MAX8212CUA Maxim Integrated, MAX8212CUA Datasheet - Page 5

• Manufacturer Part Number: MAX8212CUA
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX8211, MAX8212r

Specifications of MAX8212CUA

• Number Of Voltages Monitored: 1
• Undervoltage Threshold: 1.11 V
• Overvoltage Threshold: 1.19 V
• Output Type: Active Low, Open Drain
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: Backup
• Supply Voltage - Max: 16.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Package / Case: uSOP
• Chip Enable Signals: No
• Minimum Operating Temperature: 0 C
• Power Fail Detection: Yes
• Supply Current (typ): 15 uA
• Supply Voltage - Min: 2 V

Calculate resistor values for Figure 3 as follows:
Figure 5 shows an alternate circuit, suitable only when the
voltage being detected is also the power-supply voltage
for the MAX8211 or MAX8212.
Figure 4. MAX8211/MAX8212 Threshold Trip Voltage vs.
Ambient Temperature
1) Choose a value for R1. Typical values are in
2) Calculate R2 for the desired upper trip point
3) Calculate R3 for the desired amount of
R2 = R1
R3
R3
the 10kΩ to 10MΩ range.
V
hysteresis, where V
or, if V+ = V
=
=
U
using the formula:
R2
R2
1.250
1.230
1.210
1.190
1.170
1.150
1.130
1.110
1.090
1.070
1.050
×
×
×
-55
(V U
(V
(V L
(V U
________________________________________________________________________________________
(V U
+ −
IN
V TH
−
−
V+ = 16.5V
:
−
V+ = 2V
V TH )
V TH )
−
V L )
-25
V L )
V TH )
with Programmable Voltage Detection
L
=
is the lower trip point:
=
T
A
=
R1
R2
25
(°C)
R2
×
×
×
Microprocessor Voltage Monitors
(V U 1.15V)
(V L 1.15V)
(V U
75
(V +
1.15V
−
−
(V U
−
V L )
−
−
125
1.15V)
V L )
Calculate resistor values for Figure 5 as follows:
The circuit of Figure 5 will detect when a 5.0V (nominal)
supply goes below 4.5V, which is the V
specified in logic systems. The selected resistor values
ensure that false undervoltage alarms will not be gener-
ated, even with worst-case threshold trip values and
resistor tolerances. R3 provides approximately 75mV of
hysteresis.
Figure 5. MAX8211 Logic-Supply Low-Voltage Detector
1) Choose a value for R1. Typical values are in
2) Calculate R2:
3) Calculate R3:
Low-Voltage Detector for Logic Supply
the 10kΩ to 10MΩ range.
48.7kΩ
R2
R3
2.2MΩ
750kΩ
1%
1%
R3
R2
1%
R1
=
=
R1
R1
×
×
(V L
(V U
HYST
THRESH
1.15V
V TH
−
−
V TH )
V L )
MAX8211
V
V+
IN
=
R1
GND
OUT
×
(V L 1.15V)
V
(LOW FOR
V
1.15V
MIN
OUT
IN
−
< 4.5V)
normally
5