ADA4351-2

• Enables quick measurement of input current from the photodiode using ADA4351-2.
• The included LED allows to measure pA in light setting configuration and fA in dark setting configuration.
• The circuit is enclosed by a black box to reduce the sensitivity to ambient lighting conditions.
• Plug and play in ADALM2000 learning module

The EVAL-KW4101Z is a know-how with integrated knowledge (KWIK) demonstration board designed for evaluating current through a precision integrating transimpedance amplifier (TIA). It can measure femto ampere (fA) level of dark current of a TIA as well as pico ampere (pA) level of signal current with the included light-emitting diode (LED).

The EVAL-KW4101Z is mainly an integrator circuit with a 24pF external film capacitor. Connected to the TIA's noninverting input pin is a voltage divider circuit, with R1 and R2 being 1.27kΩ and 1kΩ, respectively. This thereby sets the common-mode input voltage (CMV) to 2.2V. The main circuit involves a sensitive photodiode and is thus confined within a black box enclosure to reduce the effects of ambient lighting conditions. See Figure 1 for the schematic diagram of the ADA4351-2 configured as an integrator with an external capacitor, resistor divider at the input, and a single supply of 5V.

Please see the User Guide for the full description.