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19-4619; Rev 2; 5/09
12V Hot-Plug Switch
General Description
The DS4560 is a self-contained hot-plug switch intended to be used on +12V power buses to limit through current and to control the power-up output-voltage ramp. The device contains an on-board 25m n-channel power MOSFET that is actively closed-loop controlled to ensure that an adjustable current limit is not exceeded. The maximum allowable current through the device is determined by an external resistor connected to the ILIM pin. The DS4560 also contains the ability to control the power-up output-voltage ramp. A capacitor connected to the VRAMP pin sets the desired voltage ramp rate. The output voltage is unconditionally clamped to keep input overvoltage stresses from harming the load. The DS4560 also contains an adjustable power-up timer. A capacitor connected to the TIMER pin determines how long after power-on reset the DS4560 should wait before starting to apply power to the load. The TIMER pin can also be driven with a digital logic output to create a device-enable function. The DS4560 contains an on-board temperature sensor with hysteresis. If operating conditions cause the device to exceed an internal thermal limit, the DS4560 either unconditionally shuts down and latches off awaiting a power-on reset (DS4560S-LO), or it waits until the device has cooled by the hysteresis amount and then restarts (DS4560S-AR). On-Board 25m Power MOSFET Adjustable Short-Circuit Current and Overload Current Limit Adjustable Output-Voltage Slew Rate Adjustable Power-Up Timer with External Enable Capability Output Overvoltage Limiting On-Board Thermal Protection On-Board Charge Pump Latchoff and Autoretry Versions Available 9.0V to 13.2V Supply Operation 8-Pin SO (150 mils) Pb-Free Package UL Certification Record E211395
Features
DS4560
Pin Configuration
TOP VIEW
GND VRAMP TIMER ILIM 1 2 3 4
+ DS4560
8 7 6 5
VCC LOAD LOAD LOAD
Applications
RAID/Hard Drives Servers/Routers PCI/PCI Express(R) InfiniBandSM Base Stations
SO (150 mils)
Ordering Information
PART DS4560S-LO+ DS4560S-LO+T DS4560S-AR+ DS4560S-AR+T THERMAL SHUTDOWN Latchoff Latchoff Autoretry Autoretry PIN-PACKAGE 8 SO 8 SO 8 SO 8 SO PIN 1 2 3 4 5, 6, 7 8 NAME GND VRAMP TIMER ILIM LOAD VCC
Pin Description
FUNCTION Ground. This is also a heat sink for the device. Output-Voltage Ramp Adjustment Power-Up Timer/Enable Current-Limit Adjustment Output Load Connection (MOSFET Source) Input Supply Voltage (MOSFET Drain)
+Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel.
PCI Express is a registered trademark of PCI-SIG Corp. InfiniBand is a trademark and service mark of the InfiniBand Trade Association.
________________________________________________________________ Maxim Integrated Products 1
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.
12V Hot-Plug Switch DS4560
ABSOLUTE MAXIMUM RATINGS
Voltage Range on VCC and LOAD Relative to GND Continuous .........................................................-0.3V to +18V 1ms Maximum ....................................................-0.3V to +22V Voltage Range on ILIM and VRAMP Relative to GND.....................................-0.3V to (VCC + 0.3V), but not to exceed +18V Voltage Range on TIMER Relative to GND ...........-0.3V to +5.0V Drain Current Continuous ...........................................................................4A Peak ...................................................................................15A Operating Junction Temperature Range ...........-40C to +135C Storage Temperature Range .............................-55C to +135C Soldering Temperature...........................Refer to the IPC/JEDEC J-STD-020 Specification.
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.
RECOMMENDED OPERATING CONDITIONS
(TJ = -40C to +135C.)
