Datasheet

MAX4838A/MAX4840A/MAX4842A
Overvoltage-Protection Controllers with
Status
FLAG
_______________________________________________________________________________________ 5
PIN NAME FUNCTION
1IN
Input. IN is both the power-supply input and the overvoltage sense input. Bypass IN to GND with
a 1µF capacitor or larger.
2 GND Ground
3 FLAG
Fault Indication Output, Open-Drain, Active Low. FLAG is asserted low during undervoltage-
lockout and overvoltage-lockout conditions. FLAG is deasserted during normal operation.
4 GATE
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).
5N.C.
No Connection. Not internally connected for µDFN package. Connected to ground for SC70
6-pin package; connect to ground or leave unconnected.
6 EN
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.
Pin Description
V
IN
V
GATE
0V
V
UVLO
0.3V
t
START
2.4V
t
BLANK
8V (6V)
t
GON
V
FLAG
5V (4V)
( ) MAX4842A
Figure 1. Startup Timing Diagram
V
IN
V
GATE
V
OVLO
0.3V
t
GOFF
0.4V
t
FLAG
5V (4V)
8V (6V)
V
FLAG
( ) MAX4842A
Figure 2. Shutdown Timing Diagram
V
IN
I
GATE
V
OVLO
80%
t
OVP
0V
8V (6V)
( ) MAX4842A
Figure 3. Power-Up Overvoltage Timing Diagram
V
GATE
0.3V
t
DIS
1.5V
V
EN
Figure 4. Disable Timing Diagram
Timing Diagrams