MAX807NCPE Maxim Integrated, MAX807NCPE Datasheet - Page 13

• Manufacturer Part Number: MAX807NCPE
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX807L, MAX807M, MAX807Nr

Specifications of MAX807NCPE

• Number Of Voltages Monitored: 1
• Monitored Voltage: 4.575 V
• Undervoltage Threshold: 4.5 V
• Overvoltage Threshold: 4.65 V
• Output Type: Active High, Active Low
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: Backup
• Power-up Reset Delay (typ): 280 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Package / Case: PDIP N
• Chip Enable Signals: Yes
• Maximum Power Dissipation: 842 mW
• Minimum Operating Temperature: 0 C
• Power Fail Detection: Yes
• Supply Current (typ): 70 uA
• Supply Voltage - Min: 0 V

Table 1. Input and Output Status in Battery-Backup Mode
Figure 12. V
Battery backup preserves the contents of RAM in the
event of a brownout or power failure. With a backup
battery installed at BATT, the MAX807 automatically
switches RAM to backup power when V
conditions are required for switchover to battery-back-
up mode: 1) V
V
inputs and outputs during battery-backup mode.
CC
PIN
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
BATT
V
must be below V
CC
LOW LINE
CC
BATT ON
BATT OK
CE OUT
RESET
RESET
NAME
CE IN
WDO
BATT
CIRCUITRY
GND
CONTROL
PFO
OUT
V
WDI
and BATT-to-OUT Switch
PFI
MR
CC
CC
Full-Featured µP Supervisory Circuit with
must be below the reset threshold; 2)
______________________________________________________________________________________
BATT
The power-fail comparator remains active in battery-backup mode for V
The power-fail comparator remains active in battery-backup mode for V
Battery switchover comparator monitors V
WDI is ignored and goes high impedance
Ground—0V reference for all signals
MR is ignored
Logic low
Logic high; the open-circuit output voltage is equal to V
Logic low
Logic high. The open-circuit output voltage is equal to V
Logic high. The open-circuit output voltage is equal to V
High impedance
Logic high. The open-circuit output voltage is equal to V
Supply current is 1µA maximum for V
Logic high when V
OUT is connected to BATT through two internal PMOS switches in series.
P
Battery-Backup Mode
. Table 1 lists the status of
P
MAX807
P
BATT
CC
exceeds 2.285V. Valid for V
falls. Two
0.1µF
OUT
BATT
CC
≤ 2.8V.
The BATT input is similar to V
switch is much smaller. This input is designed to con-
duct up to 20mA to OUT during battery backup. The
on-resistance of the PMOS switch is approximately
13Ω. Figure 12 shows the two series pass elements
between the BATT input and OUT that facilitate UL
approval. V
tion without causing a reset.
The output supply (OUT) transfers power from V
BATT to the µP, RAM, and other external circuitry. At
the maximum source current of 250mA, V
cally be 260mV below V
a 0.1µF capacitor.
The battery on (BATT ON) output indicates the status of
the internal battery switchover comparator, which con-
trols the internal V
greater than V
effect), BATT ON typically sinks 3.2mA at 0.4V. In bat-
tery-backup mode, this output sources approximately
5mA. Use BATT ON to indicate battery switchover sta-
tus, or to supply gate or base drive for an external pass
transistor for higher current applications (see the
Typical Operating Circuit).
±1.5% Reset Accuracy
for active switchover.
FUNCTION
CC
≥ 4V. Below 4V, BATT OK is forced low.
CC
BATT
CC
BATT
BATT
.
.
.
.
BATT
can exceed V
CC
CC
(ignoring the small hysteresis
and BATT switches. For V
CC
≥ 4V. Below 4V, PFO is forced low.
CC
. Decouple this terminal with
≥ 4V.
CC
Output Supply Voltage
CC
Backup-Battery Input
BATT ON Output
during normal opera-
, except the PMOS
OUT
will typi-
CC
CC
13
or