UM7027A Datasheet, PDF (4/8 Pages) Union Semiconductor, Inc. – Voltage Detector

UM70xxA
Function Description
The UM70xxA series are a set of voltage detectors equipped with a high stability voltage
reference which is connected to the negative input of a comparator-denoted as V_REF in the
following figure for NMOS output voltage detector.
When the voltage drop to the positive input of the comparator (i,e,V_B) is higher than V_REF, V_OUT
goes high, and V_B is expressed as V_BH=V_DD R_B / (R_A+R_B). If V_DD is decreased so that V_B falls to a
value less than V_REF, the comparator output inverts from high to low, V_OUT goes low, V_C is high.
If V_DD falls below the minimum operating voltage, the output becomes undefined.
The figure demonstrates the NMOS output type with positive output polarity (V_OUT is normally
open, active low). The UM70xxA series also supplies options for other output types with active
high outputs.
Application circuits shown are examples of positive output polarity (normally open, active low)
unless otherwise specified
NMOS Output Voltage Detector (UM70xxA)
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http://www.union-ic.com Rev.04 Jul.2012
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