MAX6439UTA MAXIM [Maxim Integrated Products], MAX6439UTA Datasheet - Page 8

• Manufacturer Part Number: MAX6439UTA
• Description: Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated uP Reset
• Manufacturer: MAXIM [Maxim Integrated Products]

has stabilized before power-converter or microproces-
sor activity is enabled.
These devices also have an independent µP supervisor
that monitors V
put. A manual reset function is available to allow the
user to reset the µP with a push-button.
The low-battery outputs are available in active-low
(LBO, LBOL, LBOH, LBOLH), open-drain configura-
tions. The low-battery outputs can be pulled to a volt-
age independent of V
allows the device to monitor and operate from direct
battery voltage while interfacing to higher voltage
microprocessors.
The MAX6439/MAX6440 single-output voltage monitors
provide a single low-battery output, LBO. These fixed-
threshold devices assert LBO when V
V
V
MAX6442 triple-output voltage monitors provide three
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
Figure 1a. Functional Diagram
8
BATT
LTH
V
V
BATT
CC
_______________________________________________________________________________________
and remain asserted for at least 150ms after
rises above V
CC
DETECT
DETECT
DETECT
1.23V
HTH
LTH
V
TH
and provides an active-low reset out-
HTH
CC
(see Figure 2). The MAX6441/
LBO TIMEOUT
TIMEOUT
PERIOD
or V
PERIOD
RESET
MR
Low-Battery Output
BATT
MAX6440
R
S
, up to 5.5V. This
BATT
V
CC
Q
Q
drops below
V
CC
LBO
RESET
low-battery outputs: LBOH, LBOL, and LBOLH. LBOH
asserts when V
asserted for at least 150ms after V
V
and remains asserted for at least 150ms after V
rises above V
below V
after V
rising V
plete before the LBOH/LBOLH timeout period begins.
The MAX6439–MAX6442 provide an active-low reset
output (RESET). RESET is asserted when the voltage at
V
asserted for the reset timeout period after V
the threshold. If V
before the reset timeout period is completed, the inter-
nal timer restarts. The MAX6439/MAX6441 have open-
drain reset outputs, while the MAX6440/MAX6442 have
push-pull reset outputs (see Figure 4).
Figure 1b. Functional Diagram
V
CC
HTH+
BATT
V
CC
falls below the reset threshold level. Reset remains
. LBOL asserts when V
BATT
BATT
LTH-
rises above V
input, the LBOL timeout period must com-
and remains asserted for at least 150ms
LTH+
BATT
HYST
HYST
1.23V
5%
5%
. LBOLH asserts when V
CC
drops below V
DETECT
DETECT
DETECT
goes below the reset threshold
HTH
LTH
V
TH
HTH+
BATT
(see Figure 3). For fast-
TIMEOUT
PERIOD
RESET
MR
TIMEOUT
MAX6441
PERIOD
LBO
drops below V
HTH-
BATT
Reset Output
V
CC
and remains
rises above
CC
BATT
exceeds
drops
LBOL
LBOH
LBOLH
RESET
BATT
LTH-