MAX5900LBEUT+T - Maxim Integrated

General Description

The MAX5900/MAX5901 are SOT23/TDFN hot-swap con-

trollers that allow a circuit card to be safely hot-plugged

into a live backplane without causing a glitch on

the power-supply rail. These devices operate from -9V to

-100V and provide the simplest hot-swap solution by

eliminating all external components except an external

n-channel MOSFET.

The MAX5900/MAX5901 limit the inrush current to the

load and provide a circuit-breaker function for overcurrent

protection. During startup, the circuit-breaker function is

disabled and the MAX5900/MAX5901 limit the inrush cur-

rent by gradually turning on the external MOSFET. Once

the external MOSFET is fully enhanced, the circuit-break-

er function is enabled and the MAX5900/MAX5901 pro-

vide overcurrent protection by monitoring the voltage

drop across the external MOSFET’s on-resistance.

The MAX5900/MAX5901 include an undervoltage lock-

out (UVLO) function, ON/OFF control input, and a power-

good status output, PGOOD (MAX5900) or PGOOD

(MAX5901). A built-in thermal shutdown feature is also

included to protect the external MOSFET in case of over-

heating.

The MAX5900/MAX5901 offer latched or autoretry fault

management and are available with 200mV, 300mV, or

400mV circuit-breaker thresholds. Both the MAX5900 and

MAX5901 are available in small SOT23 and TDFN pack-

ages, and are specified for the extended -40°C to +85°C

temperature range. For specific ordering information see

the Selector Guide at the end of the data sheet.

_________________________Applications

♦Requires No External Sense Resistor

Features

♦Wide -9V to -100V Operation

♦Requires No External Sense Resistor

♦Drives External N-Channel MOSFET

♦Limits Inrush Current

♦Circuit-Breaker Function

♦Less than 1mA Quiescent Current

♦ON/OFF Input Permits Load Power-Supply

Control and Sequencing

♦Adjustable Undervoltage Lockout

♦Power-Good Output with 100V Rating

♦Latching or Automatic Retry Fault Management

♦Thermal Shutdown Helps Protect the External

MOSFET

♦Space-Saving 6-Pin SOT23 and TDFN Packages

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

________________________________________________________________ Maxim Integrated Products 1

DRAIN

GND

( ) ARE FOR MAX5901 ONLY.

GATE

16ON/OFF

5PGOOD (PGOOD)

VEE

MAX5900

MAX5901

SOT23

TOP VIEW

Pin Configurations

MAX5900

VEE

ON/OFF

HOT-SWAP CONTROLLER

GND

-48V

50W ISOLATED

POWER SUPPLY

V1-

ON/OFF

LUCENT

JWO50A1

V1+

GATE

DRAIN

PGOOD

IRF540NS

GND

BACKPLANE CIRCUIT CARD

FUSE

Typical Operating Circuits

19-2077; Rev 5; 1/07

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.

Ordering Information

PART

TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX5900_ _EUT+T*

-40°C to +85°C

6 SOT23-6 U6F-6

MAX5900_ _ETT+T*

-40°C to +85°C 6 TDFN-EP**

T633-2

MAX5901_ _EUT+T*

-40°C to +85°C

6 SOT23-6 U6F-6

MAX5901_ _ETT+T*

-40°C to +85°C 6 TDFN-EP**

T633-2

*For specific part numbers, see Selector Guide at end of data

sheet.

+Denotes lead-free package.

**EP = Exposed pad.

Typical Operating Circuits continued at end of data sheet.

Simple Swapper is a trademark of Maxim Integrated Products, Inc.

Telecom Line Cards

Network Routers

Base-Station Line

Cards

Network Switches

Servers

Pin Configurations continued at end of data sheet.

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VEE = -9V to -100V, GND = 0V, ON/OFF open circuit, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VEE = -48V

and TA= +25°C.) (Notes 1, 2)

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.

