ACT4501 Rev 2, 14-Nov-12 1.25A CC/CV Step-Down DC/DC Converter FEATURES APPLICATIONS • • • • • • • Car Charger • Rechargeable Portable Devices • General-Purpose CC/CV Power Supply 10V-30V Input Voltage 40V Transparent Input Voltage Surge Up to 1.25A Constant Output Current Output Voltage up to 12V Good EMC Performance on Single Layer PCB Patent Pending ActiveCC Constant Current Control − Integrated Current Control Improves Efficiency, Lowers Cost, and Reduces Component Count • Resistor Programmable Outputs GENERAL DESCRIPTION ACT4501 is a dedicated cost-effective DC-DC converter for 5V/1A car charger applications with a wide input voltage and high efficiency. The converter operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. ACT4501 provides up to 1.25A output current at 125kHz switching frequency. − Current Limit from 500mA to 1250mA • • • • • ActiveCC is a patent-pending control scheme to achieve high accuracy sensorless constant current control. ActiveCC eliminates the expensive, high accuracy current sense resistor, making it ideal for battery charging applications and high-brightness LED drive for architectural lighting. The ACT4501 achieves higher efficiency than traditional constant current switching regulators by eliminating the sense resistor and its associated power loss. Patented cable compensation from DC Cable Compensation from 0Ω to 0.5Ω 2% Feedback Voltage Accuracy Up to 90% Efficiency 125kHz Switching Frequency Eases EMI Design Advanced Feature Set − Integrated Soft Start − Thermal Shutdown − Secondary Cycle-by-Cycle Current Limit − Protection Against Shorted ISET Pin SOP-8 Package Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency foldback at short circuit. The devices are available in a SOP-8 package and require very few external devices for operation. Efficiency vs. Load Current ACT4501-001 100 90 Efficiency (%) VIN = 12V 80 VIN = 16V 70 VIN = 24V 60 50 VOUT = 5V 40 1 10 100 1000 10000 Load Current (mA) Innovative PowerTM -1- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 ORDERING INFORMATION PART NUMBER TEMPERATURE RANGE PACKAGE PINS PACKING ACT4501SH-T -40°C to 85°C SOP-8 8 TAPE & REEL PIN CONFIGURATION SOP-8 PIN DESCRIPTIONS PIN NAME 1 HSB 2 IN 3 SW 4 GND Ground. Connect this pin to a large PCB copper area for best heat dissipation. Return FB, COMP, and ISET to this GND, and connect this GND to power GND at a single point for best noise immunity. 5 FB Feedback Input. The voltage at this pin is regulated to 0.808V. Connect to the resistor divider between output and GND to set the output voltage. 6 COMP 7 EN 8 ISET Innovative PowerTM DESCRIPTION High Voltage Bias Pin. This provides power to the internal high-side MOSFET gate driver. Connect a 10nF capacitor from HSB pin to SW pin. Power Supply Input. Bypass this pin with a 10µF ceramic capacitor to GND, placed as close to the IC as possible. Power Switching Output to External Inductor. Error Amplifier Output. This pin is used to compensate the converter. Enable Input. EN is pulled up to 5V with a 4μA current, and contains a precise 0.8V logic threshold. Drive this pin to a logic-high or leave unconnected to enable the IC. Drive to a logic-low to disable the IC and enter shutdown mode. Output Current Setting Pin. Connect a resistor from ISET to GND to program the output current. -2- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT -0.3 to 40 V SW to GND -1 to VIN + 1 V HSB to GND VSW - 0.3 to VSW + 7 V -0.3 to + 6 V 105 °C/W Operating Junction Temperature -40 to 150 °C Storage Junction Temperature -55 to 150 °C 300 °C IN to GND FB, EN, ISET, COMP to GND Junction to Ambient Thermal Resistance Lead Temperature (Soldering 10 sec.) c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability. Innovative PowerTM -3- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 ELECTRICAL CHARACTERISTICS (VIN = 14V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS Input Voltage MIN TYP 10 MAX UNIT 30 V 9.65 V VIN UVLO Turn-On Voltage Input Voltage Rising VIN UVLO Hysteresis Input Voltage Falling 1.1 V VEN = 3V, VFB = 1V 1.0 mA VEN = 3V, VO = 5V, No load 2.5 mA VEN = 0V 75 100 