LTC4415 Dual 4A Ideal Diodes with Adjustable Current Limit Features n n n n n n n n n n n n Description Dual 50m Monolithic Ideal Diodes 1.7V to 5.5V Operating Range Up to 4A Adjustable Current Limit for Each Diode Low Reverse Leakage Current (1A Max) 15mV Forward Drop in Regulation Smooth Switchover in Diode ORing Load Current Monitor Precision Enable Thresholds to Set Switchover Soft-Start to Limit Inrush Current on Start-Up Status Pins to Indicate Forward Diode Conduction Current and Thermal Limit with Warning Thermally Enhanced 16-Lead MSOP and DFN (3mm x 5mm) Packages The LTC(R)4415 contains two monolithic PowerPath ideal diodes, each capable of supplying up to 4A with typical forward conduction resistance of 50m. The diode voltage drops are regulated to 15mV during forward conduction at low currents, extending the power supply operating range and ensuring no oscillations during supply switchover. Less than 1A of reverse current flows from OUT to IN making this device well suited for power supply ORing applications. The two ideal diodes are independently enabled and prioritized using inputs EN1 and EN2. The output current limits can be adjusted independently from 0.5A to 4A using resistors on the CLIM pins. Furthermore, the ideal diode currents can be monitored via CLIM pin voltages. Applications n n n n n n Open-drain status pins indicate when the ideal diodes are forward conducting. When the die temperature approaches thermal shutdown, or if the output load exceeds the current limit threshold, the corresponding warning pins are pulled low. High Current PowerPathTM Switch Battery and Wall Adapter Diode ORing Backup Battery Diode ORing Logic Controlled High Current Power Switch Supercapacitor ORing Multiple Battery Sharing L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Forward Characteristics of LTC4415 vs MBRS410E Schottky Prioritized Power Supply ORing 100k EN1 CLIM1 CLIM2 124 4.7F STAT1 WARN1 WARN2 STAT2 124 EN2 + OUT1 LTC4415 21.5k SECONDARY POWER SOURCE IDEAL IN1 IN2 IDEAL CURRENT LIMIT 4 TO LOAD LTC4415 LOAD CURRENT (A) PRIMARY POWER SOURCE 3 SCHOTTKY DIODE MBRS410E 2 RON = 50m 1 OUT2 4415 TA01a GND 0 0 100 300 400 200 FORWARD VOLTAGE DROP (mV) 500 4415 TA01b 4415fa 1 LTC4415 Absolute Maximum Ratings (Note 1) IN1, IN2, OUT1, OUT2, CLIM1, CLIM2, STAT1, STAT2, WARN1, WARN2 Voltage........ -0.3V to 6V EN1, EN2 Voltage.................. -0.3V to Max (VINx, VOUTx) Operating Junction Temperature Range (Notes 3, 4)..............................................-40C to 125C Storage Temperature Range................... -65C to 150C Peak Reflow Temperature...................................... 260C Pin Configuration TOP VIEW IN1* 1 16 OUT1* IN1* 2 15 OUT1* EN1 3 14 STAT1 CLIM1 4 CLIM2 5 17 GND TOP VIEW IN1* IN1* EN1 CLIM1 CLIM2 EN2 IN2* IN2* 13 WARN1 12 WARN2 EN2 6 11 STAT2 IN2* 7 10 OUT2* IN2* 8 9 1 2 3 4 5 6 7 8 17 GND 16 15 14 13 12 11 10 9 OUT1* OUT1* STAT1 WARN1 WARN2 STAT2 OUT2* OUT2* MSE PACKAGE 16-LEAD PLASTIC MSOP TJMAX = 125C, JA = 35C/W TO 40C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB *ADJACENT PINS ON THE FOUR CORNERS ARE FUSED TOGETHER INTERNALLY. OUT2* DHC PACKAGE VARIATION A 16-LEAD (5mm x 3mm) PLASTIC DFN TJMAX = 125C, JA = 43C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB *ADJACENT PINS ON THE FOUR CORNERS ARE FUSED TOGETHER Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4415EDHC#PBF LTC4415EDHC#TRPBF 4415 16-Lead (5mm x 3mm) Plastic DFN -40C to 125C LTC4415IDHC#PBF LTC4415IDHC#TRPBF 4415 16-Lead (5mm x 3mm) Plastic DFN -40C to 125C LTC4415EMSE#PBF LTC4415EMSE#TRPBF 4415 16-Lead Plastic MSOP -40C to 125C LTC4415IMSE#PBF LTC4415IMSE#TRPBF 4415 16-Lead Plastic MSOP -40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 4415fa 2 LTC4415 Electrical Characteristics The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25C (Notes 2, 3). VIN1 = VIN2 = 3.6V, RCLIM = 250, unless otherwise specified. SYMBOL PARAMETER VIN1, VOUT1, Operating Supply Range VIN2, VOUT2 CONDITIONS MIN At Least One Input/Output Must Be in This Range l TYP 1.7 MAX UNITS 5.5 V VUVLO Undervoltage Lockout VINx Rising Hysteresis l 1.63 55 1.7 V mV IQF Quiescent Current In Forward Regulation (Note 5) VIN1 = VEN1 = VEN2 = 3.6V, IOUT1 = -1mA, VIN2 = VOUT2 = 0V, Measured Through GND Pin l 44 80 A IQOFF Quiescent Current In Shutdown VIN1 = VIN2 = VEN2 = 3.6V, VEN1 = 0V, VOUT1 = VOUT2 = 0V, Measured Through GND Pin l 13 28 A IQR(OUT) Reverse Turn-Off Current: OUT1 OUT2 VIN1 = 3.6V, VOUT1 = 3.7V, VIN2 = 3.5V, VOUT2 = 3.6V (VOUT1 > VOUT2) l l 18 5 40 11 A A IQR(IN) INx Pin Current In Reverse Turn-Off VOUT1 = VOUT2 = 5.5V l 4 10 A VIN1 = VIN2 = 0V, VOUT1 = VOUT2 = 5.5V ILEAK(IN) INx Pin Leakage Current 1 A VFR Forward Regulation Voltage (VINx - VOUTx) IOUTx = -1mA l -1 5 15 25 mV VRTO Reverse Turn-Off Voltage (VINx - VOUTx) l -50 -30 -10 mV RFR Forward Dynamic Resistance in Regulation IOUTx = -100mA to -300mA 18 30 m RON On-Resistance in Constant Resistance Mode IOUTx = -1A 50 70 m tON PowerPath Turn-On Time (Notes 6, 7) Before Enable VOUT1 = 1.5V, Diode 1 Before Enable VOUT2 = 1.5V, Diode 2 Before Enable VOUTx = 0V 10 23 250 s s