MAX6805US41D2-T Maxim Integrated, MAX6805US41D2-T Datasheet - Page 4

• Manufacturer Part Number: MAX6805US41D2-T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6803, MAX6804, MAX6805r

Specifications of MAX6805US41D2-T

• Number Of Voltages Monitored: 1
• Monitored Voltage: 2.85 V to 5 V
• Undervoltage Threshold: 4.026 V
• Overvoltage Threshold: 4.174 V
• Output Type: Active Low, Open Drain
• Manual Reset: Resettable
• Watchdog: No Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 40 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-143
• Chip Enable Signals: No
• Maximum Power Dissipation: 320 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 5 uA
• Supply Voltage - Min: 1 V

4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Many µP-based products require manual reset capabil-
ity, allowing the operator, a test 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 active timeout period after MR returns
high. MR has an internal 20kΩ pullup resistor, so it can
be left unconnected if not used. Connect a normally
open momentary switch from MR to GND to create a
manual reset function; external debounce circuitry is
not required.
Since the RESET output on the MAX6805 is open-drain,
this device interfaces easily with µPs that have bidirec-
tional reset pins, such as the Motorola 68HC11.
Connecting the µP supervisor’s RESET output directly
to the microcontroller’s (µC’s) RESET pin with a single
pullup resistor allows either device to assert reset
(Figure 1).
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these devices
are relatively immune to short-duration, negative-going
V
Characteristics show the Maximum Transient Duration
vs. Reset Comparator Overdrive graph. The graph
4
CC
MAX6803
_______________________________________________________________________________________
transients (glitches). The Typical Operating
—
1
2
3
4
PIN
Negative-Going V
Applications Information
MAX6804
MAX6805
—
1
2
3
4
Bidirectional Reset Pins
Interfacing to µPs with
Manual Reset Input
RESET
RESET
NAME
GND
V
MR
CC
CC
Transients
Ground
Active-Low Reset Output. RESET is asserted while V
threshold, or while MR is asserted. RESET remains asserted for a reset
timeout period (t
deasserted. RESET on the MAX6804 is push/pull. RESET on the MAX6805
is open-drain.
Active-High Reset Output. RESET is asserted high while V
reset threshold or while MR is asserted, and RESET remains asserted for a
reset timeout period (t
is deasserted. RESET on the MAX6803 is push/pull.
Manual Reset Input. A logic low on MR asserts reset. Reset remains
asserted as long as MR is low, and for the reset timeout period (t
MR goes high. Leave unconnected or connect to V
Supply Voltage Input
shows the maximum pulse width that a negative-going
V
signal. As the amplitude of the transient increases, the
maximum allowable pulse width decreases.
When V
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This
does not present a problem in most cases, since most
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
CC
RP
transient may typically have without issuing a reset
) after V
CC
RP
V
CC
MR
) after V
falls below 1V and approaches the minimum
CC
MAX6805
GND
V
rises above the reset threshold or MR is
Ensuring a Valid Reset Output
CC
FUNCTION
CC
RESET
rises above the reset threshold or MR
100kΩ
Pin Description
CC
down to V
CC
RESET
if not used.
is below the reset
MOTOROLA
CC
68HCXX
GND
V
µP
CC
is below the
RP
CC
) after
= 0