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CALIFORNIA MICRO DEVICES
PRELIMINARY CM3501
Dual USB Overcurrent Switch 750mA (VCC) / 100mA (VSBY)
Features
* * * * * * * * * * * Dual outputs, each with independent over-current protection circuitry and indicator Supports standby mode in PCs so that a peripheral can ramp down safely to a current <100mA Low ON-resistance switches Up to 750mA (VCC) / 100mA (VSBY) continuous current on each output Over-current limits at 750mA / 100mA respectively 10msec min fault blanking delay on OC# outputs prevents false overcurrent alarms Prevents backdrive current when host powered off Low operating current (95A typ.) Low quiescent current when disabled (<1A max) Small 8-Lead SOIC package PC motherboards with USB ports (i.e., can use a CM3501 for 2 ports or 2 CM3501s for 4 ports, etc) The CM3501 also prevents backdrive current flowing into the host from the connected peripheral. This can occur when VCC is removed as the host powers down, and the peripheral still has normal power applied. The 5V from the peripheral can therefore be linked to the host's VBUS, potentially causing backdrive current into the host and overloading the peripheral power supply.
Pin Diagram
GND VCC VSBY SEL SOIC-8 OC1# VOUT1 VOUT2 OC2#
Applications
Typical Application Circuit Product Description
California Micro Devices' CM3501 is a dual port USB overcurrent power switch that selects between two independent 5V inputs available on a PC, depending on the state of a logic input (SEL). The device has two pairs of power switches, and each pair is an analog "OR" function, providing a continuous voltage at both outputs during power transfer beween inputs. VCC is the main 5V supply, which can be disabled in a PC, and VSBY is the 5V standby supply which is powered up whenever the PC has power. When the `SEL' pin is at logic high, VCC is the assigned input power supply. When `SEL' is at logic low, VSBY is used to power the output, and no current is taken from VCC. Both switches can be deselected and switched off by not driving (floating) the `SEL' input, which places the chip in low power mode. Both pairs of switches have over-current protection. Depending on whether `SEL' is high or low, a current over 750mA or 100mA respectively out of either output causes the device to enter a constant-current mode, where the output voltage is progressively reduced to prevent the current from increasing further. Each output is independent of the other, so if one of the switches is switched on but is not in overcurrent mode then it will remain switched on. The OC# output becomes active only if the overcurrent condition exceeds a minimum continuous duration of 10ms. If the overcurrent condition is severe enough that the part heats up to the thermal limit TMAX, the switch turns off and the temperature cools down to TMIN. The switch then turns on again, and the device heats up again, and so on, until the fault is removed.
(c) 2002 California Micro Devices Corp. All rights reserved.
GND 5V VCC 5V VSBY Select VCC VCC VSBY SEL
OC1# VOUT1 VOUT2 VBUS OC2# VBUS 1 USB Port 1 USB Port
Simplified Electrical Schematic
VCC SEL VSBY
750mA Over current 100mA Over current 750mA Over current 100mA Over current
OC1# VOUT1
OC2# VOUT2
C0970500
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
1
CALIFORNIA MICRO DEVICES
Absolute Maximum Ratings Parameter Rating ESD Protection (All pins, HBM) 2000 VCC, VSBY Input Voltage + 5.6, GND - 0.5 Storage Temperature Range -55 to +150 Operating Ambient -40 to +85 Operating Junction -40 to +150* Output Current Loading Internally limited Package Power Dissipation 0.5
* - Internally limited
PRELIMINARY CM3501
Unit V V C A W
Operating Conditions (unless specified otherwise) Parameter Range VCC, VSBY Input Voltage 4.5 to 5.5 Ambient Temperature -40 to +85 0 to 750 ILOAD per port VCC 0 to 100 VSBY
Unit V C mA
Symbol UVLO VOUT1, VOUT2 RSW1 RSW2 ILIM VCC ILIM VSBY tFBD
TMAX TMIN
IR CC IR SBY ICC ON ISBY OFF ISBY ON ICC H Q ISBY L Q ICC L Q ISBY H Q VIH-EN VIL-EN VOL-OC
Nte -
Electrical Operating Characteristics (over operating conditions unless specified otherwise) Parameter Conditions MIN TYP MAX VCC/VSBY voltage under which 2.2 2.5 T=25C circuit locks out - will not operate Output Voltage ILOAD = 500mA, VCC = 5.0V, 4.9 SEL = 5V, T = 25C VCC Switch ON-Resistance ILOAD = 0 to 750mA; VCC = 5V 0.13 0.20 T=25C VSBY Switch ON-Resistance ILOAD = 0 to 100mA; VSBY = 5V 1.4 T = 25C VCC over-current limit VCC = 5V 750 VSBY over-current limit VSBY = 5V 100 10 20 Time delay from overcurrent detection to OC output indication (fault blanking delay) Temperature at which hot switch 150 turns off during overcurrent Temperature at which cool 125 switch turns on, after cooling from TMAX Reverse leakage from outputs VCC = 0V, VOUT = 5V, SEL floating 1 VSBY= 0V, VOUT = 5V, SEL floating to inputs - backdrive current 1 VCC operating supply current VCC = 5V, SEL = high, ILOAD = 0mA 95 VSBY standby supply current VSBY = 5V, SEL=high, ILOAD = 0mA 1 VSBY operating supply current VSBY = 5V, SEL = low, ILOAD = 0mA 95 VCC higher, quiescent current VCC = 5V, VSBY < VCC, SEL floating 40 VSBY lower, quiescent current VCC = 5V, VSBY < VCC, SEL floating 1 VCC lower, quiescent current VCC = 5V, VSBY >VCC, SEL floating 1 VSBY higher, quiescent current VCC = 5V, VSBY >VCC, SEL floating 40 EN# input Logic-1 threshold VCC = 5V 2 EN# input Logic-0 threshold VCC = 5V 0.8 OC# output Logic-0 threshold IOC = 1mA to VCC 0.4
UNIT V V mA mA ms C C A A A A A A A A V V V
The "H" version has a higher ON-resistance. All other functions are identical to the regular version.
