MAX6419UK45-T Maxim Integrated, MAX6419UK45-T Datasheet - Page 6

• Manufacturer Part Number: MAX6419UK45-T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6412, MAX6413, MAX6414, MAX6415, MAX6416, MAX6417, MAX6418, MAX6419, MAX6420r

Specifications of MAX6419UK45-T

• Number Of Voltages Monitored: 2
• Monitored Voltage: 1.6 V to 5 V
• Undervoltage Threshold: 4.388 V, Adjustable
• Overvoltage Threshold: 4.613 V, Adjustable
• Output Type: Active High, Push-Pull
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 5.4 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23
• Chip Enable Signals: No
• Maximum Power Dissipation: 571 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 2.7 uA
• Supply Voltage - Min: 1 V

Use the following formula to calculate the externally
monitored voltage (V
where V
and V
R1 and R2 can have very high values to minimize cur-
rent consumption due to low leakage currents. Set R2
to some conveniently high value (1MΩ, for example)
and calculate R1 based on the desired monitored volt-
age, using the following formula:
Many µP-based products require manual reset capabil-
ity, allowing the operator, a technician, or external logic
circuitry to initiate a reset. A logic low on MR asserts
reset. Reset remains asserted while MR is low and for
the reset timeout period after MR returns high.
The MR has an internal 20kΩ pullup resistor so it can
be left open if not used. Connect a normally open
momentary switch from MR to ground to create a man-
ual reset function (external debounce circuitry is not
required for long reset timeout periods).
A manual reset option can easily be implemented with the
MAX6415–MAX6420 by connecting a normally open
momentary switch in parallel with R2 (Figure 2). When the
switch is closed, the voltage on RESET IN goes to zero,
initiating a reset. Similar to the MAX6412/MAX6413/
MAX6414 manual reset, reset remains asserted while the
switch is closed and for the reset timeout period after the
switch is opened.
Low-Power, Single/Dual-Voltage µP Reset Circuits
with Capacitor-Adjustable Reset Timeout Delay
MAX6412–MAX6420
Figure 1. Calculating the Monitored Threshold Voltage (V
6
RST
R1
R2
V
MON_TH
MON_TH
is the reset input threshold (1.26V). Resistors
R1 = R2 x (V
V
MON_TH
SRT
RESET IN
GND
(MAX6412/MAX6413/MAX6414)
is the desired reset threshold voltage
MAX6415
MAX6416
MAX6417
MON_TH
= V
MON_TH
RST
V
):
CC

Manual Reset Input
(R1 + R2)/R2
/V
V
RST
MON_TH
- 1) (Ω)
= 1.26 x (R1 + R2)/R2
MON_TH
)
The MAX6415/MAX6416/MAX6417 contain an adjustable
reset threshold input. These devices can be used to
monitor voltages other than V
shown in the Reset Threshold section. (See Figure 3.)
Figure 2. Adding an External Manual Reset Function to the
MAX6415–MAX6420
Figure 3. Monitoring External Voltages
Monitoring Voltages Other than V
R1
R2
V
MON_TH
R1
R2
(MAX6415/MAX6416/MAX6417)
V
CC
SRT
RESET IN
GND
SRT
RESET IN
GND
MAX6415
MAX6416
MAX6417
MAX6415–
MAX6420
CC
. Calculate V
V
CC
V
CC
V
CC
Maxim Integrated
MON_TH
CC
as