Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - hot swap controller Multi-purpose QSOP 16 Surface-mount

General Description

The MAX5955 and MAX5956 are +1V to +13.2V dual

hot-swap controllers with independent on/off control for

complete protection of dual-supply systems. They allow

the safe insertion and removal of circuit cards into live

backplanes. The MAX5955 and MAX5956 operate

down to 1V provided one of the inputs is above 2.7V.

The discharged filter capacitors of the circuit card pro-

vide low impedance to the live backplane. High inrush

currents from the backplane to the circuit card can burn

up connectors and components, or momentarily collapse

the backplane power supply leading to a system reset.

The MAX5955 and MAX5956 hot-swap controllers pre-

vent such problems by gradually ramping up the output

voltage and regulating the current to a preset limit when

the board is plugged in, allowing the system to stabilize

safely. After the startup cycle is completed, two on-chip

comparators provide VariableSpeed/BiLevel™ protection

against short-circuit and overcurrent faults, as well as

immunity against system noise and load transients. In the

event of a fault condition, the load is disconnected. The

MAX5955B and MAX5956B must be unlatched after a

fault, and the MAX5955A and MAX5956A automatically

restart after a fault.

The MAX5955 and MAX5956 integrate an on-board

charge pump to drive the gates of low-cost, external n-

channel MOSFETs. The devices offer integrated fea-

tures like startup current regulation and current glitch

protection to eliminate external timing resistors and

capacitors. These devices provide open-drain status

outputs, an adjustable startup timer, and adjustable

current limits. The MAX5955 provides output undervolt-

age/overvoltage protection for each channel, while the

MAX5956 provides undervoltage/overvoltage monitor-

ing for each channel.

The MAX5955 and MAX5956 are available in a space-

saving 16-pin QSOP package.

Applications

Features

o Safe Hot Swap for +1V to +13.2V Power Supplies

with V

IN1

or V

IN2

≥ 2.7V

o Independent On/Off Control for Each Channel

o Internal Charge Pumps Generate n-Channel

MOSFET Gate Drives

o Inrush Current Regulated at Startup

o Circuit-Breaker Function

o Adjustable Circuit Breaker/Current-Limit

Threshold from 25mV to 100mV

o VariableSpeed/BiLevel Circuit Breaker Response

o Autoretry or Latched Fault Management

o Status Outputs Indicate Fault/Safe Condition

o Output Undervoltage and Overvoltage Monitoring

or Protection

MAX5955/MAX5956

Low-Voltage, Dual Hot-Swap

Controllers with Independent On/Off Control

________________________________________________________________

Maxim Integrated Products

Ordering Information

PGOOD1 PGOOD2

ON2

IN2

SENSE2

GATE2

ON1

LIM2

MON2

TOP VIEW

MAX5955

MAX5956

QSOP

TIM

IN1

GND

SENSE1

GATE1

LIM1

MON1

Pin Configuration

19-3813; Rev 0; 9/05

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.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

MAX5955AEEE -40°C to +85°C 16 QSOP

MAX5955AEEE+ -40°C to +85°C 16 QSOP

MAX5955AUEE 0°C to +85°C 16 QSOP

MAX5955AUEE+ 0°C to +85°C 16 QSOP

MAX5955BEEE -40°C to +85°C 16 QSOP

MAX5955BEEE+ -40°C to +85°C 16 QSOP

MAX5955BUEE 0°C to +85°C 16 QSOP

MAX5955BUEE+ 0°C to +85°C 16 QSOP

Variable Speed/BiLevel is a trademark of Maxim Integrated

Products, Inc.

Denotes lead-free package.

Ordering Information continued at end of data sheet.

Selector Guide and Typical Operating Circuit appear at end

of data sheet.

Base Station Line Cards

Network Switches,

Routers, Hubs

Solid-State Circuit

Breakers

RAID

Power-Supply Sequencing

Hot Plug-In Daughter

Cards

Portable Computer Device

Bays (Docking Stations)

Summary of content (15 pages)

