MAX6458UKD0C+T Maxim Integrated Products, MAX6458UKD0C+T Datasheet - Page 10

• Manufacturer Part Number: MAX6458UKD0C+T
• Description: IC SUPPLY VOLT MONITR SOT23-5
• Manufacturer: Maxim Integrated Products
• Type: Simple Reset/Power-On Resetr

Specifications of MAX6458UKD0C+T

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 50 µs Typical
• Voltage - Threshold: Adjustable/Selectable
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 8 shows the typical application circuit for detecting
an undervoltage event of a 5-cell Li+ battery stack.
Connect OUT of the MAX6457/MAX6458/MAX6460
(OUTA of the MAX6459) to the shutdown input of the DC-
DC converter to cut off power to the load in case of an
undervoltage event. Select R1 and R2 to set the trip volt-
age (see the Programming the Trip Voltage (V
tion). When the voltage of the battery stack decreases so
that V
then OUT (OUTA) goes low and disables the power sup-
ply to the load. When the battery charger restores the volt-
age of the 5-cell stack so that V
goes high and the power supply resumes driving the load.
The MAX6457–MAX6460 are ideal for overvoltage shut-
down applications. Figure 9 shows a typical circuit for
this application using a pass P-channel MOSFET. The
MAX6457–MAX6460 are powered directly from the sys-
tem voltage supply. Select R1 and R2 to set the trip volt-
age (see the Programming the Trip Voltage (V
section). When the supply voltage remains below the
selected threshold, a low logic level on OUT (OUTB for
MAX6459) turns on the p-channel MOSFET. In the case
of an overvoltage event, OUT (OUTB) asserts high, turns
off the MOSFET, and shuts down the power to the load.
Figure 10 shows a similar application using a fuse and
a silicon-controlled rectifier (SCR). An overvoltage
event turns on the SCR and shorts the supply to
ground. The surge of current through the short circuit
blows the fuse and terminates the current to the load.
Select R3 so that the gate of the SCR is properly biased
when OUT (OUTB) goes high impedance.
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Figure 9. Overvoltage Shutdown Circuit (with External Pass
MOSFET)
10
V
SUPPLY
______________________________________________________________________________________
IN
100kΩ
1µF
+ drops below V
R1
R2
Applications Information
IN+
CLEAR
MAX6457–
TH
MAX6460
Overvoltage Shutdown
V
GND
Undervoltage Lockout
- of the MAX6457–MAX6460,
CC
(OUTA FOR
MAX6459)
IN
OUT
+ > V
TH
R
PULLUP
+, OUT (OUTA)
TRIP
LOAD
) sec-
TRIP
)
The MAX6458/MAX6459 include undervoltage and
overvoltage comparators for window detection (Figures
2 and 3). The circuit in Figure 11 shows the typical con-
figuration for this application. For the MAX6458, OUT
asserts high when V
When V
(V
OUT asserts low.
The MAX6459 features two independent open-drain
outputs: OUTA (for undervoltage events) and OUTB (for
overvoltage events). When V
window, OUTA and OUTB assert high. When V
below V
Figure 10. Overvoltage Shutdown Circuit (with SCR Fuse)
Figure 11. Window Detection
TRIPLOW
V
SUPPLY
R1
R2
R3
V
CC
CC
TRIPLOW
FUSE
) or exceeds the upper limit (V
falls below the lower limit of the window
R1
R2
IN+
IN-
IN+
, OUTA asserts low while OUTB
CC
MAX6458
MAX6459
GND
V
CC
MAX6457–
MAX6460
is within the selected “window.”
GND
V
CC
MAX6458
MAX6459
(OUTA FOR
MAX6459)
OUTA
OUTB
ONLY
ONLY
OUT
CC
OUT
Window Detection
R
is within the selected
PULLUP
V
CC
R3
R
PULLUP
OUT
V
CC
SCR
TRIPHIGH
R
PULLUP
LOAD
OUTA
OUTB
CC
falls
),