Impala Linear Corporation ILC7526/7536 Final USB Dual Control Switches General Description Features The ILC7526 contains dual high side power control switches, with independent enable and flag functions, integrated into a single 8-pin SOIC package. With just a few external components, the ILC7526 can be easily configured to meet requirements for either self powered or bus powered USB (Universal Serial Bus) applications. The ILC7526 has active high ENABLE inputs, while the ILC7536 ENABLE inputs are active low. With a maximum RDSON value of 140mΩ per switch, the USB voltage drop requirements can be achieved. Each switch can also supply up to 500mA, with internal circuitry limiting the fault current to 750mA. Fault conditions are also reported to the USB controller via one of the independent flag pins. Internal circuitry provides a soft-start that eliminates momentary upstream voltage drops when the switch is enabled, especially in bus powered applications. Additional features include undervoltage lockout (2.4V), fast turn-off, 2.8V to 5.8V input voltage range, thermal shutdown to prevent switch failure from high current loads, and 3.3V and 5V logic compatible enable inputs. The ILC7526 and ILC7536 are available in both 8-pin SOIC and 8-pin mini-DIP packages. • • • • • • • • • • • • • • • 2 independent switches with ENABLE and FLAG 500mA continuous load current per switch (channel) 140mΩ maximum RDSON (switch on-resistance) 1.25A maximum short circuit current limit Thermal shutdown 110µA typical on-state supply current 0.75µA typical off-state supply current 2.4V typical undervoltage lockout 2.8V to 5.8V input voltage range 1 ms turn-on (soft-start) Fast turn-off Outputs can be forced higher than inputs (off-state) USB specification compliant Active-high or active-low ENABLE versions 8-pin SOIC or 8-pin mini-DIP packages Applications • USB host and self powered hubs • USB bus-powered hubs • USB monitors, printers, cameras and other USB controlled peripherals • Hot plug-in power supplies • Battery charger circuits Ordering Information* (TA = -40°C to =85°C) ILC7526-IK Active High Enable, SO-8 package ILC7526-IN Active High, DIP-8 package ILC7536-IK Active Low, SO-8 package ILC7536-IN Active Low, DIP-8 package VCC 5.0V 4.5V to 5.25V Upstream VBUS 100mA max 100k 100k + IN D+ 100k VBUS ILC7082-3.3 VBUS 100k 1µF D- 3.3V USB Controller VIN OUT GND 1µF ON/OFF OVERCURRENT OVERCURRENT GND ON/OFF ILC7526 ENA FLGA FLGB ENB 47µF IN 0.1µF GND VBUS OUTB + D+ DGND Data (Two Pair) to USB Controller Data Impala Linear Corporation DGND OUTA 47µF ILC7526/7536 1.5 D+ (408) 574-3939 www.impalalinear.com Dec 2000 1 Preliminary USB Dual Control Switches Figure 2: Pin Configuration ENA 1 8 OUTA FLGA 2 7 IN FLGB 3 6 GND ENB 4 5 OUTB Pin Number Pin Name Pin Description 1 ENA Enable A (input): Logic-compatible enable input. (7526 active-high, 7536 active-low). Do not float. 2 FLGA Fault Flag A (Output): Active-low, open-drain output. Indicates overcurrent, UVLO, or thermal shutdown. 3 FLGB Fault Flag B (Output): Active-low, open-drain output. Indicates overcurrent, UVLO, or thermal shutdown. 4 ENB Enable B (Input): Logic-compatible enable input. (7526 active-high, 7536 active-low). Do not float. 5 OUTB Switch Output B: Output MOSFET source. Typically connect to switched side of load. 6 GND Ground: Supply return. 7 IN 8 OUTA Supply Input: Output MOSFET drain. Also supplies IC’s internal circuitry. Connect to positive supply. Switch Output A: Output MOSFET source. Typically connect to switched side of load. ILC7526 (OUTA)8 (ENA)1 (FLGA)2 (FLGB)3 (ENB)4 LOGIC CHARGE PUMP (IN)7 LOGIC CHARGE PUMP (OUTB)5 (GND)6 Impala Linear Corporation ILC7526/7536 1.5 (408) 574-3939 www.impalalinear.com Dec 2000 2 Preliminary USB Dual Control Switches Absolute Maximum Ratings (Note 1, notes on next page) Parameter Symbol Ratings Units VIN +6 V Fault Flag Voltage VFLG +6 V Fault Flag Current IFLG 50 mA Output Voltage VOUT +6 V Output Current IOUT Internally Limited mA ENABLE Input Voltage VEN -0.3 to +12 V Storage Temperature TSTG -40 to +125 °C Operating Ambient Temperature TA -40 to +85 °C Package Thermal Resistance SOIC 8-Pin DIP θJA Lead Temperature (soldering 5 sec) θJA Input Supply Voltage °C/W °C/W 120 130 °C 260 Electrical Characteristics ILC7526IK Test circuit shown in Fig. 2. BOLDFACE type indicates limits that apply over the full operating temperature range (Note 2). Parameter Supply Current ENABLE Input Threshold Min Typ Max Units µA µA V V µA ISS Switch off, OUT = Open All switches on, OUT = Open VENTH Low to high transition High to low transition (Note 3) 0.8 2.1 1.9 2.4 VEN = 0V to 5.8V -1 +0.01 1 ENABLE Input Current IEN ENABLE Input Capacitance CEN Switch resistance Conditions Symbol RDSON 0.75 110 pF 1 VIN = 5V, IOUT = 500mA each switch VIN = 3.3V, IOUT = 500mA each switch 100 140 140 180 mΩ mΩ ms Output Turn-on Delay TON RL = 10Ω each output Output Turn-on Rise Time TOR TOFD RL = 10Ω each output 0.5 1 RL = 10Ω each output 1 20 ms µs RL = 10Ω each output 1 20 µs Output Leakage Current TOFF IOL 10 µA Continuous Load Current IOUT Each output 0.5 Short Circuit Current Limit ISCL ENABLE into load, VOUT = 4.0V 0.5 0.75 1.25 A A Current Limit Threshold ILTH Ramped load to enabled output VOUT < 4.0V, Note 2 1.6 2.2 A Output Turn-off Delay Output Turn-off Fall Time Output disabled, each output Over Temperature Shutdown Threshold OTTH TJ (Junction temperature) increasing TJ (Junction temperature) decreasing 135 125 Error Flag Output Resistance RFLG VIN = 5V, IL = 10mA VIN = 3.3V, IL = 10mA 10 15 25 40 Error Flag Off Current IFLG VFLG = 5V 0.01 1 VIN = increasing VIN = decreasing 2.5 2.3 Under Voltage Lockout Threshold Impala Linear Corporation ILC7526/7536 1.5 UVLO (408) 574-3939 www.impalalinear.com °C °C Ω Ω µA V Dec 2000 3 Preliminary USB Dual Control Switches Note 1. Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed. through correlation based on statistical control methods. Measurements are taken at constant junction temperature as close to ambient as possible using low duty pulse testing. Note 3. Off is < 0.8V and On is > 2.4V for the ILC7526. Off is > 2.4V for the ILC7536. The enable input has approximately 200mV of hysteresis. Note 2. Specified min/max limits are production tested or guaranteed 5V (1 output shown) 0.1µF 10k ILC7526 ENA IOUT OUTA FLGA IN FLGB GND ENB OutB Functional Description The ILC7526 and ILC7536 are dual high-side switches with active-high and active-low enable inputs, respectively. Fault conditions turn-off or inhibit turn-on of one or more of the output transistors, depending upon the type of fault, and also activate the open-drain error flag transistors which sink current to ground. Input and Output IN (input) is the power supply connection to the logic circuitry and the drains of both of the output MOSFET’s. OUTx (output) is the source of each MOSFET. In a typical circuit, current flows through the switch from IN to OUT toward the load. If VOUT is greater than VIN when a switch is enabled, current will flow from OUT to IN since the MOSFET is bidirectional when on. The output MOSFET and driver circuitry are also designed to allow the MOSFET source to be externally forced to a higher voltage than the drain (VOUT > VIN) when the output is off. In this situation, the ILC7526 avoids undesirable current flow from OUT to IN. If VIN < 2.5V, UVLO disables both switches. Impala Linear Corporation ILC7526/7536 1.5 (408) 574-3939 CL + RL Thermal Shutdown Thermal shutdown shuts off the affected output MOSFET’s and signals all fault flags if the die temperature exceeds 135°C. 10°C of hysteresis prevents the switch from turning on until the die temperature drops to 125°C. Overtemperature detection functions only when at least one switch is enabled. Current Limit Induced Thermal Shutdown Internal circuitry increases the output MOSFET on-resistance until the series combination of the MOSFET on-resistance and the load impedance limit current to typically 850mA. The increase in power dissipation, in most cases, will cause the ILC7526 to go into thermal shutdown, disabling affected channels. When this is undesirable, thermal shutdown can be avoided by externally responding to the fault and disabling the current limited channel before the shutdown temperature is reached. The delay between the flag indication of a current limit fault and thermal shutdown will vary with ambient temperature, board layout, and load impedance, but is typically several hundred milliseconds. The USB controller must therefore recognize a fault and disable the appropriate channel within this time. If the fault is not removed or the switch is not disabled within this time, the device will enter into a thermal oscillation of about 2Hz. This does not cause any damage to the device. www.impalalinear.com Dec 2000 4 Preliminary USB Dual Control Switches Undervoltage Lockout UVLO (undervoltage lockout) prevents the output MOSFET from turning on until VIN