Terminal Voltage (with respect to GND, unless otherwise noted)

VEE, DRAIN, PGOOD, PGOOD ............................-120V to +0.3V

ON/OFF to VEE .........................................................-0.3V to +4V

GATE to VEE ......................................................... -0.3V to +12V

Current into Any Pin............................................................±3mA

Continuous Power Dissipation (TA= +70°C)

6-Pin SOT23 (derate 9.1mW/°C above +70°C)...........727mW

6-Pin TDFN (derate 18.2mW/°C above +70°C) ........1454mW

Junction to Case Thermal Resistance, θJC (TDFN) ........8.5°C/W

Maximum Junction Temperature .....................................+150°C

Storage Temperature Range .............................-60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Supply Voltage VEE

-100

-9 V

Supply Current IGND Measured at GND 0.5 1.3 mA

VEE = -36V to -72V 7.5 9.5

11.6

VEE = -100V 8 10

11.6

External Gate Drive VGS VGATE - VEE

VEE = -9V 6 7

Load Voltage Slew-Rate

Magnitude SR | dVDRAIN/dt |, CLOAD = 10µF, VEE = -9V to -36V 4.5 10 17

V/ms

Default UVLO VUVLO |VEE| increasing

-34.5 -31.5 -28.5

UVLO Hysteresis 3.5 V

ON/OFF Input Resistance

RON/OFF

20 32 50 kΩ

Drain to VEE Resistance RDVEE

466

kΩ

ON/OFF Reference

Threshold

VON/OFF

(VON/OFF - VEE) increasing

1.14 1.26

1.38 V

ON/OFF Hysteresis 140 mV

Start Delay (Note 3) tON 150

300

500 ms

ON/OFF Off Delay (Note 4)

tOFF VGATE - VEE < 1V 9 20 32 ms

MAX590_ _AEUT 170

200

240

MAX590_ _BEUT 265

300

345

Circuit-Breaker

Threshold VCB VDRAIN - VEE

MAX590_ _CEUT 365

400

455

CGATE = 1nF 1.5 3

CGATE = 4.7nF 2.5 4.5

Circuit-Breaker Delay

(Note 5) tCB

(VDRAIN - VEE) > VCB

until (VGATE - VEE ) <

1V, 200mV overdrive

step CGATE = 10nF 4 6

µs

Restart Delay (Note 3) tRS After circuit-breaker event, MAX590_A_EUT only 150

300

500 ms

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

_______________________________________________________________________________________ 3

Note 1: All currents into device pins are positive, all currents out of device pins are negative, and all voltages are referenced to

GND, unless otherwise noted.

Note 2: All specifications are 100% tested at TA= +25°C. Specifications over -40°C to +85°C are guaranteed by characterization.

Note 3: This is the delay time from a valid on condition until VGS begins rising. Valid on conditions are: the device is not in undervolt-

age lockout; ON/OFF is not driven low; and the device is not in thermal shutdown.

Note 4: This is the delay from a valid low on ON/OFF until VGS falls. Pulses on ON/OFF less than tOFF are ignored, offering glitch

immunity.

Note 5: Guaranteed by design, not production tested.

Note 6: For a detailed description, see the Power-Good Output section.

ELECTRICAL CHARACTERISTICS (continued)

(VEE = -9V to -100V, GND = 0V, ON/OFF open circuit, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VEE = -48V

and TA= +25°C.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN TYP MAX

UNITS

PGOOD (PGOOD)

Assertion Threshold

(Note 6)

VPG VDRAIN - VEE; MAX590_A,

MAX590_L only 0.75 ✕ VCB mV

PGOOD (PGOOD)

Output Low Voltage VOL MAX5900, VPGOOD - VEE, IOL = 1mA;

MAX5901, VPGOOD - VEE, IOL = 1mA 0.6

1.65

Power-Good Output Open-

Drain Leakage Current IOH VPGOOD - VEE = 100V (MAX5900);

VPGOOD - VEE = 100V (MAX5901) 0.2 10 µA

Thermal Shutdown

Temperature TSD Junction temperature

+125

°C

Thermal Shutdown

Hysteresis THY 15 °C

Typical Operating Characteristics

(VEE = -48V, GND = 0V, and TA= +25°C, unless otherwise noted. See Figure 6 for test circuits.)