PARAMETER Supply Voltage RILIM Value CVRAMP Value CTIMER Value TIMER Turn-On Voltage TIMER Turn-Off Voltage SYMBOL VCC RILIM CVRAMP CTIMER VON VOFF (Notes 1, 2) CONDITIONS MIN 9.0 20 0.04 0.04 2.6 -0.3 TYP MAX 13.2 400 5.00 5.00 5 +2.0 F F V V UNITS V
ELECTRICAL CHARACTERISTICS
(VCC = +12V, TJ = +25C, unless otherwise noted.)
PARAMETER Supply Current UVLO Rising UVLO Falling UVLO Hysteresis On-Resistance MOSFET Output Capacitance LOAD Voltage During Off State Delay Time from Enable to Beginning of Conduction Gate-Charging Time from Conduction to 90% of VOUT Shutdown Junction Temperature Thermal Hysteresis TIMER Charging Current Overvoltage Clamp SYMBOL ICC VUVLOR VUVLOF VUVLOH R ON C OUT VLOFF t POND t GCT TSHDN THYS ITIMER VOVC (Note 4) CVRAMP = 1F CVRAMP = 1F, CLOAD = 1000F (Note 5) (Note 5) 70 13.5 48 120 5 66 135 40 80 15.0 92 16.5 80 150 (Note 3) 7.5 6.5 CONDITIONS MIN TYP 1.1 8.0 7.0 1 25 500 200 32 MAX 2.00 8.5 7.5 UNITS mA V V V m pF mV ms ms C C A V
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12V Hot-Plug Switch
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +12V, TJ = +25C, unless otherwise noted.)
PARAMETER Short-Circuit Limit Overload Limit LOAD Voltage Slew Rate VRAMP Charging Current SYMBOL I SCL I OVL SRLOAD I VRAMP RILIM = 56 RILIM = 56 CONDITIONS (Note 6) (Note 7) MIN 2.0 3.5 0.13 70 TYP 2.5 4.4 0.15 80 MAX 3.0 5.9 0.18 92 UNITS A A V/ms A
DS4560
CVRAMP = 1F
Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7:
All voltages are referenced to ground. Currents entering the IC are specified positive and currents exiting the IC are negative. This supply range guarantees that the LOAD voltage is not clamped by the overvoltage limit. Supply current specified with no load on the LOAD pin. VLOFF voltage specified with a 2.5mA load applied to LOAD. Not production tested. Guaranteed by design. ISCL is the current limit when the output voltage is initially ramping up. IOVL is the current limit after the output voltage ramping is complete.
Typical Operating Characteristics
(VCC = 12V, TA = +25C, RILIM = 56, VCC = 12V, CTIMER = 0.1F, CVRAMP = 0.1F, unless otherwise noted.)
CURRENT LIMIT vs. RILIM
IOVL
DS4560 toc01
CURRENT LIMIT vs. TEMPERATURE
DS4560 toc02
OVERVOLTAGE CLAMP vs. TEMPERATURE
DS4560 toc03
10
7 6 IOVL CURRENT LIMIT (A) 5 4 3 2 ISCL 1
16.4 16.2 OVERVOLTAGE CLAMP (V) 16.0 NO LOAD 15.8 15.6 15.4 15.2 15.0 10 LOAD
CURRENT LIMIT (A)
1 ISCL
0.1 10 100 RILIM () 1000
0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
-40 -20
0
20
40
60
80 100 120 140
TEMPERATURE (C)
ON-RESISTANCE vs. TEMPERATURE
DS4560 toc04
SUPPLY CURRENT vs. TEMPERATURE
1.75 1.50 ICC (mA) 1.25 1.00 0.75 0.50 0.25 5V/div 0V
DS4560 toc05
TYPICAL DS4560 TURN-ON WAVEFORMS VCC = 18V, 10 RESISTIVE LOAD
DS4560 toc06
45
2.00
40
VCC LOAD VRAMP TIMER
RON (m)
35
30
25
20 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
0 -40 -20 0 20 40 60 80 100 120 140 2ms/div TEMPERATURE (C)
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12V Hot-Plug Switch DS4560
Typical Operating Characteristics (continued)
(VCC = 12V, TA = +25C, RILIM = 56, VCC = 12V, CTIMER = 0.1F, CVRAMP = 0.1F, unless otherwise noted.)
