UNISONIC TECHNOLOGIES CO., LTD US1528 Preliminary CMOS IC USB HIGH-SIDE POWER SWITCH ADVANCE INFORMATION DESCRIPTION The UTC US1528 is an integrated high-side power switch. It is designed particularly for self-powered and bus-powered USB (Universal serial bus) applications. The UTC US1528 meets the requirements of the USB. The low on-resistance of the switch meets USB voltage drop requirements. When the output load becomes higher than the current-limit threshold, the UTC US1528 switches into constant- current mode and limits the output current at 1.4A (TYP). An open-drain flag, playing a role as the MOSFET output, is included to indicate error conditions to the local USB controller. A thermal shutdown circuit protects this device from catastrophic switch failure, which is caused by increasing power dissipation when continuous heavy loads or short circuit occurs. In addition, soft start is used to avoid the momentary voltage drop generated on the upstream port that may occur when the switch is enabled in bus-powered applications. A UVLO (under-voltage lockout) circuit is used to keep the device off unless there is a valid input voltage present, and an enable input that is compatible with both 3.3V and 5V logic. The UTC US1528 can be used for high-side power protection switch, USB power management, USB host and self-powered hubs, hot plug-in power supplies and battery-charger circuits. FEATURES * Open-Drain Fault Flag * Low on-Resistance MOSFET: Typical 110mΩ(at 5.0V) * Operating Voltage Varying From 3.0V to 5.5V * Output can be Forced Higher than Input when Operating in Off State. * Slow Turn-On (Soft-Start) and Fast Turn-Off * On-State Supply Current: 100 µA (TYP) * Standby Supply Current: 1µA (TYP) * Current Limit: 1.4A (TYP) * Thermal Shutdown Protection Circuit * UVLO (Under-Voltage Lockout): 2.4V (TYP) * Logic Level Enable Pin, Available with Active-High/Low Version ORDERING INFORMATION Ordering Number US1528XG-S08-R Package SOP-8 www.unisonic.com.tw Copyright © 2010 Unisonic Technologies Co., Ltd Packing Tape Reel 1 of 8 QW-R502-457.b US1528 Preliminary PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 PIN NAME GND 2, 3 IN 4 EN EN 5 FLG 6, 7, 8 OUT CMOS IC DESCRIPTION Ground. Input Supply: Output MOSFET source, which also supplies IC's internal circuitry. Connect to positive supply. Active-High switch enable input. A logic low turns on the switch. Active-Low switch enable input. A logic low turns on the switch. Open-Drain Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent, thermal shutdown and UVLO. Switch Output: Output MOSFET drain. Typically connect to switched side of load. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 8 QW-R502-457.b US1528 Preliminary CMOS IC BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 8 QW-R502-457.b US1528 Preliminary CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Supply Voltage VIN +6.0 V Fault Flag Voltage VFLG +6.0 V Fault Flag Current IFLG 50 mA Output Voltage VOUT +6.0 V Output Current IOUT Internally Limited Enable Input VEN -0.3~6 V Storage Temperature TSTG -65~+150 °C Notes: Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. OPERATING RATINGS PARAMETER Supply Voltage Ambient Operating Temperature RATINGS +3~+5.5 -40~85 UNIT V °C SYMBOL θJA RATINGS 160 UNIT °C/W THERMAL DATA PARAMETER Junction to Ambient SYMBOL VIN TOPR ELECTRICAL CHARACTERISTICS (VIN=+5V, TA=25°C) PARAMETER SYMBOL IS(OFF) IS(ON) VIH VIL IEN(H) IEN(L) TEST CONDITIONS switch off, OUT = open switch on, OUT = open low to high transition high to low transition(Note) VEN= VOH(min)= 2.5V VEN= VOL(max)= 1.0V UNIT µA IN Supply Current (Note) µA V EN/ EN Enable Threshold 0.8 V 0.01 1 µA EN/ EN Input Current 0.01 1 µA 1 pF EN/ EN Input Capacitance VIN= 5V, IOUT=500mA 110 140 mΩ Switch Resistance RON 130 180 mΩ VIN= 3.3V, IOUT=500mA OUT Turn-On Delay tON RL=10Ω 0.03 ms OUT Turn-On Rise Time tR RL=10Ω, CL=100µF 0.5 ms OUT Turn-Off Delay tOFF RL=10Ω 1 20 µs OUT Turn-Off Fall Time tF RL=10Ω 1 20 µs OUT Leakage Current IO(LEAK) 1 10 µA Short Circuit Current Limit ISHORT Enable into load 1.0 1.4 2.0 A Circuit Limit Threshold Ramped load applied to enabled output 2.0 2.7 3.5 A Overtemperature Shutdown TJ increasing 135 °C OTThreshold Threshold 125 °C TJ decreasing VIN=5V, IL=10mA 10 25 Ω FLG Output Resistance RON(FLAG) VIN=3.3V, IL=10mA 15 40 Ω FLG Off Current IFLAG VFLAG=5V 0.01 1 µA VIN=increasing 2.5 V UVLO Threshold VUVLO VIN=decreasing 2.3 V Note:For the UTC US1528, off is ≥ 2.5V and on is ≤ 0.8V. The enable input, EN has approximately 200mV of hysteresis. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN TYP 1 100 MAX 5 160 2.5 4 of 8 QW-R502-457.b US1528 Preliminary CMOS IC FUNCTIONAL DESCRIPTION The UTC US1528 is high-side single channel power switch; it has an enable input in active low. Fault conditions turn off or inhibit turn-on of the output transistors. Input and Output IN pin (input) is the power supply connection to the logic circuitry and the source of the output MOSFET. OUT pin (output) is the output MOSFET’s drain. Current flows through the switch from IN pin to OUT pin toward the load in many applications. All OUT pins must be connected together to the load. The output MOSFET and driving circuit are also designed to allow the MOSFET drain to be externally forced to a higher voltage than the source (VOUT > VIN) when the switch is off. This avoids undesirable drain-to-body diode current flow by connecting the body to the most positive voltage. If VOUT >VIN when switch is enabled, current will flow from VOUT to VIN. Thermal Shutdown Thermal shutdown is designed to prevent this device from being damaged due to excessive power dissipation. It is used to turn off the output MOSFET if the temperature is higher than135°C, 10°C of hysteresis prevents the switch from turning on until the die temperature drops to 125°C. Thermal shutdown circuit functions only when the switch is enabled. Undervoltage Lockout UVLO (Undervoltage Lockout) turns off the MOSFET switch once the input voltage falls below 2.3V (TYP) and if the input voltage exceeds 2.5V (TYP), the switch will be turned on. UVLO detection functions only when the switch is enabled. Current Sensing and Limiting The current limit threshold is fixed internally, allowing a 0.5A minimum current to flow through the output MOSFET. However, the current limit threshold can prevent the output MOSFET and external load from being damage. A current sense circuit protects the MOSFET switch’s output current. If output current becomes higher than the current limit threshold, the output MOSFET switch is turned off. The reaction to an overcurrent is measured with the following scenarios: Switch Enabled into Heavy Load If the switch is powered on or enabled into a heavy load or short-circuit, the switch enters a constant-current mode immediately, reducing the output voltage. Heavy Load Applied to Enabled Switch When a heavy load is applied, a large-undesired transient current occurs which may damage the switch. Then the current limit circuit may turn off the switch, folding back into constant-current mode. Fault Flag Fault flag is an open-drained output of an N-channel MOSFET. It drops low to indicate error conditions as follows: current limiting, UVLO, or thermal shutdown. The flag output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 8 QW-R502-457.b US1528 Preliminary CMOS IC APPLICATIONS INFORMATION Supply Filtering In order to control supply transients, a bypass capacitor is located nearly between IN to GND. 0.1µF ~ 1µF is suitable (See Figure 1). Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance) to damage internal control circuitry. Input transients must not exceed the absolute maximum supply voltage (VIN Max = 6V) even for a short duration. EN/ EN , The Active-High/Low Enable Input For a clearly defined input, the EN/ EN pin, with 0.2V hysteresis, must be driven logic high or logic low. Floating the input may cause unpredictable operation. EN/ EN should not be allowed to go negative with respect to GND. Soft Start The UTC US1528 is high impedance when off and slowly becomes a low impedance as it turns on. This reduces inrush current and related voltage drop that results from charging a capacitive load, satisfying the USB voltage drop requirements, for bus-powered applications as shown in Figure 2. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 6 of 8 QW-R502-457.b US1528 Preliminary CMOS IC APPLICATIONS INFORMATION (Cont.) In Figure 3, the soft start circuit is shown, and the soft start circuit can be utilized to meet USB transient regulation specifications with large load capacitances (CBULK >10µF). The device will provide inrush current limiting for these applications. When hot-plug events occur, the soft start is used to eliminate the upstream voltage droop due to the inrush current. The soft-start protects power supplies from damage caused by highly capacitive loads. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 7 of 8 QW-R502-457.b US1528 Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT VCC 5.0V 10k Upstream VBUS 100mA max. 3.3V LDO VBUS D+ IN 3.3V USB Controller OUT VIN ON/OFF 1μF OC GND 1μF D- 100k UTC US1528L EN Ferrite Beads V BUS OUT FLG GND + D+ 150μF D- IN GND 0.1μF USB Port1 GND Ferrite Beads GND Data Data Single-Port Self-Powered USB Hub Application UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 8 of 8 QW-R502-457.b