Specifications

www.digikey.com/maxim-industrial 43
Programmable logic controllers (PLCs)
Isolated power-supply functions
Benefits
• Eliminates expensive external
components
– Build redundant systems without the
power-dissipation disadvantages of
Schottky diodes
• Reduces costs
– Low-power dissipation
– Smaller size in space-saving TSSOP
package
– Eliminates heatsinks for high-power
applications
MAX5079
The MAX5079 OR-ing MOSFET controller replaces OR-ing diodes
in high-reliability, redundant, parallel-connected power supplies.
The controller allows the use of low-R
ON
, n-channel power MOSFETs
to replace Schottky diodes. The MAX5079 operates from 2.75V to
13.2V and includes a charge pump to drive the high-side n-channel
MOSFET. Operating over the -40°C to +85°C temperature range, the
MAX5079 is available in a space-saving 14-pin TSSOP package.
OR-ing FET controller supports main and battery-backup power to improve
system reliability
Typical operating circuit for the MAX5079 supporting a main and backup power supply.
BUS
COMMON
GATE BUSIN
POWER SUPPLY 1
(PS1)
POWER SUPPLY 2
(PS2)
1V TO 13.2V
V
OUT1
V
OUT2
UVLO
OVI
GND
U1
STH
AUXIN
>2.75V
FTH
PGOOD
V
BUS
R
STH
R
FTH
R
FTH
C
STH
R
STH
C
STH
C
EXT
C
EXT
C
BUS
N1
V
IN
C+ C-
OVP
GATE BUSIN
1V TO 13.2V
UVLO
OVI
U2
STH
AUXIN
>2.75V
PGOOD
V
BUS
N2
V
IN
C+ C-
OVP
GNDFTH
SUB 75N 03-04
SUB 75N 03-04
MAX5079
MAX5079