0.5

0.7

0.6

0.9

0.8

1.0

1.1

-100 -60-80 -40 -20 0

SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX5900/01 toc01

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

100kΩ FROM ON/OFF TO GND

0.55

0.65

0.60

0.75

0.70

0.85

0.80

0.90

-50 0 25-25 50 75 100 125

SUPPLY CURRENT vs. TEMPERATURE

MAX5900/1 toc02

TEMPERATURE (°C)

IEE (mA)

VEE = -75V

VEE = -48V

VEE = -12V

-37.5

-35.5

-36.5

-34.5

-33.5

-32.5

-31.5

-30.5

-29.5

-28.5

-27.5

-26.5

-25.5

DEFAULT UNDERVOLTAGE LOCKOUT

vs. TEMPERATURE

MAX9500/01 toc03

TEMPERATURE (°C)

VUVLO (V)

-50 0 25-25 50 75 100 125

DECREASING |VEE|

INCREASING |VEE|

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

4 _______________________________________________________________________________________

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

-100 -80 -60 -40 -20 0

GATE DRIVE VOLTAGE

vs. INPUT VOLTAGE

MAX5900/1 toc04

INPUT VOLTAGE (V)

VGS (V)

150

250

200

350

300

400

450

-50 25 50-25 0 75 100 125

RESTART DELAY

vs. TEMPERATURE

MAX5900/01 toc05

TEMPERATURE (°C)

tRS (ms)

5ms/div

STARTUP WAVEFORMS

(RL = OPEN, CL = 10µF)

MAX5900/1 toc07

A: VGS, 10V/div C: VOUT, 50V/div

B: IIN, 200mA/div D: PGOOD, 50V/div

5ms/div

STARTUP WAVEFORMS

(RL = 40Ω, CL = 10µF)

MAX5900/1 toc08

A: VGS, 10V/div C: VOUT, 50V/div

B: IIN, 1A/div D: PGOOD, 50V/div

5ms/div

STARTUP WAVEFORMS

(RL = 40Ω, CL = 100µF)

MAX5900/1 toc09

A: VGS, 10V/div C: VOUT, 50V/div

B: IIN, 1A/div D: PGOOD, 50V/div

2µs/div

CIRCUIT-BREAKER EVENT

(CGATE = 1000pF, VOVERDRIVE = 20mV)

MAX5900/1 toc10

D: PGOOD, 50V/div C: VGS, 10V/div

B: VDS, 500mV/div

Typical Operating Characteristics (continued)

(VEE = -48V, GND = 0V, and TA= +25°C, unless otherwise noted. See Figure 6 for test circuits.)

STARTUP WAVEFORMS

(RL = 90Ω, CL = 100µF)

MAX5900/01 toc06

40ms/div

A: VGS, 5V/div C: VEE, 50V/div

B: IIN, 1A/div D: VDRAIN, 40V/div

-100 -60-80 -40 -20 0

SLEW RATE vs. VEE

MAX5900/01 toc12

VEE (V)

SLEW RATE (V/ms)

TA = +120°C

TA = +25°C

TA = -40°C

2µs/div

CIRCUIT-BREAKER EVENT

(CGATE = 1000pF, VOVERDRIVE = 200mV)

MAX5900/1 toc11

D: PGOOD, 50V/div C: VGS, 10V/div

B: VDS, 500mV/div

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

_______________________________________________________________________________________ 5

Detailed Description

The MAX5900/MAX5901 are integrated hot-swap con-

troller ICs contained in 6-pin SOT23/TDFN packages.

They allow a board to be safely hot plugged into a live

backplane without causing a glitch on the power-sup-

ply rail. They are well suited for -48V telecom power

systems, allowing a cost-effective, simple, and com-

pact design. The MAX5900/MAX5901 operate from -9V

to -100V to cover the standard telecom voltage range,

and to serve more generalized applications. These

devices require only an external n-channel power MOS-

FET to provide hot-swap control. Figure 1 shows a

functional diagram of the MAX5900/MAX5901.

The MAX5900/MAX5901 control an external n-channel

power MOSFET placed in the negative power-supply

pathway. When power is first applied, the MAX5900/

MAX5901 keep the MOSFET turned off. The MAX5900/

MAX5901 hold the MOSFET off indefinitely if ON/OFF is

held low, if the supply voltage is below the undervolt-

age lockout level, or if the die temperature exceeds

+125°C. If none of these conditions exist for 300ms

(typ), the MAX5900/MAX5901 begin to gradually turn

on the MOSFET. During this turn-on phase, the

MAX5900/MAX5901 slowly enhance the MOSFET, Figure 1. Functional Diagram

VEE

ON/OFF

GND

MAX5900

MAX5901

GATE

34.5kΩ*

466kΩ*

1kΩ*

828kΩ*

DRAIN

*RELATIVE TOLERANCE ±1%, ABSOLUTE TOLERANCE ±20% TYPICAL.