TURN-ON WAVEFORMS 10 RESISTIVE LOAD
DS4560 toc07
TURN-ON WAVEFORMS 3300F CAPACITIVE LOAD
DS4560 toc08
VCC 2V/div 0V LOAD 2V/div
VCC
LOAD 0V LOAD CURRENT
500mA/div 0mA
LOAD CURRENT
500mA/div 0mA
5ms/div
5ms/div
TURN-ON WAVEFORMS VCC = 18V, 10 RESISTIVE LOAD
DS4560 toc09
THERMAL SHUTDOWN WITH AUTORETRY DS4560S-AR+, VCC = 18V, 10 RESISTIVE LOAD
DS4560 toc10
VCC VCC 5V/div LOAD 0V LOAD 5V/div 0V
LOAD CURRENT 500mA/div 0mA 5ms LOAD CURRENT 500mA/div 0mA 500ms/div
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12V Hot-Plug Switch
Block Diagram/Typical Application Circuit
+12V VCC
DS4560
UVLO +5V VREG CHARGE PUMP CURRENT LIMIT
LOAD ILIM RILIM
LOAD
VCC
DS4560
80A +5V
R
THERMAL LIMIT
80A OVERVOLTAGE LIMIT R
2.5V
TIMER EXTERNAL DISABLE CTIMER
VRAMP CVRAMP
GND
Detailed Description
The DS4560 begins to operate when VCC exceeds the undervoltage lockout level, VUVLOR. At this level, the enable circuit and TIMER pin become active. Once the device has been enabled, a gate voltage is applied to the power MOSFET, allowing current to begin flowing from VCC to LOAD. The speed of the output-voltage ramp is controlled by the capacitance placed at the VRAMP pin. The load current is continuously monitored during the initial voltage ramping (ISCL) and during normal operation (IOVL). If the current exceeds the current limit that is set by the external resistance at ILIM, the gate voltage of the power MOSFET is decreased, reducing the output current to the set current limit.
Current is limited by the DS4560 comparing the voltage difference between the LOAD and ILIM pins to an internal reference voltage. If the output current exceeds the limit that is set by the RILIM resistor, the gate voltage of the power MOSFET is decreased, which reduces the output current to the load. When the output power is initially ramping up, the current limit is ISCL. Once the voltage ramping is complete, the current limit is IOVL. The lower ISCL current limit protects the source if there is a dead short on initial power-up. The DS4560 acts as a fuse and automatically disables the current flowing to the load when the temperature of the power MOSFET has exceeded the shutdown junction temperature, TSHDN.
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12V Hot-Plug Switch DS4560
Enable/Timer
The voltage level of the TIMER pin is compared to an internal source (see the Block Diagram). When the level on the pin exceeds VON, the comparator outputs a low level. This then turns on the voltage ramp circuit, enabling the device's output. This TIMER pin can be configured into one of four different modes of operation listed in Table 1. The TIMER pin was designed to work with most logic families. The TIMER pin will have at least 250mV of hysteresis between VON and VOFF. It is recommended that any logic gate used to drive the TIMER pin be tested to ensure proper operation. Once the device has been enabled, there is a delay (tPOND) until conduction begins from VCC to LOAD. This delay is the time required for the charge pump to bring the gate voltage of the power MOSFET above its threshold level. Once the gate is above the threshold level, conduction begins and the output voltage begins ramping. put high voltage level of the gate exceeds the VON level, and the gate can sink the ITIMER current.
Enable with Delay/Disable Mode An open-collector device is connected in parallel with CTIMER. When the pin is held low, the DS4560 is disabled. When the open-collector driver is high impedance, the internal current source begins to charge CTIMER as in the delayed mode.
