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Part: MAX4273
Category:
Interface and Interconnect
Description: 3V to 12V, Current-Limiting, Hot Swap Controllers With Autoretry, Dualspeed/bilevel Fault Protection
Company: Maxim Integrated Products
Datasheet: Download MAX4273 datasheet File size : 416 kB
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Datasheet text preview:
19-1694; Rev 1a; 4/01
KIT ATION EVALU E AILABL AV
3V to 12V Current-Limiting Hot Swap Controllers with Autoretry, DualSpeed/BiLevel Fault Protection
General Description
The MAX4271/MAX4272/MAX4273 comprise a comp l e t e family of integrated 3V to 12V hot-swap controllers. They allow the safe insertion and removal of circuit cards into live backplanes. The discharged filter capacitors of the circuit card provide a 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. This family of hot-swap controllers prevents such problems by 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 DualSpeed/BiLevelTM p r o t e c t i o n against short circuits, load glitches, and overcurrent conditions. In the event of a fault condition, the load is disconnected. Fault recovery is handled by unlatching (MAX4271), autoretry (MAX4272), or programmed (MAX4273) methods. The MAX4271 family includes many integrated features that reduce component count and design time. An onboard charge pump provides the gate drive for a lowcost, external N-FET. Integrated features like startup current regulation and current glitch protection eliminate external timing resistors and capacitors. Also featured are an open-drain status output to indicate a fault condition, and an adjustable overcurrent response time. The MAX4271 (latched fault protection) and MAX4272 (autoretry fault protection) come in 8-pin SO packages. The MAX4273 (full function) comes in the space-saving 1 6 - p i n QSOP package and 16-pin SO p a c k a g e . All parts are specified across the extended temperature range, and have an absolute maximum rating of 15V to provide extra protection against inductive kickback during board removal.
DualSpeed/BiLevel is a trademark of Maxim Integrated Products.
Features
o Provide Safe Hot Swap for +3V to +12V Power Supplies with Few External Components o Unique Current Regulation Architecture Minimizes N-FET Linear Mode Duration o Autoretry Feature (MAX4272/MAX4273) o DualSpeed/BiLevel Current Limit Protects Against Current Glitches and Short Circuits o Power-On RESET (MAX4273) o 15V Absolute Maximum Rating Protects Against Inductive Kickbacks During Board Removal o Internal Charge Pump Generates Gate Drive for External N-MOSFET o Status Output Pin Indicates Fault/Safe Condition o Space-Saving 8-Pin SO, 16-Pin QSOP Packages
MAX4271/MAX4272/MAX4273
________________________Applications
Base Stations RAID Remote-Access Servers Network Routers and Switches ISDN
Ordering Information
PART M A X 4 2 7 1ESA M A X 4 2 7 2ESA M A X 4 2 7 3EEE MAX4273ESE 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 SO 8 SO 16 QSOP 16 SO
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
BACKPLANE VCC REMOVABLE CARD 2.7V TO 13.2V RSENSE M1 N VOUT CBOARD IN STAT GND ON STAT CSPD ON SENSE GATE
MAX4271 MAX4272
CTIM GND CTIM
________________________________________________________________ Maxim Integrated Products
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For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
3V to 12V Current-Limiting Hot Swap Controllers with Autoretry, DualSpeed/BiLevel Fault Protection MAX4271/MAX4272/MAX4273
ABSOLUTE MAXIMUM RATINGS
