MAX4838A Datasheet, PDF (1/11 Pages) Maxim Integrated Products – Overvoltage-Protection Controllers with Status FLAG

19-3979; Rev 0; 2/06
Overvoltage-Protection Controllers with
Status FLAG
General Description
The MAX4838A/MAX4840A/MAX4842A 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 MAX4838A/MAX4840A/
MAX4842A turn off the low-cost external n-channel
FET(s) to prevent damage to the protected components.
An internal charge pump eliminates the need for external
capacitors and drives the FET gate for a simple,
robust solution.
The MAX4838A has a 7.4V overvoltage threshold, and
the MAX4840A has a 5.8V overvoltage threshold. The
MAX4842A has a 4.7V overvoltage threshold. The
MAX4838A/MAX4840A have an undervoltage-lockout
(UVLO) threshold of 3.25V, while the MAX4842A has a
UVLO of 2.5V. In addition to the single FET configura-
tion, the devices can be configured with back-to-back
external FETs to prevent currents from being back-dri-
ven 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
MAX4838A/MAX4840A/MAX4842A have an open-drain
FLAG output. The FLAG output asserts immediately to
an overvoltage fault.
Additional features include a ±15kV (HBM) ESD-pro-
tected input (when bypassed with a 1µF capacitor) and
a shutdown pin (EN) to turn off the device.
All devices are offered in a small 6-pin SC70 and 6-pin
1.5mm x 1.0mm µDFN packages and are specified
over the -40°C to +85°C extended temperature range.
Applications
Cell Phones
Digital Still Cameras
PDAs and Palmtop Devices
MP3 Players
PART
MAX4838A
MAX4840A
MAX4842A
Selector Guide
UVLO
THRESHOLD
(V)
OV
TRIP
LEVEL
(V)
EN
INPUT
FLAG
OUTPUT
3.25
7.4 Yes Open-Drain
3.25
5.8 Yes Open-Drain
2.50
4.7 Yes Open-Drain
Features
♦ Overvoltage Protection Up to +28V
♦ Preset 7.4V, 5.8V, or 4.7V Overvoltage Trip Level
♦ Drives Low-Cost nMOS FET
♦ Internal 50ms Startup Delay
♦ Internal Charge Pump
♦ Undervoltage Lockout
♦ ±15kV ESD-Protected Input
♦ Voltage Fault FLAG Indicator
♦ 6-Pin SC70 and µDFN Packages
♦ Lead Free
Ordering Information
PART
PIN-
PACKAGE
TOP
MARK
PKG
CODE
MAX4838AEXT+T
MAX4838AELT+
6 SC70
6 µDFN
ACY
KU
X6S-1
L611-1
MAX4840AEXT+T
MAX4840AELT+
6 SC70
6 µDFN
ACZ
KV
X6S-1
L611-1
MAX4842AEXT+T 6 SC70
ADA
X6S-1
MAX4842AELT+*
6 µDFN
KW
L611-1
Note: All devices specified for the -40°C to +85°C extended
temperature range.
*Future product—contact factory for availability.
+Denotes lead-free package.
INPUT
+1.2V TO +28V
1µF
Typical Operating Circuit
OUTPUT
NMOS
1
IN
4
GATE
V_IO
MAX4838A
MAX4840A
MAX4842A
6
EN
3
FLAG
2
GND
NOTE: EN AND PULLUP
RESISTOR
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.