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MAX5976A/MAX5976B

2.7V to 18V, 7A, Hot-Swap Solution

General Description

The MAX5976A/MAX5976B are integrated solutions for

hot-swap applications requiring the safe insertion and

removal of circuit line cards from a live backplane. The

devices integrate a hot-swap controller, 24mI power

MOSFET, and electronic circuit-breaker protection in a

single package. The ICs are designed for protection of

2.7V to 18V supply voltages.

The devices provide inrush current control and short-

circuit detection during startup. During normal operation,

the devices provide circuit-breaker protection against

overload and short-circuit conditions. The circuit-breaker

function disconnects the power to the load if the load

current exceeds the circuit-breaker limit. The devices

are factory-calibrated to deliver accurate overcurrent

protection with Q10% accuracy. During a fault condi-

tion, the MAX5976A enters an autoretry mode while the

MAX5976B latches off. Both versions feature a resistor-

adjustable variable speed circuit-breaker threshold and

overtemperature protection. Additional features include

power-good and fault indicator outputs.

The ICs are available in a 16-pin, 5mm x 5mm, TQFN-

EP package and fully specified over the -40

C to +85

operating temperature range.

Applications

RAID Systems

Storage Bridge Bay

Disk Drive Power

Server I/O Cards

Industrial

Features

S 2.7V to 18V Operating Voltage Range

S 24mI Internal Power MOSFET

S 7A Load Current Capability

S No Sense Resistor Required

S ±10% Circuit-Breaker Threshold Accuracy

S Adjustable Circuit-Breaker Current

S Variable Speed Circuit-Breaker Response

S Thermal Protection

S Power-Good and Fault Outputs

S Latch-Off or Automatic Retry Options

S Drive-Present Signal Input

S Active-Low and Active-High Enables

19-5542; Rev 1; 4/11

Note: All devices are specified over the -40°C to +85°C

operating temperature range.

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

Ordering Information

Typical Application Circuit

EVALUATION KIT

AVAILABLE

IN OUT

PRESDET

LOAD

(7A)

PRESDET

ON1

REG

GND

2.7V TO 18V

2.7V TO 6V

MAX5976A

MAX5976B

FAULT

µP

ON2

FAULT

REMOVABLE CARD

PART PIN PACKAGE

FAULT

MANAGEMENT

MAX5976AETE+ 16 TQFN-EP* Autoretry

MAX5976BETE+ 16 TQFN-EP* Latched Off

Summary of content (9 pages)

PAGE 1
9-5542; Rev 1; 4/11 TION KIT EVALUA BLE IL AVA A 2.7V to 18V, 7A, Hot-Swap Solution Features The MAX5976A/MAX5976B are integrated solutions for hot-swap applications requiring the safe insertion and removal of circuit line cards from a live backplane. The devices integrate a hot-swap controller, 24mI power MOSFET, and electronic circuit-breaker protection in a single package. The ICs are designed for protection of 2.7V to 18V supply voltages. S 2.
PAGE 2
MAX5976A/MAX5976B 2.7V to 18V, 7A, Hot-Swap Solution ABSOLUTE MAXIMUM RATINGS IN to GND...............................................................-0.3V to +20V CB to GND...............................................-0.3V to (VREG + 0.3V) ON1, REG to GND...................................................-0.3V to +6V OUT, ON2, PRESDET to GND................ -0.3V to the lower of (VIN + 0.3V) and +20V PG, FAULT to GND................................................-0.
PAGE 3
2.7V to 18V, 7A, Hot-Swap Solution (VIN = 12V, VON1 = 2V, VON2 = VPRESDET = 0V, RCB = 40kI, TA = TJ = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (Note 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS OPEN-DRAIN OUTPUTS FAULT, PG Output Low Voltage VOL Low-impedance state, IFAULT = IPG = 5mA 0.
PAGE 4
Typical Operating Characteristics (continued) (VIN = 12V, VON1 = 2V, RCB = 40kω, VON2 = VPRESDET = 0V, TA = +25°C, unless otherwise noted.) TURN-ON WAVEFORM ON-RESISTANCE vs. TEMPERATURE 0V 30 0V 25 0V 20 0A 10 35 TEMPERATURE (°C) 60 0V VOUT 10V/div ILOAD = 5A ON1 RISING/FALLING THRESHOLD VOLTAGE vs.
PAGE 5
2.7V to 18V, 7A, Hot-Swap Solution PRESDET OUT OUT OUT TOP VIEW 12 11 10 9 ON2 13 CB 14 MA5976A MA5976B REG 15 EP* 1 2 3 4 IN IN IN + GND ON1 16 8 OUT 7 PG 6 FAULT 5 IN TQFN *CONNECT EP TO GND. Pin Description PIN NAME 1 GND FUNCTION 2–5 IN 6 FAULT Fault Status Output. FAULT is an open-drain, active-low output. FAULT asserts low when an overcurrent or overtemperature condition triggers a shutdown. 7 PG Power-Good Output. PG is an open-drain, active-high output.
PAGE 6
2.7V to 18V, 7A, Hot-Swap Solution MAX5976A/MAX5976B Functional Diagram IN OUT 2500X FAULT CHARGE PUMP TEMP SENSE 6µA 2X VREG S SET Q 1mA UVLO CB_COMP CONTROL LOGIC R CLR 15µA Q 1V SNS_OK ON1 1.25V REFERENCE GENERATOR LDO 1.21V 10µA PG ON2 PRESDET O.
PAGE 7
2.7V to 18V, 7A, Hot-Swap Solution Enable Logic and Undervoltage Lockout Threshold The MAX5976A/MAX5976B enable the output as shown in Table 1. The ICs turn on the output only when VON1 is high (VON1 > 1.21V) while ON2 and PRESDET are low. The devices turn off the output when VON1 falls below 1.21V - VHYS or whenever ON2 or PRESDET are above VIH. A resistive divider from IN to ON1 and ground provides the flexibility to set the undervoltage lockout threshold to any desired level between VUVLO and 18V.
PAGE 8
MAX5976A/MAX5976B 2.7V to 18V, 7A, Hot-Swap Solution Power-Good Delay The devices feature an open-drain, power-good output that asserts after 16ms (typ), indicating that OUT has reached (0.9 x VIN) voltage. devices' internal switch goes into normal operation. Use the following equation to calculate the resistors values for the desired undervoltage threshold:  VIN  R1 =  - 1 × R2 V   ON1_TH  REG The devices include a linear regulator that outputs 2.6V at REG.
PAGE 9
2.7V to 18V, 7A, Hot-Swap Solution REVISION NUMBER REVISION DATE 0 9/10 Initial release 1 4/11 Added the Package Thermal Characteristics and Startup sections. DESCRIPTION PAGES CHANGED — 2, 7 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.