MAXIM MAX3806GTC+T

The MAX3806 is a high-gain linear preamplifier for distance measurement applications using a laser beam. The device operates from a single +5.0V supply and converts current from an AC-coupled photodiode into a single-ended voltage signal. The input accepts single pulses or bursts of pulses with widths down to 30ns. The amplifier remains linear with input amplitudes from 42nAp (SNR = 3) to 40μAp. It can also withstand overload signals as large as 2mAp. The output stage is designed to drive a high-impedance load to deliver the output-voltage swing at the lowest possible power dissipation. The gain of the preamplifier stage is selected using the GAIN pin to be 60kΩ or 30kΩ. There is also an internal 14dB attenuator that is selected using the ATT pin. The output stage can be disabled (high impedance). The device is available in a 3mmx3mm, 12-pin TQFN package and operates over the -40℃ to +105℃ temperature range.

The MAX3806 preamplifier consists of a selectable-gain transimpedance amplifier, a selectable 14dB attenuator, and an output-driver block. The selectable-gain transimpedance amplifier linearly boosts the signal from the photodiode. This block is followed by an attenuator block that allows the user to attenuate the signal by 14dB selected by the ATT pin. The final block is the output driver that can be disabled by asserting the DIS pin.

• +5V Supply Voltage
• Linearity Range Up to 40μAp
• Overload Current Up to 2mAp
• 50mW Power Dissipation at +5.0V
• 1.5pA/√Hz Noise Density at 60kΩ Gain
• 14nARMS Input-Referred Noise at 60kΩ Gain
• Selectable Gains (60kΩ, 30kΩ)
• Selectable 14dB Attenuation

• Laser Sensors for Portable Distance Measurement
• Laser Sensors for Industrial Applications