19-3044; Rev 1; 4/04
Overvoltage Protection Controllers with
Status FLAG
General Description
The MAX4838–MAX4842 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–MAX4842 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. The MAX4842 has a 4.7V over-
voltage threshold. The MAX4838–MAX4841 have an
undervoltage lockout (UVLO) threshold of 3.25V while
the MAX4842 has a UVLO of 3.0V. In addition to the
single FET configuration, the devices can be config-
ured with back-to-back external FETs to prevent cur-
rents 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/MAX4842 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/
MAX4842).
All devices are offered in a small 6-pin SC70 package
and are specified for operation from -40°C to +85°C.
♦
Overvoltage Protection Up to 28V
♦
Preset 7.4V, 5.8V, or 4.7V Overvoltage Trip Level
♦
Drive Low-Cost NMOS FET
♦
Internal 50ms Startup Delay
♦
Internal Charge Pump
♦
Undervoltage Lockout
♦
15kV ESD-Protected Input
♦
Voltage Fault
FLAG
Indicator
♦
6-Pin SC70 Package
Features
MAX4838–MAX4842
Ordering Information
PART
MAX4838EXT-T
MAX4839EXT-T
MAX4840EXT-T
MAX4841EXT-T
MAX4842EXT-T
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
6 SC70-6
6 SC70-6
6 SC70-6
6 SC70-6
6 SC70-6
TOP
MARK
ABW
ABY
ABX
ABZ
ACE
Typical Operating Circuit
Applications
Cell Phones
Digital Still Cameras
PDAs and Palmtop Devices
MP3 Players
1
INPUT
+1.2V TO +28V
OUTPUT
NMOS
IN
GATE
4
V
IO
Selector Guide
PART
OV
UVLO
TRIP
EN
THRESHOLD
LEVEL INPUT
(V)
(V)
3.25
3.25
3.25
3.25
3.00
7.4
7.4
5.8
5.8
4.7
Yes
No
Yes
No
Yes
FLAG
OUTPUT
Open-Drain
Push-Pull
Open-Drain
Push-Pull
Open-Drain
1µF
MAX4838–
MAX4842
6
2
EN
GND
FLAG
3
NOTE: EN AND PULLUP
RESISTOR ON MAX4838/
MAX4840/MAX4842 ONLY.
MAX4838EXT-T
MAX4839EXT-T
MAX4840EXT-T
MAX4841EXT-T
MAX4842EXT-T
Pin Configuration appears at end of data sheet.
1
________________________________________________________________
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.
Overvoltage Protection Controllers with
Status FLAG
MAX4838–MAX4842
ABSOLUTE MAXIMUM RATINGS
IN to GND ..............................................................-0.3V to +30V
GATE to GND ........................................................-0.3V to +12V
EN, FLAG
to GND ....................................................-0.3V to +6V
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SC70 (derate 3.1mW/°C above +70°C) .............245mW
Operating Temperature Range ..........................-40°C to +85°C
Junction Temperature .................................................... +150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= +5V (MAX4838–MAX4841), V
IN
= +4V (MAX4842), T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 1)
PARAMETER
Input Voltage Range
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
MAX4838/MAX4839
Overvoltage Trip Level
OVLO
MAX4840/MAX4841
MAX4842
MAX4838/MAX4839
MAX4840/MAX4841
MAX4842
No load,
EN
= GND or 5.5V,
V
IN
= 5.4V (MAX4838–MAX4841)
No load,
EN
= GND or 4.4V,
V
IN
= 4.3V (MAX4842)
V
IN
= 2.9V (MAX4838–MAX4841),
V
IN
= 2.7V (MAX4842)
V
GATE
I
PD
V
OL
V
OH
I
OH
V
IH
V
IL
I
LKG
I
GATE
sourcing 1µA
MAX4838–MAX4841
MAX4842
9
7.5
60
0.4
0.4
2.4