s tON(SD) PowerPath Turn-On from Shutdown (Note 7) Both Diodes Disabled and VOUTx = 1.5V Before Enable Both Diodes Disabled and VOUTx = 0V Before Enable 70 320 s s tSWITCH PowerPath Switchover Time VINx (2.6V to 4.6V) to VOUTx Starts Rising, Both Diodes Enabled, OUT1 and OUT2 Tied Together 9 s tOFF PowerPath Turn-Off Time Disable to IIN Falling from 100mA to 1mA 2 s tSS Soft-Start Duration (Note 8) VOUTx = 0V 2 ms Current Monitor Current Monitor Ratio ICLIMx /IOUTx When IOUTx = -4A ICLIMx /IOUTx When IOUTx = -2A VCLIM CLIM Clamp Voltage In Current Limit ILIM(ADJ) Current Limit Adjustability 0.9 0.8 1 1 1.1 1.2 mA/A mA/A Current Limit 0.5 l 0.5 V 4 A 8 15 % % Accuracy of Adjustable Current Limit Threshold VOUTx = VINx - 0.5V, Current Limit = 4A VOUTx = VINx - 0.5V, Current Limit = 2A l l ILIM(INT) Internal Current Limit RCLIMx = 0, VOUTx = 0V l TWARN Thermal Warning Threshold Rising Temperature Hysteresis 130 15 C C TSD Thermal Shutdown Threshold Rising Temperature Hysteresis 160 20 C C 4 6 9 A Open-Drain Status Outputs (STAT1, WARN1, STAT2, WARN2) VOL Open-Drain Output Low Voltage Current Into Open-Drain Output = 3mA l 0.05 0.4 V tSTAT(ON) Open-Drain Output High Leakage Current Open-Drain Output Voltage = 5.5V l 0 1 A STAT Turn-On Time (Note 6) EN1 Rising to STAT1 Pull-Down EN2 Falling to STAT2 Pull-Down 5 18 s s 4415fa 3 LTC4415 Electrical Characteristics The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25C (Notes 2, 3). VIN1 = VIN2 = 3.6V, RCLIM = 250, unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN tSTAT(OFF) STAT Turn-Off Time Disable to STAT Pull-Up tWARN(ON) WARN Turn-On Time Current Limit to WARN Pull-Down tWARN(OFF) WARN Turn-Off Time Out of Current Limit to WARN Pull-Up TYP MAX UNITS 2 s 500 s 5 s Enable Inputs (EN1, EN2) VENTH EN1 Rising and EN2 Falling Thresholds VENHYST EN1 and EN2 Hysteresis l 760 800 840 mV 55 VEN1 = VEN2 = 3.6V Enable Pin Current When Pulled High 0 l mV 1 A Note 4: The LTC4415 includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 5: One channel enabled. Quiescent current is identical for each channel. Note 6: Enable inputs are driven to supply levels. Other diode is already enabled so the chip bias circuits are active. Note 7: Turn-on time is measured from enable to IOUTx rising through 1mA. When the output voltage is more than 1.2V, soft-start is disabled and turn-on is faster. Note 8: Current ramps from zero to the current limit during the soft-start duration. Soft-start is measured from 10% to 90% of the current limit. If the load condition is such that the current does not need to go up to the current limit during start-up, the output voltage may reach steady state sooner. Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Unless otherwise specified, current into a pin is positive and current out of a pin is negative. Note 3: The LTC4415 is tested under pulsed load conditions such that TJ TA. The LTC4415E is guaranteed to meet performance specifications from 0C to 85C. Specifications over the -40C to 125C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC4415I is guaranteed over the full -40C to 125C operating junction temperature range. The junction temperature (TJ in C) is calculated from the ambient temperature (TA in C) and power dissipation (PD in Watts) according to the formula: TJ = TA + (PD * JA) Note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental factors. Typical Performance Characteristics TA = 25C, VIN1 = VIN2 = 3.6V, RCLIM = 250 unless otherwise noted. On-Resistance vs Temperature I-V Characteristics RCLIM = 124 On-Resistance vs VIN 80 80 70 70 60 60 2 1 0 125C 90C 25C -40C 0 50 150 200 100 FORWARD VOLTAGE DROP (mV) 250 4415 G01 RON (m) 3 RON (m) FORWARD CURRENT (A) 4 50 50 40 40 30 30 20 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 4415 G02 20 1 2 3 4 INPUT VOLTAGE (V) 5 6 4415 G03 4415fa 4 LTC4415 Typical Performance Characteristics TA = 25C, VIN1 = VIN2 = 3.6V, RCLIM = 250 unless otherwise noted. Reverse Leakage Current vs Temperature Quiescent Current vs Temperature 100 ILEAK(IN) (A) 100n QUIESCENT CURRENT (A) 1 VOUT = 5.5V 10n VOUT = 3.6V 1n 100p 10p -50 -25 0 BOTH DIODES ON 80 60 ONE DIODE ON (IQF) 40 BOTH DIODES OFF (IQOFF) 20 0 -50 -25 25 50 75 100 125 150 TEMPERATURE (C) QUIESCENT CURRENT (A) VIN = 0V 100 0 4415 G04 100 7 CURRENT LIMIT 2 4 3 OUTPUT CURRENT (A) RCLIM = 124 4 3 RCLIM = 249 2 0 5 1 0 2 4 3 OUTPUT VOLTAGE (V) 1.30 1.20 1.20 DEVICE 1 (HIGH RATIO) DEVICE 2 DEVICE 3 (LOW RATIO) 0.80 0.70 -50 -25 IOUT = 2A RCLIM = 124 0 5 6 VOUT = 0V RCLIM = 0 5 RCLIM = 124 4 3 RCLIM = 249 2 1 RCLIM = 1000 0 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 4415 G09 Current Monitor Ratio vs IOUT 1.30 0.90 4 3 INPUT VOLTAGE (V) 4415 G08 Current Monitor Ratio vs Temperature 1.00 2 1 6 RCLIM = 1000 4415 G07 1.10 BOTH DIODES OFF (IQOFF) 20 Short-Circuit Current vs Temperature 5 ICLIM/IOUT (mA/A) 1 40 4415 G06 RCLIM = 0 1 RCLIM = 124 ICLIM/IOUT (mA/A) IQF (A) CURRENT LIMIT (A) 20 0 ONE DIODE ON (IQF) 7 VIN = 3.6V 6 80 0 60 Current Limit vs Output Voltage 40 BOTH DIODES ON 4415 G05 Quiescent Current vs Output Current 60 Quiescent Current vs