure normal amplifier operation when no power-down is required. The combination of very low input voltage and current noise, along with a 3.9GHz gain bandwidth product, make the OPA847 an ideal amplifier for wideband transimpedance applications. As a voltage gain stage, the OPA847 is optimized for a flat frequency response at a gain of +20V/V and is stable down to gains as low as +12V/V. New external compensation techniques allow the OPA847 to be used at any inverting gain with excellent frequency response control. Using this technique in a differential Analog-to-Digital Converter (ADC) interface application, shown below, can deliver one of the highest dynamic range interfaces available.