CONTROL

LOGIC

PGOOD

(PGOOD)

( ) ARE FOR THE MAX5901 ONLY.

VEE

3V N

MAX5900 MAX5901 NAME FUNCTION

11V

EE Negative Supply Voltage Input and External n-Channel MOSFET Source

Connection

2 2 DRAIN

Drain Sense Input for External n-Channel MOSFET. Connect DRAIN as close as

possible to the MOSFET’s drain and use wide circuit traces to assure good

thermal coupling between the MAX5900/MAX5901 and the MOSFET (see the

Layout Guidelines section).

3 3 GATE Gate Drive Output for External n-Channel MOSFET

4 4 GND Ground Connection.

5—PGOOD Power-Good Output. PGOOD is an n-channel, open-drain, active-low output,

referenced to VEE.

— 5 PGOOD Power-Good Output. PGOOD is an n-channel, open-drain, active-high output,

referenced to VEE.

6 6 ON/OFF

ON/OFF Control Input. ON/OFF is referenced to VEE. Drive ON/OFF above 1.38V

or leave unconnected to enable the device. Drive ON/OFF below 1V to disable

the device. ON/OFF is also used to adjust the UVLO threshold. See the Under-

voltage Lockout section in the Applications Information. Internally clamped to

nominally 3V through a 1kΩ resistor (see Figure 1).

— — EP Exposed Pad (TDFN only). Connect to VEE.

Pin Description

allowing the voltage on the load, i.e. the drain of the

MOSFET, to fall no faster than 10V/ms (typ). The inrush

current to the load is thus limited to a level proportional

to the load capacitance, and the constant load voltage

slew rate. After the MOSFET is fully enhanced, and the

load voltage is settled to its final value, the MAX5900A/

MAX5901A and MAX5900L/MAX5901L monitor the volt-

age drop from the MOSFET’s drain-to-source (VDS). If

the voltage drop exceeds 75% of the circuit-breaker

threshold the MAX5900A/MAX5901A or MAX5900L/

MAX5901L turn off the MOSFET, disconnecting the

load immediately. Because the circuit-breaker function

is not activated until the MOSFET is fully enhanced, it

takes approximately 10ms for the MAX5900A/

MAX5901A or MAX5900L/MAX5901L to react to an out-

put short circuit at startup. If no circuit-breaker fault

exists, the power-good output is asserted. Then, if any

of four conditions exist, the power-good output

deasserts and the MOSFET is turned off . The four con-

ditions are: the voltage across the MOSFET exceeds

the circuit-breaker threshold; the supply voltage magni-

tude falls below the undervoltage lockout level; the die

temperature exceeds +125°C; or ON/OFF is forced low.

After a circuit-breaker fault, the MAX5900L/MAX5901L

keep the MOSFET off until the power is cycled, or the

part is reset by toggling ON/OFF low for at least 20ms

(typ). After a circuit-breaker fault, the MAX5900A/

MAX5901A automatically restart in 300ms (typ). All ver-

sions automatically restart after a thermal fault, or an

undervoltage shutdown, if the fault condition goes away

for at least 300ms (typ).

ON/OFF offers external control of the MAX5900/

MAX5901, facilitating power-supply sequencing, and

may also be used to change the UVLO level. UVLO

keeps the external MOSFET switched off as long as the

magnitude of the input voltage is less than a desired

level.

A power-good output, PGOOD (MAX5900) or PGOOD

(MAX5901), asserts when the external MOSFET is fully

enhanced and the drain-source voltage is at least 25%

below the circuit-breaker threshold. PGOOD and

PGOOD are open-drain outputs referenced to VEE, and

can withstand up to 100V above VEE.

A thermal shutdown feature protects the external MOS-

FET by turning it off if the die temperature of the

MAX5900/MAX5901 exceeds +125°C. The MAX5900/

MAX5901 must be in good thermal contact with the

external MOSFET. See the Layout Guidelines section in

the Applications Information.

