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19-3443; Rev 3; 4/10
KIT ATION EVALU ILABLE AVA
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
General Description
The MAX5924/MAX5925/MAX5926 1V to 13.2V hot-swap controllers allow the safe insertion and removal of circuit cards into live backplanes. These devices hot swap supplies ranging from 1V to 13.2V provided that the device supply voltage, VCC, is at or above 2.25V and the hotswapped supply, VS, does not exceed VCC. The MAX5924/MAX5925/MAX5926 hot-swap controllers limit the inrush current to the load and provide a circuitbreaker function for overcurrent protection. The devices operate with or without a sense resistor. When operating without a sense resistor, load-probing circuitry ensures a short circuit is not present during startup, then gradually turns on the external MOSFET. After the load probing is complete, on-chip comparators provide overcurrent protection by monitoring the voltage drop across the external MOSFET on-resistance. In the event of a fault condition, the load is disconnected. The MAX5924/MAX5925/MAX5926 include many integrated features that reduce component count and design time, including configurable turn-on voltage, slew rate, and circuit-breaker threshold. An on-board charge pump provides the gate drive for a low-cost, external n-channel MOSFET. The MAX5924/MAX5925/MAX5926 are available with open-drain PGOOD and/or PGOOD outputs. The MAX5925/MAX5926 also feature a circuit breaker with temperature-compensated R DS(ON) sensing. The MAX5926 features a selectable 0ppm/C or 3300ppm/C temperature coefficient. The MAX5924 temperature coefficient is 0ppm/C and the MAX5925 temperature coefficient is 3300ppm/C. Autoretry and latched faultmanagement configurations are available (see the Selector Guide). o o o o o o o o o o
Features
Hot Swap 1V to 13.2V with VCC 2.25V Drive High-Side n-Channel MOSFET Operation With or Without RSENSE Temperature-Compensated RDS(ON) Sensing Protected During Turn-On into Shorted Load Adjustable Circuit-Breaker Threshold Programmable Slew-Rate Control Programmable Turn-On Voltage Autoretry or Latched Fault Management 10-Pin MAX(R) or 16-Pin QSOP Packages
MAX5924/MAX5925/MAX5926
Ordering Information
PART MAX5924AEUB MAX5924BEUB MAX5924CEUB* MAX5924DEUB* MAX5925AEUB MAX5925BEUB* MAX5925CEUB* MAX5925DEUB* MAX5926EEE TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 10 MAX 10 MAX 10 MAX 10 MAX 10 MAX 10 MAX 10 MAX 10 MAX 16 QSOP-EP**
*Future product--contact factory for availability. **EP = Exposed pad.
Typical Operating Circuits
TYPICAL OPERATION WITHOUT RSENSE BACKPLANE VS VCC REMOVABLE CARD 1V TO VCC 2.25V TO 13.2V RCB CB VCC GATE SENSE OUT SC_DET RSC N VOUT
Applications
Base Stations RAID Remote-Access Servers Network Routers and Switches Servers Portable Device Bays
GND
GND
MAX5925 MAX5926
MAX is a registered trademark of Maxim Integrated Products, Inc.
SEE FIGURE 1 FOR A DETAILED TYPICAL OPERATING CIRCUIT WITHOUT RSENSE.
Selector Guide appears at end of data sheet. Pin Configurations appear at end of data sheet.
Typical Operating Circuits continued at end of data sheet.
1
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.) VCC .........................................................................-0.3V to +14V GATE*.....................................................................-0.3V to +20V All Other Pins ............-0.3V to the lower of (VCC + 0.3V) or +14V SC_DET Current (200ms pulse width, 15% duty cycle) ...140mA Continuous Current (all other pins) .....................................20mA Continuous Power Dissipation (TA = +70C) 10-Pin MAX (derate 6.9mW/C above +70C) ...........556mW 16-Pin QSOP (derate 18.9mW/C above +70C).......1509mW Operating Temperature Range ...........................-40C to +85C Junction Temperature .....................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C Soldering Temperature (reflow) .......................................+260C
*GATE is internally driven and clamped. Do not drive GATE with external source.
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
(VCC, EN (MAX5924/MAX5925), EN1 (MAX5926) = +2.7V to +13.2V; EN2 (MAX5926) = 0V; VS (see Figure 1) = +1.05V to VCC; TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = 5V, RL = 500 from OUT to GND, CL = 1F, SLEW = open, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER POWER SUPPLIES VCC Operating Range VS Operating Range Supply Current UNDERVOLTAGE LOCKOUT (UVLO) UVLO Threshold VCC UVLO Deglitch Time VCC UVLO Startup Delay LOAD-PROBE Load-Probe Resistance (Note 3) Load-Probe Timeout Load-Probe Threshold Voltage CIRCUIT BREAKER VCC = 2.7V and VCB TC = high = 1V (MAX5926), MAX5924 2.7V VCC 13.2V VCC = 2.7V, VCB = 1V, TA = +25C 2.7V VCC 13.2V, TA = +25C VCC = 2.7V and VCB = 1V, TA = +85C 2.7V VCC 13.2V, TA = +85C 37 34 30 40 40 50 37 40 50 50 60 42 50 A 60 60 70 RLP tLP VLP,TH (Note 4) 2.7V < VCC < 5V 5V < VCC < 13.2V 4 3 43 172 30 10 102 200 65 20 205 235 ms mV VUVLO tDG tD,UVLO Default value, VS and VCC increasing, Figure 1 (Note 2) 123 1.73 2.06 900 200 350 2.47 V s ms VCC VS ICC VS as defined in Figure 1 FET is fully enhanced, SC_DET = VCC 2.7 1.0 1.5 13.2 VCC 2.5 V V mA SYMBOL CONDITIONS MIN TYP MAX UNITS
