-48V Simple Swapper Hot-Swap Switches

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1 ; Rev a; 1/1-48V Simple Swapper Hot-Swap Switches General Description The MX5911/MX5912 are fully integrated hot-swap switches for negative supply rails. These devices allow the safe insertion and removal of circuit cards into live backplanes or ports without causing problematic glitches on the negative power-supply rail. They also monitor various circuit parameters and disconnect the load if a fault condition occurs, alerting the host with a logic-level FULT output. The MX5911/MX5912 operate over a voltage range of -16V to -65V and are designed to permit hot plugging of an IP phone into a hub, but are not limited to that operation. During startup, an internal power FET regulates the current between the backplane power source and the load to 28m for MX5911 and 415m for MX5912. fter startup, the FET is fully enhanced to reduce its on-resistance. To ensure robust operation, the MX5911/ MX5912 contain built-in safety features that prevent damage to the internal FET. They include an enable input, which responds to positive logic signals (+3.3V or +5V), allowing the host system to disconnect the load. ENLE is also used to reset the device after a latching fault condition occurs. The MX5911/MX5912 Simple Swapper hot-swap Is monitor four parameters for these fault conditions: undervoltage lockout (), power-not-good, zerocurrent detection, and thermal shutdown. These devices are available in the extended temperature range, -4 to +85. The MX5911 and MX5912 come in 8-pin and 16-pin SOI packages, respectively. pplications Features Provides Safe Hot Swap for -16V to -65V Power Supplies 28m urrent Limit for MX m urrent Limit for MX5912 Zero-urrent Load Disconnect Integrated Power FET Status Output Reports Fault ondition Internal Switch-Protection ircuitry uilt-in Thermal Shutdown an Vary Up to ±5V with Respect to GND TOP VIEW GTE FULT Ordering Information PRT TEMP. RNGE PIN-PKGE MX5911ES -4 to SO MX5912ESE -4 to SO Simple Swapper is a trademark of Maxim Integrated Products, Inc. Pin onfigurations MX GND MX5911/MX5912 IP Phones Network Routers Network Switches Internet ppliances Power-Over-LN 4 8 SO 5 ENLE Typical Operating ircuit N..* 1 16 N..* N..* 2 15 (-48V) GTE V 3.3kΩ.1µF MX5911 MX5912 LOD FULT MX GND POSITIVE LOGI FULT ENLE N..* ENLE N..* GND 16 SO GND *THESE PINS RE NOT INTERNLLY ONNETED. Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at , or visit Maxim s website at

2 MX5911/MX5912 SOLUTE MXIMUM RTINGS Voltages are with respect to GND, unless otherwise noted v to -7V...+.3V to ( -.3V) ENLE to...-.3v to +11V ENLE to...-.3v to +7V FULT to...-.3v to +11V to...-.3v to +11V...-5V to +5V to...-.3v to +7V FULT Sink urrent...1m Stresses beyond those listed under bsolute 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. ELETRIL SPEIFITIONS ontinuous Output urrent...internally Limited ontinuous Power Dissipation (T = +7 ) 8-Pin SO (derate 5.9mW/ above +7 )...47mW 16-Pin SO (derate 12.9mW/ above +7 )...139mW Operating Temperature Range...-4 to +85 Junction Temperature Storage Temperature Range...-6 to +15 Lead Temperature (soldering, 1s)...+3 ( = -48V, GND = =, = open circuit, V ENLE = +3.3V, and T = -4 to +85, unless otherwise noted. Typical values are at T = +25.) PRMETER SYMOL ONDITIONS MIN TYP MX UNITS Input Voltage Range V Supply urrent I IN Measured at GND at the end of output voltage slew Maximum urrent I OUT(MX) = + 5V DMOS On-Resistance R DS(ON) MX5911 I OUT = -225m, MX5912 I OUT = -35m Leakage urrent Measured on when internal DMOS is shut off m MX MX m Ω 1 µ ENLE Low Voltage V IL Referenced to.8 V ENLE High Voltage V IH Referenced to 2. V ENLE High Input urrent I IH V ENLE = +3.3V 14 3 µ ENLE Low Pulse Width (Note 1) t EPW 2 ns FULT Output Low Voltage V OL I FULT = 3m.4 V FULT Output Leakage urrent I OH V FULT = +3.3V 1 µ Zero-urrent Detection Threshold Zero-urrent Detection Threshold Hysteresis Zero-urrent Detection Delay (Note 2) IF TH Decreasing load current m IF HY 1.5 m IF DEL ms urrent-limit Delay (Note 3) t LIMIT shorted to GND 1 2 µs Power-Good Threshold V PG -, - decreasing V Power-Good Hysteresis PG HYS % of V PG 5 % 2