PAGE 1
9-3813; Rev 0; 9/05 KIT ATION EVALU E L B A IL AVA Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control The MAX5955 and MAX5956 are +1V to +13.2V dual hot-swap controllers with independent on/off control for complete protection of dual-supply systems. They allow the safe insertion and removal of circuit cards into live backplanes. The MAX5955 and MAX5956 operate down to 1V provided one of the inputs is above 2.7V.
PAGE 2
MAX5955/MAX5956 Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation (TA = +70°C) 16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW Operating Temperature Range MAX59_ _ _U_ _ ...................................................0°C to +85°C MAX59_ _ _E_ _ ................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .........
PAGE 3
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control (VIN_ = +1V to +13.2V provided at least one supply is higher than +2.7V, VON1 = VON2 = +2.7V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VIN1 = +5V, VIN2 = +3.3V, and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN VON_ < 4.5V ON_ Input Bias Current ON_ Pulse-Width Low IBON tUNLATCH VIN1 = VIN2 = +13.2V TYP UNITS 0.03 VON_ > 4.5V 100 VON_ = 4.5V 0.
PAGE 4
Typical Operating Characteristics (Typical Operating Circuits, Q1 = Q2 = Fairchild FDB7090L, VIN1 = +5V, VIN2 = +3.3V, VON1 = VON2 = +2.7V, TA = +25°C, unless otherwise noted. Channels 1 and 2 are identical in performance. Where characteristics are interchangeable, channels 1 and 2 are referred to as X and Y.) 1.8 1.6 IINX + IINY IIN (mA) 1.0 IINX 0.8 B 1.0 0.2 0 0 2 4 6 8 10 12 14 0.2 2 4 6 8 10 12 -40 14 10 35 60 TEMPERATURE (°C) GATE-DRIVE VOLTAGE vs.
PAGE 5
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control SLOW-COMPARATOR THRESHOLD vs. RLIM STARTUP PERIOD vs. RTIM 100 1 50 40 80 tSTART (ms) SLOW-COMP. THRESHOLD 60 MAX5955/56 toc11 MAX5955/56 toc10 120 VSC,TH (mV) TURN-OFF TIME (ms) 10 60 30 40 20 20 10 0 0 0.1 0 20 25 30 35 40 45 50 55 60 65 70 75 80 MAX5955/56 toc12 TURN-OFF TIME vs.
PAGE 6
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control MAX5955/MAX5956 Pin Description PIN 1 NAME FUNCTION Channel 1 Status Output (Open Drain, see the Absolute Maximum Ratings). PGOOD1 asserts high when hot PGOOD1 swap is successful and channel 1 is within regulation. PGOOD1 asserts low during startup, when ON1 is low, when channel 1 is off, or when channel 1 has any fault condition. 2 TIM Startup Timer Setting. Connect a resistor from TIM to GND to set the startup period.
PAGE 7
OUT1 Q1 RSENSE1 MON1 GATE1 SENSE1 IN1 3mA VSC, TH CHARGE PUMP VFS, TH 543mV 687mV RTIM TIM STARTUP OSCILLATOR TO STARTUP LOGIC BLOCKS ON2 0.875V UVLO CURRENT CONTROL AND STARTUP LOGIC SLOW COMP. FAST COMP. FAST DISCHARGE LIM1 ON1 2.4V PGOOD1 DEVICE CONTROL LOGIC TIMING OSCILLATOR BIAS AND REFERENCES 2.4V N PGOOD2 CHARGE-PUMP OSCILLATOR TO STARTUP LOGIC BLOCKS CHARGE PUMP 543mV 687mV 100µA FAST DISCHARGE SLOW COMP. FAST COMP.
PAGE 8
Startup Period RTIM sets the duration of the startup period from 0.45s to 50ms (see the Setting the Startup Period, RTIM section). The default startup period is fixed at 9ms when TIM is floating. The startup period begins after the following three conditions are met: 1) VIN1 or VIN2 exceeds the UVLO threshold (2.4V) for the UVLO to startup delay (37.5ms). 2) VON1 and VON2 exceed the ON threshold (0.875V).
PAGE 9
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control Fast-Comparator Startup Period During the startup period, the fast comparator regulates the gate voltage to ensure that the voltage across the sense resistor does not exceed the startup fast-comparator threshold voltage (VSU,TH), VSU,TH is scaled to two times the slow-comparator threshold (VSC,TH).
PAGE 10
MAX5955/MAX5956 Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control Table 1.
PAGE 11
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control COMPONENT MANUFACTURER Dale-Vishay Sense Resistors MOSFETs IRC 704-264-8861 www.irctt.com 888-522-5372 www.fairchildsemi.com International Rectifier 310-233-3331 www.irf.com Motorola 602-244-3576 www.mot-sps.com/ppd t START 128 × 800pF where tSTART is the desired startup period. Startup Sequence There are two ways of completing the startup sequence.
PAGE 12
MAX5955/MAX5956 Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control CBOARD = 6µF and the load does not draw any current during the startup period. With no gate capacitor the inrush current, charge, and discharge times are: 6µF × 100µA + 0 = 1A 600pF + 0 0 × 10.4V + 60nC t CHARGE = = 0.6ms 100µA 0 × 10.4V + 60nC tDISCHARGE = = 0.02ms 3mA IINRUSH = With a 22nF gate capacitor the inrush current, charge, and discharge times are: 6µF × 100µA + 0 = 26.5mA 600pF + 22nF 22nF × 10.
PAGE 13
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control BACKPLANE VIN REMOVABLE CARD WITH NO HOT-INSERTION PROTECTION VOUT HIGH-CURRENT PATH CBOARD 0.1µF IN_ When the output is short circuited, the voltage drop across the external MOSFET becomes large. Hence, the power dissipation across the switch increases, as does the die temperature.
PAGE 14
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control MAX5955/MAX5956 Typical Operating Circuit Q1 VOUT1 VIN1 0.1µF * IN1 ON1 * ON1 SENSE1 GATE1 CBOARD1 * * * ON2 ON2 MON1 * PGOOD1 PGOOD1 PGOOD2 PGOOD2 GND MAX5955 MAX5956 IN2 * MON2 GND SENSE2 GATE2 LIM2 LIM1 * * CBOARD2 TIM * * VIN2 VOUT2 Q2 0.1µF *OPTIONAL * REQUIRED COMPONENTS. SEE THE ON_ COMPARATORS SECTION.
PAGE 15
Low-Voltage, Dual Hot-Swap Controllers with Independent On/Off Control Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.