19-3044; Rev 0; 10/03
Overvoltage Protection Controllers with
Status FLAG
General Description
Features
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.
ꢀ Overvoltage Protection Up to 28V
ꢀ Preset 7.4V or 5.8V Overvoltage Trip Level
ꢀ Drive Low-Cost NMOS FET
ꢀ Internal 50ms Startup Delay
ꢀ Internal Charge Pump
ꢀ Undervoltage Lockout
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.
ꢀ 15kV ESD-Protected Input
ꢀ Voltage Fault FLAG Indicator
ꢀ 6-Pin SC70 Package
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.
Ordering Information
PIN-
PACKAGE
TOP
MARK
PART
TEMP RANGE
MAX4838EXT-T
MAX4839EXT-T
MAX4840EXT-T
MAX4841EXT-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
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
Typical Operating Circuit
Cell Phones
Digital Still Cameras
PDAs and Palmtop Devices
MP3 Players
INPUT
+1.2V TO +28V
OUTPUT
NMOS
1
4
3
Selector Guide
IN
GATE
V
IO
1µF
OV
UVLO
MAX4838–
MAX4841
TRIP
LEVEL
(V)
EN
FLAG
THRESHOLD
(V)
PART
INPUT OUTPUT
6
2
EN
FLAG
NOTE: EN AND PULLUP
RESISTOR ON MAX4838/
MAX4840 ONLY.
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 Open-Drain
GND
No
Yes Open-Drain
No Push-Pull
Push-Pull
Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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.