Preamplifier Receives Nanoamp Signals to Minimize Cost in Optical Distance-measurement Systems

(Product News, 2 Dec 2009)

Maxim Integrated Products introduces the MAX3806, a high-sensitivity, high-dynamic-range TIA (transimpedance amplifier) for laser-based distance-measurement applications such as automotive active cruise control, industrial safety curtains, and consumer/construction range finders. This TIA can receive an input signal as low as 42nAp-p and amplify it to the range required by low-cost differential ADCs, while handling overload signals of up to 2mAp-p. A pin-selectable gain setting of 30kilohms or 60kilohms allows the MAX3806 to achieve typical bandwidths of 98MHz and 49MHz, respectively, for a variety of applications using the same device.

An on-chip attenuator can quickly reduce the gain by 14dB to help suppress unwanted signals. These integrated functions eliminate the need for multiple TIAs and analog switching multiplexers, thus saving board space and cost. The device's high dynamic range (42nAp-p to 40microamps p-p) enables designers to use the same front-end receiver circuit for multiple applications.

The MAX3806 operates from a single 5.0V supply, and is specified over the -40 degrees Celsius to +105 degrees Celsius AEC-Q100 Level 2 temperature range. It is available in a lead-free, 12-pin TQFN package.