ICB
Circuit-Breaker Programming Current
ICB25
TC = low (MAX5926), MAX5925 (Note 5)
ICB85
TC = low (MAX5926), MAX5925 (Note 5)
2
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
ELECTRICAL CHARACTERISTICS (continued)
(VCC, EN (MAX5924/MAX5925), EN1 (MAX5926) = +2.7V to +13.2V; EN2 (MAX5926) = 0V; VS (see Figure 1) = +1.05V to VCC; TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = 5V, RL = 500 from OUT to GND, CL = 1F, SLEW = open, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Circuit-Breaker Programming Current During Startup Circuit-Breaker Enable Threshold Circuit-Breaker Comparator Offset Voltage Fast Circuit-Breaker Offset Resistor Slow Circuit-Breaker Delay Fast Circuit-Breaker Delay Circuit-Breaker Trip Gate Pulldown Current Circuit-Breaker Temperature Coefficient OUT Current MOSFET DRIVER External Gate Drive Load Voltage Slew Rate Gate Pullup Current Capacity ENABLE COMPARATOR EN, EN1 Reference Threshold EN, EN1 Hysteresis EN, EN1 Input Bias Current DIGITAL OUTPUTS (PGOOD, PGOOD) Power-Good Output Low Voltage Power-Good Output Open-Drain Leakage Current Power-Good Trip Point Power-Good Hysteresis VOL IOH IOL = 1mA PGOOD/PGOOD = 13.2V VCB_EN 0.3 0.2 3.6 0.36 0.4 1 4.7 V A V V VEN/UVLO VEN,HYS IEN EN (MAX5924/MAX5925) = VCC, EN1 (MAX5926) = VCC VEN (MAX5924/MAX5925) or VEN1 (MAX5926) rising 0.747 0.795 30 8 50 0.850 V mV nA VGS SR IGATE VGATE - VOUT 2.7V VCC 13.2V 4.2 2.19 239 5.5 9.5 0.84 7.2 V V/ms A SLEW = open, CGATE = 10nF CSLEW = 300nF, CGATE = 10nF (Note 8) VGATE = 0V SYMBOL ICB,SU VCB,EN VCB_OS RCBF tCBS tCBF IGATE,PD TCICB IOUT Figure 3 VCB - VSENSE = 10mV VCB - VSENSE = 500mV VGATE = 2.5V, VCC = 13.2V MAX5924, TC = high (MAX5926) MAX5925, TC = low (MAX5926) 13.5 1.2 0.95 VGATE - VOUT, rising gate voltage (Note 6) 2.3 CONDITIONS MIN TYP 2 x ICB 3.6 0.3 1.9 1.6 280 27 0 3300 120 4.65 4.7 2.7 2.95 MAX UNITS A V mV k ms ns mA ppm/C A
MAX5924/MAX5925/MAX5926
VTHPGOOD VGATE - VOUT, rising gate voltage VPG,HYS
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
ELECTRICAL CHARACTERISTICS (continued)
(VCC, EN (MAX5924/MAX5925), EN1 (MAX5926) = +2.7V to +13.2V; EN2 (MAX5926) = 0V; VS (see Figure 1) = +1.05V to VCC; TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = 5V, RL = 500 from OUT to GND, CL = 1F, SLEW = open, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Autoretry Delay Input Voltage Input Bias Current Time to Clear a Latched Fault SYMBOL tRETRY VIH VIL IBIAS TCLR Logic high at 13.2V MAX5924A/MAX5924B MAX5925A/MAX5925B MAX5926 in latched mode 3 200 CONDITIONS Autoretry mode MIN 0.6 2.0 0.4 TYP 1.6 MAX 3.3 UNITS s V A S LOGIC AND TIMING (TC, LATCH (MAX5926), EN2 (MAX5926)
All devices are 100% tested at TA = +25C and +85C. All temperature limits at -40C are guaranteed by design. VCC drops 30% below the undervoltage lockout voltage during tDG are ignored. RLP is the resistance measured between VCC and SC_DET during the load-probing phase, tLP. Tested at +25C & +85C. Guaranteed by design at -40C. The circuit-breaker programming current increases linearly from VCC = 2.25V to 5V. See the Circuit-Breaker Current vs. Supply Voltage graph in the Typical Operating Characteristics. Note 6: See the Startup Mode section for more information. Note 7: VGATE is clamped to 17V (typ) above ground. Note 8: dv/dt = 330 x 10-9/CSLEW (V/ms), nMOS device used for measurement was IRF9530N. Slew rate is measured at the load. Note 1: Note 2: Note 3: Note 4: Note 5:
Typical Operating Characteristics
(VCC = 5V, CL = 1F, CSLEW = 330nF, CGATE = 10nF, RL = 500, Figure 1, TA = +25C, unless otherwise noted.)
MAX5926 SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX5924 toc01
MAX5926 SUPPLY CURRENT vs. TEMPERATURE
MAX5924 toc02
GATE-DRIVE VOLTAGE vs. SUPPLY VOLTAGE
MAX5924 toc03
2.0
2.4 VCC = VS 2.0 VCC = 13.2V 1.6
7
VCC = VS
ENABLED
1.6
6 VGATE - VS (V)
ICC (mA)
ICC (mA)
1.2
DISABLED
5
1.2 VCC = 3.0V 0.8
VCC = 5.0V
VS = 1V VS = 3V VS = VCC VS = 5V
0.8
4
VCC = 2.25V 3
0.4
0.4 0 2 4 6 8 VCC (V) 10 12 14 -40 -15 10 35 TEMPERATURE (C) 60 85
0
2 2 4 6 8 VCC (V) 10 12 14
4
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Typical Operating Characteristics (continued)
(VCC = 5V, CL = 1F, CSLEW = 330nF, CGATE = 10nF, RL = 500, Figure 1, TA = +25C, unless otherwise noted.)
