Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - hot swap controller -48 V SOIC 8 Surface-mount

General Description

The MAX5921/MAX5939 hot-swap controllers allow a cir-

cuit card to be safely hot plugged into a live backplane.

The MAX5921/MAX5939 operate from -20V to -80V and

are well suited for -48V power systems. These devices

are pin compatible with both the LT1640 and LT4250 and

provide improved features over these devices.

The MAX5921/MAX5939 provide a controlled turn-on to

circuit cards preventing damage to board connectors,

board components, and preventing glitches on the

power-supply rail. The MAX5921/MAX5939 provide

undervoltage, overvoltage, and overcurrent protection.

These devices ensure that the input voltage is stable

and within tolerance before applying power to the load.

Both the MAX5921 and MAX5939 protect a system

against overcurrent and short-circuit conditions by turn-

ing off the external MOSFET in the event of a fault con-

dition. The MAX5921/MAX5939 protect against input

voltage steps by limiting the load current to a safe level

without turning off power to the load.

The device features an open-drain power-good status

output, PWRGD or PWRGD for enabling downstream

converters (see Selector Guide). A built-in thermal shut-

down feature is also included to protect the external

MOSFET in case of overheating. The MAX5939 features

a latched fault output. The MAX5921 contains built-in

autoretry circuitry after a fault condition.

The MAX5921/MAX5939 are available in an 8-pin SO

package and operate in the extended -40°C to +85°C

temperature range.

Applications

Telecom Line Cards

Network Switches/Routers

Central-Office Line Cards

Server Line Cards

Base-Station Line Cards

Features

♦ Allows Safe Board Insertion and Removal

from a Live -48V Backplane

♦ Pin-Compatible with LT1640 and LT4250

♦ Circuit Breaker Immunity to Input Voltage Steps

and Current Spikes

♦ 450mA GATE Pulldown Current During Short-

Circuit Condition

♦ Exponential GATE Pulldown Current

♦ Withstands -100V Input Transients with No

External Components

♦ Programmable Inrush and Short-Circuit Current

Limits

♦ Operates from -20V to -80V

♦ Programmable Overvoltage Protection

♦ Programmable Undervoltage Lockout

with Built-In Glitch Filter

♦ Overcurrent Fault Integrator

♦ Powers Up into a Shorted Load

♦ Power-Good Control Output

♦ Thermal Shutdown Protects External MOSFET

MAX5921/MAX5939

-48V Hot-Swap Controllers with External

SENSE

and High Gate Pulldown Current

________________________________________________________________ Maxim Integrated Products 1

GATE

SENSEV

DRAINOV

PWRGD

(PWRGD)

TOP VIEW

MAX5921

MAX5939

() FOR MAX5921B/F AND MAX5939B/F.

Pin Configuration

Ordering Information

19-2946; Rev 1; 2/06

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

MAX5921AESA -40°C to +85°C 8 SO

MAX5921BESA -40°C to +85°C 8 SO

Typical Operating Circuit and Selector Guide appear at end

of data sheet.

Ordering Information continued at end of data sheet.

Summary of content (18 pages)

