MAX16134 Datasheet, PDF (19/23 Pages) Maxim Integrated Products – Low-Voltage, Precision, Single/Dual/Triple/Quad-Voltage μP Supervisors

MAX16132–MAX16135
Low-Voltage, Precision, Single/Dual/Triple/
Quad-Voltage μP Supervisors
Applications Information
Unused Inputs
The MAX16132–MAX16135 are capable of monitoring
inputs for undervoltage and overvoltage events within a
very narrow voltage window. Connect any unused IN_
input to its nominal voltage setting.
Setting Input Thresholds
The MAX16132–MAX16135 reset devices that monitor
input within a window-threshold set by the input tolerance
selection. Tolerance setting determines the boundary for
undervoltage and overvoltage thresholds. The selected
nominal input voltage must stay within the window threshold
for the MAX16132–MAX16135 not to issue a reset signal.
See below for threshold calculation for 2.5V nominal input
voltage and ±10% input tolerance:
V_INNOM = 2.5V
TOL = ± 10 %
( ) ( ) ^VUVTH ^{= V}INNOM ^{1 − 10 % = 2.5V 1 − 0.1}
= 2.5V − 0.250V = 2.250V
( ) ( ) ^VOVTH ^{= V}INNOM ^{1 + 10 % = 2.5V 1 + 0.1}
= 2.5V + 0.250V = 2.750V
The MAX16132–MAX16135 feature ±1% threshold
accuracy over temperature. This excursion must be
added to the calculated undervotlage and overvoltage
threshold settings to account for the threshold variation
as shown below:
( ) ^VUVTH_EXC ^{= V}UVTH ^{1 ± 1 %}
( ) ^{= 2.250V 1 ± 0.01 = 2.250V ± 0.0225V}
( ) ^VOVTH_EXC ^{= V}OVTH ^{1 ± 1 %}
( ) ^{= 2.750V 1 ± 0.01 = 2.750V ± 0.0275V}
Where V_{UVTH_EXC} is the undervoltage threshold variation
and V_{OVTH_EXC} is the overvoltage threshold variation.
Undervoltage/Overvoltage-Detection Circuit
The open-drain outputs of the MAX16132–MAX16135
can be configured to detect an undervoltage/overvoltage
condition. Figure 2 shows the MAX1632 reset output
deriving the gate of a PFET low to turn on an LED when
there is an overvoltage/undervoltage event on IN.
Where V_INNOM is the selected nominal input voltage, TOL
is the input tolerance, V_UVTH is undervotlage threshold
voltage and V_OVTH is the overvoltage threshold voltage.
Figure 2. Undervoltage/Overvoltage Detection Circuit with LED
Indicator
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