MAX5924/MAX5925/MAX5926
GATE DRIVE VOLTAGE vs. TEMPERATURE
MAX5924 toc04
CIRCUIT-BREAKER CURRENT vs. HOT-SWAP VOLTAGE
MAX5924 toc05
CIRCUIT-BREAKER CURRENT vs. SUPPLY VOLTAGE (TC = 3300ppm/C)
VCC = VS
MAX5924 toc06
6.0 VCC = VS 5.5 VCC = 5.0V 5.0 VGS (V) 4.5 4.0 3.5 3.0 -40 -15 10 35 TEMPERATURE (C) 60 VCC = 3.0V
56 TC = 3300ppm/C 52
55
53 ICB (A) TC = 0ppm/C VCC = 13.2V 0 2 4 6 8 10 12 14
CB ( )
48
51
44 VCC = 13.2V 40 49
36 85 VS (V)
47 2 4 6 8 VCC (V) 10 12 14
CIRCUIT-BREAKER CURRENT vs. SUPPLY VOLTAGE (TC = 0ppm/C)
MAX5924 toc07
CIRCUIT-BREAKER PROGRAMMING CURRENT vs. TEMPERATURE
MAX5924 toc08
SLEW RATE vs. CSLEW
MAX5924 toc09
39.4 39.2 39.0 ICB (A) 38.8 38.6 38.4 38.2 2
VCC = VS
80 VCC = VS = 5V 70 60 ICB (A) TC = 3300ppm/C 50 40 TC = 0ppm/C 30 20
100
SLEW RATE (V/ms) 35 60 85
10
1
0.1 -40 -15 10 0 500 1000 CSLEW (nF) 1500 2000 TEMPERATURE (C)
4
6
8 VCC (V)
10
12
14
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5
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Typical Operating Characteristics (continued)
(VCC = 5V, CL = 1F, CSLEW = 330nF, CGATE = 10nF, RL = 500, Figure 1, TA = +25C, unless otherwise noted.)
TURN-ON WAVEFORM (CSLEW = OPEN)
MAX5924 toc10
TURN-ON WAVEFORM (CSLEW = 330nF)
MAX5924 toc11
GATE
5V/div 0V
GATE
5V/div 0V
OUT
5V/div 0V 5V/div 0V 200s/div
OUT
5V/div 0V 5V/div 0V 2ms/div
PGOOD
PGOOD
TURN-OFF WAVEFORM
MAX5924 toc12
OVERCURRENT CIRCUIT-BREAKER EVENT
MAX5924 toc13
1A/div EN1 5V/div 0V IFET 0A tCBS GATE 5V/div GATE 0V OUT PGOOD 5V/div 0V PGOOD 0V 2s/div 400s/div 0V 10V/div 0V 5V/div 10V/div
SHORT-CIRCUIT CIRCUIT-BREAKER EVENT
MAX5924 toc14
AUTORETRY DELAY
MAX5924 toc15
IFET
1A/div
EN1 tD,UVLO
5V/div 0V tRETRY
0A GATE 5V/div 0V 5V/div 0V 5V/div PGOOD 0V 2s/div SC_DET
5V/div 0V
OUT
OUT
100mV/div 0V 400ms/div
6
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Typical Operating Characteristics (continued)
(VCC = 5V, CL = 1F, CSLEW = 330nF, CGATE = 10nF, RL = 500, Figure 1, TA = +25C, unless otherwise noted.)
MAX5924/MAX5925/MAX5926
OVERCURRENT FAULT AND AUTORETRY DELAY
MAX5924 toc16
UVLO DELAY AND LOAD PROBING
MAX5924 toc17
EN1 GATE
5V/div 0V 5V/div 0V 5V/div 0V
EN1
5V/div 0V tD,UVLO tLP 5V/div 0V
SC_DET
SC_DET
OUT
200mV/div 0V 400ms/div
OUT
100mV/div 0V 40ms/div
UVLO RESPONSE
MAX5924 toc18
UVLO DEGLITCH RESPONSE
MAX5924 toc19
>tDG 2V/div GATE GATE 2V/div 0V 1V/div VCC 0V 200s/div 200s/div VCC 0V _______________________________________________________________________________________
7
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Pin Description
PIN MAX5924A/ MAX5924B/ MAX5924C/ MAX5924D/ MAX5926 MAX5925A/ MAX5925B/ MAX5925C MAX5925D 1 1 1 NAME FUNCTION
VCC
Power-Supply Input. Connect VCC to a voltage between 2.47V and 13.2V. VCC must always be equal to or greater than VS (see Figure 1). Short-Circuit Detection Output. Connect SC_DET to VOUT through a series resistor, RSC, when not using RSENSE. SC_DET forces current (limited to 200mA) into the external load through RSC at startup to determine whether there is a short circuit (load probing). Connect SC_DET directly to VCC when using RSENSE, Do not connect SC_DET to VCC when not using RSENSE in an attempt to disable load probing. ON/OFF Control Input. Drive EN high to enable the device. Drive EN low to disable the device. An optional external resistive-divider connected between VCC, EN, and GND sets the programmable turn-on voltage. Open-Drain Active-Low Power-Good Output Open-Drain Active-High Power-Good Output Ground Slew-Rate Adjustment Input. Connect an external capacitor between SLEW and GND to adjust the gate slew rate. Leave SLEW unconnected for the default slew rate. Gate-Drive Output. Connect GATE to the gate of the external n-channel MOSFET. Output Voltage. Connect OUT to the source of the external MOSFET. Circuit-Breaker Sense Input. Connect SENSE to OUT when not using an external RSENSE (Figure 1). Connect SENSE to the drain of the external MOSFET when using an external RSENSE (Figure 2). Circuit-Breaker Threshold Programming Input. Connect an external resistor, RCB, from CB to VS to set the circuit-breaker threshold voltage. Active-High ON/OFF Control Input. Drive EN1 high to enable the device when EN2 is low. Drive EN1 low to disable the device, regardless of the state of EN2. An optional external resistive-divider between VCC, EN1, and GND sets the programmable turn-on voltage while EN2 is low. Active-Low ON/OFF Control Input. Drive EN2 low to enable the device when EN1 is high. Drive EN2 high to disable the device, regardless of the state of EN1. Latch Mode Input. Drive LATCH low for autoretry mode. Drive LATCH high for latched mode. Circuit-Breaker Temperature Coefficient Selection Input. Drive TC low to select a 3300ppm/C temperature coefficient. Drive TC high to select a 0ppm/C temperature coefficient. No Connection. Not internally connected. Exposed Pad. Connect EP to GND.
2
2
2
SC_DET
3 4 -- 5 6
3 -- 4 5 6
-- 4 7 5 12
EN PGOOD PGOOD GND SLEW
7 8 9
7 8 9
13 14 15
GATE OUT SENSE
10
10
16
CB
--
--
3
EN1
--
--
6
EN2
--
--
8
LATCH
-- -- --
-- -- --
9 10, 11 EP
TC N.C. EP
8
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
BACKPLANE VS VCC REMOVABLE CARD 1V TO VCC 2.25V TO 13.2V RCB 10 CB VCC GND 1F GATE SENSE OUT SC_DET V+ ON (ON*) CL RSC 20k
EN EN2
EN (EN1**) EN2** TC**
MAX5925 MAX5926
PGOOD**
PGOOD (PGOOD*) LATCH** GND SLEW CSLEW DC-DC CONVERTER GND
*MAX5925A AND MAX5925C. **MAX5926.
Figure 1. Typical Operating Circuit (Without RSENSE)
BACKPLANE VS VCC 10
REMOVABLE CARD 1V TO VCC 2.25V TO 13.2V RCB 10 CB VCC SENSE GATE OUT SC_DET V+ ON (ON*) CL 20k RSENSE
GND
1F
EN EN2 VCC
EN (EN1**) EN2** TC**
MAX5924 MAX5926
PGOOD**
PGOOD (PGOOD*) LATCH** GND SLEW CSLEW GND
*MAX5924A AND MAX5924C. **MAX5926.
DC-DC CONVERTER
Figure 2. Typical Operating Circuit (With RSENSE)
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9
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
GATE
50k VCC CHARGE PUMP VZ = 9V
SLEW
A
N
2A
MAX5924 MAX5925 MAX5926
VCC
N CB 75k VCB,TH SLOW COMPARATOR
RLP SC_DET
VS OUT TIMER
RCBF 0.2V VCBF,TH 75k TC*** ICB PGOOD* LOGIC CONTROL VCC EN/(EN1***) VCC 0.8V VCC GND PGOOD** LATCH*** FAST COMPARATOR OSCILLATOR
SENSE
1.24V *MAX5924B, MAX5924D, MAX5925B, MAX5925D, MAX5926 ONLY. **MAX5924A, MAX5924C, MAX5925A, MAX5925C, MAX5926 ONLY. ***MAX5926 ONLY.
EN2***
Figure 3. Functional Diagram
10
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Detailed Description
The MAX5924/MAX5925/MAX5926 are hot-swap controller ICs designed for applications where a line card is inserted into a live backplane. Normally, when a line card is plugged into a live backplane, the card's discharged filter capacitors provide a low impedance that can momentarily cause the main power supply to collapse. The MAX5924/MAX5925/MAX5926 are designed to reside either in the backplane or in the removable card to provide inrush current limiting and short-circuit protection. This is achieved using an external n-channel MOSFET and an optional external current-sense resistor. Several critical parameters can be configured: * Slew rate (inrush current) * Circuit-breaker threshold * Turn-on voltage * Fault-management mode (MAX5926) * Circuit-breaker temperature coefficient (MAX5926) See the Selector Guide for a device-specific list of factory-preset features and parameters.
VCC RISES ABOVE VUVLO
MAX5924/MAX5925/MAX5926
NO ENABLE TRUE?
YES UVLO 200ms DELAY FAULT MANAGEMENT
YES
RSENSE PRESENT?
NO
DISABLE FAULT PROTECTION, ENABLE LOAD PROBE
ICB,SU = 2 x ICB DISABLE SLOW COMPARATOR
LOAD PROBE SUCCESSFUL? YES
NO
SLEW-RATE-LIMITED STARTUP
Startup Mode
It is important that both VCC and VS rise at a minimum rate of 100mV/ms during the critical time when power voltages are below those values required for proper logic control of internal circuitry. This applies for 0.5V VCC 2.5V and 0.5V VS 0.8V. This is particularly true when LATCH is tied high. The MAX5924/MAX5925/MAX5926 control an external MOSFET placed in the positive power-supply pathway. When power is first applied, the MAX5924/MAX5925/ MAX5926 hold the MOSFET off indefinitely if the supply voltage is below the undervoltage lockout level or if the device is disabled (see the EN (MAX5924/MAX5925), EN1/EN2 (MAX5926) section). If neither of these conditions exist, the device enters a UVLO startup delay period for 200ms. Next, the MAX5924/MAX5925/ MAX5926 detect whether an external sense resistor is present; and then autoconfigure accordingly (see Figure 4). * If no sense resistor is present, bilevel fault protection is disabled and load-probing circuitry is enabled (see the Load Probing section). If load probing is not successful, the fault is managed according to the selected fault management mode (see the Latched and Auto-Retry Fault Management section). If load probing (see the Load Probing section) is successful, slew-rate limiting is employed to gradually turn on the MOSFET.
NO VGS VCB,EN VGS VTHPGOOD YES ENABLE STANDARD BILEVEL FAULT PROTECTION BEGIN NORMAL OPERATION
PGOOD
Figure 4. Startup Flow Chart
* If the device detects an external RSENSE, circuitbreaker threshold is set at 2xICB, the slow comparator is disabled, the startup phase begins without delay for load probing, and slew-rate limiting is employed to gradually turn on the MOSFET. During the startup phase, the voltage at the load, VOUT, rises at a rate determined by the selected slew rate (see the Slew Rate section). The inrush current, IINRUSH, to the load is limited to a level proportional to the load capacitance, CL, and the slew rate: IINRUSH = CL x SR 1000
where SR is the slew rate in V/ms and CL is load capacitance in F. For operation with and without RSENSE, once VGATE V OUT exceeds V CB,EN , PGOOD and/or PGOOD assert. When VGATE - VOUT = VCB,EN, the MAX5924/ MAX5925/MAX5926 enable standard bilevel fault protection with normal ICB (see the Bilevel Fault Protection section).
11
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Load Probing
The MAX5924/MAX5925/MAX5926 load-probing circuitry detects short-circuit conditions during startup. Load probing is active only when no external R SENSE is detected. As the device begins load probing, SC_DET is connected to VCC through an internal switch with an on-resistance of RLP (Figure 6). VCC then charges the load with a probe current limited at 200mA. (Figure 1) IPROBE = (VCC - VOUT)/(RLP + RSC) If the load voltage does not reach VLP,TH (0.2V typ) within tLP, a short-circuit fault is detected and the startup mode is terminated according to the selected faultmanagement mode (see the Fault Management section and Figure 5). If no fault condition is present, PGOOD/PGOOD asserts at the end of the startup period (see the Turn-On Waveforms in the Typical Operating Characteristics). Load probing can only be, and must be, employed when not using an external RSENSE.
VOUT SR = dV dt CL = SMALL SR = dV dt
Normal Operation
In normal operation, after startup is complete, protection is provided by turning off the external MOSFET when a fault condition is encountered. Dual-speed/ bilevel fault protection incorporates two comparators with different thresholds and response times to monitor the current: 1) Slow comparator. This comparator has a 1.6ms (typ) response time. The slow comparator ignores low-amplitude momentary current glitches. After an extended overcurrent condition, a fault is acknowledged and the MOSFET gate is discharged. 2) Fast comparator. This comparator has a quick response time and a higher threshold voltage. The fast comparator turns off the MOSFET immediately when it detects a large high-current event such as a short circuit. In each case, when a fault is encountered, the powergood output deasserts and the device drives GATE low. After a fault, the MAX5924A, MAX5924B, MAX5925A, and MAX5925B latch GATE low and the MAX5924C, MAX5924D, MAX5925C, and MAX5925D enter the autoretry mode. The MAX5926 has selectable latched or autoretry modes. Figure 7 shows the slow comparator response to an overcurrent fault.
VOUT IINRUSH
VLP,TH (0.2V typ) CL = LARGE CL = SMALL I PROBE
PGOOD*
PGOOD**
ILOAD
ILOAD tPROBE < tLP
VGATE VTHPGOOD
Figure 5. Startup Waveform
14
3.0V TO 6.7V
VOUT
12
RLP ()
10
8
ILIM ILOAD
6 VCC = VS 4 2 4 6 8 VCC (V) 10 12 14
tCBS
*MAX5924B, MAX5924D, MAX5925B, MAX5925D, AND MAX5926 ONLY. **MAX5924A, MAX5924C, MAX5925A, MAX5925C, AND MAX5926 ONLY.
Figure 6. Load-Probe Resistance vs. Supply Voltage
12
Figure 7. Slow Comparator Response to an Overcurrent Fault
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Bilevel Fault Protection
Bilevel Fault Protection in Startup Mode Bilevel fault protection is disabled in startup mode, and is enabled when VGATE-VOUT exceeds VCB,EN at the end of the startup period. When no RSENSE is detected, neither slow nor fast comparator is active during startup because the high RD(ON) of the MOSFET when not fully enhanced would signal an artificially-high VIN-VSENSE voltage. Load probing prior to startup insures that the output is not short circuited. When RSENSE is detected, the slow comparator is disabled during startup while the fast comparator remains active. The overcurrent trip level is higher than normal during the startup period because the ICB is temporarily doubled to ICB,SU at this time. This allows higher than normal startup current to allow for output capacitor charging current. Slow Comparator The slow comparator is disabled during startup while the external MOSFET turns on. If the slow comparator detects an overload condition while in normal operation (after startup is complete), it turns off the external MOSFET by discharging the gate capacitance with I GATE,PD . The magnitude of I GATE,PD depends on the external MOSFET gate-to-source voltage, VGS. The discharge current is strongest immediately following a fault and decreases as the MOSFET gate is discharged (Figure 8a).
MAX5924/MAX5925/MAX5926
Table 1. Selecting Fault Management Mode (MAX5926)
LATCH Low High FAULT MANAGEMENT Autoretry mode Latched mode
Fast Comparator The fast comparator is used for serious current overloads or short circuits. If the load current reaches the fast comparator threshold, the device quickly forces the MOSFET off. The fast comparator has a response time of 280ns, and discharges GATE with IGATE,PD (Figure 8a). The fast comparator is disabled during startup when no RSENSE is detected
Latched and Autoretry Fault Management
The MAX5924A, MAX5924B, MAX5925A, and MAX5925B latch the external MOSFET off when an overcurrent fault is detected. Following an overcurrent fault, the MAX5924C, MAX5924D, MAX5925C, and MAX5925D enter autoretry mode. The MAX5926 can be configured for either latched or autoretry mode (see Table 1). In autoretry, a fault turns the external MOSFET off then automatically restarts the device after the autoretry delay, tRETRY. During the autoretry delay, pull EN or EN1 low to restart the device. In latched mode, pull EN or EN1 low for at least 100s to clear a latched fault and restart the device.
Power-Good Outputs
The power-good output(s) are open-drain output(s) that deassert: * When VCC < VUVLO * During tD,UVLO * When VGS < VTHPGOOD * During load probing * When disabled (EN = GND (MAX5924/MAX5925), EN1 = GND or EN2 = high (MAX5926)) * During fault management * During t RETRY or when latched off (MAX5924A, MAX5924B, MAX5925A, MAX5925B, or MAX5926 (LATCH = low)).
60 VCC = 13.2V 50 40 30 20 10 0 0 1 2 3 4 5 6 7 VGS (V)
IGATE, PD (mA)
PGOOD/PGOOD asserts only if the part is in normal mode and no faults are present.
Figure 8a. Gate Discharge Current vs. MOSFET Gate-to-Source Voltage
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13
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Undervoltage Lockout (UVLO)
UVLO circuitry prevents the MAX5924/MAX5925/ MAX5926 from turning on the external MOSFET until VCC exceeds the UVLO threshold, VUVLO, for tD,UVLO. UVLO protects the external MOSFET from insufficient gate-drive voltage, and tD,UVLO ensures that the board is fully plugged into the backplane and VCC is stable prior to powering the hot-swapped system. Any input voltage transient at VCC below the UVLO threshold for more than the UVLO deglitch period, tDG, resets the device and initiates a startup sequence. Device operation is protected from momentary input-voltage steps extending below the UVLO threshold for a deglitch period, tDG. However, the power-good output(s) may momentarily deassert if the magnitude of a negative step in VCC exceeds approximately 0.5V, and VCC drops below VUVLO. Operation is unaffected and the power-good output(s) assert(s) within 200s as shown in Figure 8b. This figure also shows that if the UVLO condition exceeds tDG = 900s (typ), the power-good output(s) again deassert(s) and the load is disconnected. IINRUSH(A) = CL dVOUT = CL x SR dt x 1000
where CL is the load capacitance in F and SR is the selected MAX5924/MAX5925/MAX5926 output slew rate in V/ms. For example, assuming a load capacitance of 100F and using the value of SR = 10V/ms, the anticipated inrush current is 1A. If a 16V/ms output slew rate is used, the inrush current increases to 1.6A. Choose SR so the maximum anticipated inrush current does not trip the fast circuit-breaker comparator during startup.