3 ELETRIL SPEIFITIONS (continued) ( = -48V, GND = =, = open circuit, V ENLE = +3.3V, and T = -4 to +85, unless otherwise noted. Typical values are at T = +25.) PRMETER SYMOL ONDITIONS MIN TYP MX UNITS Power-Not-Good Output Delay (Note 4) Thermal Shutdown Temperature (Note 5) PG DEL fter - increases above (V PG + PG HYS ) T J ms Default open circuit, increasing V Hysteresis omparator Threshold open circuit, percentage of threshold Referenced to, open circuit, increasing Note 1: Minimum ENLE low pulse width required to unlatch fault condition. Note 2: The delay from I OUT falling below the zero-current threshold until FULT is latched low and is disabled. Note 3: The time from an output overcurrent or short-circuit condition until the output goes into current limit. Note 4: The time from falling until FULT is asserted low. FULT is not latched for Power-Not-Good condition. Note 5: When the device goes into thermal shutdown, the output is disabled and FULT is latched low. o 12 % V Input Resistance R 95 kω MX5911/MX5912 Typical Operating haracteristics ( = -48V, GND = =, = open circuit, V ENLE = +3.3V, R LOD = 1.8kΩ, T = +25, unless otherwise noted.) SUPPLY URRENT (m) NO LOD SUPPLY URRENT vs. SUPPLY VOLTGE MX5911 toc1 SUPPLY URRENT (m) SUPPLY URRENT vs. MIENT TEMPERTURE NO LOD MX5911 toc2 ON-RESISTNE (Ω) ON-RESISTNE vs. MIENT TEMPERTURE I LOD = 15m MX5911 toc SUPPLY VOLTGE (V) TEMPERTURE ( ) TEMPERTURE ( ) 3

4 MX5911/MX5912 Typical Operating haracteristics (continued) ( = -48V, GND = =, = open circuit, V ENLE = +3.3V, R LOD = 1.8kΩ, T = +25, unless otherwise noted.) MX5911 TURN-ON WVEFORMS (R L = 1.8kΩ, L = NONE) MX5911 toc4 : ENLE, 5V/div :, 2V/div t = 1µs/div : FULT, 2V/div MX5911 TURN-ON WVEFORMS (R L = 1.8kΩ, L = 47µF) MX5911 toc5 t = 2ms/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div MX5911 TURN-OFF WVEFORMS (R L = 1.8kΩ, L = NONE) t = 1µs/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div MX5911 toc6 MX5911 TURN-OFF WVEFORMS (R L = 1.8kΩ, L = 47µF) MX5911 toc7 MX5911 OVERURRENT RESPONSE MX5911 ZERO-URRENT RESPONSE MX5911 toc8 MX5911 toc9 t = 1ms/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div t = 5ms/div : FULT, 5V/div : I OUT, 2m/div :, 5V/div t = 5ms/div : FULT, 5V/div : I OUT, 5m/div :, 5V/div MX5912 TURN-ON WVEFORMS (R L = 1.8kΩ, L = NONE) MX5911 toc1 MX5912 TURN-ON WVEFORMS (R L = 1.8kΩ, L = 47µF) MX5911 toc11 MX5912 TURN-OFF WVEFORMS (R L = 1.8kΩ, L = NONE) MX5911 toc12 t = 1µs/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div t = 1ms/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div t = 1µs/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div 4