µA 808 824 mV Standby Supply Current Shutdown Supply Current Feedback Voltage 9.05 792 Internal Soft-Start Time Error Amplifier Transconductance VFB = VCOMP = 0.8V, ∆ICOMP = ± 10µA Error Amplifier DC Gain 9.35 800 µs 650 µA/V 4000 V/V Switching Frequency VFB = 0.808V 115 125 130 kHz Foldback Switching Frequency VFB = 0V 10 16 38 kHz 85 88 93 % Maximum Duty Cycle Minimum On-Time 800 ns COMP to Current Limit Transconductance VCOMP = 1.2V 1.75 A/V Switch Current Limit Duty = 50% 1.8 A Slope Compensation Duty = DMAX 0.75 A 1 V 25000 A/A ISET Voltage ISET to IOUT DC Room Temp Current Gain IOUT / ISET CC Controller DC Accuracy RISET = 19.6kΩ, VIN = 10V - 30V 1020 1200 1380 mA EN Threshold Voltage EN Pin Rising 0.75 0.8 0.85 V EN Hysteresis EN Pin Falling EN Internal Pull-up Current High-Side Switch ON-Resistance SW Off Leakage Current VEN = VSW = 0V Thermal Shutdown Temperature Temperature Rising Innovative PowerTM -4- 80 mV 4 µA 0.3 Ω 1 155 10 µA °C www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 FUNCTIONAL BLOCK DIAGRAM IN AVIN BANDGAP, REGULATOR, & SHUTDOWN CONTROL EN PVIN OSCILLATOR VREF = 0.808V EMI CONTROL HSB PWM CONTROLLER VREF = 0.808V FB SW + CC CONTROL COMP ISET FUNCTIONAL DESCRIPTION regulating output voltage to regulating output current, and the output voltage will drop with increasing load. CV/CC Loop Regulation As seen in Functional Block Diagram, the ACT4501 is a peak current mode pulse width modulation (PWM) converter with CC and CV control. The converter operates as follows: The Oscillator normally switches at 125kHz. However, if FB voltage is less than 0.6V, then the switching frequency decreases until it reaches a typical value of 20kHz at VFB = 0.15V. A switching cycle starts when the rising edge of the Oscillator clock output causes the High-Side Power Switch to turn on and the Low-Side Power Switch to turn off. With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes low, the High-Side Power Switch turns off. Enable Pin The ACT4501 has an enable input EN for turning the IC on or off. The EN pin contains a precision 0.8V comparator with 75mV hysteresis and a 4µA pull-up current source. The comparator can be used with a resistor divider from VIN to program a startup voltage higher than the normal UVLO value. It can be used with a resistor divider from VOUT to disable charging of a deeply discharged battery, or it can be used with a resistor divider containing a thermistor to provide a temperature-dependent shutoff protection for over temperature battery. The thermistor should be thermally coupled to the battery pack for this usage. At this point, the SW side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using HSB as the positive rail. This pin is charged to VSW + 5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 0.808V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Output current will increase until it reaches the CC limit set by the ISET resistor. At this point, the device will transition from Innovative PowerTM If left floating, the EN pin will be pulled up to roughly 5V by the internal 4µA current source. It can be driven from standard logic signals greater than 0.8V, or driven with open-drain logic to provide digital on/off control. Thermal Shutdown The ACT4501 disables switching when its junction temperature exceeds 155°C and resumes when the temperature has dropped by 20°C. -5- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 APPLICATIONS INFORMATION Inductor Selection Output Voltage Setting The inductor maintains a continuous current to the output load. This inductor current has a ripple that is dependent on the inductance value: Figure 1: Output Voltage Setting Higher inductance reduces the peak-to-peak ripple current. The trade off for high inductance value is the increase in inductor core size and series resistance, and the reduction in current handling capability. In general, select an inductance value L based on ripple current requirement: L= Figure 1 shows the connections for setting output voltage. Select the proper ratio of the feedback resistors RFB1 and RFB2 based on output voltage. Typically, use RFB2 ≈ 10kΩ determine RFB1 from the following equation: ⎛ V ⎞ RFB1 = RFB2 ⎜ OUT −1⎟ ⎝ 0.808V ⎠ the two the and (2) where VIN is the input voltage, VOUT is the output voltage, fSW is the switching frequency, ILOADMAX is the maximum load current, and KRIPPLE is the ripple factor. Typically, choose KRIPPLE = 30% to correspond to the peak-to-peak ripple current being 30% of the maximum load current. (1) With a selected inductor value the peak-to-peak inductor current is estimated as: CC Current Setting ACT4501 constant current value is set by a resistor connected between the ISET pin and GND. The CC output current is linearly proportional to the current flowing out of the ISET pin. The voltage at ISET is roughly 1V and the current gain from ISET to output is roughly 25000 (25mA/1µA). To determine the proper resistor for a desired current, please refer to Figure 2 below. ILPK _ PK = VOUT × (VIN _VOUT ) L × VIN × fSW 1 ILPK = ILOADMAX + ILPK _ PK 2 IOUTMAX = ILIM _ Output Current vs. RISET ACT4501-002 1600 1400 (4) The selected inductor should not saturate at ILPK. The maximum output current is calculated as: Curve for Programming Output CC Current 1800 (3) The peak inductor current is estimated as: Figure 2: Output Current (mA) VOUT × (VIN _VOUT ) VIN fSW ILOADMAX K RIPPLE 1 I _ 2 LPK PK (5) LLIM is the internal current limit, which is typically 2.5A, as shown in Electrical Characteristics Table. 1200 1000 800 600 External High Voltage Bias Diode 400 It is recommended that an external High Voltage Bias diode be added when the system has a 5V fixed input or the power supply generates a 5V output. This helps improve the efficiency of the regulator. The High Voltage Bias diode can be a low cost one such as IN4148 or BAT54. 200 0 0 10 20 30 40 50 60 70 80 90 RISET (kΩ) Innovative PowerTM -6- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 APPLICATIONS INFORMATION CONT’D for ceramic type. In the case of tantalum or electrolytic capacitors, the ripple is dominated by RESR multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR. Figure 3: External High Voltage Bias Diode For ceramic output capacitor, typically choose a capacitance of about 22µF. For tantalum or electrolytic capacitors, choose a capacitor with less than 50mΩ ESR. Rectifier Diode Use a Schottky diode as the rectifier to conduct current when the High-Side Power Switch is off. The Schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage. This diode is also recommended for high duty cycle operation and high output voltage applications. Input Capacitor The input capacitor needs to be carefully selected to maintain sufficiently low ripple at the supply input of the converter. A low ESR capacitor is highly recommended. Since large current flows in and out of this capacitor during switching, its ESR also affects efficiency. The input capacitance needs to be higher than 10µF. The best choice is the ceramic type, however, low ESR tantalum or electrolytic types may also be used provided that the RMS ripple current rating is higher than 50% of the output current. The input capacitor should be placed close to the IN and G pins of the IC, with the shortest traces possible. In the case of tantalum or electrolytic types, they can be further away if a small parallel 0.1µF ceramic capacitor is placed right next to the IC. Output Capacitor The output capacitor also needs to have low ESR to keep low output voltage ripple. The output ripple voltage is: VRIPPLE = IOUTMAX K RIPPLE RESR + VIN 2 28 × fSW LC OUT (6) where IOUTMAX is the maximum output current, KRIPPLE is the ripple factor, RESR is the ESR of the output capacitor, fSW is the switching frequency, L is the inductor value, and COUT is the output capacitance. In the case of ceramic output capacitors, RESR is very small and does not contribute to the ripple. Therefore, a lower capacitance value can be used Innovative PowerTM -7- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 STABILITY COMPENSATION If RCOMP is limited to 15kΩ, then the actual cross over frequency is 3.4 / (VOUTCOUT). Therefore: Figure 4: Stability Compensation CCOMP = 1.2 ×10 −5 