Slew Rate
The MAX5924/MAX5925/MAX5926 limit the slew rate of VOUT. Connect an external capacitor, CSLEW, between SLEW and GND to adjust the slew-rate limit. Floating SLEW sets the maximum slew rate to the minimum value. Calculate CSLEW using the following equation: CSLEW = 330 10-9 / SR where, SR is the desired slew rate in V/ms and CSLEW is in nF. This equation is valid for CSLEW 100nF. For higher SR, see the Typical Operating Characteristics. A 2A (typ) pullup current clamped to 1.4V causes an initial jump in the gate voltage, VGATE, if CGATE is small and the slew rate is slow (Figure 3). Figure 9 illustrates how the addition of gate capacitance minimizes this initial jump. CGATE should not exceed 25nF.
Determining Inrush Current
Determining a circuit's inrush current is necessary to choose a proper MOSFET. The MAX5924/MAX5925/ MAX5926 regulate the inrush current by controlling the output-voltage slew rate, but inrush current is also a function of load capacitance. Determine an anticipated inrush current using the following equation:
GATE 2V/div VCC VGATE
VS = VCC = 13.2V CSLEW = 1F CL = 10F
MOSFET ONLY 5V/div MOSFET AND CGATE = 20nF 0V
1V/div
PGOOD 200s/div
1V/div
0V
10ms/div
Figure 8b. PGOOD Behavior with Large Negative Input-Voltage Step when VS is Near VS(MIN)
Figure 9. Impact of CGATE on the VGATE Waveform
14
______________________________________________________________________________________
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
EN (MAX5924/MAX5925), EN1/EN2 (MAX5926)
The enable comparators control the on/off function of the MAX5924/MAX5925/MAX5926. Enable is also used to reset the fault latch in latch mode. Pull EN or EN1 low for 100s to reset the latch. A resistive divider between EN or EN1, VS, and GND sets the programmable turnon voltage to a voltage greater than VUVLO (Figure 10). from the potentially damaging effects of excessive current. As load current flows through RDS(ON) (Figure 12) or RSENSE (Figure 13), a voltage drop is generated. After VGS exceeds VCB,EN, the MAX5924/MAX5925/ MAX5926 monitor this voltage to detect overcurrent conditions. If this voltage exceeds the circuit-breaker threshold, the external MOSFET turns off and the power-good output(s) deassert(s). To accommodate different MOSFETs, sense resistors, and load currents, the MAX5924/MAX5925/MAX5926 voltage across RCB can be set between 10mV and 500mV. The value of the circuit-breaker voltage must be carefully selected based on VS (Figure 11).
MAX5924/MAX5925/MAX5926
Selecting a Circuit-Breaker Threshold
The MAX5924/MAX5925/MAX5926 offer a circuit-breaker function to protect the external MOSFET and the load
VS RCB R1 CB EN (EN1) R2 VCC GATE SENSE OUT
MAX5924_ MAX5925_ MAX5926
(EN2) SC_DET GND VS,TURN-ON =
RSC
( ) ARE FOR MAX5926 ONLY.
(R2 + R1) VEN/UVLO R2
No RSENSE Mode When operating without RSENSE, calculate the circuitbreaker threshold using the MOSFET's RDS(ON) at the worst possible operating condition, and add a 20% overcurrent margin to the maximum circuit current. For example, if a MOSFET has an R DS(ON) of 0.06 at T A = +25C, and a normalized on-resistance factor of 1.75 at TA = +105C, the RDS(ON) used for calculation is the product of these two numbers, or (0.06) x (1.75) = 0.105. Then, if the maximum current is expected to be 2A, using a 20% margin, the current for calculation is (2A) x (1.2) = 2.4A. The resulting minimum circuit-breaker threshold is then a product of these two numbers, or (0.105) x (2.4A) = 0.252V. Using this method to choose a circuit-breaker threshold allows the circuit to operate under worst-case conditions without causing a circuitbreaker fault, but the circuit-breaker function will still detect a short circuit or a gross overcurrent condition.
Figure 10. Adjustable Turn-On Voltage
15,000
TC = 0ppm/C
15,000
TC = 3300ppm/C VS = 1.5V VS = 1.4V
12,000 VS = 1.5V RCB(MAX) () 9000 RCB(MAX) () VS = 1.4V VS = 1.3V VS = 1.2V 3000 VS = 1.1V VS = 1.0V 0 -40 -15 10 35 60 85 TEMPERATURE (C)
12,000
9000 VS = 1.3V 6000 VS = 1.2V VS = 1.1V VS = 1.0V 0 -40 -15 10 35 60 85 TEMPERATURE (C)
6000
3000
Figure 11. Maximum Circuit-Breaker Programming Resistor vs. Temperature
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15
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
To determine the proper circuit-breaker resistor value use the following equation, which refers to Figure 12: RCB =
(ITRIPSLOW
x RDS(ON)( T)) + VCB ,OS ICB
where ITRIPSLOW is the desired slow-comparator trip current. The fast-comparator trip current is determined by the selected RCB value and cannot be adjusted independently. The fast-comparator trip current is given by: ITRIPFAST = ICB x (RCBF + RCB) VCB ,OS RDS(ON)( T)
minimum circuit-breaker threshold is then a product of this current and RSENSE = 0.06, or (0.06) x (2.4A) = 0.144V. Using this method to choose a false circuitbreaker threshold allows the circuit to operate under worst-case conditions without causing a circuit-breaker fault, but the circuit-breaker function will still detect a short-circuit or a gross overcurrent condition. To determine the proper circuit-breaker resistor value, use the following equation, which refers to Figure 13: RCB =
(ITRIPSLOW
x RSENSE) + VCB ,OS ICB
SC_DET must be connected to OUT through the selected RSC when not using RSENSE.
