TIDUDO6B May 2019 – October 2020
The power source for this TIDA-01580 device is the CR3032, a lithium-ion coin cell. Selection of the CR2032 coin-cell battery as the power source was due to the ubiquity of the battery type, particularly in small form factor systems. The voltage characteristics of the CR3032 lithium-ion coin cell battery are also ideal. The output voltage remains relatively flat throughout the discharge life, until the cell is nearly depleted. When the remaining charge in the coin-cell battery is nearly depleted, the output voltage drops off relatively quickly. The temperature characteristics of lithium-ion batteries are also superior to that of alkaline cells, particularly at lower temperatures. This superiority is due to lithium-ion cells having a non-aqueous electrolyte that performs better than the aqueous electrolytes commonly found in alkaline batteries.
Given an appropriate weather-proof enclosure, this TI reference design system is suited for both indoor and outdoor use. Immediately following the battery is a bulk capacitor. This TI reference design uses a coin-cell battery tray that prevents an end-user from inserting the battery backwards, which may eliminate the need for the reverse Schottky diode. The bulk capacitor is sized to prevent too much voltage sag, particularly during the initial transition into the on state (see Figure 2-18).