Datasheet

MAX6361–MAX6364
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
_______________________________________________________________________________________ 5
1.234
1.235
1.236
MAX6364
RESET IN THRESHOLD
vs. TEMPERATURE
MAX6361 toc10
TEMPERATURE (°C)
THRESHOLD (V)
-40 20 40-20 0 60 80
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
1.0
1.9
1.6
1.3
2.8
2.5
2.2
MAX6364
RESET IN TO RESET PROPAGATION DELAY
vs. TEMPERATURE
MAX6361 toc11
TEMPERATURE (°C)
PROPAGATION DELAY (µs)
-40 20 40-20 0 60 80
V
OD
= 50mV
Pin Description
Backup-Battery Input. When V
CC
falls below the reset threshold, BATT switches to OUT if V
BATT
is 20mV
greater than V
CC
. When V
CC
rises 20mV above V
BATT
, V
CC
switches to OUT. The 40mV hysteresis
prevents repeated switching if V
CC
falls slowly.
BATT6
Supply Voltage, 0 to 5.5V. Reset is asserted when V
CC
drops below the reset threshold voltage (V
TH
).
Reset remains asserted until V
CC
rises above V
TH
and for at least 150ms after V
CC
rises above V
TH
.
V
CC
4
Output. OUT sources from V
CC
when it is above the reset threshold (V
TH
), and from the greater of V
CC
or
BATT when V
CC
is below V
TH
.
OUT5
GroundGND2
PIN
Active-Low Reset Output. RESET is continuously low when V
CC
is below the reset threshold (V
TH
), MR is
low, or RESET IN is low. It asserts in pulses when the internal watchdog times out. RESET remains low for
the reset timeout period (t
RP
) after V
CC
rises above the reset threshold, after the manual reset input goes
from low to high, after RESET IN goes high, or after the watchdog triggers a reset event. The MAX636_L
is an active-low push-pull output while the MAX636_P is an active-low open-drain output.
RESET
Active-High Reset Output. RESET is continuously high when V
CC
is below the reset threshold (V
TH
), MR is
low, or RESET IN is low. It asserts in pulses when the internal watchdog times out. RESET remains high
for the reset timeout period (t
RP
) after V
CC
rises above the reset threshold, after the manual reset input
goes from low to high, after RESET IN goes high, or after the watchdog triggers a reset event. The
MAX636_H is an active-high open-drain output.
RESET
1
FUNCTIONNAME
0
3
2
1
4
5
6
7
8
9
10
01234
BATTERY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6361 toc09
V
CC
(V)
BATTERY SUPPLY CURRENT (µA)
V
BATT
= 2.8V
V
BATT
= 2.5V
V
TH
= 2.93V
V
BATT
= 2.3V
MAX6361 Manual-Reset Input. Maintaining logic low on MR asserts a reset. Reset output remains assert-
ed for at least 150ms (t
RP
) after MR transitions from low to high. Leave unconnected or connected to V
CC
if not used.
MR
3
MAX6364 Reset Input. When RESET IN falls below 1.235V, reset is asserted. Reset output remains
asserted as long as RESET IN is low and for at least 150ms (t
RP
) after RESET IN goes high.
MAX6363 Battery-On Output. BATT ON goes high in battery backup mode.
MAX6362 Watchdog Input. If WDI remains high or low for longer than the watchdog timeout period (t
WD
), the
internal watchdog timer runs out and a reset pulse is triggered for the reset timeout period (t
RP
) (Figure 1). The
internal watchdog clears whenever reset asserts or whenever WDI sees a rising or falling edge.
RESET IN
BATT ON
WDI