A circuit-breaker function monitors the voltage across

the external MOSFET, VDS, and turns off the MOSFET if

VDS exceeds the circuit-breaker threshold, VCB. The

circuit-breaker function is enabled after the MOSFET is

fully enhanced. Three threshold voltage options are

available—200mV, 300mV, and 400mV. One version is

available with no circuit-breaker function. circuit-break-

er fault management for the MAX5900/MAX5901 is

offered with two different configurations—latched and

automatic retry.

Latched Circuit Breaker

After a circuit-breaker trip event, the latched versions

(MAX5900L/MAX5901L) drive GATE to VEE, turning off

the external MOSFET, and PGOOD (PGOOD) is

deasserted. A latched-off condition needs to be reset

by toggling ON/OFF low for at least 20ms, or by cycling

the power supply, VEE.

Automatic Retry Circuit Breaker

After a circuit-breaker trip event, the automatic retry

versions (MAX5900A/MAX5901A) drive GATE to VEE,

turning off the external MOSFET, and PGOOD

(PGOOD) is deasserted. If the start conditions are met

for a full 300ms (tRS) the start sequence is initiated. The

start conditions are: the device is not in UVLO; ON/OFF

is not driven low; and the device is not in thermal shut-

down.

No Circuit Breaker

For the versions without a circuit-breaker MAX5900N

(MAX5901N), PGOOD (PGOOD) is asserted when the

MOSFET is fully enhanced. Once powered up, the

MAX5900N/MAX5901N ignore the MOSFET drain-to-

source voltage (VDS) for applications where a circuit-

breaker function is not desired.

Applications Information

ON/

OFF

Control Input

The ON/OFF control input provides three hot-swap

functions: external ON/OFF control; setting of the UVLO

level; and resetting after a circuit-breaker event has

caused the MAX5900L/MAX5901L to turn off the exter-

nal MOSFET. Pulling ON/OFF to VEE for at least 20ms

(tOFF) forces the MAX5900/MAX5901 to turn off the

external MOSFET (see Figure 2 for a circuit example).

To reset the MAX5900L/MAX5901L after a circuit-

breaker event, toggle ON/OFF to VEE for at least 20ms

(tOFF).

ON/OFF can be used to sequence power supplies.

Connecting a capacitor from ON/OFF to VEE will delay

the rise of ON/OFF proportional to the capacitance and

input impedance of ON/OFF, typically 32kΩ(Figure 3).

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

6 _______________________________________________________________________________________

Turn-On and Turn-Off Delays

After power is applied, or ON/OFF is released, there is

a 300ms delay (tON) before the gate ramp is started.

This delay is also the automatic restart time delay.

In the event of a circuit-breaker condition or an over-

temperature fault condition, the turn-off delay is less

than 2µs. An undervoltage condition must exist for at

least 20ms (tOFF) before the MAX5900/MAX5901 turn

off the external MOSFET. ON/OFF must be held low for

at least 20ms (tOFF) before the MAX5900/MAX5901 turn

off the external MOSFET. Turn-off delay minimizes spu-

rious shutdowns due to noisy signals or momentary

voltage spikes, as well as preventing accidental

resetting of the circuit-breaker latch (MAX5900L/

MAX5901L).

Thermal Shutdown

A thermal shutdown feature helps protect the external

MOSFET. If the die temperature of the MAX5900/

MAX5901 exceeds +125°C, the MOSFET is turned off.

For accurate performance, the MAX5900/MAX5901

must be in close thermal contact with the external

MOSFET (see the Layout Guidelines section). Due to

the low power dissipation of the MAX5900/MAX5901, its

junction temperature will typically be within a few

degrees of the MOSFET. All versions of the MAX5900/

MAX5901 automatically restart from a temperature fault

when the junction temperature drops below +110°C.

Undervoltage Lockout

The MAX5900/MAX5901 turn off the external MOSFET if

the magnitude of the input voltage is below the level set

by ON/OFF for longer than 20ms (tOFF). If ON/OFF is

left unconnected, the lockout voltage (VUVLO) defaults

to -31.5V. VUVLO may also be set to any value within

the power-supply range by using external resistors. To

set the lockout voltage to a value between -9V and

-100V, use a resistor-divider connected between GND

and VEE, with the center node of the divider connected

to ON/OFF. For example, use a 3kΩresistor (R1 in

Figure 2) from ON/OFF to VEE and calculate the other

resistor, R2, using:

where VUVLO is the desired lockout voltage, and

VON/OFF is the ON/OFF reference threshold specified in

the Electrical Characteristics table (typically 1.26V).

