MAX6453UT29S-T Maxim Integrated, MAX6453UT29S-T Datasheet - Page 6

• Manufacturer Part Number: MAX6453UT29S-T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6453, MAX6454, MAX6455, MAX6456r

Specifications of MAX6453UT29S-T

• Number Of Voltages Monitored: 1
• Monitored Voltage: 1.8 V to 5 V
• Undervoltage Threshold: Adjustable
• Overvoltage Threshold: Adjustable
• Output Type: Active Low, Push-Pull
• Manual Reset: Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 280 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23
• Chip Enable Signals: No
• Maximum Power Dissipation: 696 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 7 uA
• Supply Voltage - Min: 1 V

µP Supervisors with Separate V
Manual Reset Outputs
Figure 1. MAX6453/MAX6454 Timing Diagram
The reset output is typically connected to the reset
input of a microprocessor (µP). A µP’s reset input starts
or restarts the µP in a known state. The MAX6453–
MAX6456 µP supervisory circuits provide the reset
logic to prevent code-execution errors during power-
up, power-down and brownout conditions (see the
Typical Operating Circuit).
RESET changes from high to low whenever the moni-
tored voltage (RSTIN or V
threshold voltages. When V
respective reset threshold voltages, RESET remains low
for the reset timeout period, and then goes high. RESET
changes from high to low after MR input is held low for
the extended (typ) setup timeout period and deasserts
140ms (min) after MR deasserts.
RESET is guaranteed to be in the proper output logic
state for V
reset logic when V
Valid RESET Output Down to V
Figure 2. MAX6455/MAX6456 Timing Diagram
6
MROUT
MR
_______________________________________________________________________________________
CC
inputs ≥ 1V. For applications requiring valid
MROUT
RESET
CC
MR
is less than 1V, see the Ensuring a
Detailed Description
RSTIN
CC
210ms
CC
) drops below the reset
= 0V section.
and V
Reset Output
CC
exceed their
LONG SETUP PERIOD
The MAX6453/MAX6454 contain a manual reset output
(MROUT) that asserts low immediately after driving MR
low and remains low for the reset timeout period after
MR goes high (Figure 1). The pushbutton manual reset
has no effect on the RESET output. MROUT output can
be used to drive an NMI (nonmaskable interrupt) on the
processor to save valuable data.
The MAX6455/MAX6456’s MROUT is asserted immedi-
ately upon driving MR low. Driving MR low for longer
than the extended (typ) setup timeout period asserts
RESET. When MR is deasserted, MROUT and RESET
remain asserted low for the reset timeout period after
MR goes high (Figure 2).
The MAX6453–MAX6456 monitor the voltage on RSTIN
using an adjustable reset threshold set with an external
resistor voltage divider (Figure 3). Use the following for-
mula to calculate the externally monitored voltage
(V
where V
and V
Resistors R1 and R2 can have very high values to mini-
mize current consumption due to low leakage currents.
Set R2 to some conveniently high value (250kΩ, for
example) and calculate R1 based on the desired reset
threshold voltage, using the following formula:
MON-TH
TH-RSTIN
MON_TH
V
):
MON-TH
R1 = R2
Adjustable Input Voltage (RSTIN)
CC
is the reset input threshold (0.63V).
is the desired reset threshold voltage
= V
✕
TH-RSTIN
(V
210ms
Reset and
MON_TH
✕
/V
(R1 +R2)/R2
TH
- 1)Ω
Manual Reset