Datasheet

existing state while system-level testing occurs. Leave
MARGIN unconnected or connect to BP if unused. An
internal 10µA current source pulls MARGIN to BP.
MARGIN overrides MR if both are asserted at the
same time. The state of RESET, OV, and WDO does not
change while MARGIN = GND.
RESET , OV , and WDO Outputs
The MAX6887/MAX6888 feature three active-low open-
drain outputs: RESET, OV, and WDO. After power-up or
overvoltage/undervoltage conditions, RESET and OV
remain in their active states until their timeout periods
expire and no undervoltage/overvoltage conditions are
present (see Figure 2).
OV asserts when any monitored input is above its over-
voltage threshold and remains asserted until all inputs
are below their thresholds and its respective 25µs time-
out period expires. Connect OV to MR to bring RESET
low during an overvoltage condition. OV requires a
pullup resistor (unless connected to MR).
RESET asserts when any monitored input is below its
undervoltage threshold or MR is asserted. RESET
remains asserted for 200ms after all assertion-causing
conditions have been cleared. Configure RESET to
assert when the watchdog timer expires by connecting
WDO to MR. RESET requires a pullup resistor.
WDO asserts when the watchdog timer expires. See
the
Configuring the Watchdog Timer section for a com-
plete description. WDO requires a pullup resistor.
Configuring the Watchdog Timer
A watchdog timer monitors microprocessor (µP) soft-
ware execution for a stalled condition and resets the µP
if it stalls. Connect the watchdog timer output WDO to
the reset input or a nonmaskable interrupt of the µP.
The watchdog timer features independent initial and
normal watchdog timeout periods of 102.4s and 1.6s,
respectively.
MAX6887/MAX6888
Hex/Quad, Power-Supply Supervisory Circuits
_______________________________________________________________________________________ 9
Table 2. MAX6888 Threshold Options
UV THRESHOLDS (V) OV THRESHOLDS (V)
PART
IN1 IN2 IN3 IN4 IN1 IN2 IN3 IN4
MAX6888AETE 4.620 3.060 2.310 1.670 5.360 3.540 2.680 1.930
MAX6888BETE 4.620 3.060 2.310 0.557 5.360 3.540 2.680 0.643
MAX6888CETE 4.620 3.060 1.670 0.557 5.360 3.540 1.930 0.643
MAX6888DETE 3.060 2.310 1.670 1.390 3.540 2.680 1.930 1.610
MAX6888EETE 3.060 2.310 1.670 0.557 3.540 2.680 1.930 0.643
MAX6888FETE 3.060 2.310 1.390 0.557 3.540 2.680 1.610 0.643
MAX6888GETE 3.060 2.310 0.557 0.557 3.540 2.680 0.643 0.643
MAX6888HETE 3.060 1.670 0.557 0.557 3.540 1.930 0.643 0.643
MAX6888QETE 0.557 0.557 0.557 0.557 0.643 0.643 0.643 0.643
MAX6888IETE 4.380 2.880 2.190 1.580 5.620 3.700 2.810 2.020
MAX6888JETE 4.380 2.880 2.190 0.527 5.620 3.700 2.810 0.673
MAX6888KETE 4.380 2.880 1.580 0.527 5.620 3.700 2.020 0.673
MAX6888LETE 2.880 2.190 1.580 1.310 3.700 2.810 2.020 1.680
MAX6888METE 2.880 2.190 1.580 0.527 3.700 2.810 2.020 0.673
MAX6888NETE 2.880 2.190 1.310 0.527 3.700 2.810 1.680 0.673
MAX6888OETE 2.880 2.190 0.527 0.527 3.700 2.810 0.673 0.673
MAX6888PETE 2.880 1.580 0.527 0.527 3.700 2.020 0.673 0.673
MAX6888RETE 0.527 0.527 0.527 0.527 0.673 0.673 0.673 0.673