RSENSE Mode When operating with R SENSE , calculate the circuitbreaker threshold using the worst possible operating conditions, and add a 20% overcurrent margin to the maximum circuit current. For example, with a maximum expected current of 2A, using a 20% margin, the current for calculation is (2A) x (1.2) = 2.4A. The resulting
where, ITRIPSLOW is the desired slow-comparator trip current. The fast-comparator trip current is determined by the selected RCB value and cannot be adjusted independently. The fast-comparator trip current is given by: ITRIPFAST = ICB x (RCBF + RCB) VCB ,OS RSENSE
SC_DET should be connected to V CC when using RSENSE.
ILOAD RDS(ON)
VS
ILOAD RSENSE VOUT RCB
VS RCB
VOUT
CB
SENSE
GATE
OUT SLOW COMPARATOR
CB
GATE
SENSE OUT VCB,TH SLOW COMPARATOR
VCB,TH
MAX5925 MAX5926
RCBF
VCB,OS FAST COMPARATOR
MAX5925 MAX5926
RCBF
VCB,OS
FAST COMPARATOR TC SELECT ICB VCB,OS VCBF,TH
TC SELECT
ICB VCB,OS VCBF,TH
Figure 12. Circuit Breaker Using RDS(ON)
Figure 13. Circuit Breaker Using RSENSE
16
______________________________________________________________________________________
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Circuit-Breaker Temperature Coefficient
In applications where the external MOSFET's on-resistance is used as a sense resistor to determine overcurrent conditions, a 3300ppm/C temperature coefficient is desirable to compensate for the RDS(ON) temperature coefficient. Use the MAX5926's TC input to select the circuit-breaker programming current's temperature coefficient, TCICB (see Table 2). The MAX5924 temperature coefficient is preset to 0ppm/C, and the MAX5925's is preset to 3300ppm/C. Setting TCICB to 3300ppm/C allows the circuit-breaker threshold to track and compensate for the increase in the MOSFET's RDS(ON) with increasing temperature. Most MOSFETs have a temperature coefficient within a 3000ppm/C to 7000ppm/C range. Refer to the MOSFET data sheet for a device-specific temperature coefficent. RDS(ON) and ICB are temperature dependent, and can therefore be expressed as functions of temperature. At a given temperature, the MAX5925/MAX5926 indicate an overcurrent condition when: ITRIPSLOW x RDS(ON)(T) ICB(T) x RCB + |VCB,OS| where VCB,OS is the worst-case offset voltage. Figure 14 graphically portrays operating conditions for a MOSFET with a 4500ppm/C temperature coefficient.
MAX5924/MAX5925/MAX5926
Table 2. Programming the Temperature Coefficient (MAX5926)
TC High Low TCICB (ppm/C) 0 3300
Table 3. Suggested External MOSFETs
APPLICATION CURRENT (A) 1 2 5 10 PART International Rectifier IRF7401 Siliconix Si4378DY Siliconix SUD40N02-06 Siliconix SUB85N02-03 DESCRIPTION SO-8 SO-8 DPAK D2PAK
50 45 VCB AND VSENSE (mV) 40 35 30 25 20 -40 -15 10 35 60 85 110 TEMPERATURE (C) VS = VCC = 13.2V, RCB = 672, ITRIPSLOW = 5A, RDS(ON)(25) = 6.5m CIRCUIT-BREAKER TRIP REGION (VSENSE VCB)
Applications Information
Component Selection
n-Channel MOSFET Most circuit component values may be calculated with the aid of the MAX5924-MAX5926. The "Design calculator for choosing component values" software can be downloaded from the MAX5924-MAX5926 Quickview on the Maxim website. Select the external n-channel MOSFET according to the application's current and voltage level. Table 3 lists some recommended components. Choose the MOSFET's on-resistance, RDS(ON), low enough to have a minimum voltage drop at full load to limit the MOSFET power dissipation. High RDS(ON) can cause undesired power loss and output ripple if the board has pulsing loads or triggers an external undervoltage reset monitor at full load. Determine the device power-rating requirement to accommodate a short circuit on the board at startup with the device configured in autoretry mode. Using the MAX5924/MAX5925/MAX5926 in latched mode allows the consideration of MOSFETs with higher RDS(ON) and lower power ratings. A MOSFET can typically with-
VSENSE = RDS(ON)(T) x ILOAD(MAX) (4500ppm/C) VCB = ICB(T) x RCB + VCB,OS (3300ppm/C)
Figure 14. Circuit-Breaker Trip Point and Current-Sense Voltage vs. Temperature
stand single-shot pulses with higher dissipation than the specified package rating. Low MOSFET gate capacitance is not necessary since the inrush current limiting is achieved by limiting the gate dv/dt. Table 4 lists some recommended manufacturers and components. Be sure to select a MOSFET with an appropriate gate drive (see the Typical Operating Characteristics). Typically, for V CC less than 3V, select a 2.5V V GS MOSFET.
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17
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Table 4. Component Manufacturers
COMPONENT Sense Resistors MOSFETs MANUFACTURER Dale-Vishay IRC Fairchild International Rectifier PHONE 402-564-3131 828-264-8861 888-522-5372 310-233-3331 www.vishay.com www.irctt.com www.fairchildsemi.com www.irf.com WEBSITE
Optional Sense Resistor Select the sense resistor in conjunction with RCB to set the slow and fast circuit-breaker thresholds (see the Selecting a Circuit-Breaker Threshold section). The sense-resistor power dissipation depends on the device configuration. If latched mode is selected, PRSENSE = (IOVERLOAD)2 x RSENSE; if autoretry is selected, then P RSENSE = (I OVERLOAD ) 2 x R SENSE x (t ON /t RETRY ). Choose a sense-resistor power rating of twice the PRSENSE for long-term reliable operation. In addition, ensure that the sense resistor has an adequate I2T rating to survive instantaneous short-circuit conditions.