1
1.47
0.65
1
15
15
7.0
5.5
4.4
SYMBOL
V
IN
UVLO
V
IN
falling
MAX4838–MAX4841
MAX4842
CONDITIONS
MIN
1.2
3.0
2.8
3.25
3.0
50
7.4
5.8
4.7
100
80
50
140
130
240
µA
220
150
10
8.0
mA
V
V
µA
V
V
µA
kV
µA
V
7.8
6.1
5.0
V
TYP
MAX
28.0
3.5
3.2
UNITS
V
V
mV
Overvoltage Trip Level Hysteresis
mV
IN Supply Current
I
IN
UVLO Supply Current
GATE Voltage
GATE Pulldown Current
FLAG
Output Low Voltage
FLAG
Output High Voltage
FLAG
Output High Leakage
EN
Input High Voltage
EN
Input Low Voltage
EN
Input Leakage
IN ESD rating
V
IN
> V
OVLO
, V
GATE
= 5.5V
1.2V
≤
V
IN
< UVLO, I
SINK
= 50µA
V
IN
≥
OVLO, I
SINK
= 1mA
I
SOURCE
= 100µA,
FLAG
deasserted,
MAX4839/MAX4841
V
FLAG
= 5.5V,
FLAG
deasserted,
MAX4838/MAX4840/MAX4842
MAX4838/MAX4840/MAX4842
MAX4838/MAX4840/MAX4842
MAX4838/MAX4840/MAX4842,
EN
= GND or 5.5V
C
IN
≥
1µF
Human Body Model
IEC 1000-4-2
2
_______________________________________________________________________________________
Overvoltage Protection Controllers with
Status FLAG
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +5V (MAX4838–MAX4841), V
IN
= +4V (MAX4842), T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 1)
PARAMETER
TIMING
Startup Delay
FLAG
Blanking Time
GATE Turn-On Time
t
START
t
BLANK
t
GON
V
IN
> V
UVLO
, V
GATE
> 0.3V, Figure 1
V
GATE
= 0.3V, V
FLAG
= 2.4V, Figure 1
V
GATE
= 0.3V to 8V (MAX4838–MAX4841),
V
GATE
= 0.3V to 6V (MAX4842), C
GATE
=
1500pF, Figure 1
V
IN
increasing from 5V to 8V at 3V/µs
(MAX4838–MAX4841), V
IN
increasing from
4V to 6V at 2V/µs (MAX4842),
V
GATE
= 0.3V, C
GATE
= 1500pF, Figure 2
V
IN
increasing from 5V to 8V at 3V/µs
(MAX4838–MAX4841), V
IN
increasing from
4V to 6V at 2V/µs (MAX4842), V
FLAG
= 0.4V,
Figure 2
V
IN
increasing from 0 to 8V
(MAX4838–MAX4841), V
IN
increasing from
0V to 6V (MAX4842), I
GATE
= 80% of I
PD
,
Figure 3
V
EN
= 2.4V, V
GATE
= 0.3V,
MAX4838/MAX4840/MAX4842, Figure 4
20
20
50
50
10
80
80
ms
ms
ms
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX4838–MAX4842
GATE Turn-Off Time
t
GOFF
6
20
µs
FLAG
Assertion Delay
t
FLAG
5.8
µs
Initial Overvoltage Fault Delay
t
OVP
100
ns
Disable Time
t
DIS
580
ns
Note 1:
All parts are 100% tested at +25°C. Electrical limits across the full temperature range are guaranteed by design and
correlation.
Typical Operating Characteristics
(V
IN
= +5V, MAX4838; Si9936DY external MOSFET in back-to-back configuration; T
A
= +25°C, unless otherwise noted.)
REVERSE CURRENT
vs. OUTPUT VOLTAGE
MAX4838 toc01
MAX4838 toc02
SUPPLY CURRENT vs. INPUT VOLTAGE
600
500
SUPPLY CURRENT (µA)
400
300
200
100
0
0
5
10
15
20
25
30
INPUT VOLTAGE (V)
0.1
3.5
1000
MAX4838–MAX4841
GATE VOLTAGE vs. INPUT VOLTAGE
MAX4838 toc03
12
SINGLE MOSFET
REVERSE CURRENT (µA)
100
9
GATE VOLTAGE (V)
10
6
MAX4840
MAX4841
3
MAX4838
MAX4839
1
BACK-TO-BACK MOSFETS
0
4.0
4.5
5.0
5.5
3
4
5
6
7
8
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
_______________________________________________________________________________________
3
Overvoltage Protection Controllers with
Status FLAG
MAX4838–MAX4842
Typical Operating Characteristics (continued)
(V
IN
= +5V, MAX4838; Si9936DY external MOSFET in back-to-back configuration; T
A
= +25°C, unless otherwise noted.)
