MAX16040PLA31+T Maxim Integrated Products, MAX16040PLA31+T Datasheet - Page 11

• Manufacturer Part Number: MAX16040PLA31+T
• Description: IC BATTERY BACKUP 3.08V 8-UDFN
• Manufacturer: Maxim Integrated Products
• Type: Battery Backup Circuitr

Specifications of MAX16040PLA31+T

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 3.08V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-µDFN
• Undervoltage Threshold: 3 V
• Overvoltage Threshold: 3.15 V
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 0 V
• Supply Current (typ): 22 uA
• Maximum Power Dissipation: 380.6 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

BATTON is a push-pull output that asserts high when in
battery-backup mode. BATTON typically sinks 3.2mA
at a 0.4V saturation voltage. In battery-backup mode,
this terminal sources approximately 10µA from OUT.
Use BATTON to indicate battery-switchover status or to
supply base drive to an external pass transistor for
higher current applications (see Figure 3).
An internal 1.235V reference sets the RESETIN thresh-
old voltage. RESET asserts when the voltage at
RESETIN is below 1.235V. Use the RESETIN function to
monitor a secondary power supply.
Use the following equations to set the reset threshold
voltage (V
Figure 4):
where V
choose a value for R2 and calculate R1.
Since the input current at RESETIN is 25nA (max), large
values (up to 1MΩ) can be used for R2 with no signifi-
cant loss in accuracy.
Figure 3. MAX16035/MAX16039 BATTON Driving an External Pass Transistor
REF
( ) FOR MAX16035 ONLY
RTH
= 1.235V. To simplify the resistor selection,
R1 = R2 [(V
V
) of the secondary power supply (see
RTH
______________________________________________________________________________________
(MAX16035/MAX16039 Only)
(MAX16036/MAX16040 Only)
= V
REF
RTH
RESETIN Comparator
(R1 / R2 + 1)
/ V
2.4V TO 5.5V
BATTON Indicator
GND
BATT
REF
V
CC
Circuits in Small µDFN Packages
) - 1]
MAX16035
MAX16039
BATTON
(CEOUT)
(CEIN)
RESET
OUT
Low-Power Battery Backup
The MAX16033–MAX16040 issue an interrupt (nonmask-
able or regular) to the µP when a power failure occurs.
The power line is monitored by two external resistors con-
nected to the power-fail input (PFI). When the voltage at
PFI falls below 1.235V, the power-fail output (PFO) drives
the processor’s NMI input low. An earlier power-fail warn-
ing can be generated if the unregulated DC input of the
regulator is available for monitoring. The MAX16033–
MAX16040 turn off the power-fail comparator and force
PFO low when V
age (see Figure 1). The MAX160_ _L devices provide
push-pull PFO outputs. The MAX160_ _P devices provide
open-drain PFO outputs.
Figure 4. Setting RESETIN Voltage for the
MAX16036/MAX16040
ADDRESS
DECODE
0.1µF
CE
R1
R2
CMOS RAM
V
IN
CC
falls below the reset threshold volt-
A0–A15
RESET
µP
Power-Fail Comparator
RESETIN
MAX16036
MAX16040
V
CC
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