Figure 2 shows an example circuit with VUVLO set for

-20V. To defeat the UVLO, simply connect a single 100kΩ

resistor between ON/OFF and GND, as shown in Figure 4.

RR VUVLO

21 126 1 =× −

⎛

⎝

⎜⎞

⎠

⎟

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

_______________________________________________________________________________________ 7

HOT-SWAP CONTROLLER

OPTIONAL

-48V

VEE

GND

47kΩ

3kΩ

MAX5900

GND

ON/OFF

MAX5901

DGND

HOT-SWAP CONTROLLER #1

VEE

GND

MAX5900

GND

ON/OFF

HOT-SWAP CONTROLLER #2

VEE

GND

ON/OFF

MAX5901

MAX5900

MAX5901

Figure 2. Programmed -20V Lockout With Optional

Optocoupler On/Off Control

Figure 3. Power-Supply Sequencing

Figure 4. Defeating Undervoltage Lockout

HOT-SWAP CONTROLLER

-48V

VEE

GND

100kΩMAX5900

GND

ON/OFF

MAX5901

Power-Good Output

The power-good output, PGOOD (PGOOD), is open-

drain and asserts when the external MOSFET is fully

enhanced and VDS is less than VPG (75% of the circuit-

breaker threshold, VCB). For versions without the circuit-

breaker function (MAX5900N/MAX5901N), PGOOD

(PGOOD) asserts when the external MOSFET is fully

enhanced.

PGOOD (PGOOD) deasserts within 2µs when a circuit-

breaker event occurs or if the die temperature exceeds

+125°C. PGOOD (PGOOD) deasserts if |VEE| < |VUVLO|

for longer than 20ms or ON/OFF is held low for longer

than 20ms.

The MAX5900 PGOOD is active-low and the MAX5901

PGOOD is active-high. Both are open-drain N-channel

MOSFETs with their sources connected to VEE, and can

withstand up to 100V.

Selecting a Circuit-Breaker Threshold

The MAX5900A/MAX5901A and the MAX5900L/

MAX5901L offer a circuit-breaker function to protect the

external MOSFET and the load from the potentially

damaging effects of excessive current. As load current

flows through the external MOSFET, a voltage, VDS, is

generated from drain to source due to the MOSFET’s

on-resistance RDS(ON). The MAX5900A/MAX5901A and

MAX5900L/MAX5901L monitor VDS when the external

MOSFET is fully enhanced. If VDS exceeds the circuit-

breaker threshold, the external MOSFET is turned off

and PGOOD (PGOOD) is deasserted.

To accommodate different MOSFETs and different load

currents, the MAX5900/MAX5901 are available with cir-

cuit-breaker threshold voltages of 200mV, 300mV, and

400mV.

The circuit-breaker function is intended to disconnect

the load if a gross overcurrent or short-circuit condition

occurs. For calculating the circuit-breaker threshold,

use the MOSFET’s RON at the worst possible operating

condition, and add a 25% overcurrent margin to the

maximum circuit current. For instance, if a MOSFET has

an RON of 0.06Ωat TA= +25°C, and a normalized on-

resistance factor of 1.75 at TA= +130°C (from the

MOSFET data sheet), the RON used for calculation is

the product of these two numbers, or (0.06Ω) x (1.75) =

0.105Ω. Then, if the maximum current is expected to be

2A, using a 25% margin, the current for calculation is

(2A) x (1.25) = 2.5A. The resulting minimum circuit-

breaker threshold is then the product of these two

results, or (0.105Ω) x (2.5A) = 0.263V. The next highest

minimum available threshold is 0.265V of the

MAX590_ _BEUT, which is an ideal choice given these

parameters. Using this method to choose a circuit-

breaker threshold allows the circuit to operate under

worst-case conditions without causing a circuit-breaker

fault, but the circuit-breaker function will still operate if a

short-circuit or gross overcurrent condition occurs. See

Table 1 for MOSFET suggestions. The MAX5900N/

MAX5901N have no circuit-breaker function. For these

parts choose an external MOSFET that meets the load

requirements.