PAGE 1
9-2946; Rev 1; 2/06 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current Features The MAX5921/MAX5939 hot-swap controllers allow a circuit card to be safely hot plugged into a live backplane. The MAX5921/MAX5939 operate from -20V to -80V and are well suited for -48V power systems. These devices are pin compatible with both the LT1640 and LT4250 and provide improved features over these devices.
PAGE 2
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current ABSOLUTE MAXIMUM RATINGS All Voltages Are Referenced to VEE, Unless Otherwise Noted Supply Voltage (VDD - VEE )................................-0.3V to +100V DRAIN, PWRGD, PWRGD ....................................-0.3V to +100V PWRGD to DRAIN .............................................… -0.3V to +95V PWRGD to VDD .......................................................-95V to +85V SENSE (Internally Clamped) ....
PAGE 3
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current (VEE = 0V, VDD = 48V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C, unless otherwise noted.) (Notes 1, 4) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VDRAIN = 48V 10 80 250 µA 1.1 1.7 2.0 V 1.0 1.6 2.
PAGE 4
Typical Operating Characteristics (VDD = +48V, VEE = 0V, TA = +25°C, unless otherwise noted.) TA = +25°C TA = +85°C 500 TA = +25°C 400 TA = -40°C 300 12 11 10 200 9 100 8 0 7 40 60 80 54 52 50 48 46 44 42 40 0 20 40 60 80 -40 100 -15 10 35 60 85 GATE PULLUP CURRENT vs. TEMPERATURE GATE PULLDOWN CURRENT vs. TEMPERATURE AFTER A FAULT GATE PULLDOWN CURRENT vs. OVERDRIVE DURING A CURRENT FAULT 44.4 44.2 44.0 43.8 43.6 43.
PAGE 5
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current MAX5921/MAX5939 V+ 5V R 5kΩ PWRGD/PWRGD VDD + OV VOV DRAIN VS +48V - VDRAIN MAX5921 MAX5939 UV GATE VEE SENSE VUV VSENSE Figure 1a. Test Circuit 1 + PWRGD/PWRGD VS VDD + OV DRAIN VS MAX5921 MAX5939 IRF530 0.1µF UV VEE 10kΩ 10Ω GATE VUV +48V - +20V - SENSE Figure 1b.
PAGE 6
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current Timing Diagrams 2V 1.255V 2V 1.205V OV 1.255V 1.125V UV 0V tPLHUV tPHLUV 0V tPHLOV tPLHOV GATE GATE 1V 1V 1V Figure 2. OV to GATE Timing 1V Figure 3. UV to GATE Timing 100mV 60mV SENSE UV VEE tPHLCL tPHLSENSE GATE 1V GATE 1V Figure 4a. SENSE to GATE Timing 6 Figure 4b.
PAGE 7
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current DRAIN 1.4V 1.4V ∆VGATE - VGATE = 0V VEE tPHLDL GATE tPHLGH PWRGD 1V PWRGD VEE 1V VEE 1.4V DRAIN ∆VGATE - VGATE = 0V 1.4V GATE VEE tPHLDL tPHLGH PWRGD VEE PWRGD 1V VDCEN - VDRAIN = 0V 1V VDCEN - VDRAIN = 0V Figure 5a. DRAIN to PWRGD/PWRGD Timing Figure 5b.
PAGE 8
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current MAX5921/MAX5939 Pin Description PIN MAX5921A/ MAX5921E MAX5939A/ MAX5939E MAX5921B/ MAX5921F MAX5939B/ MAX5939F 1 — NAME FUNCTION PWRGD Power-Good Signal Output. PWRGD is an active-low open-drain status output referenced to VEE. PWRGD latches low when VDRAIN - VEE ≤ VDL and VGATE > ∆VGATE indicating a power-good condition. PWRGD is open drain otherwise. Power-Good Signal Output.
PAGE 9
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current Board Removal If the circuit card is removed from the backplane, the voltage at the UV falls below the UVLO detect threshold, and the MAX5921/MAX5939 turn off the external MOSFET. Power-Supply Ramping Current Limit and Electronic Circuit Breaker The MAX5921/MAX5939 can reside either on the backplane or the removable circuit board (Figure 6a).
PAGE 10
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current Load Current Regulation (Short-Circuit Condition) INRUSH CURRENT 1A/div GATE - VEE 10V/div DRAIN 50V/div VEE 50V/div 4ms/div Figure 6b. Inrush Control Waveforms If the voltage between VEE and SENSE reaches the current-limit trip voltage (VCL), the MAX5921/MAX5939 pull down the GATE and regulate the current through the external MOSFET such that VSENSE - VEE < VCL.
PAGE 11
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current VEE 20V/div DRAIN 20V/div GATE - VEE 10V/div INRUSH CURRENT 5A/div 1ms/div MAX5921/MAX5939 DRAIN 50V/div ID (Q1) 2A/div 400µs/div Figure 7. Short-Circuit Protection Waveform Figure 8. Voltage Step-On Input Supply Figure 10 shows how to program the undervoltage and overvoltage trip thresholds using three resistors. With R4 = 549kΩ, R5 = 6.49kΩ, and R6 = 10kΩ, the undervoltage threshold is set to 38.
PAGE 12
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current -48V RTN (SHORT PIN) -48V RTN R4 VGATE - VEE 2V/div VUV = 1.255 8 3 R4 + R5 + R6 R5 + R6 VDD UV R5 ID (Q1) 2A/div R4 + R5 + R6 VOV = 1.255 R6 2 MAX5921 MAX5939 OV VEE R6 -48V 10ms/div Figure 9. Automatic Restart After a Short Circuit Overcurrent Fault Integrator The MAX5921/MAX5939 feature an overcurrent fault integrator.
PAGE 13
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current MAX5921/MAX5939 ACTIVE-HIGH ENABLE MODULE -48V RTN (SHORT PIN) -48V RTN VIN+ VOUT+ VDD R4 MAX5921B/F MAX5939B/F UV PWRGD I1 ON/OFF Q2 C3 Q3 VGH R5 VIN∆VGATE * OV VOUT- VEE VDL DRAIN R6 VEE SENSE GATE R3 C2 R2 R1 -48V Q1 *DIODES INC. SMAT70A Figure 11.
PAGE 14
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current -48V RTN (SHORT PIN) PWRGD GND R4 549kΩ 1% VDD MAX5921A MAX5921E MAX5939A MAX5939E UV R5 6.49kΩ 1% OV * R6 10kΩ 1% R7 51kΩ 5% VEE SENSE R1 0.02Ω 5% PWRGD GATE R2 10Ω 5% -48V *DIODES INC. SMAT70A DRAIN R3 1kΩ 5% C3 100µF 100V C2 15nF 100V Q1 IRF530 Figure 13.
PAGE 15
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current t1 t3H t5H VOL VSENSE t2L t4L VGATE 500µs x 128 Figure 14. MAX5921A Overcurrent Fault Example The lowest practical RDS(ON), within budget constraints and with values from 14mΩ to 540mΩ, are available at 100V breakdown. Ensure that the temperature rise of Q1 junction is not excessive at normal load current for the package selected.
PAGE 16
MAX5921/MAX5939 -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current Selector Guide PART MAXIMUM CURRENT-LIMIT MAXIMUM CURRENT-LIMIT DURATION (ms) DUTY CYCLE DCEN POLARITY FAULT MANAGEMENT MAX5921AESA Active-Low PWRGD Autoretry 0.5 1/128 MAX5921BESA Active-High PWRGD Autoretry 0.5 1/128 MAX5921EESA Active-Low PWRGD Autoretry 2 1/128 MAX5921FESA Active-High PWRGD Autoretry 2 1/128 MAX5939AESA Active-Low PWRGD Latched 0.
PAGE 17
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current BACKPLANE CIRCUIT CARD GND GND (SHORT PIN) VDD UV MAX5921 MAX5939 OV VEE SENSE GATE PWRGD DRAIN VIN+ LUCENT JW050A1-E INPUT1 -48V (INPUT1) N VIN- -48V (INPUT2) INPUT2 ______________________________________________________________________________________ 17 MAX5921/MAX5939 Typical Operating Circuit
PAGE 18
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.) DIM A A1 B C e E H L N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .