19-1988; Rev 3; 8/03 -100V SOT23 Simple Swapper Hot-Swap Controllers 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 packages, 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. 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 Package Ordering Information PART TEMP RANGE PIN-PACKAGE MAX5900_ _EUT-T* -40°C to +85°C 6 SOT23-6 MAX5901_ _EUT-T* -40°C to +85°C 6 SOT23-6 *For specific part numbers, see Selector Guide at end of data sheet. _________________________Applications TelecomNo Line Cards Sense Resistor Network Switches ♦ Requires External Network Routers Servers Base-Station Line Cards Pin Configuration TOP VIEW VEE 1 Typical Operating Circuits DRAIN 2 ON/OFF 5 PGOOD (PGOOD) 4 GND 50W ISOLATED POWER SUPPLY BACKPLANE CIRCUIT CARD GND MAX5900 MAX5901 6 GATE 3 HOT-SWAP CONTROLLER V 1+ LUCENT JWO50A1 MAX5900 GND ON/OFF VEE ON/OFF PGOOD SOT23-6 ( ) ARE FOR MAX5901 ONLY. DRAIN GATE V 1- Typical Operating Circuits continued at end of data sheet. -48V FUSE IRF540NS Simple Swapper is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX5900/MAX5901 General Description The MAX5900/MAX5901 are SOT23 hot-swap controllers 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 current by gradually turning on the external MOSFET. Once the external MOSFET is fully enhanced, the circuit breaker function is enabled and the MAX5900/MAX5901 provide overcurrent protection by monitoring the voltage drop across the external MOSFET’s on-resistance. The MAX5900/MAX5901 include an undervoltage lockout (UVLO) function, ON/OFF control input, and a powergood status output, PGOOD (MAX5900) or PGOOD (MAX5901). A built-in thermal shutdown feature is also included to protect the external MOSFET in case of overheating. MAX5900/MAX5901 100V SOT23 Simple Swapper Hot-Swap Controllers ABSOLUTE MAXIMUM RATINGS 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 Maximum Junction Temperature .....................................+150°C Storage Temperature Range .............................-60°C to +150°C Lead Temperature...........................................................(Note 1) Note 1: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. This limit permits only the use of solder profiles recommended in the industry standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow. Preheating is required. Hand or wave soldering is not allowed. 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 (VEE = -9V to -100V, GND = 0, ON/OFF open circuit, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VEE = -48V and TA = +25°C.) (Notes 2, 3) PARAMETER SYMBOL Supply Voltage VEE Supply Current IGND CONDITIONS Measured at GND Load Voltage Slew Rate Magnitude Default UVLO VGS SR VUVLO VGATE - VEE Drain to VEE Resistance ON/OFF Reference Threshold VEE = -100V 8 10 11.6 V VEE = -9V 6 7 4.5 10 17 V/ms -34.5 -31.5 -28.5 V 50 kΩ | dVDRAIN/dt |, CLOAD = 10µF, VEE = -9V to -36V |VEE| increasing 20 RDVEE VON/OFF 32 V 466 (VON/OFF - VEE) increasing 1.14 1.26 kΩ 1.38 140 tON tOFF 2 mA 1.3 11.6 RON/OFF ON/OFF Off Delay (Note 5) Restart Delay (Note 4) V 3.5 Start Delay (Note 4) Circuit Breaker Delay (Note 6) UNITS -9 0.5 ON/OFF Hysteresis Circuit Breaker Threshold MAX 9.5 UVLO Hysteresis ON/OFF Input Resistance TYP 7.5 VEE = -36V to -72V External Gate Drive MIN -100 VCB tCB tRS (VDRAIN - VEE) > VCB until (VGATE - VEE ) < 1V, 200mV overdrive step mV 150 300 500 ms 9 20 32 ms MAX590_ _AEUT 170 200 240 MAX590_ _BEUT 265 300 345 MAX590_ _CEUT 365 400 455 VGATE - VEE < 1V VDRAIN - VEE V CGATE = 1nF 1.5 3 CGATE = 4.7nF 2.5 4.5 CGATE = 10nF 4 6 300 500 After circuit breaker event, MAX590_A_EUT only 150 _______________________________________________________________________________________ mV µs ms -100V SOT23 Simple Swapper Hot-Swap Controllers (VEE = -9V to -100V, GND = 0, ON/OFF open circuit, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VEE = -48V and TA = +25°C.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PGOOD (PGOOD) Assertion Threshold (Note 7) VPG VDRAIN - VEE; MAX590_A, MAX590_L only PGOOD (PGOOD) Output Low Voltage VOL MAX5900, VPGOOD - VEE, IOL = 1mA; MAX5901, VPGOOD - VEE, IOL = 1mA 0.6 1.65 V Power-Good Output OpenDrain Leakage Current IOH VPGOOD - VEE = 100V (MAX5900); VPGOOD - VEE = 100V (MAX5901) 0.2 10 µA Thermal Shutdown Temperature TSD Junction temperature Thermal Shutdown Hysteresis THY 0.75 ✕ VCB mV +125 °C 15 °C Note 2: 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 3: All specifications are 100% tested at TA = +25°C. Specifications over -40°C to +85°C are guaranteed by characterization. Note 4: This is the delay time from a valid on condition until VGS begins rising. Valid on conditions are: the device is not in undervoltage lockout; ON/OFF is not driven low; and the device is not in thermal shutdown. Note 5: 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 6: Guaranteed by design, not production tested. Note 7: For a detailed description, see the Power-Good Output section of the data sheet. Typical Operating Characteristics (VEE = -48V, GND = 0, and TA = +25°C, unless otherwise noted. See Figure 6 for test circuits.) 100kΩ FROM ON/OFF TO GND 1.0 VEE = -75V 0.85 0.80 0.8 VEE = -48V VUVLO (V) IEE (mA) 0.9 MAX5900/1 toc02 0.90 MAX5900/01 toc01 1.1 SUPPLY CURRENT (mA) DEFAULT UNDERVOLTAGE LOCKOUT vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 0.75 0.70 VEE = -12V 0.7 0.65 0.6 0.55 -100 -80 -60 -40 INPUT VOLTAGE (V) -20 0 DECREASING |VEE| INCREASING |VEE| -35.5 -36.5 -37.5 0.60 0.5 -25.5 -26.5 -27.5 -28.5 -29.5 -30.5 -31.5 -32.5 -33.5 -34.5 MAX9500/01 toc03 SUPPLY CURRENT vs. INPUT VOLTAGE -50 -25 0 25 50 75 TEMPERATURE (°C) 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX5900/MAX5901 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VEE = -48V, GND = 0, and TA = +25°C, unless otherwise noted. See Figure 6 for test circuits.) GATE DRIVE VOLTAGE vs. INPUT VOLTAGE STARTUP WAVEFORMS (RL = 90Ω, CL = 100µF) MAX5900/01 toc05 450 MAX5900/1 toc04 10.5 400 10.0 A 0 350 tRS (ms) 9.5 9.0 8.5 MAX5900/01 toc06 RESTART DELAY vs. TEMPERATURE 11.0 0 B 0 C 300 250 8.0 0 200 7.5 7.0 D 150 -60 -40 -20 0 -50 -25 0 25 50 75 TEMPERATURE (°C) STARTUP WAVEFORMS RL = OPEN, CL = 10µF STARTUP WAVEFORMS RL = 40Ω, CL = 10µF A 100 125 A: VGS, 5V/div B: IIN, 1A/div A 0 0 0 B 0 B 0 B 0 C 0 C 0 C D 0 D 0 D 5ms/div A: VGS, 10V/div B: IIN, 1A/div CIRCUIT BREAKER EVENT (CGATE = 1000pF, VOVERDRIVE = 20mV) B 0 B 0 C 0 C 0 SLEW RATE vs. VEE TA = +120°C 11 SLEW RATE (V/ms) A 0 C: VOUT, 50V/div D: PGOOD, 50V/div 12 MAX5900/1 toc11 0 A: VGS, 10V/div B: IIN, 1A/div C: VOUT, 50V/div D: PGOOD, 50V/div CIRCUIT BREAKER EVENT (CGATE = 1000pF, VOVERDRIVE = 200mV) MAX5900/1 toc10 A 5ms/div 5ms/div C: VOUT, 50V/div D: PGOOD, 50V/div C: VEE, 50V/div D: VDRAIN, 40V/div A 0 A: VGS, 10V/div B: IIN, 200mA/div 40ms/div STARTUP WAVEFORMS RL = 40Ω, CL = 100µF MAX5900/1 toc08 INPUT VOLTAGE (V) MAX5900/1 toc09 -80 MAX5900/1 toc07 -100 MAX5900/01 toc12 VGS (V) MAX5900/MAX5901 -100V SOT23 Simple Swapper Hot-Swap Controllers 10 9 TA = +25°C 8 TA = -40°C 7 6 2µs/div D: PGOOD, 50V/div B: VDS, 500mV/div 4 C: VGS, 10V/div 2µs/div D: PGOOD, 50V/div B: VDS, 500mV/div C: VGS, 10V/div -100 -80 -60 -40 VEE (V) _______________________________________________________________________________________ -20 0 -100V SOT23 Simple Swapper Hot-Swap Controllers PIN MAX5900 MAX5901 1 1 NAME VEE FUNCTION 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 (aee Layout Guidelines). 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. 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 Undervoltage Lockout in the Applications Information section of this datasheet. Internally clampted to nominally 3V through a 1kΩ resistor (see Figure 1). 6 6 Detailed Description The MAX5900/MAX5901 are integrated hot-swap controller ICs contained in 6-pin SOT23 packages. They allow a board to be safely hot plugged into a live backplane without causing a glitch on the power-supply rail. They are well suited for -48V telecom power systems, allowing a cost-effective, simple, and compact 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 MOSFET 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 undervoltage 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, allowing the voltage on the load, i.e. the drain of the MOSFET, to fall no faster than 10V/ms (typ). The inrush MAX5900 MAX5901 GND 828kΩ* ON/OFF CONTROL LOGIC 1kΩ* 34.5kΩ* PGOOD (PGOOD) 3V N VEE VEE VEE 466kΩ* GATE DRAIN ( ) ARE FOR THE MAX5901 ONLY. * RELATIVE TOLERANCE ±1%, ABSOLUTE TOLERANCE ±20% TYPICAL. Figure 1. Functional Diagram _______________________________________________________________________________________ 5 MAX5900/MAX5901 Pin Description MAX5900/MAX5901 100V SOT23 Simple Swapper Hot-Swap Controllers 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 voltage 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 output 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 conditions are: the voltage across the MOSFET exceeds the circuit breaker threshold; the supply voltage magnitude 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 versions 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 MOSFET 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 Layout Guidelines in the Applications Information section. 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 6 available—200mV, 300mV, and 400mV. One version is available with no circuit breaker function. Circuit breaker 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 shutdown. 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-tosource voltage (VDS) for applications where a circuitbreaker 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 external MOSFET. Pulling ON/OFF to VEE for at least 20ms (t OFF) forces the MAX5900/MAX5901 to turn off the external MOSFET (see Figure 2 for a circuit example). To reset the MAX5900L/MAX5901L after a circuitbreaker 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). _______________________________________________________________________________________ -100V SOT23 Simple Swapper Hot-Swap Controllers GND OPTIONAL MAX5900 MAX5901 R2 47kΩ ON/OFF GND ON/OFF R1 3kΩ DGND VEE -48V Figure 2. Programmed -20V Lockout With Optional Optocoupler On/Off Control 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 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 HOT-SWAP CONTROLLER #1 GND MAX5900 MAX5901 GND ON/OFF C VEE HOT-SWAP CONTROLLER #2 MAX5900 MAX5901 GND ON/OFF 2C 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 3kΩ resistor (R1 in Figure 2) from ON/OFF to VEE and calculate the other resistor, R2, using: V R2 = R1 × UVLO − 1 1.26 VEE where V UVLO is the desired lockout voltage, and VON/OFF is the ON/OFF reference threshold specified in the Electrical Characteristics table (typically 1.26V). VEE Figure 3. Power-Supply Sequencing 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 overtemperature 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 spurious shutdowns due to noisy signals or momentary voltage spikes, as well as preventing accidental 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. HOT-SWAP CONTROLLER GND 100kΩ MAX5900 MAX5901 GND ON/OFF VEE -48V Figure 4. Defeating Undervoltage Lockout _______________________________________________________________________________________ 7 MAX5900/MAX5901 HOT-SWAP CONTROLLER MAX5900/MAX5901 100V SOT23 Simple Swapper Hot-Swap Controllers Power-Good Output The power-good output, PGOOD (PGOOD), is opendrain 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 circuitbreaker 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. 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 controlling the load voltage slew rate, but inrush current is also a function of load capacitance. Determine inrush current using: I=C 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 circuit 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 0.06Ω at TA = +25°C, and a normalized onresistance factor of 1.75 at T A = +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 8 dV = C × SR dt 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. Suggested External MOSFETs SUGGESTED EXTERNAL MOSFET SUGGESTED MAXIM PART 0.25 IRFL110 MAX590_ _CEUT 0.5 IRFL4310 MAX590_ _BEUT 1 IRFR3910 MAX590_ _CEUT MAXIMUM ILOAD (A) 2 IRF540NS MAX590_ _BEUT 3 IRF1310NS MAX590_ _BEUT 4 IRF1310NS MAX590_ _CEUT VIN = -9V to -90V _______________________________________________________________________________________ -100V SOT23 Simple Swapper Hot-Swap Controllers GROUND U1 SOT23-6 MAX5900/MAX5901 POWER IN M1 SOT-223 S D G POWER OUT Chip Information TRANSISTOR COUNT: 678 PROCESS: BiCMOS Figure 5. Circuit Board Layout Example GND 100kΩ VIN GND 100µF + MAX5900 V - ON/OFF MAX5901 PGOOD (PGOOD) VEE GATE VIN + V - DRAIN VEE (a) SUPPLY CURRENT 50kΩ MAX5900 V ON/OFF MAX5901 PGOOD (PGOOD) GATE DRAIN (b) VUVLO GND GND 100kΩ + VIN - 48V MAX5900 ON/OFF MAX5901 PGOOD (PGOOD) V VEE GATE + - MAX5900A ON/OFF MAX5901A PGOOD (PGOOD) VEE GATE DRAIN V DRAIN SCOPE SCOPE 50kΩ (c) GATE DRIVE VOLTAGE (d) RETRY TIMEOUT GND GND 48V + 50kΩ MAX5900 ON/OFF MAX5901 PGOOD (PGOOD) - VEE GATE RL 50kΩ CL 48V SCOPE + - MAX5900 ON/OFF MAX5901 PGOOD (PGOOD) VEE DRAIN GATE SCOPE DRAIN SCOPE SCOPE SCOPE SCOPE SCOPE SCOPE (e) TURN-ON WAVEFORMS 50kΩ (f) CIRCUIT BREAKER EVENT Figure 6. Test Circuits _______________________________________________________________________________________ 9 MAX5900/MAX5901 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. 100V SOT23 Simple Swapper Hot-Swap Controllers MAX5900/MAX5901 Selector Guide PART CIRCUIT BREAKER FUNCTION CIRCUIT BREAKER THRESHOLD POWER-GOOD OUTPUT LOGIC TOP MARK MAX5900NNEUT* None None Active-Low AAQV MAX5900AAEUT* Auto Retry 200mV Active-Low AAQJ MAX5900ABEUT* Auto Retry 300mV Active-Low AAQK MAX5900ACEUT* Auto Retry 400mV Active-Low AAQL MAX5900LAEUT* Latched 200mV Active-Low AAQM MAX5900LBEUT* Latched 300mV Active-Low AAQN MAX5900LCEUT* Latched 400mV Active-Low AAQO MAX5901NNEUT* None None Active-High AAQW MAX5901AAEUT* Auto Retry 200mV Active-High AAQP MAX5901ABEUT* Auto Retry 300mV Active-High AAQQ MAX5901ACEUT* Auto Retry 400mV Active-High AAQR MAX5901LAEUT* Latched 200mV Active-High AAQS MAX5901LBEUT* Latched 300mV Active-High AAQT MAX5901LCEUT* Latched 400mV Active-High AAQU *Requires special solder temperature profile described in the Absolute Maximum Ratings section. Typical Operating Circuits (continued) BACKPLANE 50W ISOLATED POWER SUPPLY CIRCUIT CARD GND HOT-SWAP CONTROLLER V+ MAX5901 GND ON/OFF VEE 1MΩ PGOOD MAX5003* INDIV DRAIN 39kΩ GATE GND -48V FUSE IR540NS *MAX5003 IS A 110V PWM CONTROLLER. 10 ______________________________________________________________________________________ -100V SOT23 Simple Swapper Hot-Swap Controllers 6LSOT.EPS PACKAGE OUTLINE, SOT-23, 6L 21-0058 F 1 1 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 ____________________ 11 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX5900/MAX5901 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.)