Determining Inrush Current

Determining a circuit’s inrush current is necessary to

help choose the proper MOSFET. The MAX5900/

MAX5901 regulate the inrush current by means of con-

trolling the load voltage slew rate, but inrush current is

also a function of load capacitance. Determine inrush

current using:

where C is the load capacitance, and SR is the

MAX5900/MAX5901 Load Voltage Slew-Rate

Magnitude from the Electrical Characteristics table. For

example, assuming a load capacitance of 100µF, and

using the typical value of 10V/ms for the slew rate, the

inrush current is 1A typical.

If the maximum possible Load Voltage Slew Rate is

used, the maximum inrush current calculates to 1.7A.

Choose a MOSFET with a maximum pulsed current

specification that exceeds the maximum inrush current.

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

8 _______________________________________________________________________________________

M A XIM U M

ILOA D

( A )

SU GG ESTED

EXTER N AL

M O SF ET

SU GG ESTED

M A XIM PA R T

0.25 IRFL110 M AX 590_ _C E U T

0.5 IRFL4310 M AX 590_ _BE U T

1 IRFR3910 M AX 590_ _C E U T

2 IRF540NS M AX 590_ _BE U T

3 IRF1310NS M AX 590_ _BE U T

4 IRF1310NS M AX 590_ _C E U T

Suggested External MOSFETs

VIN = -9V to -90V

IS==×CdV

dt CR

Layout Guidelines

Good thermal contact between the MAX5900/

MAX5901 and the external MOSFET is essential for the

thermal shutdown feature to operate effectively. Place

the MAX5900/MAX5901 as close as possible to the

drain of the external MOSFET, and use wide circuit

board traces for good heat transfer. See Figure 5 for an

example of a PC board layout.

Chip Information

TRANSISTOR COUNT: 678

PROCESS: BiCMOS

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

_______________________________________________________________________________________ 9

Figure 5. Circuit Board Layout Example

GROUND

POWER IN

POWER

OUT

SOT-223

SDG

SOT23-6 MAX5900/MAX5901

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

VIN

100µF

MAX5900

MAX5901

100kΩ

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

VIN

50kΩ

MAX5900

MAX5901

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

VIN MAX5900

MAX5901

100kΩ

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

48V MAX5900A

MAX5901A

50kΩ

SCOPE

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

48V

MAX5900

MAX5901

50kΩRL

SCOPE

GND

ON/OFF

VEE GATE DRAIN

PGOOD

(PGOOD)

48V MAX5900

MAX5901

50kΩ

SCOPE SCOPE

SCOPE

(a) SUPPLY CURRENT

(e) TURN-ON WAVEFORMS

(b) VUVLO

(d) RETRY TIMEOUT

(f) CIRCUIT-BREAKER EVENT

Figure 6. Test Circuits

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

10 ______________________________________________________________________________________

Selector Guide

+Denotes lead-free package.

PART CIRCUIT-BREAKER

FUNCTION

CIRCUIT-BREAKER

THRESHOLD

(mV)

POWER-GOOD

OUTPUT LOGIC TOP MARK

MAX5900NNEUT+T None None Active-Low AAQV

MAX5900AAEUT+T Autoretry 200 Active-Low AAQJ

MAX5900ABEUT+T Autoretry 300 Active-Low AAQK

MAX5900ACEUT+T Autoretry 400 Active-Low AAQL

MAX5900LAEUT+T Latched 200 Active-Low AAQM

MAX5900LBEUT+T Latched 300 Active-Low AAQN

MAX5900LCEUT+T Latched 400 Active-Low AAQO

MAX5901NNEUT+T None None Active-High AAQW

MAX5901AAEUT+T Autoretry 200 Active-High AAQP

MAX5901ABEUT+T Autoretry 300 Active-High AAQQ

MAX5901ACEUT+T Autoretry 400 Active-High AAQR

MAX5901LAEUT+T Latched 200 Active-High AAQS

MAX5901LBEUT+T Latched 300 Active-High AAQT

MAX5901LCEUT+T Latched 400 Active-High AAQU

PART CIRCUIT-BREAKER

FUNCTION

CIRCUIT-BREAKER

THRESHOLD

(mV)