Output-Voltage Ramp
The voltage ramp circuit uses an operational amplifier to control the gate bias of the n-channel power MOSFET. When the timer/enable circuit is disabled, a FET is used to keep CVRAMP discharged, which forces the output voltage to GND. Once the enable/timer circuit has been enabled, an internal current source, I VRAMP , begins to charge the external capacitor, CVRAMP, connected to the VRAMP pin. The amplifier controls the gate of the power MOSFET so that the LOAD output voltage divided by two tracks the rising voltage level of CVRAMP. The output voltage continues to ramp until it reaches either the input VCC level or the overvoltage clamp limits. The equation for the outputvoltage ramp function is: dVLOAD/dt = 2 x (IVRAMP/CVRAMP)
Automatic Enable Mode When V CC exceeds V UVLOR , the gate holding the TIMER node low is released. The internal current source brings the node to a level greater than VON, enabling the device. Delayed Automatic Enable Mode When V CC exceeds V UVLOR , the gate holding the TIMER node low is released. The internal current source (ITIMER) then begins charging CTIMER. When C TIMER is charged to a level greater than V ON, the device turns on. The equation for the delay time is:
tDELAY = (CTIMER x VON)/ITIMER
Thermal Shutdown
The DS4560 enters a thermal shutdown state when the temperature of the power MOSFET reaches or exceeds TSHDN, approximately +135C. When TSHDN is exceeded, the thermal-limiting circuitry disables the DS4560 using the enable circuitry. The DS4560 is offered in two different versions: an autoretry version and a latchoff version.
Enable/Disable Mode A logic gate or open-collector device can be connected to the TIMER pin to enable or disable the device. When the TIMER pin is held low, the device is disabled. When an open-collector device is used to drive the TIMER pin, the DS4560 is enabled when the open collector is in its high-impedance state by the internal current source bringing the TIMER node high. The TIMER pin is also compatible with most logic families if the out-
Autoretry Version (DS4560S-AR) The autoretry verson continually monitors the temperature once it has entered thermal shutdown. If the junction temperature falls below approximately +95C (TSHDN - THYS), the power MOSFET is re-enabled. See the Thermal Shutdown with Autoretry graph for details.
Table 1. TIMER Pin Modes
MODE OF OPERATION Automatic Enable Delayed Automatic Enable Enable/Disable Enable with Delay/Disable TIMER PIN SETUP No connection to TIMER pin. Capacitor CTIMER connected to TIMER. Open-collector device. Open-collector device and CTIMER.
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12V Hot-Plug Switch
Latchoff Version (DS4560S-LO) Once the latchoff version has entered thermal shutdown, it does not attempt to turn back on. The only way to turn this device back on is to cycle the power to the device. When power is reapplied to VCC, the junction temperature needs to be less than T SHDN for the device to be enabled.
Applications Information
The GND pin of the DS4560 is also a heat sink for the device. This pin should be connected to a large trace or plane capable of dissipating heat from the device.
DS4560
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE 8 SO PACKAGE CODE -- DOCUMENT NO. 21-0041
Overvoltage Limit
The overvoltage-limiting clamp monitors the VRAMP level compared to an internal voltage reference. When the voltage on VRAMP exceeds VOVC/2, the gate voltage of the n-channel power MOSFET is reduced, limiting the voltage on LOAD to V OVC even as V CC increases. If the device is in overvoltage for an extended period of time, the device may overheat and enter thermal shutdown. This is caused by the power created by the voltage drop across the power MOSFET and the load current. See the Thermal Shutdown with Autoretry graph for details.
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12V Hot-Plug Switch DS4560
Revision History
REVISION NUMBER 0 1 2 REVISION DATE 6/08 9/08 5/09 Initial release. In the Recommended Operating Conditions, changed the TIMER Turn-On Voltage (VON) maximum specification from "VCC + 0.3V" to "5V." Added the UL certification number to the Features section. DESCRIPTION PAGES CHANGED -- 2 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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

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