19-2735; Rev 1; 3/04
ORing MOSFET Controlle rs w ith Fa s te s t
Fa ult Is ola tion for Re dunda nt Pow e r Supplie s
Ge n e ra l De s c rip t io n
Fe a t u re s
Critical loads often employ parallel-connected power
supplies with redundancy in order to enhance system
reliability. The MAX8535/MAX8536/MAX8585 are highly
integrated but inexpensive MOSFET controllers that pro-
vide isolation and redundant power capability in high-reli-
ability systems. The MAX8535/MAX8585 are used in 12V
systems, and have an internal charge pump to drive the
♦ Simple, Integrated, and Inexpensive ORing
MOSFET Controller
♦ ORing MOSFET Drive for 12V
(MAX8535/MAX8585) and 3.3V or 5V
(MAX8536) Bus
♦ Eliminates ORing Diode Power Dissipation and
gates of the n-channel pass elements to V + 10V. The
CC
Reverse Leakage Current
MAX8536 is used in 3.3V and 5V systems, with a charge-
pump output of V + 5V.
♦ Provides N + 1 Redundant Supply Capability for
CC
Highly Reliable Systems
During startup, the MAX8535/MAX8536/MAX8585 moni-
tor the voltage drop across external MOSFETs. Once
♦ Isolates Failed Supply from Output Bus in <1µs
♦ Reverse-Current Flow Detection
♦ Programmable Soft-Start
V
CC
a p p roa c he s or e xc e e d s the b us volta g e , the
MOSFETs a re turne d on. The MAX8535/MAX8536/
MAX8585 feature a dual-purpose TIMER input. A single
external resistor from TIMER to ground sets the turn-on
speed of the external MOSFETs. Optionally, the TIMER
input can be used as a logic-enable pin. Once the
device is turned on, the MAX8535/MAX8536/MAX8585
monitor the load, protecting against overvoltage, under-
voltage, and reverse-current conditions.
♦ Logic-Enable Input
♦ Adjustable Overvoltage and Undervoltage Trip
Points
♦ Fault-Indicator Output
Ove rvolta g e a nd und e rvolta g e fa ult thre s hold s a re
adjustable and can be disabled. The current-limit trip
♦ Space-Saving 8-Pin µMAX Package
p oints a re s e t b y the e xte rna l MOSFETs ’ R
,
Ord e rin g In fo rm a t io n
DS(ON)
reducing component count. An open-drain logic-low
fault output indicates if an overvoltage, undervoltage, or
reverse-current fault occurs.
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
MAX8535EUA
MAX8535AEUA
MAX8536EUA
MAX8585EUA
®
8 µMAX
All d e vic e s c ome in a s p a c e -s a ving 8-p in µMAX
package and are specified over the extended -40°C to
+85°C temperature range.
8 µMAX
8 µMAX
Typ ic a l Op e ra t in g Circ u it
µMAX is a registered trademark of Maxim Integrated Products, Inc.
OUTPUT:
Ap p lic a t io n s
3.3V/5V
(MAX8536),
12V
+V -V
O O
Silver Box Supplies for Servers
(MAX8535)
OUT+
On-Board Redundant Power Supplies in Blade
Servers
Network/Telecom Power Supplies
Rectifiers
SILVER BOX
OR
RECTIFIERS
Redundant Power Supplies in High-Availability
Systems
GATE
CS
V
CC
FAULT
MAX8535
MAX8536
MAX8585
GND
N.C.
UVP
OVP
TIMER
Pin Configuration, Functional Diagrams, and Typical
Application Circuits appear at end of data sheet.
OUT-
________________________________________________________________ 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.