POWER-GOOD

OUTPUT LOGIC TOP MARK

MAX5900NNETT+T None None Active-Low AJT

MAX5900AAETT+T Autoretry 200 Active-Low AJU

MAX5900ABETT+T Autoretry 300 Active-Low AJV

MAX5900ACETT+T Autoretry 400 Active-Low AJW

MAX5900LAETT+T Latched 200 Active-Low AJX

MAX5900LBETT+T Latched 300 Active-Low AJY

MAX5900LCETT+T Latched 400 Active-Low AJZ

MAX5901NNETT+T None None Active-High AKA

MAX5901AAETT+T Autoretry 200 Active-High AKB

MAX5901ABETT+T Autoretry 300 Active-High AKC

MAX5901ACETT+T Autoretry 400 Active-High AKD

MAX5901LAETT+T Latched 200 Active-High AKE

MAX5901LBETT+T Latched 300 Active-High AKF

MAX5901LCETT+T Latched 400 Active-High AKG

SOT23

TDFN

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

______________________________________________________________________________________ 11

VEE

ON/OFF

HOT-SWAP CONTROLLER

GND

-48V

50W ISOLATED

POWER SUPPLY

GND

INDIV

V+

1MΩ

39kΩ

MAX5003*

GATE

DRAIN

PGOOD

IR540NS

GND

*MAX5003 IS A 110V PWM CONTROLLER.

CIRCUIT CARD

MAX5901

BACKPLANE

FUSE

Typical Operating Circuits (continued)

MAX5900

MAX5901

VEE

DRAIN

GATE

ON/OFF

PGOOD (PGOOD)

GND

* EXPOSED PAD

( ) ARE FOR MAX5901 ONLY.

* EXPOSED PAD CONNECTED TO VEE.

TDFN

3mm x 3mm

TOP VIEW

Pin Configurations (continued)

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

12 ______________________________________________________________________________________

6LSOT.EPS

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.)

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

______________________________________________________________________________________ 13

6, 8, &10L, DFN THIN.EPS

21-0137

PACKAGE OUTLINE, 6,8,10 & 14L,

TDFN, EXPOSED PAD, 3x3x0.80 mm

Package Information (continued)

(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.)

MAX5900/MAX5901

-100V, SOT23/TDFN, Simple Swapper

Hot-Swap Controllers

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.

14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

COMMON DIMENSIONS

SYMBOL MIN. MAX.

A 0.70 0.80

D 2.90 3.10

E 2.90 3.10

A1 0.00 0.05

L 0.20 0.40

PKG. CODE N D2 E2 eJEDEC SPEC b[(N/2)-1] x e

PACKAGE VARIATIONS

0.25 MIN.k

A2 0.20 REF.

2.30±0.101.50±0.106T633-1 0.95 BSC MO229 / WEEA 1.90 REF0.40±0.05

1.95 REF0.30±0.050.65 BSC2.30±0.108T833-1

2.00 REF0.25±0.050.50 BSC2.30±0.1010T1033-1

2.40 REF0.20±0.05- - - - 0.40 BSC1.70±0.10 2.30±0.1014T1433-1

1.50±0.10

MO229 / WEEC

MO229 / WEED-3

0.40 BSC - - - - 0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10

T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF

T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

-DRAWING NOT TO SCALE-

H22

21-0137

PACKAGE OUTLINE, 6,8,10 & 14L,

TDFN, EXPOSED PAD, 3x3x0.80 mm

2.30±0.10 MO229 / WEED-3 2.00 REF0.25±0.05

0.50 BSC

1.50±0.1010T1033-2

Package Information (continued)

(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.)

Revision History

Pages changed at Rev 5: 1–4, 10, 12–14

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MAX5900LCEUT+T MAX5900NNETT+T MAX5900NNEUT+T MAX5901AAETT+T MAX5901AAEUT+T

MAX5901ABETT+T MAX5901ABEUT+T MAX5901ACETT+T MAX5901ACEUT+T MAX5901LAETT+T

MAX5901LAEUT+T MAX5901LBETT+T MAX5901LBEUT+T MAX5901LCETT+T MAX5901LCEUT+T

MAX5901NNETT+T MAX5901NNEUT+T MAX5900ABETT+T