Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - OR controller, electrical elements n-channel uMAX 8 N+1 OR controller

General Description

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

gates of the n-channel pass elements to V

+ 10V. The

MAX8536 is used in 3.3V and 5V systems, with a charge-

pump output of V

+ 5V.

During startup, the MAX8535/MAX8536/MAX8585 moni-

tor the voltage drop across external MOSFETs. Once

approaches or exceeds the bus voltage, the

MOSFETs are turned 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.

Overvoltage and undervoltage fault thresholds are

adjustable and can be disabled. The current-limit trip

points are set by the external MOSFETs’ R

DS(ON)

reducing component count. An open-drain logic-low

fault output indicates if an overvoltage, undervoltage, or

reverse-current fault occurs.

All devices come in a space-saving 8-pin µMAX

package and are specified over the extended -40°C to

+85°C temperature range.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Applications

Silver Box Supplies for Servers

On-Board Redundant Power Supplies in Blade

Servers

Network/Telecom Power Supplies

Rectifiers

Redundant Power Supplies in High-Availability

Systems

Features

♦ 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

Reverse Leakage Current

♦ Provides N + 1 Redundant Supply Capability for

Highly Reliable Systems

♦ Isolates Failed Supply from Output Bus in <1µs

♦ Reverse-Current Flow Detection

♦ Programmable Soft-Start

♦ Logic-Enable Input

♦ Adjustable Overvoltage and Undervoltage Trip

Points

♦ Fault-Indicator Output

♦ Space-Saving 8-Pin µMAX Package

MAX8535/MAX8536/MAX8585

ORing MOSFET Controllers with Fastest

Fault Isolation for Redundant Power Supplies

________________________________________________________________ Maxim Integrated Products 1

MAX8535

MAX8536

MAX8585

GATE CS

FAULT

UVP

OVP

GND

TIMER

SILVER BOX

RECTIFIERS

OUT+

OUT-

REDUNDANT OUTPUT BUS

-V

N.C.

OUTPUT:

3.3V/5V

(MAX8536),

12V

(MAX8535)

Typical Operating Circuit

Ordering Information

19-2735; Rev 1; 3/04

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.

PART TEMP RANGE PIN-PACKAGE

MAX8535EUA -40°C to +85°C 8 µMAX

MAX8535AEUA -40°C to +85°C 8 µMAX

MAX8536EUA -40°C to +85°C 8 µMAX

MAX8585EUA -40°C to +85°C 8 µMAX

Pin Configuration, Functional Diagrams, and Typical

Application Circuits appear at end of data sheet.

EVALUATION KIT

AVAILABLE

Summary of content (20 pages)

PAGE 1
9-2735; Rev 1; 3/04 K ATION EVALU BLE AVAILA IT ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies Features 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 provide isolation and redundant power capability in high-reliability systems.
PAGE 2
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies ABSOLUTE MAXIMUM RATINGS GATE to GND (MAX8535/MAX8535A/MAX8585)...-0.3V to +28V VCC to GND (MAX8535/MAX8535A/MAX8585) .....-0.3V to +18V CS, FAULT to GND (MAX8535/MAX8535A/MAX8585) ......................-0.3V to +15V GATE to GND (MAX8536) ............................ -0.3V to (VCC + 6V) VCC, CS, FAULT to GND (MAX8536) .......................-0.3V to +6V OVP, UVP, TIMER to GND..........................
PAGE 3
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies (VCC = 12V (MAX8535/MAX8535A/MAX8585), VCC = 5V (MAX8536), VCS = VCC - 0.1V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, TA = 0°C to +85°C, unless otherwise noted.) PARAMETER SYMBOL Charge-Pump Switching Frequency CONDITIONS MIN TYP RTIMER = 20kΩ 187 RTIMER = 125kΩ 450 RTIMER = open 500 VTIMER = 1.5V 550 MAX UNITS kHz TIMER TIMER Voltage 1.219 1.25 1.
PAGE 4
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies ELECTRICAL CHARACTERISTICS (continued) (VCC = 12V (MAX8535/MAX8535A/MAX8585), VCC = 5V (MAX8536), VCS = VCC - 0.1V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, TA = 0°C to +85°C, unless otherwise noted.
PAGE 5
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies (VCC = 12V (MAX8535/MAX8535A/MAX8585), VCC = 5V (MAX8536), VCS = VCC - 0.1V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS CHARGE-PUMP VOLTAGE Gate Voltage VGATE Measured from VGATE to VCC, VCC = 3.3V (MAX8536) 5 6 VCC = 5V (MAX8536) 5 6 VCC = 12V (MAX8535/MAX8535A/MAX8585) 9 12 1.200 1.
PAGE 6
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies ELECTRICAL CHARACTERISTICS (continued) (VCC = 12V (MAX8535/MAX8535A/MAX8585), VCC = 5V (MAX8536), VCS = VCC - 0.1V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS OVERVOLTAGE PROTECTION OVP Fault Threshold VOVP OVP rising 1.20 OVP Bias Current 1.281 V 0.
PAGE 7
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies VCC > VCCOK CS + 0.01V CS ALL TRANSITIONS ARE ASYNCHRONOUS CS - 0.03V CS - 0.4V STANDBY: CPMP: OFF GATE: LOW VCC VSHARE LATCH IREVERSE BLANKING IFORWARD 500ms TIMER >1V IREVERSE VSHARE = (CS - VCC) < 0.4V IFORWARD = (VCC - CS) > 0.01V IREVERSE = (CS - VCC) > 0.03V WAIT FOR VSHARE CS - VCC > 0.4V CS - VCC < 0.
PAGE 8
MAX8535 Typical Operating Characteristics (VCC = 12V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, BUS = 100µF, TA = +25°C, unless otherwise specified.) SUPPLY CURRENT vs. TEMPERATURE GATE-CHARGE CURRENT vs. TIMER RESISTANCE (RTIMER) TA = +25°C 40 TA = -40°C 30 20 3.2 10 3.0 TIMER = GND 2.8 2.6 TIMER IS UNCONNECTED 2.4 2.2 0 2.0 10 1000 100 -40 -20 0 20 40 60 80 RESISTANCE (kΩ) TEMPERATURE (°C) MAX8535 REVERSE-CURRENT THRESHOLD vs. TEMPERATURE UVP AND OVP LEAKAGE CURRENT vs.
PAGE 9
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies TIMER-ENABLED STARTUP AND SHUTDOWN WAVEFORMS (VCC = 12V, VBUS = 12V) TIMER-ENABLED STARTUP AND SHUTDOWN WAVEFORMS (VCC = 12V, VBUS = 0V) MAX8535/MAX8536 toc07 MAX8535/MAX8536 toc08 VTIMER 2V/div VTIMER 1V/div IMOSFET 50mA/div IMOSFET 10A/div VGATE 20V/div VGATE 20V/div VCS 10V/div VCS 10V/div 4ms/div 4ms/div UVP FAULT WAVEFORM (R1 = 100Ω) REVERSE-CURRENT FAULT WAVEFORM (R1 = 10Ω) MAX8535/MAX8536 toc10 MAX8535
PAGE 10
MAX8536 Typical Operating Characteristics (VCC = 12V, RTIMER = 25kΩ, UVP = 2V, OVP = 1V, CGATE = 0.01µF, BUS = 100µF, TA = +25°C, unless otherwise specified.) GATE-CHARGE CURRENT vs. TIMER RESISTANCE (RTIMER) SUPPLY CURRENT vs. TEMPERATURE 15 10 MAX8535/MAX8536 toc13 TA = -40°C TA = +85°C 20 2.2 2.0 SUPPLY CURRENT (mA) TA = +25°C 25 5 1.8 TIMER IS UNCONNECTED 1.6 TIMER = GND 1.4 1.2 0 1.0 10 1000 100 -40 -20 0 20 40 60 TEMPERATURE (°C) MAX8536 REVERSE-CURRENT THRESHOLD vs.
PAGE 11
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies TIMER-ENABLED STARTUP AND SHUTDOWN WAVEFORMS (VCC = 5V, VBUS = 5V) TIMER-ENABLED STARTUP AND SHUTDOWN WAVEFORMS (VCC = 5V, VBUS = 0V) MAX8535/MAX8536 toc18 MAX8535/MAX8536 toc19 VTIMER 2V/div VTIMER 2V/div IMOSFET 50mA/div IMOSFET 1A/div VGATE 10V/div VGATE 10V/div VCS 5V/div VCS 5V/div 4ms/div 10ms/div UVP FAULT WAVEFORM (R1 = 100Ω) REVERSE-CURRENT FAULT WAVEFORM (R1 = 10Ω) MAX8535/MAX8536 toc21 MAX8535/MAX
PAGE 12
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies Pin Description PIN NAME 1 GATE Gate Drive Output. Bypass GATE with a 0.01µF capacitor to ground. 2 GND Ground 3 VCC Power-Supply Input. Bypass VCC with a 0.1µF capacitor to ground. UVP Undervoltage Input. Connect a resistor-divider from the VCC to GND with the center point connected to UVP. Leave high impedance if not used. UVP fault threshold must be set above VCCOK threshold.
PAGE 13
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies CS The voltage drop across the external MOSFETs is measured between the VCC and CS inputs. CS connects to the positive side of the system bus. The voltage drop across the CS and VCC determines operation modes. IFORWARD is defined as VCC - CS > 0.01V. IREVERSE is defined as CS - V CC > 0.03V in all except the MAX8585. In the MAX8585, IREVERSE = 0V.
PAGE 14
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies Normally, the external MOSFET’s gate capacitance is sufficient to serve as a reservoir capacitor. If the MOSFETs are located at a significant distance from the MAX8535/MAX8536/MAX8585, place a local bypass capacitor (0.01µF, typ) across GATE and GND. For slower turn-on times, add a small capacitor between GATE and GND and a series resistor between GATE and the gate of the MOSFETs.
PAGE 15
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies GATE VCC VCC CHARGE PUMP 400mV CS *0mV OFFSET IN THE MAX8585 10mV 30mV* CLK SHUTDOWN VCC FAULT CONTROL LOGIC VOLTAGE SHARE REVERSE CURRENT FORWARD CURRENT 14.5V OVERVOLTAGE INTERNAL OVP OVERVOLTAGE EXTERNAL UNDERVOLTAGE 1.25V IOSC TIMER ENABLE UVP 1.25V REF MAX8535 MAX8585 1.25V GND Figure 1.
PAGE 16
Typical Application Circuits Q1 AND Q2 2XSUB75N03-04 30V/4mΩ +VO -VO OUTPUT: 12V/20A OUT+ C3 1nF R3 SILVER BOX 53.6kΩ OR RECTIFIERS C1 0.01µF, 50V R5 100kΩ GATE R2 51kΩ OUTPUT BUS R1 10Ω CS FAULT VCC C2 0.1µF, 16V MAX8535 MAX8585 UVP R4 10kΩ OVP TIMER GND R6 10kΩ R7 24.9kΩ OUTENABLE Figure 3. Typical Application Circuit for 12V/20A Output with OVP and UVP Q1 AND Q2 2XSUB75N03-04 30V/4mΩ +VO -VO OUTPUT: 3.3V OR 5V/20A OUT+ C3 1nF R1 10Ω R3 SILVER BOX 13.3kΩ OR RECTIFIERS C1 0.
PAGE 17
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies MAX8535/MAX8536/MAX8585 Q1 SUB75N03-04 30V/4mΩ +VO -VO OUTPUT: 12V/20A OUT+ SILVER BOX OR RECTIFIERS R2 51kΩ C1 0.01µF, 50V GATE ON C2 0.1µF, 16V OFF MAX8535 MAX8585 R4 7.5kΩ TIMER ENABLE CS FAULT VCC GND UVP OUTPUT BUS C3 1nF R1 10Ω N.C. OVP R3 7.5kΩ OUT- Figure 5.
PAGE 18
MAX8535/MAX8536/MAX8585 ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies V+ Q1A AND Q2A 2XSUB75N03-04 30V/4mΩ +VO -VO VCCA = 12V/20A OUT+ R3A SILVER BOX 53.6kΩ A C1A 0.01µF, 50V R5A 100kΩ GATE C2A 0.1µF, 16V UVP R4A 10kΩ CS U1 VCC R2A 51kΩ FAULT MAX8535 MAX8585 GND TIMER OUTPUT BUS C3A 1nF R1A 10Ω OVP R6A 10kΩ R7A 24.9kΩ OUTQ1B AND Q2B 2XSUB75N03-04 30V/4mΩ VCCB = 12V/20A OUT+ R3B SILVER BOX 53.6kΩ B C1B 0.01µF, 50V R2B 51kΩ GATE C2B 0.
PAGE 19
ORing MOSFET Controllers with Fastest Fault Isolation for Redundant Power Supplies Chip Information TRANSISTOR COUNT: 3011 PROCESS: BiCMOS TOP VIEW GATE 1 8 GND 2 7 FAULT VCC 3 6 OVP UVP 4 5 TIMER MAX8535 MAX8536 MAX8585 CS µMAX ______________________________________________________________________________________ 19 MAX8535/MAX8536/MAX8585 Pin Configuration
PAGE 20
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 4X S 8 E ÿ 0.50±0.1 8 INCHES DIM A A1 A2 b H c D e E H 0.6±0.1 1 L 1 α 0.6±0.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 6∞ 0∞ 0.0207 BSC 8LUMAXD.