I'm evaluating the Rohm BD48/BD49 series voltage detector. I'm having trouble understanding the data sheet.
I want to generate a high signal when the input voltage is above a desired threshold (3.0 volts, so the BD4xx30x), and low when it's below that. This chip comes in two varieties, one of which is an "open drain" and the other is "CMOS". The data sheet says:
For both the open drain type ... and the CMOS output type ... When the voltage applied to the VDD pins reaches the appropriate threshold voltage, the VOUT terminal voltage switches from either “High” to “Low” or from “Low” to “High”.
I think that means high-to-low, or low-to-high respectively? I.E. A) the open drain type when input voltage is below the threshold generates a high signal on the output pin (but as mentioned elsewhere, only via an external pullup), which goes low when input voltage exceeds the threshold, while B) the CMOS type generates a low signal when the input voltage is below the threshold, which switches high when the input voltage exceeds the threshold.
So I think that I want the BD49 CMOS series, with its Vout hooked straight to the control pin (active high) of the chip I want to pair it with. Is that right? I'm guessing based mostly on some assumptions of the accompanying figures.