
General Description
The MAX4838–MAX4841 are overvoltage protection ICs
that protect low-voltage systems against voltages of up
to 28V. If the input voltage exceeds the overvoltage trip
level, the MAX4838–MAX4841 turn off the low-cost
external N-channel FET(s) to prevent damage to the
protected components. An internal charge pump elimi-
nates the need for external capacitors and drives the
FET gate for a simple, robust solution.
The MAX4838/MAX4839 have a 7.4V overvoltage
threshold, and the MAX4840/MAX4841 have a 5.8V
overvoltage threshold. All devices have an undervolt-
age lockout threshold of 3.25V. 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.
On power-up, the device waits for 50ms before driving
GATE high.
FLAG
is held low for an additional 50ms
after GATE goes high before deasserting. The
MAX4838/MAX4840 have an open-drain
FLAG
output,
and the MAX4839/MAX4841 have a push-pull
FLAG
output. The
FLAG
output asserts immediately to an
overvoltage fault.
Additional features include a 15kV ESD-protected input
(when bypassed with a 1μF capacitor) and a shutdown
pin (
EN
) to turn off the device (MAX4838/MAX4840).
All devices are offered in a small 6-pin SC70 package
and are specified for operation from -40°C to +85°C.
Applications
Cell Phones
Digital Still Cameras
PDAs and Palmtop Devices
MP3 Players
Features
o
Overvoltage Protection Up to 28V
o
Preset 7.4V or 5.8V Overvoltage Trip Level
o
Drive Low-Cost NMOS FET
o
Internal 50ms Startup Delay
o
Internal Charge Pump
o
Undervoltage Lockout
o
15kV ESD-Protected Input
o
Voltage Fault
FLAG
Indicator
o
6-Pin SC70 Package
M
Overvoltage Protection Controllers with
Status FLAG
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX4838–
MAX4841
INPUT
+1.2V TO +28V
IN
EN
GATE
FLAG
GND
1
6
4
2
3
OUTPUT
V
IO
1
μ
F
NOTE: EN AND PULLUP
RESISTOR ON MAX4838/
MAX4840 ONLY.
NMOS
Typical Operating Circuit
Ordering Information
19-3044; Rev 0; 10/03
Pin Configuration appears at end of data sheet.
PART
TEMP RANGE
PIN-
PACKAGE
TOP
MARK
MAX4838
EXT-T
MAX4839
EXT-T
MAX4840
EXT-T
MAX4841
EXT-T
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
6 SC70-6
6 SC70-6
6 SC70-6
6 SC70-6
ABW
ABY
ABX
ABZ
Selector Guide
PART
UVLO
THRESHOLD
(V)
OV
TRIP
LEVEL
(V)
EN
INPUT
FLAG
OUTPUT
MAX4838EXT-T
MAX4839EXT-T
MAX4840EXT-T
MAX4841EXT-T
3.25
3.25
3.25
3.25
7.4
7.4
5.8
5.8
Yes
No
Yes
No
Open-Drain
Push-Pull
Open-Drain
Push-Pull