CSLEW =
330 x 10 -9 330 x 10 -9 = = 0.1F SR 3.3 V
ms
2) Select a MOSFET and determine the worst-case power dissipation. 3) Minimize power dissipation at full load current and at high temperature by selecting a MOSFET with an appropriate RDS(ON). Assume a 20C temperature difference between the MAX5924/MAX5925/ MAX5926 and the MOSFET. For example, at room temperature the IRF7822's RDS(ON) = 6.5m. The temperature coefficient for this device is 4000ppm/C. The maximum RDS(ON) for the MOSFET at TJ(MOSFET) = +105C is:
ppm RDS(ON)105 = 6.5m x 1 + (105C - 25C) x 4000 C = 8.58m
No-Load Operation
The internal circuitry is capable of sourcing a current at the OUT terminal of up to 120A from a voltage VIN + VGS. If there is no load on the circuit, the output capacitor will charge to a voltage above VIN until the external MOSFET's body diode conducts to clamp the capacitor voltage at VIN plus the body-diode VF. When testing or operating with no load, it is therefore recommended that the output capacitor be paralleled with a resistor of value: R = VX / 120A where VX is the maximum acceptable output voltage prior to hot-swap completion.
The power dissipation in the MOSFET at full load is: PD = I2 R = (5A)2 x 8.58m = 215mW 4) Select RCB. Since the MOSFET's temperature coefficient is 4000ppm/C, which is greater than TC ICB (3300ppm/C), calculate the circuit-breaker threshold at high temperature so the circuit breaker is guaranteed not to trip at lower temperature during normal operation (Figure 15). ITRIPSLOW = IFULL LOAD + 20% = 5A + 20% = 6A RDS(ON)105 = 8.58m (max), from step 2 ICB85 = 58A x (1 + (3300ppm/C x (85 - 25)C) = 69.5A (min) RCB =
Design Procedure
Given: * VCC = VS = 5V * CL = 150F * Full-Load Current = 5A * No RSENSE * IINRUSH = 500mA Procedures: 1) Calculate the required slew rate and corresponding CSLEW: I V SR = INRUSH = 3.3 1000 x CL ms
(ITRIPSLOW
x RDS(ON)105 ICB85
) + VCB,OS
RCB = ((6A x 8.58m) + 4.7mV)/69.5A = 808
18
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1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Layout Considerations
Keep all traces as short as possible and maximize the high-current trace dimensions to reduce the effect of undesirable parasitic inductance. Place the MAX5924/ MAX5925/MAX5926 close to the card's connector. Use a ground plane to minimize impedance and inductance. Minimize the current-sense resistor trace length (<10mm), and ensure accurate current sensing with Kelvin connections. 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. An efficient way to achieve good power dissipation on a surface-mount package is to lay out two copper pads directly under the MOSFET package on both sides of the board. Connect the two pads to the ground plane through vias, and use enlarged copper mounting pads on the top side of the board. It is important to maximize the thermal coupling between the MOSFET and the MAX5925/MAX5926 to balance the device junction temperatures. When the temperatures of the two devices are equal, the circuit-breaker trip threshold is most accurate. Keep the MOSFET and the MAX5925/MAX5926 as close to each other as possible to facilitate thermal coupling.
HIGH-CURRENT PATH
MAX5924/MAX5925/MAX5926
SENSE RESISTOR
RCB
MAX5924 MAX5925 MAX5926
Figure 15. Kelvin Connection for the Current-Sense Resistor
Selector Guide
PART MAX5924A MAX5924B MAX5924C MAX5924D MAX5925A MAX5925B MAX5925C MAX5925D MAX5926 CIRCUIT-BREAKER TEMPCO (ppm/C) 0 0 0 0 3300 3300 3300 3300 0 or 3300 (Selectable) POWER-GOOD OUTPUT FAULT MANAGEMENT Latched Latched Autoretry Autoretry Latched Latched Autoretry Autoretry Latched or Autoretry (Selectable) PGOOD (OPEN-DRAIN) -- -- -- -- PGOOD (OPEN-DRAIN) -- -- -- --
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19
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor MAX5924/MAX5925/MAX5926
Pin Configurations
TOP VIEW
VCC 1 SC_DET 2 VCC 1 SC_DET EN PGOOD (PGOOD) GND 2 3 4 5 10 CB 9 SENSE OUT GATE SLEW EN1 3 PGOOD 4 GND 5 EN2 6 PGOOD 7
EP
16 CB 15 SENSE 14 OUT 13 GATE
MAX5924 MAX5925
8 7 6
MAX5926
12 SLEW 11 N.C. 10 N.C. 9 TC
MAX
( ) FOR THE MAX5924A, MAX5924C, MAX5925A, AND MAX5925C.
LATCH 8
QSOP
Typical Operating Circuits (continued)
BACKPLANE VS VCC TYPICAL OPERATION WITH RSENSE REMOVABLE CARD RSENSE 1V TO VCC 2.25V TO 13.2V RCB CB VCC GND SENSE GATE OUT
Chip Information
TRANSISTOR COUNT: 3751 PROCESS: BiCMOS
N
VOUT
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 10 MAX 16 QSOP-EP PACKAGE CODE U10CN+1 E16E-1 DOCUMENT NO. 21-0061 21-0112
GND
MAX5924 MAX5926
SEE FIGURE 2 FOR A DETAILED TYPICAL OPERATING CIRCUIT WITH RSENSE.
20
______________________________________________________________________________________
1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense Resistor
Revision History
REVISION NUMBER 0 1 2 3 REVISION DATE 8/05 6/06 10/06 4/10 Initial release Revised data sheet title, General Description, Features, EC table, Typical Operating Circuit, and added No-Load Operation section. Initial release of MAX5924BEUB and revised EC table. Revised EC table. DESCRIPTION PAGES CHANGED -- 1-13, 15-18 1-4, 10-12 2-4
MAX5924/MAX5925/MAX5926
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 21
(c) 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

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