5 Typical Operating haracteristics (continued) ( = -48V, GND = =, = open circuit, V ENLE = +3.3V, R LOD = 1.8kΩ, T = +25, unless otherwise noted.) MX5912 TURN-OFF WVEFORMS (R L = 1.8kΩ, L = 47µF) MX5911 toc13 t = 1ms/div : ENLE, 5V/div : FULT, 2V/div :, 2V/div MX5912 OVERURRENT RESPONSE MX5911 toc14 t = 4ms/div : FULT, 5V/div : I OUT, 2m/div :, 2V/div MX5912 ZERO-URRENT RESPONSE MX5911 toc15 t = 4ms/div : FULT, 5V/div : I OUT, 1m/div :, 2V/div MX5911/MX5912 Pin Description PIN NME MX5911 MX GTE FUNTION Gate of the Internal Power MOSFET. Normally leave open circuit. To slow down the output voltage ramp, connect two capacitors, one to and one to. See GTE onnections for details. 2 4, 5, 12, 13 Voltage Input Terminal. ypass, to GND with a.1µf capacitor to improve noise immunity. 3 6 FULT ENLE Fault Logic Output, open-drain. Tie FULT to the positive logic supply with a 3.3kΩ resistor. Referenced to. Digital Ground. Ground reference level for the external positive logic, FULT, and ENLE. can vary up to ±5V with respect to GND to accommodate differential ground voltages in large systems. ENLE Input. Turns on and off the internal FET. ENLE is a positive logiclevel input referenced to. Drive ENLE high to enable. Drive ENLE low to disable. Pulse ENLE low to reset the MX5911/ MX5912 after a latched fault condition occurs GND nalog Ground. Ground reference level for,, and Voltage Output Terminal 8 15 Undervoltage Lockout Input. Leave open circuit for default setting of -28V. lternatively, can be connected to a resistive divider to set the lockout voltage (see the hanging the Undervoltage Lockout Setting section). The comparator threshold level is V with respect to. 1, 2, 8, 9, 16 N.. No onnection. No internal connection. 5

6 MX5911/MX5912 ENLE GND V PG (min) = 1.8V V PG -, V PG (typ) = 2V V PG (max) = 2.2V POWER GOOD 2.11MΩ 99.5kΩ LEVEL SHIFTER V REF MX5911/MX5912 Figure 1. Functional lock Diagram ONTROL LOGI FULT Detailed Description Figure 1 shows a functional block diagram. The MX5911/MX5912 are hot-swap switches for negative supply rails. The devices allow the safe insertion and removal of circuit cards into live backplanes or ports without causing undue glitches on the negative powersupply rail. They operate over the -16V to -65V voltage range. The devices act as a current regulator, using their on-board FET to limit the amount of current drawn from the backplane to 28m for MX5911 and 415m for MX5912. If the load current exceeds that current limit, the internal switch behaves like a constant current source. The MX5911/MX5912 monitor the input voltage, the output voltage, the output current, and the die temperature. They assert their FULT output if they detect an error condition. zero-current load disconnect feature activates if the load current drops below 8m for over 35ms. They also GTE POWER-GOOD HYSTERESIS (5% OF V PG) POWER-NOT-GOOD DELY include an enable input that responds to positive logic, allowing the host system to turn the FET switch on or off. The enable input is also used to reset the devices after an error condition has latched the output FET off. Normal Operation Startup When power is first applied with ENLE high, or when ENLE is asserted, the MX5911/MX5912 limit the current to the load to 28m/415m. If the output voltage has not reached the power-good threshold within the 14ms power-good delay, FULT is pulled low. FULT stays low until the output voltage exceeds the power-good threshold, at which time it is released and becomes high impedance. Undervoltage Lockout Fault If, where is the desired voltage at which the fault occurs, FULT is pulled low and the internal FET is turned off. If the condition persists for over 35ms (IF DEL ), the FET is latched off. The default voltage is -28V, but it can be adjusted using an external resistive divider (see the hanging the Undervoltage Lockout Setting section). Once the FET is latched off, ENLE must be pulsed low then brought back high to release FULT and enable. Thermal Shutdown Fault The MX5911/MX5912 monitor their internal die temperatures. If the temperature of the die exceeds +14, FULT is pulled low and the internal FET is latched off. ENLE must be pulsed low and then brought high again to reset the FET latch, and release FULT, provided the die is below the thermal shutdown temperature by 5 (typ). Power-Not-Good Fault If - is more than the power-good threshold for over 14ms, FULT is pulled low. When the output voltage exceeds the power-good threshold, FULT is released. FULT output is not latched during a powernot-good fault. Zero-urrent Detection If the load current drops below 8m for over 35ms, FULT is pulled low and the FET is latched off. ENLE must be pulsed low and then brought high again to release FULT and enable. pplications Information hosing Device The MX5911 will output up to 28m (typ) and the MX5912 up to 415m (typ). In applications where high heat is expected, use the MX5912 for its superior 6