VIN 80 0 25 50 75 100 125 150 TEMPERATURE (C) SHORT-CIRCUIT CURRENT (A) 10 25 50 75 100 125 150 TEMPERATURE (C) 4415 G10 DEVICE 1 (HIGH RATIO) 1.10 1.00 DEVICE 2 0.90 DEVICE 3 (LOW RATIO) 0.80 0.70 RCLIM = 124 0 2 1 3 OUTPUT CURRENT (A) 4 4415 G11 4415fa 5 LTC4415 Typical Performance Characteristics TA = 25C, VIN1 = VIN2 = 3.6V, RCLIM = 250 unless otherwise noted. Enable and Disable Response for Large Load Capacitor VOUT1 2V/DIV Enable and Disable Response for Small Load Capacitor VOUT1 2V/DIV COUT1 = 1200F RLOAD1 = 8 1ms/DIV 4415 G12 VOUT1,2 1V/DIV COUT1 = 47F RLOAD1 = 8 Load Step Response 1ms/DIV 4415 G13 STAT1 5V/DIV STAT2 5V/DIV 3.6V VIN 5V/DIV 3.6V VIN 5V/DIV VOUT 5V/DIV 3.6V 10mA 4415 G14 COUT = 4.7F RCLIM = 167 UVLO Thresholds vs Temperature UVLO THRESHOLDS (V) EN1 THRESHOLDS (V) RISING (TURN ON) 1.630 1.610 1.590 FALLING (TURN OFF) 1.570 100s/DIV 4415 G15 0.900 0.875 0.875 0.850 0.850 0.825 RISING (TURN ON) 0.800 0.775 FALLING (TURN OFF) 0.750 0 25 50 75 100 125 150 TEMPERATURE (C) 4415 G18 0.700 -50 -25 40s/DIV 4415 G16 EN2 Thresholds vs Temperature 0.900 0.725 1.550 -50 -25 COUT = 4.7F RCLIM = 167 EN1 Thresholds vs Temperature 1.650 3.6V 1A EN2 THRESHOLDS (V) 40s/DIV 4415 G17 IOUT 10A/DIV IOUT 5A/DIV COUT = 47F RLOAD = 8 RCLIM = 124 COUT = 47F 20s/DIV RLOAD = 3.6 VOUT1 = VOUT2 (SHORTED) VOUT 5V/DIV WARN 5V/DIV 0.1A 3.55V Short-Circuit Response at Heavy Load Short-Circuit Response 3.5A IIN 2A/DIV VIN1 = 3.6V VIN2 = 2.6V IIN1 2A/DIV WARN1 5V/DIV STAT1 5V/DIV EN1 5V/DIV WARN1 5V/DIV STAT1 5V/DIV EN1 5V/DIV VOUT 0.5V/DIV VIN2 = 4.6V VIN1, VIN2 1V/DIV IIN1 2A/DIV VIN 0.5V/DIV Switchover in Diode-OR Application RISING (TURN OFF) 0.825 FALLING (TURN ON) 0.800 0.775 0.750 0.725 0 25 50 75 100 125 150 TEMPERATURE (C) 4415 G19 0.700 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 4415 G20 4415fa 6 LTC4415 Typical Performance Characteristics TA = 25C, VIN1 = VIN2 = 3.6V, RCLIM = 250 unless otherwise noted. Power Loss vs Output Current 1.0 Efficiency vs Output Current 100 RCLIM = 124 98 EFFICIENCY (%) POWER LOSS (W) 0.8 0.6 0.4 0.2 0 RCLIM = 124 99 2 1 3 OUTPUT CURRENT (A) 96 95 94 93 92 125C 25C -40C 0 97 125C 25C -40C 91 4 4415 G21 90 0 2 1 3 OUTPUT CURRENT (A) 4 4415 G22 Pin Functions IN1 (Pins 1, 2): Diode 1 Anode and Positive Power Supply for LTC4415. Bypass IN1 with a ceramic capacitor of at least 4.7F. Pins 1 and 2 are fused together on the package. These pins can be grounded when not used. EN1 (Pin 3): Enable Input for Diode 1. A high signal greater than VENTH enables Diode 1. CLIM1 (Pin 4): Current Limit Adjust and Monitor Pin for Diode 1. Connect a resistor from CLIM1 to ground to set the current limit; the diode 1 current can then be monitored by measuring the voltage on CLIM1 pin. A fixed 6A internal current limit is active when this pin is shorted to ground. Do not leave this pin open. Minimize stray capacitance on this pin to generally less than 200pF (see Applications Information for more details). CLIM2 (Pin 5): Current Limit Adjust and Monitor Pin for Diode 2. Connect a resistor from CLIM2 to ground to set the current limit; the diode 2 current can then be monitored by measuring the voltage on CLIM2 pin. A fixed 6A internal current limit is active when this pin is shorted to ground. Do not leave this pin open. Minimize stray capacitance on this pin to generally less than 200pF (see Applications Information for more details). EN2 (Pin 6): Enable Input for Diode 2. A low signal less than VENTH enables Diode 2. IN2 (Pins 7, 8): Diode 2 Anode and Positive Power Supply for LTC4415. Bypass IN2 with a ceramic capacitor of at least 4.7F. Pins 7 and 8 are fused together on the package. These pins can be grounded when not used. OUT2 (Pins 9, 10): Diode 2 Cathode and Output of LTC4415. Bypass OUT2 with a ceramic capacitor of at least 4.7F. Pins 9 and 10 are fused together on the package. Leave these pins open when not used. STAT2 (Pin 11): Status Indicator for Diode 2. Open-drain output pulls down during forward diode conduction. This pin can be left open or grounded when not used. WARN2 (Pin 12): Overcurrent and Thermal Warning Indicator for Diode 2. Open-drain output pulls down when diode 2 current exceeds its current limit or die temperature is close to thermal shutdown. WARN1 (Pin 13): Overcurrent and Thermal Warning Indicator for Diode 1. Open-drain output pulls down when diode 1 current exceeds its current limit or die temperature is close to thermal shutdown. 