CM3503 CALMIRCO | Alldatasheet

Document overview

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Technical content

Features

  • High-side high current switch with active low Enable
  • Very low on-resistance switch (0.07? typ.)
  • Up to 1.4A continuous current on the output
  • Over-current limits at 1.4A min
  • 10msec min fault blanking delay on OC# output 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

  • 2 USB ports 5V supply overcurrent protection Pin Diagram Product Description California Micro Devices’ CM3503 is a USB overcurrent power switch that provides power to two USB ports. The device has a very low on-resistance power switch that provides the V BUS voltage at the USB output ports with minimal voltage drop. When the EN# pin is logic low, the power switch is ON, and VCC is connected to the output V OUT. When the EN# pin is logic high, the power switch is OFF, and no power is available at the output. The power switch has full over -current protection. Whenever the current limit of the switch is exceeded, the device enters a constant -current mode, where the output voltage is progressively reduced to prevent the current from increasing further. The OC# output becomes active low only if the overcurrent condition exceeds at least 10ms. This fault blanking delay prevents false alarms from being reported to the host USB controller. If the overcurrent condition is severe enough that the part heats up to the thermal limit T MAX, then the switch will be turned off and the temperature cools down. At T MIN the switch then turns on again, and the device heats up again, and so on, until the fault is removed. The CM3503 also prevents backdrive current flowing into the host from the connected peripheral. This can occur when 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 backdriv e current into the host and overloading the peripheral power supply. Typical Application Circuit Simplified Electrical Schematic SOIC-8 VCC EN# GND VCC VOUT VOUT OC# VOUT EN# OC# VOUT VCC Over current protect

1 USB Port

EN# GND VCC VOUT VOUT OC# VOUT VCC

Note: This is a preliminary datasheet only. Data subject to change at any time. © 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 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 Input Voltage 4.5 to 5.5 V Ambient Temperature -40 to +85 °C ILOAD VCC 0 to 1400 mA Electrical Operating Characteristics (over operating conditions unless specified otherwise) Symbol Parameter Conditions MIN TYP MAX UNIT UVLO VCC voltage under which circuit locks out - will not operate T=25°C 2.2 2.5 V RSW Switch ON-Resistance ILOAD = 0 to 1400mA; VCC = 5V, T = 25°C 0.07 0.1 Ω RSWa Switch ON-Resistance ILOAD = 0 to 1400mA; VCC = 5V, T = 0 to +85°C 0.125 Ω RSWb Switch ON-Resistance ILOAD = 0 to 1400mA; VCC = 5V, T = -40 to +85°C 0.125 Ω VOUT Output Voltage ILOAD = 1000mA, VCC = 5.0V, EN#=0V, T=25°C 4.9 V ILIM Over-current limit VCC = 5V T=25°C 1400 2000 2600 mA tFBD Time delay from overcurrent detection to OC# output indication (fault blanking delay) 10 20 30 ms TMAX Temperature at which switch turns off during overcurrent 150 °C TMIN Temperature at which switch turns on, after cooling from TMAX 125 °C IRCC Reverse leakage from output to input VCC = 0V, VOUT = 5V, EN# = high, T=25°C µA ICC Operating supply current EN# = low 95 µA ICCQ Quiescent current EN# = high 1 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

Note: This is a preliminary datasheet only. Data subject to change at any time. © 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 power source. Pins 2 & 3 must be connected together externally VOUT provides the power for the load s. The internal MOSFET switch is designed for very low voltage drops from the voltage input pins at the full rated current. Pins 6, 7 & 8 must be connected together externally. Current loads of up to 1.4A are allowed. Current loads above 1.4A 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 the switch immediately turn s off. Once the part has cooled to 125’C then the switch automatically turns on again. During the cold -start interval when the input is initially applied, internal circuitry provides a soft turn -on for the switch, which limits peak in-rush current. EN# is the active low logic input pin that is used to control the power switch . Set EN# high (>2V) to deselect V OUT, and set EN# low (<0.8V) to select VOUT. OC# is an active low open-drain output voltage , indicating an overcurrent fault condition has been detected at VOUT. There is a built-in 10msec (min.) fault blanking delay aft er the overcurrent fault condition has been detected, before th is output becomes active low. The OC# output deasserts only when both the overcurrent condition stops and when the voltage drop across the switch is less than 1V. An external pull-up resistor of 10k - 100k is required if the OC# output is used. GND is the negative reference for all voltages. Pin Descriptions Pin No. Symbol Description 1 GND Negative reference for all voltages. 2 VCC Power Primary High current Positive supply input.

3 VCC Power supply input connected to pin 2

4 EN# Active low enable pin

5 OC# Active low when VOUT is in overcurrent mode. External pull-up resistor required.

6 VOUT Output connected to pins 7 and 8

7 VOUT Output connected to pins 6 and 8

8 VOUT Output connected to pins 6 and 7

STANDARD PART ORDERING INFORMATION Pins Package Ordering Part Number1 Part Marking

8 SOIC CM3503-02SN CM3503-02SN

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

Note: This is a preliminary datasheet only. Data subject to change at any time. © 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 Response to Momentary Overcurrent Fault IOUT VOUT OC# Temp. >1400mA <150’C VOUT drops to reduce IOUT OC# goes inactive as soon as overcurrent condition stops <1300mA OC# goes active after 10ms (min) 20ms (typ.) delay IOUT VOUT OC# Temp. TMAX = 150’C TMIN = 125’C 150’C 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 >1400mA

Note: This is a preliminary datasheet only. Data subject to change at any time. © 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 CM3503 Quiescent supply current vs. supply voltage 100 120 VCC [V] ICC [uA] OC# Fault Blanking Delay 3.5 4 4.5 5 5.5 6 VCC [V] Delay [msec] CM3503 V OUT - IOUT characteristic 0 1 2 3 4 5 6 IOUT [A] VOUT [V]

Note: This is a preliminary datasheet only. Data subject to change at any time. © 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