MAX4840EXT-T Maxim Integrated Products, MAX4840EXT-T Datasheet - Page 7

• Manufacturer Part Number: MAX4840EXT-T
• Description: Communication ICs - Various
• Manufacturer: Maxim Integrated Products
• Type: Overvoltage Protection Controllerr

Specifications of MAX4840EXT-T

• Mounting Style: SMD/SMT
• Package / Case: SC-70-6
• Supply Current: 0.14 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

cally 50ms after the GATE starts going high. At this
point the device is in its on state.
At any time if V
low and GATE is driven to ground.
The MAX4838–MAX4842 can be used with either a sin-
gle MOSFET configuration as shown in the Typical
Operating Circuit, or can be configured with a back-to-
back MOSFET as shown in Figure 7.
The MAX4838–MAX4842 can drive either a single
MOSFET or back-to-back MOSFETs. The back-to-back
configuration has almost zero reverse current when the
input supply is below the output.
If reverse current leakage is not a concern, a single
MOSFET can be used. This approach has half the loss
of the back-to-back configuration when used with simi-
lar MOSFET types, and is a lower cost solution. Note
that if the input is actually pulled low, the output is
pulled low as well due to the parasitic body diode in the
Figure 6. State Diagram
V
IN
< UVLO
Applications Information
IN
_______________________________________________________________________________________
drops below UVLO, FLAG is driven
Overvoltage Protection Controllers with
GATE DRIVEN HIGH
TIMER STARTS
OVLO CHECK
FLAG = HIGH
FLAG = LOW
FLAG = LOW
FLAG = LOW
GATE HIGH
COUNTING
STANDBY
STARTUP
GATE = 0
GATE = 0
MOSFET Configuration
ON
V
t = 50ms
V
t = 50ms
IN
IN
> UVLO
< OVLO
V
IN
> OVLO
MOSFET. If this is a concern, then the back-to-back
configuration should be used.
The MAX4838–MAX4842 are designed for use with
either a single n-channel MOSFET or dual back-to-back
n-channel MOSFETs. In most situations, MOSFETs with
R
input supply is near the UVLO maximum of 3.5V con-
sider using a MOSFET specified for a lower V
age. Also the V
withstand the full 28V IN range of the MAX4838–
MAX4842. Table 1 shows a selection of MOSFETs
appropriate for use with the MAX4838–MAX4842.
For most applications, bypass IN to GND with a 1µF
ceramic capacitor. If the power source has significant
inductance due to long lead length, take care to pre-
vent overshoots due to the LC tank circuit and provide
protection if necessary to prevent exceeding the 30V
absolute maximum rating on IN.
The MAX4838–MAX4842 provide protection against volt-
age faults up to 28V, but this does not include negative
voltages. If negative voltages are a concern, connect a
Schottky diode from IN to GND to clamp negative
input voltages.
ESD performance depends on a number of conditions.
The MAX4838–MAX4842 are specified for 15kV typical
ESD resistance on IN when IN is bypassed to ground
with a 1µF ceramic capacitor. Contact Maxim for a reli-
Figure 7. Back-to-Back External MOSFET Configuration
DS(ON)
0 TO 28V
INPUT
1µF
specified for a V
DS
1
6
2
IN
EN
GND
should be 30V for the MOSFET to
MAX4838–
MAX4842
IN Bypass Considerations
Status FLAG
GS
FLAG
GATE
ESD Test Conditions
of 4.5V work well. If the
MOSFET Selection
4
3
NMOS
NOTE: EN AND PULLUP
RESISTOR ON MAX4838/
MAX4840/MAX4842 ONLY.
V
IO
OUTPUT
GS
volt-
7