MAX6443US26L+T Maxim Integrated Products, MAX6443US26L+T Datasheet - Page 7

• Manufacturer Part Number: MAX6443US26L+T
• Description: IC MPU RESET 2.625V SOT143-4
• Manufacturer: Maxim Integrated Products
• Type: Simple Reset/Power-On Resetr

Specifications of MAX6443US26L+T

• Number Of Voltages Monitored: 1
• Output: Push-Pull, Totem Pole
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 2.625V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-143, SOT-143B, TO-253AA
• Monitored Voltage: 1 V to 5.5 V
• Undervoltage Threshold: 2.55 V
• Overvoltage Threshold: 2.7 V
• 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
• Supply Voltage (min): 1 V
• Supply Current (typ): 7 uA
• Maximum Power Dissipation: 320 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MAX6443US26L+T; MAX6443US26L+TTR

To minimize data loss and speed system recovery,
many applications interrupt the processor or reset only
portions of the system before a processor hard reset is
asserted. The extended setup time of the MAX6443–
MAX6452 manual reset inputs allows the same push-
button (connected to both the processor interrupt and
the extended MR1 input, as shown in Figure 6) to con-
trol both the interrupt and hard reset functions. If the
pushbutton is closed for less than t
only interrupted. If the system still does not respond
properly, the pushbutton (or two buttons for the dual
manual reset) can be closed for the full extended setup
period to hard reset the processor. If desired, connect
an LED to the RESET output to blink off (or on) for the
reset timeout period to signify when the pushbutton is
Figure 3. MAX6447/MAX6448/MAX6451/MAX6452 MR2
Assertion DebouncingTiming Diagram
Figure 5. Calculating the Monitored Threshold Voltages
RESET
MR2
V
MON_TH
R1
R2
COUNTER RESET
V
MON_TH
= 0.63 x (R1 + R2) / R2
t < 210ms
µP Reset Circuits with Long Manual Reset
Applications Information
_______________________________________________________________________________________
RSTIN
GND
MAX6449
MAX6451
Interrupt Before Reset
t = 210ms
RESET
V
CC
MR
, the processor is
V
CC
closed long enough for a hard reset (the same LED
might be used as the front-panel power-on display).
The MAX6447/MAX6448/MAX6451/MAX6452 dual manu-
al resets are useful in applications in which both an
extended and immediate setup periods are needed.
Figure 7 illustrates the insertion and removal of a smart
card. MR1 monitors a front-panel pushbutton. When
closed for t
min. Because MR1 is internally pulled to V
50kΩ resistor, the front-panel switch can be connected to
Figure 4. MAX6447/MAX6448/MAX6451/MAX6452 MR2
Deassertion Debouncing Timing Diagram
Figure 6. Interrupt Before Reset Application Circuit
RESET
MR2
+3.3V
V
GND
POSITIVE EDGE
CC
TIMEOUT PERIOD
MR
MAX6443L
210ms
, RESET one-shot pulses low for 140ms
Smart Card Insertion/Removal
RESET
MR1
Setup Period
DEBOUNCING PERIOD
LED
ASSERTED
NO RESET
OUTPUT
210ms
PUSHBUTTON SWITCH:
CLOSE FOR < 4.48s
FOR SYSTEM INTERRUPT;
CLOSE FOR > 6.72s FOR
SYSTEM RESET
RESET
NMI
V
µ
CC
CC
P
through a
7