MAX4842
GATE VOLTAGE vs. INPUT VOLTAGE
MAX4838 toc04
GATE VOLTAGE vs. INPUT VOLTAGE
MAX4838 toc05
MAX4838–MAX4841
POWER-UP RESPONSE
MAX4838 toc06
12
11.0
I
GATE
= 0
10.5
GATE VOLTAGE (V)
I
GATE
= 4µA
9
GATE VOLTAGE (V)
MAX4842
6
5V
0V
10V
IN
GATE
10.0
I
GATE
= 8µA
0V
5V
OUT
3
9.5
0V
5V
R
OUT
=
∞
C
OUT
= 0
20ms/div
FLAG
0
0
1
2
3
4
5
6
7
8
INPUT VOLTAGE (V)
9.0
5.0
5.1
5.2
5.3
5.4
5.5
INPUT VOLTAGE (V)
MAX4838–MAX4841
POWER-UP RESPONSE
MAX4838 toc07
MAX4842
POWER-UP RESPONSE
MAX4838 toc08
MAX4842
POWER-UP RESPONSE
MAX4838 toc09
5V
IN
0V
10V
0V
1A
I
IN
0A
5V
0V
20ms/div
R
OUT
= 5Ω
FLAG
GATE
4V
0V
8V
IN
4V
0V
8V
IN
GATE
0V
4V
0V
4V
0V
OUT
R
OUT
=
∞
C
OUT
= 0
20ms/div
FLAG
0V
800mA
0A
4V
0V
GATE
I
IN
R
OUT
= 5Ω
FLAG
20ms/div
OVERVOLTAGE RESPONSE
MAX4838 toc10
POWER-UP OVERVOLTAGE RESPONSE
MAX4838 toc11
POWER-DOWN RESPONSE
MAX4838 toc12
8V
5V
10V
0V
40mA
IN
8V
0V
GATE PULLED UP
TO IN WITH 100Ω
IN
5V
0V
10V
R
LOAD
= 50Ω
R
FLAG
= 100kΩ TO +5V
IN
GATE
5V
GATE
0V
50mA
I
GATE
GATE
0V
5V
OUT
0V
5V
FLAG
0V
10ms/div
0A
5V
0V
C
GATE
= 1500pF
400ns/div
I
GATE
FLAG
0A
5V
FLAG
0V
1µs/div
4
_______________________________________________________________________________________
Overvoltage Protection Controllers with
Status FLAG
Pin Description
PIN
MAX4838/
MAX4840/
MAX4842
1
2
MAX4839/
MAX4841
1
2
NAME
FUNCTION
MAX4838–MAX4842
IN
GND
Input. IN is both the power-supply input and the overvoltage sense input. Bypass IN to
GND with a 1µF capacitor or larger.
Ground
Fault Indication Output, Active Low.
FLAG
is asserted low during undervoltage lockout
and overvoltage lockout conditions.
FLAG
is deasserted during normal operation.
FLAG
is open-drain on the MAX4838/MAX4840/MAX4842, and push-pull on the
MAX4839/MAX4841.
Gate-Drive Output. GATE is the output of an on-chip charge pump. When V
UVLO
< V
IN
<
V
OVLO
, GATE is driven high to turn on the external N-channel MOSFET(s).
No Connection. Can be connected to GND.
Device Enable Input, Active Low. Drive
EN
low or connect to ground to allow normal
device operation. Drive
EN
high to turn off the external MOSFET.
3
3
FLAG
4
5
6
4
5, 6
—
GATE
N.C.
EN
Timing Diagrams
V
IN
0V
5V (4V)
V
UVLO
t
GON
8V (6V)
t
START
V
GATE
0.3V
t
BLANK
V
FLAG
( ) MAX4842
2.4V
V
FLAG
0.4V
( ) MAX4842
V
GATE
0.3V
V
IN
5V (4V)
t
GOFF
8V (6V)
V
OVLO
t
FLAG
Figure 1. Startup Timing Diagram
Figure 2. Shutdown Timing Diagram
V
IN
0V
8V (6V)
V
OVLO
t
OVP
80%
V
GATE
0.3V
V
EN
1.47V
t
DIS
I
GATE
( ) MAX4842
Figure 3. Power-Up Overvoltage Timing Diagram
Figure 4. Disable Timing Diagram
5
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