7 (-16V TO -65V) +3.3V POSITIVE LOGI 3.3kΩ R1 R2.1µF Figure 2. Voltage Set by an External Resistive Divider heat dissipation properties, and always solder all of its pins to a large section of circuit board copper. Logic ontrol The enable input responds to +3.3V logic signals and will force the internal FET off if it is pulled low. This feature allows the host to disconnect the load from the power bus if required. dditionally, all fault conditions that latch the internal FET off must be cleared by pulsing ENLE low for at least 2ns, then reasserting ENLE before normal operation can resume. GTE onnections GTE connects to the gate of the internal N-channel power MOSFET. Normally this pin should be left open circuit. To slow down the voltage ramp at VOUT, connect capacitors from GTE to and VIN. Size the capacitors so that the GTE to VIN capacitor is ten times the size of the GTE to VOUT capacitor. This technique to slow down the output voltage ramp will also cause the output discharge time to increase if the capacitor values exceed about 1nF. dditionally, this technique will cause the time delay for a power-notgood fault to increase. FULT ENLE GND MX5911 MX5912 HOOSE R1 1kΩ, THEN LULTE R2 USING: R2 = R1-1 () LOD FULT Output The FULT output is open-drain and is pulled low if the MX5911/MX5912 detect an undervoltage fault, a thermal fault, a power-not-good fault, or a zero-current fault. See the Normal Operation section for specific details of fault operation. onnect FULT to the logic supply with a pullup resistor; 3.3kΩ is sufficient in most cases. hanging the Undervoltage Lockout Setting The value defaults to -28V if the pin is left open circuit. The lockout voltage can be changed with a resistive divider. onnect the divider from to GND, and connect the center node of the divider to the pin. Figure 2 shows an example circuit. Use R1 1kΩ, then calculate R2 using: R2= R1 x where () is the desired lockout voltage. hip Information TRNSISTOR OUNT: 121 PROESS: imos ( ) MX5911/MX5912 7

8 MX5911/MX5912 Package Information SOIN.EPS 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. 8 Maxim Integrated Products, 12 San Gabriel Drive, Sunnyvale, Maxim Integrated Products Printed US is a registered trademark of Maxim Integrated Products.

+65V Simple Swapper Hot-Swap Switches

19-176; Rev ; 7/1 +65V Simple Swapper Hot-Swap Switches General Description The MX591/MX5917 are fully integrated hot-swap switches for positive supply rails. These devices allow the safe insertion and