IN to GND ..........+15V STAT, OUTC, LLMON, AUXVCC to GND ......-0.3V to +14V GATE to GND ....-0.3V to (VIN + 8.5V) GATE to LLMON (Note 1)........-1V to +8.5V INC, ON to GND (Note 2) ........-1V to +14V CEXT to GND .....-8.5V to (VIN + 0.3V) CSPD, CTON, REF to GND ..-0.3V to the lower of (VIN + 0.3V) or +12V VSENSE, RTH, CTIM to GND.....-0.3V to (VIN + 0.3V) Current into INC, ON (Note 2) ...........±2mA Current into Any Other Pin .....±50mA Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 5.9mW/°C above +70°C).........471mW 16-Pin QSOP (derate 8.3mW/°C above +70°C)..667mW 16-Pin SO (derate 8.7mW/°C above +70°C).......696mW Operating Temperature Range ...-40°C to +85°C Storage Temperature Range .....-65°C to +150°C Lead Temperature (soldering, 10s) .........+300°C
Note 1: GATE can be pulled below LLMON, but current must be limited to 2mA. Note 2: INC and ON can be pulled below ground. Limiting the current to 2mA ensures that these pins are never lower than about -0.8V.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +2.7V to +13.2V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25°C.) (Note 3)
PARAMETER POWER SUPPLIES Input Voltage Range Supply Current CURRENT CONTROL Slow Comparator Threshold Slow Comparator Response Time V SC,TH tC S P D VIN - VSENSE CSPD = floating CSPD = 100nF to GND 5k on RTH to VIN Fast Comparator Threshold V FC,TH MAX4273 only 75k on RTH to VIN RTH = GND MAX4271/MAX4272 Fast Comparator Response Time SENSE Input Bias Current MOSFET DRIVER Startup Period (Notes 4, 5) Gate Charge Current MAX4271/MAX4272 CTIM = 100nF tS T A R T IG A T E MAX4273 CTON = 100nF No capacitor GATE = IN (Note 6) 21 21 31 31 5.5 100 41 41 ms µs µA tFCD IB , S E N S E 10mV overdrive, from overload condition to gate discharging VSENSE = VIN TA = +25°C TA = TMIN to TMAX TA = +25°C TA = TMIN to TMAX TA = +25°C TA = TMIN to TMAX 45 43.5 10 10 45 43.5 675 650 180 200 350 0.2 10 750 20 20 50 50 55 56 40 40 55 56 825 840 220 ns µA mV mV µs ms VIN IQ VON = VIN 2.7 0.6 13.2 1 V mA SYMBOL CONDITIONS MIN TYP MAX UNITS
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3V to 12V Current-Limiting Hot Swap Controllers with Autoretry, DualSpeed/BiLevel Fault Protection
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +2.7V to +13.2V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +5V and TA = +25°C.) (Note 3)
PARAMETER SYMBOL CONDITIONS Time from trigger to VGATE < 0.1V (triggered by either the ON input or the slow comparator), CGATE = 1000pF to GND Time from current overload to VGATE < 0.1V (triggered by the fast comparator, during normal operation), CGATE = 1000pF to GND Voltage at which internal zener clamp circuitry is triggered, measured with respect to VIN (MAX4271/MAX4272), measured with respect to VLLMON (MAX4273) Measured with respect to VIN, IGATE = 8.5µA VIN 5V VIN 2.7V 5 V 2.7 0.4 25 1 70 2.75 195 µA 75 200 550 mA MIN TYP MAX UNITS
MAX4271/MAX4272/MAX4273
Slow Turn-Off Time
tS L O W , O F F
60
µs
Fast Turn-Off Time
t FAST,OFF
15
µs
Maximum Gate Protection Voltage
6.7
7.5
V
Minimum Gate Drive Voltage
During fast discharge, due to a fast comparator fault in normal operation Gate Discharge Current IG A T E , D I S During startup (current regulation provided by fast comparator) During normal discharge, due to a slow comparator fault in normal mode, or by ON going low LLMON Overvoltage Threshold GATE Overvoltage Threshold LLMON Impedance REFERENCE (MAX4273) Output Voltage Line Regulation Load Regulation ON AND RESET COMPARATORS Threshold Voltage Hysteresis Power-Supply Rejection Ratio Propagation Delay V HYST PSRR tD , C O M P 2.7V VIN 13.2V 10mV overdrive, ON going positive or negative, INC going negative INC going positive V REF
VREF, LINE
Startup is initiated only after VLLMON is less than this voltage (MAX4273) Startup is initiated only after VGATE is less than this voltage Impedance to GND, after a fault (MAX4273) No load, VIN = 5V 2.7V VIN 13.2V, no load IREF = 0 to 100µA, VIN = 5V
0.1 0.1 1 1.164 1.2 1 0.6 1.236 8 3 0.6
V V k V mV mV
V REF,
LOAD
VIN = 5V, rising threshold at ON or INC
0.575
0.6 3
0.625 ±1
V mV mV/V µs
10 100 150 200
ms
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