4415fa 7 LTC4415 Pin Functions STAT1 (Pin 14): Status Indicator for Diode 1. Open-drain output pulls down during forward diode conduction. This pin can be left open or grounded when not used. OUT1 (Pins 15, 16): Diode 1 Cathode and Output of LTC4415. Bypass OUT1 with a ceramic capacitor of at least 4.7F. Pins 15 and 16 are fused together on the package. Leave these pins open when not used. GND (Exposed Pad Pin 17): Device Ground. The exposed pad must be soldered to PCB ground to provide both electrical connection to ground and good thermal conductivity to PCB. Block Diagram IOUT1 1000 3 15, 16 P1 GATE DRIVER CURRENT LIMIT TEMPERATURE SENSOR IOUT2 1000 UVLO2 EN2 OUT2 WARN1 STAT1 CLIM2 13 14 5 OUT2 IN2 7, 8 6 4 OUT1 IN1 1, 2 UVLO1 EN1 OUT1 CLIM1 9, 10 P2 GATE DRIVER CURRENT LIMIT TEMPERATURE SENSOR WARN2 STAT2 12 11 4415 BD 4415fa 8 LTC4415 Operation The diodes are enabled using level-sensitive enable inputs EN1 and EN2 with opposite polarity to achieve a prioritizer function with minimal quiescent current during diode-OR implementation. The enable threshold on the enable pins (VENTH) is 800mV (typical) with one-sided hysteresis of 55mV (typical). For rising voltage on the EN1 pin, Diode 1 is enabled when VEN1 > 800mV (typical), and on the falling edge it is disabled when VEN1 < 745mV (typical). For falling voltage on the EN2 pin, Diode 2 is enabled when VEN2 < 800mV (typical), and on the rising edge it is disabled when VEN1 > 855mV (typical). EN1 or EN2 pin voltages should not exceed the highest voltage on the input (IN1, IN2) or output (OUT1, OUT2) pins. Forward conduction of the LTC4415 diodes has three operating ranges as a function of the load current, as shown in Figure 1 and described below: 1. For small load current, a low forward voltage drop (VFR = 15mV typical) is maintained by modulating the series resistance offered by the PFETs (P1/P2) in the current paths as shown in the Block Diagram. This operating mode is referred to as constant VFR regulation. In battery-powered and low headroom applications, the low forward drop of the ideal diodes extend the operating range beyond that of Schottky diodes. 2. At higher load currents, the LTC4415 gate driver can no longer modulate the series resistance of the PFETs (P1/P2) to maintain constant forward drop. This transition occurs when the gate voltage of the series PFETs (P1/P2) has been brought down to GND. The ideal diodes subsequently operate with constant resistance, RON, between inputs and outputs, IN1/IN2 and OUT1/ OUT2, respectively. 3. As the load current exceeds the current limit, the series PFETs offer higher resistance between IN1/IN2 and OUT1/OUT2 by reducing the gate drive in order to limit the load current; so the forward voltage drop increases rapidly. This operating mode is referred to as constant current operation. CONSTANT CURRENT ILIM SLOPE = 1 RON CURRENT (A) The LTC4415 consists of two PowerPath ideal diode circuits within a single package. Each diode in the LTC4415 is capable of supplying a maximum rated output current of 4A from its input supply with typical forward conduction resistance of 50m. SLOPE = 1 RFR VFR FORWARD VOLTAGE (V) CONSTANT RESISTANCE CONSTANT VOLTAGE 4415 F01 Figure 1. Forward Characteristics of LTC4415 When the output of either diode is driven higher than its input by an alternate supply, conduction through that diode is suspended to prevent reverse conduction from OUT1/ OUT2 to IN1/IN2. This function allows implementation of a power supply OR function by simply tying the outputs OUT1 and OUT2 together. Current Limit Setting The output current limit of each diode can be set independently by connecting resistors from the current limit adjust pins CLIM1 and CLIM2 to ground. The current out of the CLIM1 and CLIM2 pins are 1/1000 of the ideal diode output currents IOUT1 and IOUT2 respectively. When the load currents increase so that the CLIM1 or CLIM2 pin voltages exceeds 0.5V, the LTC4415 detects an overcurrent condition and regulates the current to a fixed value. The required value of resistor RCLIM for output current limit of ILIM is calculated as follows: RCLIM = 1000 * 0.5V ILIM The allowed range of RCLIM is 125 to 1000 unless the CLIM1/CLIM2 pins are shorted to GND, in which case the LTC4415 limits the load current using a fixed internal current limit of 6A. Overcurrent Status When either of the ideal diodes is operating in current limit, the corresponding warning pin, WARN1/WARN2, is pulled low by an open-drain NFET after a 500s delay. Normal operation resumes and the warning pin is released 4415fa 9 LTC4415 Operation when the load current decreases below the current limit. Power consumption in LTC4415 increases during operation in current limit due to the large voltage drop across the PFET devices (P1 or P2). Load Current Monitor The current limit pins output 1/1000th of the ideal diode output current. The voltage across the current limit resistor can be measured to monitor the current through each ideal diode as follows: IOUT = 1000 * VCLIM RCLIM Note that the current monitor function via VCLIM is not available when CLIM pins are grounded to use the fixed internal current limit. Soft-Start An internal soft-start is included for each ideal diode to minimize the start-up inrush current. When either of the diodes start forward conduction, the load current ramps from zero to the set current limit over a period of 2ms. The soft-start can be monitored by observing the CLIM1 and CLIM2 pin voltages when they are connected to grounded resistors. Soft-start duration is reduced to 0.5ms (typical) when the CLIM pins are grounded. In order to minimize output droop during switchover between input sources in power supply ORing applications, soft-start is disabled when the output voltage is above 1.2V. Forward Conduction Status Monitor Active low open-drain output status signals, STAT1 and STAT2, indicate the forward conduction status of each ideal diode. With resistor pull-ups on these status pins, a low voltage indicates forward conduction from input to output, IN1/IN2 to OUT1/OUT2, respectively. The status pins go to high impedance when the respective ideal diodes are disabled, during reverse turn-off conditions, or during thermal shutdown. Thermal Warning and Shutdown Thermal sensors within the LTC4415 monitor the die temperature when either of the diodes are enabled. When the die temperature exceeds the warning threshold (130C), the WARN1/WARN2 pins are pulled down with open-drain NFETs while the LTC4415 continues to operate normally. This gives some time for the user to reduce the load current to avoid thermal shutdown. The warning signal is deasserted when the die temperature cools down below 115C. Thermal shutdown is triggered when the internal die temperature increases beyond the fault threshold (160C). Status pins, STAT1/STAT2, are deasserted during thermal shutdown to indicate the interruption in forward condition. Normal operation resumes when the die temperature cools below 140C. Note that prolonged operation at the overtemperature condition degrades device reliability. Figure 2 shows WARN followed by thermal shutdown caused by an output short-circuit to ground. Time to thermal shutdown varies depending on power dissipation, ambient temperature and board layout. The output current ramps up after the device cools down below 140C, but shuts down repeatedly as the device overheats due to persistent short. VOUT 2V/DIV OUTPUT SHORTED TO GND IOUT 2A/DIV STAT 5V/DIV THERMAL SHUTDOWN RESTART DUE TO THERMAL HYSTERESIS WARN 5V/DIV VIN = 3.6V RCLIM = 124 COUT = 4.7F 10ms/DIV 4415 F02 Figure 2. Current Limit Warning and Thermal Shutdown on Output Short Circuit The thermal sensors are independent for each diode to warn of, or shut down the heat generating path so that it does not hinder the normal operation of the other path. Depending on the amount of heat generated, the whole die may still heat up and eventually shut down the other channel. 4415fa 10 LTC4415 Operation Undervoltage Lockout Each ideal diode contains an independent UVLO control circuit so that one input experiencing undervoltage lockout does not hinder normal operation of the other channel. The diode conduction path is turned off and the status signal, STAT1/STAT2, is deasserted during an undervoltage condition. Applications Information Stability Considerations Any capacitance on the CLIM pins adds a pole to the current control loop. Therefore, stray capacitance on these pins must be kept to a minimum. Although the maximum allowed value of the current limit adjust resistor is 1000, any additional capacitance on these pins reduces the maximum allowed resistance, consequently increasing the minimum allowed current limit. For stable operation, the pole frequency at the CLIM pins should be kept above 800kHz. Therefore, if the CLIM pin parasitic capacitance is CP, the following equation should be used to calculate the maximum allowed resistor RCLIM: RCLIM 1 2 * 800kHz *CP When the voltage at the CLIM pins are monitored using a long cable, such as an oscilloscope probe, decouple the parasitic capacitance of the probe and the monitor system using a series resistor as shown in Figure 3, where a 20k resistor has been added between the CLIM pin and the probe to ensure stable operation. Input and Output Capacitors High current transients through parasitic inductance on the input and output sides of the ideal diodes can cause voltage spikes on the IN1/IN2/OUT1/OUT2 pins. These current transients can occur on power plug-in, load disconnect MONITOR or switching, disable, or even thermal shutdown. Limit inductance and/or increase bypass capacitors to prevent pin voltages from exceeding the absolute maximum rating of 6V. Some ESR in these capacitors may be helpful in dampening the resonances and minimizing the ringing caused by hot plugging or load switching. Refer to Application Note 88, entitled, "Ceramic Input Capacitors Can Cause Overvoltage Transients" for a detailed discussion and mitigation of this phenomenon. The values of the input and output decoupling capacitors also depends on the maximum allowable droop during switchover in power supply ORing applications. Typical duration for LTC4415 ideal diodes to switchover from reverse turn-off to forward conduction, tSWITCH, is 9s. Therefore, the minimum decoupling capacitance, C, required for a specified maximum output voltage droop, V, when one of the input voltages drops, can be calculated as follows: C= ILOAD * t SWITCH V where ILOAD is the load current at the time of switchover. For example, the required value of output capacitance for a 100mV maximum droop in the output voltage during quick switchover at 1A load would be 100F. Note that both supplies share the load during switchover, and therefore reduce the droop, when the voltage on the falling supply pin changes slowly. 20k CMONITOR RCLIM CP CLIM PIN 4415 F03 Figure 3. Current Monitor with High Capacitance Probe/Instrument 4415fa 11 LTC4415 Applications Information Board Layout Considerations When laying out the printed circuit board, the following checklist should be followed to ensure proper operation of the LTC4415: 1. Connect the exposed pad of the package (Pin 17) directly to a large PC board ground to minimize thermal impedance. Correctly soldered to a 2500mm2 double-sided 1oz copper board, the DFN package has a thermal resistance (JA) of approximately 43C/W. Failure to make good contact between the exposed pad on the backside of the package and an adequately sized ground plane results in much larger thermal resistance, raising the die temperature for given power dissipation. An example layout for double layer board is given in Figure 4. Via holes are used in the board under and near the device to conduct heat away from the device to the bottom layer. 2. The traces to the input supplies, outputs and their decoupling capacitors should be short and wide to minimize the impact of parasitic inductance. Connect the GND side of the capacitors directly to the ground plane of the board. The decoupling capacitors provide the transient current to the internal power MOSFETs and their drivers. 3. Minimize the parasitic capacitance on CLIM1 and CLIM2 pins for stable operation. OUT1 IN1 EN1 WARN1 CLIM2 WARN2 EN2 IN2 STAT1 CLIM1 STAT2 OUT2 4415 F04 Figure 4. Example Board Layout for a Double-Sided PCB 4415fa 12 LTC4415 Typical Applications Precision enable inputs and independent status outputs provide flexibility in power supply back up and load share applications using the two high current ideal diode circuits in the LTC4415, as shown in the following examples. The features shown in these application circuits can be combined in custom applications as needed. The enable overlap minimizes the load voltage droop during switchover. Both input power supplies provide power to the load during the overlap. The status output pins can be pulled up to the output voltage or to a logic power supply. Automatic Switchover to a Backup Battery and KeepAlive Power Source Prioritized Switchover to a Backup Battery Figure 6 illustrates an application circuit for automatic switchover to the backup battery if the primary power source voltage falls below the backup battery voltage. The wired-AND of the status outputs is used to drive the gate of a pair of back-to-back connected external NMOS (M1 and M2) when both primary and backup power sources are absent or below UVLO or during thermal shutdown of LTC4415. Under these conditions, the keep-alive source supplies power to critical components of the system. At the same time, the wired-AND status output turns off The application circuit, Figure 5, illustrates switchover from a primary power source to backup power at a precise input voltage using the prioritized power supply-OR application circuit. Diode 2 is enabled when the primary power source voltage on diode 1 input falls below the threshold given as follows: R1+R2 VIN1 < 0.8V * 1+ R3 As VIN1 falls further, diode 1 is disabled when the primary power source voltage falls below the threshold determined by the resistor divider on enable pin EN1: PRIMARY POWER SOURCE M3 The built-in hysteresis on the enable pins in the LTC4415 provides some overlap of diode enables around the switchover of power supplies. Resistor R2 can be optionally used for additional overlap between the two supplies. The additional overlap is given by: R2 R3 RCLIM1 BACKUP + BAT + IDEAL M1 M2 LOAD 47F GND 4415 F06 OUT1 LTC4415 EN1 CLIM1 STAT1 CLIM2 WARN1 WARN2 RCLIM2 STAT2 EN2 SECONDAY POWER SOURCE (BAT) DMN2215UDM R1 47k Figure 6. Automatic Switchover to a Backup Battery with Provision for Keep-Alive Power to the Load When Both Are Absent IN1 R1 KEEP ALIVE/ COIN CELL OUT1 EN2 IDEAL OUT2 IN2 R2 R2 when << 1 R3 R3 PRIMARY POWER SOURCE IDEAL LTC4415 EN1 CLIM1 STAT1 CLIM2 WARN1 WARN2 STAT2 OPTIONAL R1 VIN1 < ( 0.8V - VENHYST ) * 1+ R2+R3 VOVERLAP VENTH * IN1 IN2 IDEAL 4.7F TO LOAD 470k 470k 470k 470k OUT2 4415 F05 GND Figure 5. Prioritized Power Supply ORing 4415fa 13 LTC4415 Typical Applications non-critical high current loads. If the status resistors are pulled up through the keep-alive power source itself as shown in Figure 6, the output voltage is limited to: Multiple Battery Charging Figure 7 illustrates an application circuit for automatic dual battery charging from a single charger. The battery with lower voltage receives larger charging current until both battery voltages are equal, then both are charged. While both batteries are charging simultaneously, the higher capacity battery gets proportionally higher current from the charger. For Li-Ion batteries, both batteries achieve the charger float voltage minus the forward regulation voltage of 15mV. This concept can be extended to more than two batteries using additional LTC4415. The STAT1, STAT2 pins provide information as to when the batteries are being charged. For intelligent control, the EN1/EN2 input pins can be used with a microcontroller as shown in Figure 9 later in this section. VOUT = VKEEP_ALIVE - Vgs(M1,2) where Vgs(M1,2) is the voltage drop from gate to source of the composite NMOS device (M1 and M2). The pull-up resistor, R1, consumes power from the keep-alive source when the primary or backup sources supply power to the load. The primary power source or backup battery supplies power to the load when either of them are higher than the output voltage. Current limit on any of the diode power paths can be set to automatically fold back as the output voltage drops (to reduce power consumption), by switching out a resistor on the CLIM pin, as shown in Figure 6 for diode 1. The gate of NMOS M3 can optionally be fed from a resistor divided output voltage to adjust the output voltage threshold of current foldback. L1 1.5H VIN 4.5V TO 5.5V R1 10k R2 1k D1 LED C1 10F SW VINSENSE PVIN 50k SENSE 10F LTC4001 TO P FROM P FAULT BATSENS EN PROG IDET R3 10k 25C R4 549 TIMER SS C2 0.22F R5 549 GNDSENS + STAT1 WARN1 WARN2 STAT2 EN2 NTC OUT1 LTC4415 EN1 CLIM1 CLIM2 PGND CHRG IDEAL IN1 BAT IN2 IDEAL GND LOAD1 BAT1 1.5k 1.5k OUT2 + LOAD2 BAT2 4415 F07 C3 0.1F Figure 7. Dual Battery Charging from a Single Charger 4415fa 14 LTC4415 Typical Applications Load Sharing by Multiple Batteries and Automatic Switchover to a Preferred Power Supply (Such as a Wall Adapter) Microcontrolled Power Switch with Reverse Blocking, Selectable Current Limit, Soft-Start and Monitoring An application circuit for dual battery load sharing with automatic switchover to a wall adapter (when present) is shown in Figure 8. In the absence of the wall adapter, the higher voltage battery provides the load current until it has discharged to the voltage of the other battery. The load is then shared between the two batteries according to their capacities, the higher capacity battery providing proportionally higher current to the load unless limited by its current limit. When a wall adapter is applied, the output voltage rises as the body diode of PFET MP1 conducts and both of the ideal diode paths in the LTC4415 stop conducting due to reverse turn-off. At this time, the wired-OR status signal pulls up the gate voltage of NFET MN1, pulling down the gate voltage of power PFET MP1, turning it on. The wiredOR status signal indicates whether the wall adapter or either of the two batteries is supplying the load current. The two application circuits described in Figure 7 and Figure 8 can be cascaded for dual battery charging and load sharing. Figure 9 illustrates an application circuit for microcontroller monitoring and control of two power sources. The microcontroller monitors the input supply voltages and commands the LTC4415 through EN1/EN2 inputs. Currents through the ideal diodes are monitored by the microcontroller measuring CLIM1/CLIM2 pin voltages using ADCs. The current limit can be adjusted for either diode using an external FET as shown in this application for diode 1 with MN1. The two ideal diode outputs are connected together for power source ORing, or they may feed different loads. Parallel Diodes for Lower Resistance or Higher Current Output The two ideal diodes in the LTC4415 can be connected in parallel as shown in Figure 10 to achieve a low resistance PowerPath. The master enable input, ENABLE, turns on diode 2. EN1 is tied to the output so that diode 1 conducts only after the output has charged up (by diode 2 according to its current limit setting). Diode 1 is disabled when the WALL ADAPTER MP1 IRFHS9301 BAT1 + IDEAL IN1 470k LTC4415 EN1 CLIM1 CLIM2 BAT2 OUT1 + EN2 IN2 STAT1 WARN1 WARN2 STAT2 IDEAL GND OUT2 STAT 470k 4.7F 4.7H MN1 IRLML2402 PVIN1 VIN PVIN2 SW2 SW1A FB2 VOUT1 1.0M LTC3521 221k ON OFF BURST PWM VOUT2 1.8V 10F 0.6A 137k SW1B VOUT1 3.3V 0.8A 4.7H FB1 SW3 SHDN1 FB3 SHDN2 SHDN3 PGOOD1 PWM PGOOD2 PGND1A PGOOD3 PGND1B GND PGND2 68.1k 4.7H VOUT3 1.2V 10F 0.6A 100k 100k 4415 F08 Figure 8. Dual Battery Load Sharing with Automatic Switchover to a Wall Adapter 4415fa 15 LTC4415 Typical Applications PRIMARY POWER SOURCE IDEAL IN1 OUT1 LTC4415 EN1 CLIM1 CLIM2 MICROCONTROLLER LOAD 470k STAT1 WARN1 WARN2 STAT2 MN1 IRLML2402 EN2 AUXILLIARY POWER SOURCE IN2 IDEAL OUT2 4.7F GND 4415 F09 Figure 9. Microcontrolled PowerPath Monitoring and Control POWER SOURCE IDEAL IN1 OUT1 LTC4415 EN1 CLIM1 CLIM2 ENABLE EN2 IN2 LOAD 470k STAT1 WARN1 WARN2 STAT2 IDEAL OUT2 4415 F10 GND D1 1N5817 Figure 10. Parallel Diodes with Current Limit Foldback and Reverse Polarity Protection output falls below a threshold set by the resistor divider on EN1 pin. This arrangement results in current limit foldback, reducing the current limit of the parallel diodes to that of only diode 2 when the output voltage falls, thus controlling power dissipation. An optional Schottky diode can be inserted in series with the chip ground as shown in Figure 10 to protect LTC4415 against input power source reverse polarity. The presence of the Schottky shifts the UVLO and enable pin thresholds by a voltage equal to the forward voltage drop of the Schottky diode. Power Backup Using Supercapacitors and Optional Keep-Alive Cell An application of dual backup power is shown on the last page of this data sheet. Diode 2 provides power to