MAX4843 Datasheet, PDF (1/9 Pages) Maxim Integrated Products – Overvoltage Protection Controllers with Low Standby Current

19-3649; Rev 0; 4/05
Overvoltage Protection Controllers with
Low Standby Current
General Description
The MAX4843–MAX4846 overvoltage protection con-
trollers protect low-voltage systems against high-voltage
faults of up to 28V. When the input voltage exceeds the
overvoltage threshold, these devices turn off a low-cost,
external n-channel FET(s) to prevent damage to the pro-
tected components. An internal charge pump eliminates
the need for external capacitors and drives the FET gate
for a simple, robust solution.
The overvoltage trip level is set to 7.4V (MAX4843),
6.35V (MAX4844), 5.8V (MAX4845), or 4.65V
(MAX4846). When the input voltage drops below the
undervoltage lockout (UVLO) threshold, the devices
enter a low standby current mode (10µA). The
MAX4843/MAX4844/ MAX4845 have a UVLO threshold
of 4.15V, and the MAX4846 has a UVLO threshold of
2.5V. In addition to the single FET configuration, the
devices can be configured with back-to-back external
FETs to prevent currents from being back-driven into the
adapter.
An additional feature includes a ±15kV ESD-protected
input when bypassed with a 1µF capacitor to ground. All
devices are offered in a small (1.5mm x 1.0mm) 6-pin
µDFN package and are specified for operation over the
-40°C to +85°C temperature range.
Applications
Cell Phones
Digital Still Cameras
PDAs and Palmtop Devices
MP3 Players
Features
o Overvoltage Protection Up to 28V
o Preset 7.4V, 6.35V, 5.8V, or 4.65V Overvoltage Trip
Level
o Low (10µA) Undervoltage Lockout Standby
Current
o Drives Low-Cost n MOSFET
o Internal 50ms Startup Delay
o Internal Charge Pump
o Overvoltage Fault FLAG Indicator
o 6-Pin (1.5mm x 1.0mm) µDFN Package
Ordering Information
PART*
PIN-
PACKAGE
UVLO
(V)
OVLO TOP
(V) MARK
MAX4843ELT 6 µDFN
4.15
7.40
BE
MAX4844ELT 6 µDFN
4.15
6.35
BF
MAX4845ELT 6 µDFN
4.15
5.80
BG
MAX4846ELT 6 µDFN
2.50
4.65
BH
*All devices are specified over the -40°C to +85°C temperature
range.
Typical Operating Circuit
Pin Configuration
INPUT
+1.2V TO +28V
N
1
4
IN
GATE
1µF
VIO
MAX4843–
MAX4846
2 _GND
FLAG ³
OUTPUT
TOP VIEW
IN 1
6 N.C.
MAX4843–
GND 2 _MAX4846 5 N.C.
FLAG 3
4 GATE
µDFN
________________________________________________________________ Maxim Integrated Products 1
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