(c) 2003 California Micro Devices Corp. All rights reserved
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
2
CALIFORNIA MICRO DEVICES
Pin Functions VCC is the higher current power source. Whenever the
SEL pin is above 2V it will be selected, and VSBY will be deselected.
PRELIMINARY CM3501
During the cold-start interval when the input is initially applied, internal circuitry provides a soft turn-on for the switches, which limits peak in-rush current.
VSBY is the lower current power source. Whenever the
SEL pin is below 0.8V it will be selected, and VCC will be deselected. The two VSBY power switches can only supply 100mA. VSB VOUT1 provides the power for a USB port. The internal MOSFET switches are designed for low voltage drops from the voltage input pins at their full rated currents.
SEL is the 3-level logic input pin that is used to
control which of the power switch pairs are turned on. Set SEL high to select VCC, set SEL low to select VSBY, or allow SEL to float to deselect both power switches. The external device driving the SEL pin must able to source and sink 100A while maintaining the proper VIL/VIH levels.
VOUT2 provides the power for a second USB port. The
internal MOSFET switches are designed for low voltage drops from the voltage input pins at their full rated currents. Current loads of up to 750mA are allowed (from Vcc). Current loads above 750mA may cause the constantcurrent limiting circuit to operate - reducing the output voltage. Continuous over-current loads will cause the part's internal temperature to rise. If the internal temperature exceeds 150'C then any switch that is in overcurrent mode will be immediately turned off. Any switch that is not in overcurrent mode will remain on - it will not be affected by the over-temperature detection. Once the part has cooled to 125'C then the switch or switches that were in overcurrent mode will be automatically turned on again.
OC1#, OC2# are independent, active low opendrain outputs, indicating an overcurrent fault condition has been detected at VOUT1 or VOUT2. There is a builtin 10msec (min.) fault blanking period after the overcurrent fault condition has been detected, before these outputs become active. The OC# outputs become deasserted only when both the overcurrent condition stops and when the voltage drop across the switch is less than 1V. External pull-up resistors of 10k - 100k are required if the OC# outputs are used.
GND is the negative reference for all voltages.
Pin No. 1 2 3 4 5 6 7 8
Symbol GND VCC VSBY SEL OC2# VOUT2 VOUT1 OC1#
Pin Functions Description Negative reference for all voltages. High current positive supply input. Standby positive supply input. Also provides internal power. 3-level logic input. High = VCC, Low = VSBY, Floating = both off Active low when VOUT2 is in overcurrent mode. Output voltage internally switched to either VCC or VSBY input source. Output voltage internally switched to either VCC or VSBY input source. Active low when VOUT1 is in overcurrent mode.
STANDARD PART ORDERING INFORMATION Pins 8 Package SOIC Ordering Part Number CM3501-02SN
1
Part Marking CM3501-02SN
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
(c) 2003 California Micro Devices Corp. All rights reserved
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3
CALIFORNIA MICRO DEVICES
PRELIMINARY CM3501
OC# Response to Momentary Overcurrent Fault
>750mA <700mA
IOUT
VOUT drops to reduce IOUT
VOUT
OC#
__ _
OC# goes active after 10ms (min) 20ms (typ.) delay
OC# goes inactive as soon as overcurrent condition stops
<150'C
DieTemp.
OC# Response to Continuous Overcurrent Fault
>750mA
IOUT
VOUT drops to reduce IOUT
Re-powers when temperature drops to 125'C Total powerdown when over-temperature limit reached
VOUT
OC#
OC# goes active after 10ms (min) 20ms (typ.) delay OC# stays low TMAX = 150'C 150'C
Temp.
TMIN = 125'C Note: The other port stays on (unless it is also in current limit.)
(c) 2003 California Micro Devices Corp. All rights reserved
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
4
CALIFORNIA MICRO DEVICES
Typical Operating Characteristics
CM3501 ICC vs. VCC
120 110 100 90 80 ICC [uA] 70 60 50 40 30 20 4 4.2 4.4 4.6 4.8 V CC [V] 5 5.2 5.4 5.6
PRELIMINARY CM3501
Idd(SEL=Vdd) Idd(SEL=floats )
CM3501 Vout-Iout characteristic (SEL=0V, Vsby active)
6
5
4 V OUT [V]
3
2
1
0 0 0.1 0.2 0.3 IOUT [A] 0.4 0.5 0.6
(c) 2003 California Micro Devices Corp. All rights reserved
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
5
CALIFORNIA MICRO DEVICES
PRELIMINARY CM3501
CM3501 Vout-Iout characteristic (SEL=5V, Vdd active)
6
5
4 VOUT [V]
3
2
1
0 0 0.5 1 1.5 IOUT [A] 2 2.5 3 3.5
OC# Fault Blanking Delay
60
50
40 Delay [msec]
30
20
10
0 3.5 4 4.5 V CC [V]
(c) 2003 California Micro Devices Corp. All rights reserved
5
5.5
6
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
6
CALIFORNIA MICRO DEVICES
PRELIMINARY CM3501
SOIC-8 Package Dimensions
(c) 2003 California Micro Devices Corp. All rights reserved
09/10/03
430 N. McCarthy Blvd, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
7

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