the triple DC/DC converter (LTC3521) when the primary input power (VDD) is available, possibly from a wall adapter. When the input power falls below the supercapacitor voltage, the supercapcitor provides power to the LTC3521. The supercapacitor charger (LTC3625) provides a power failure comparator output signal (PFO) when its input voltage falls below a preset voltage defined by the resistive divider on the PFI input. The PFO signal is available to start the shutdown of high current applications. When the supercapacitor discharges to a voltage level determined by the resistor divider on EN1 input of LTC4415, the wired-AND status signal of LTC4415 pulls up because neither of the diode paths in LTC4415 are conducting and the coin cell provides power through a back-to-back connected pair of NFETs, M1 and M2. The wired-AND status signal is available to signal that only low current circuits such as real-time clock or memory remain enabled while operating from the coin cell. 4415fa 16 LTC4415 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DHC Package 16-Lead Plastic DFN (5mm x 3mm) (Reference LTC DWG # 05-08-1872 Rev O) Variation A 0.65 0.05 1.29 0.05 3.50 0.05 1.65 0.05 2.20 0.05 (2 SIDES) PACKAGE OUTLINE 0.25 0.05 0.50 BSC 4.40 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 5.00 0.10 (2 SIDES) R = 0.20 TYP 9 R = 0.115 TYP 0.40 0.10 16 1.29 REF 3.00 0.10 (2 SIDES) 1.65 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PIN 1 NOTCH 0.200 REF 0.75 0.05 0.00 - 0.05 8 1 0.25 0.05 0.50 BSC (DHC16 Var A) DFN 0410 4.40 0.10 (2 SIDES) BOTTOM VIEW--EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 4415fa 17 LTC4415 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MSE Package 16-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1667 Rev E) BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 0.102 (.112 .004) 5.23 (.206) MIN 2.845 0.102 (.112 .004) 0.889 0.127 (.035 .005) 8 1 1.651 0.102 (.065 .004) 1.651 0.102 3.20 - 3.45 (.065 .004) (.126 - .136) 0.305 0.038 (.0120 .0015) TYP 16 0.50 (.0197) BSC 4.039 0.102 (.159 .004) (NOTE 3) RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 0.35 REF 0.12 REF DETAIL "B" CORNER TAIL IS PART OF DETAIL "B" THE LEADFRAME FEATURE. FOR REFERENCE ONLY 9 NO MEASUREMENT PURPOSE 0.280 0.076 (.011 .003) REF 16151413121110 9 DETAIL "A" 0 - 6 TYP 3.00 0.102 (.118 .004) (NOTE 4) 4.90 0.152 (.193 .006) GAUGE PLANE 0.53 0.152 (.021 .006) DETAIL "A" 1.10 (.043) MAX 0.18 (.007) SEATING PLANE 0.17 - 0.27 (.007 - .011) TYP 1234567 8 0.50 (.0197) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE. 0.86 (.034) REF 0.1016 0.0508 (.004 .002) MSOP (MSE16) 0911 REV E 4415fa 18 LTC4415 Revision History REV DATE DESCRIPTION A 4/12 Clarified footnotes and added new Note 5 for quiescent current PAGE NUMBER 3, 4 Changed FET MP1 part number on Figure 8 15 4415fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 19 LTC4415 Typical Application Power Backup Using Supercapacitors and Optional Keep-Alive Cell KEEP-ALIVE/COIN CELL M1 M2 VDD VOUT VIN 294k 100k EN PFI CTL LTC3625 VSEL GND SW1 L1 3.3H L2 3.3H SW2 VMID PROG IDEAL IN1 GND PFO RPROG 78.7k CTOP 360F 300k CBOT 360F 200k DMN2215UDM OUT1 47F LTC4415 EN1 125 STAT1 WARN1 WARN2 STAT2 CLIM1 CLIM2 47k 22F EN2 IDEAL GND BURST 4.7H 137k 68.1k LTC3521 PWM VOUT2 1.8V 10F 0.6A FB2 VOUT1 1.0M 221k ON OFF OUT2 PVIN1 VIN PVIN2 SW2 SW1A SW1B VOUT1 3.3V 1A 125 IN2 4.7H FB1 SW3 SHDN1 FB3 SHDN2 SHDN3 PGOOD1 PWM PGOOD2 PGND1A PGOOD3 PGND1B GND PGND2 4.7H VOUT3 1.2V 10F 0.6A 100k 100k 4415 TA02 Related Parts PART NUMBER DESCRIPTION COMMENTS LTC4411 2.6A Low Loss Ideal Diode Monolithic Low Loss PowerPath, ThinSOT Package LTC4412 PowerPath Controller 3V to 28V Input Voltage Range, ThinSOT Package LTC4413-1/ LTC4413-2 Dual 2.6A, 2.5V to 5.5V, Ideal Diodes in 3mm x 3mm DFN 140m On-Resistance, Overvoltage Protection Sensor with Drive Output LTC4414 36V, Low Loss PowerPath Controller for Large PFETs Drives Large QG PFETs, 3.5V to 36V LTC4416 36V, Low Loss Dual PowerPath Controllers Designed to Drive Large and Small QG PFETs, 3.5V to 36V LTC4352 Low Voltage Ideal Diode Controller With Monitoring Controls Single N-Channel MOSFET, Input Supply Monitors, 2.9V to 18V LTC4354 Negative High Voltage Diode-OR Controller and Monitor Controls Two N-Channel MOSFETs, 4.5V to 80V LTC4355 Positive High Voltage Diode-OR Controller and Monitor Controls Two N-Channel MOSFETs, 9V to 80V LTC4357 Positive High Voltage Ideal Diode Controller Controls Single N-Channel MOSFET, 9V to 80V LTC4358 5A Monolithic Ideal Diode 20m N-Channel MOSFET, 9V to 26.5V LTC4066 USB Power Controller and Li-Ion Linear Charger with Low Loss Ideal Diode Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and 5V Wall Adapter LTC4425 Linear Supercapacitor Charger with Current-Limited Ideal Diode and V/I Monitor 50m On-Resistance, 2.7V to 5.5V, Programmable Current Limit, Programmable Output Voltage Mode LTC2952 Pushbutton Ideal Diode PowerPath Controller with Supervisor Controls Two P-Channel MOSFETs, 2.7V to 28V 4415fa 20 Linear Technology Corporation LT 0412 REV A * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2011