exceeds approximately 2.5V. In the undervoltage state, the FLAG will be low. After the switch turns on, if the voltage drops below approximately 2.3V, UVLO shuts off the output MOSFET and signals fault flag. Undervoltage detection functions only when at least one switch is enabled. Current Sensing and Limiting The current-limit threshold is preset internally. The preset level prevents damage to the output MOSFET and external load but allows a minimum current of 0.5A through the output MOSFET of each channel. The current-limit circuit senses a portion of the output FET switch current. The reaction to an overcurrent condition varies with three scenarios: APPLICATIONS INFORMATION Supply Filtering A 0.1µF to 1µF bypass capacitor from IN to GND, located at the device, is strongly recommended to control supply transients. Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance) to damage internal control circuitry. Input or output transients must not exceed the absolute maximum output supply voltage (VIN MAX = 6V) even for a short duration. 3.0V to 5.5V ILC7526 ENA Switch Enabled into Short Circuit If a switch is powered on or enabled into a heavy load or short circuit, the switch immediately goes into a constantcurrent mode, reducing the output voltage. The fault flag goes low until the load is reduced. Short Circuit Applied to Output When a heavy load is applied, a large transient current may flow until the current limit circuitry will respond. Once this occurs, the device limits current to less than the short-circuit current limit specification. Current-Limit Response The ILC7526 current-limit profile exhibits a small foldback effect of approximately 500mA. Once this current-limit threshold is exceeded the device enters constant-current mode. This constant current is specified as the short circuit current limit in the “Electrical Characteristics” table. it is important to note that the device will deliver load current up to the current-limit threshold which is typically 1.6A OUTA FLGA IN FLGB GND ENB OutB 0.1µF to 1µF Enable Input EN must be driven logic high or logic low for a clearly defined input. Floating the input may cause unpredictable operation. EN should not be allowed to go negative with respect to GND. Soft-Start The ILC7526 presents a high impedance when off, and slowly becomes a low impedance as it turns on. This reduces in rush current and related voltage drop that results from charging a capacitive load, satisfying the USB voltage drop requirements for bus-powered applications. Fault Flag FLG is an N-channel, open-drain MOSFET output. The faultflag is active (low) for one or more of the following conditions: undervoltage (while 2V < VIN < 2.7), current limit, or thermal shutdown. The flag output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. Multiple FLG pins may be wired “NORed” to a common pull-up resistor. Impala Linear Corporation ILC75267536 1.5 (408) 574-3939 www.impalalinear.com Dec 2000 5 Preliminary USB Dual Control Switches Package Dimensions All dimensions in inches 0.197 0.190 8-Pin SOIC 0.155 0.150 Pin 1 identifier 0.244 0.228 0.012 0.009 0.069 0.053 0.060 0.040 0.019 0.013 8-Pin DIP 0.8° 0.050 0.016 0.011 0.004 0.019 0.013 0.260 0.240 0.260 0.240 0.260 0.240 0.260 0.240 0.260 0.240 0.260 0.240 0.260 0.240 0.260 0.240 Devices sold by Impala Linear Corporation are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Impala Linear Corporation makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Impala Linear Corporation makes no warranty of merchantability or fitness for any purpose. Impala Linear Corporation reserves the right to discontinue production and change specifications and prices at any time and without notice. This product is intended for use in normal commercial applications. Applications requiring an extended temperature range, unusual environmental requirements, or high reliability applications, such as military and aerospace, are specifically not recommended without additional processing by Impala Linear Corporation. Life Support Policy Impala Linear Corporation’s products are not authorized for use as critical components in life support devices or systems. 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. Impala Linear Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in an Impala Linear Corporation product. No other circuits, patents, licenses are implied. Impala Linear Corporation ILC7526/7536 1.5 (408) 574-3939 www.impalalinear.com Dec 2000 6