CM3501 CALMIRCO | Alldatasheet

Document overview

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Technical content

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 (95µA typ.)
  • Low quiescent current when disabled (<1µA max)
  • Small 8-Lead SOIC package

Applications

  • 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 w hen V CC 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 V BUS, potentially causing backdrive current into the host and overloading the peripheral power supply. Pin Diagram 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 V SBY is the 5V standby supply which is powered up whenever the PC has power. When the ‘SEL’ pin is at logic high, V CC is the assigned input power supply. When ‘SEL’ is at logic low, V SBY is used to power the output, and no current is taken from V CC. 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 i f the overcurrent condition excee ds 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 T MIN. The switch then turns on again, and the device heats up again, and so on, until the fault is removed. Typical Application Circuit Simplified Electrical Schematic SOIC-8 VCC SEL GND VSBY OC1# VOUT1 OC2# VOUT2

1 USB Port VBUS

1 USB Port

OC1# VOUT1 OC2# VOUT2 5V VCC 5V VSBY Select VCC SEL OC1# VOUT1 VCC 750mA Over current 100mA Over current OC2# VOUT2 VSBY 750mA Over current 100mA Over current

© 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 Absolute Maximum Ratings Parameter Rating Unit ESD Protection (All pins, HBM) ± 2000 V VCC, VSBY Input Voltage + 5.6, GND - 0.5 V Storage Temperature Range Operating Ambient Operating Junction -55 to +150 -40 to +85 -40 to +150* Output Current Loading Internally limited A Package Power Dissipation 0.5 W * - Internally limited Operating Conditions (unless specified otherwise) Parameter Range Unit VCC, VSBY Input Voltage 4.5 to 5.5 V Ambient Temperature -40 to +85 °C ILOAD per port VCC VSBY 0 to 750 0 to 100 mA Electrical Operating Characteristics (over operating conditions unless specified otherwise) Symbol Parameter Conditions MIN TYP MAX UNIT UVLO VCC/VSBY voltage under which circuit locks out - will not operate T=25°C 2.2 2.5 V VOUT1, VOUT2 Output Voltage ILOAD = 500mA, VCC = 5.0V, SEL = 5V, T = 25°C 4.9 V RSW1 VCC Switch ON-Resistance ILOAD = 0 to 750mA; VCC = 5V T=25°C 0.13 0.20 Ω RSW2 VSBY Switch ON-Resistance ILOAD = 0 to 100mA; VSBY = 5V T = 25°C 1.4 Ω ILIM VCC VCC over-current limit VCC = 5V 750 mA ILIM VSBY VSBY over-current limit VSBY = 5V 100 mA tFBD Time delay from overcurrent detection to OC output indication (fault blanking delay) 10 20 ms TMAX Temperature at which hot switch turns off during overcurrent 150 °C TMIN Temperature at which cool switch turns on, after cooling from TMAX 125 °C IR CC IR SBY Reverse leakage from outputs to inputs – backdrive current VCC = 0V, VOUT = 5V, SEL floating VSBY= 0V, VOUT = 5V, SEL floating µA ICC ON VCC operating supply current VCC = 5V, SEL = high, ILOAD = 0mA 95 µA ISBY OFF VSBY standby supply current VSBY = 5V, SEL=high, ILOAD = 0mA 1 µA ISBY ON VSBY operating supply current VSBY = 5V, SEL = low, ILOAD = 0mA 95 µA ICC H Q VCC higher, quiescent current VCC = 5V, VSBY < VCC, SEL floating 40 µA ISBY L Q VSBY lower, quiescent current VCC = 5V, VSBY < VCC, SEL floating 1 µA ICC L Q VCC lower, quiescent current VCC = 5V, VSBY >VCC, SEL floating 1 µA ISBY H Q VSBY higher, quiescent current VCC = 5V, VSBY >VCC, SEL floating 40 µA VIH-EN EN# input Logic-1 threshold VCC = 5V 2 V VIL-EN EN# input Logic-0 threshold VCC = 5V 0.8 V VOL-OC OC# output Logic-0 threshold IOC = 1mA to VCC 0.4 V Nte – The “H” version has a higher ON -resistance. All other functions are identical to the regular version.

© 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 Pin Functions VCC is the higher current power source. Whenever the SEL pin is above 2V it will be s elected, and VSBY will be deselected. 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. VOUT2 provides the power for a second USB port. The internal MOSFET switches are designed for low voltage drops from the volta ge input pins at their full rated currents. Current loads of up to 750mA are allowed (from Vcc). Current loads above 750mA may cause the constant - current 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. 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. 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 V CC, set SEL low to select VSBY, or allow SEL to float to d eselect both power switches. The external device driving the SEL pin must able to source and sink 100 µA while maintaining the proper VIL/VIH levels. OC1#, OC2 # are independent , active low open - drain outputs, indicating an overcurrent fault condition has been detected at VOUT1 or VOUT2. There is a built - in 10msec (min.) fault blanking period after the overcurrent fault condition has been detected, before these outputs become active. The OC# outputs become deasserted only w hen 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 Functions Pin No. Symbol Description 1 GND Negative reference for all voltages. 2 VCC High current positive supply input. 3 VSBY Standby positive supply input. Also provides internal power. 4 SEL 3-level logic input. High = VCC, Low = VSBY, Floating = both off 5 OC2# Active low when VOUT2 is in overcurrent mode. 6 VOUT2 Output voltage internally switched to either VCC or VSBY input source. 7 VOUT1 Output voltage internally switched to either VCC or VSBY input source. 8 OC1# Active low when VOUT1 is in overcurrent mode. STANDARD PART ORDERING INFORMATION Pins Package Ordering Part Number1 Part Marking

8 SOIC CM3501-02SN CM3501-02SN

Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.

© 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 OC# Response to Momentary Overcurrent Fault IOUT VOUT OC# DieTemp. >750mA <150’C VOUT drops to reduce IOUT OC# goes inactive as soon as overcurrent condition stops <700mA OC# goes active after 10ms (min) 20ms (typ.) delay IOUT VOUT OC# Temp. TMAX = 150’C TMIN = 125’C 150’C OC# Response to Continuous Overcurrent Fault VOUT drops to reduce IOUT Total powerdown when over-temperature limit reached Re-powers when temperature drops to 125’C OC# goes active after 10ms (min) 20ms (typ.) delay OC# stays low Note: The other port stays on (unless it is also in current limit.) >750mA

© 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 Typical Operating Characteristics CM3501 I CC vs. VCC 100 110 120 VCC [V] ICC [uA] Idd(SEL=Vdd) Idd(SEL=floats) CM3501 Vout-Iout characteristic (SEL=0V, Vsby active) IOUT [A] VOUT [V]

© 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 6 CM3501 Vout-Iout characteristic (SEL=5V, Vdd active) 0 0.5 1 1.5 2 2.5 3 3.5 IOUT [A] VOUT [V] OC# Fault Blanking Delay 3.5 4 4.5 5 5.5 6 VCC [V] Delay [msec]

© 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