VOUTCOUT (14) (F) STEP 3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the cross over frequency, an additional compensation capacitor CCOMP2 is required. The condition for using CCOMP2 is: ⎞ ⎛ 1.1 × 10 −6 ,0.012 × VOUT ⎟⎟ RESRCOUT ≥ Min⎜⎜ ⎠ ⎝ COUT c: CCOMP2 is needed only for high ESR output capacitor AVDC The dominant pole P1 is due to CCOMP: G EA fP1 = 2 π AVEA C COMP The second pole P2 is the output pole: I OUT fP 2 = 2 π V OUT C OUT The first zero Z1 is due to RCOMP and CCOMP: 1 f Z1 = 2π RCOMP CCOMP2 CCOMP 2 = 1 (7) (16) Table 2 shows some calculated results based on the compensation method above. (8) Table 1: Typical Compensation for Different Output Voltages and Output Capacitors (9) (10) (11) 2πR COMP C COMP2 COUT RESRCOUT RCOMP Though CCOMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value CCOMP2 such as 100pF may improve stability against PCB layout parasitic effects. And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used): fP 3 = VOUT COUT RCOMP CCOMP CCOMP2c 2.5V 47μF SP CAP 25kΩ 1.5nF 3.3V 47μF SP CAP 25kΩ 1.8nF None 5V 47μF SP CAP 25kΩ 2.2nF None 2.5V 220μF/6.3V/30mΩ 25kΩ 1.5nF 100pF 220μF/6.3V/30mΩ 25kΩ 1.8nF 100pF 5V 220μF/6.3V/30mΩ 25kΩ 2.2nF 100pF c: CCOMP2 is needed for high ESR output capacitor. CCOMP2 ≤ 47pF is recommended. STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP: CC Loop Stability 2 πVOUT C OUT fSW 10 G EA GCOMP × 0 .808 V = 2 . 75 × 10 8 VOUT C OUT (Ω) The constant-current control loop is internally compensated over the 400mA-1500mA output range. No additional external compensation is required to stabilize the CC current. (12) STEP 2. Set the zero fZ1 at 1/4 of the cross over frequency. If RCOMP is less than 15kΩ, the equation for CCOMP is: C COMP = 1 .8 × 10 −5 R COMP Innovative PowerTM (F) None 3.3V The following steps should be used to compensate the IC: R COMP = (15) And the proper value for CCOMP2 is: The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 3. The DC loop gain of the system is determined by the following equation: 0 . 808 V = AVEA G COMP I OUT (Ω) Output Cable Resistance Compensation To compensate for resistive voltage drop across the charger's output cable, the ACT4501 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. Use the curve in Figure 4 to choose the proper (13) -8- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 STABILITY COMPENSATION CONT’D feedback resistance values for cable compensation. RFB1 is the high side resistor of voltage divider. 2) Place input decoupling ceramic capacitor CIN as close to IN pin as possible. CIN is connected power GND with vias or short and wide path. In the case of high RFB1 used, the frequency compensation needs to be adjusted correspondingly. As show in Figure 6, adding a capacitor in paralled with RFB1 or increasing the compensation capacitance at COMP pin helps the system stability. 3) Return FB, COMP and ISET to signal GND pin, and connect the signal GND to power GND at a single point for best noise immunity. 4) Use copper plane for power GND for best heat dissipation and noise immunity. Figure 5: 5) Place feedback resistor close to FB pin. Cable Compensation at Various Resistor Divider Values 6) Use short trace connecting HSB-CHSB-SW loop Figure 7 shows an example of PCB layout. Delta Output Voltage vs. Output Current Delta Output Voltage (V) VIN = 12V V0UT = 5V 0.25 R 0.2 1 FB =3 R FB 1 R FB 0.15 R FB 0.1 1 R FB1 0.05 1 00 =2 =2 =2 k 70 40 k 00k = 15 RFB1 = k ACT4501-003 0.3 0k 100k k RFB1 = 51 0 0 200 400 600 800 1000 Output Current (mA) Figure 6: Figure 7: PCB Layout Frequency Compensation for High RFB1 Figure 8 gives one typical car charger application schematics and associated BOM list. PC Board Layout Guidance When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. 1) Arrange the power components to reduce the AC loop size consisting of CIN, IN pin, SW pin and the schottky diode. Innovative PowerTM -9- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 Figure 8: Typical Application Circuit for 5V/1A Car Charger Table 2: BOM List for 5V/1A Car Charger ITEM REFERENCE 1 U1 IC, ACT4501SH, SOP-8 Active-Semi 1 2 C1 Capacitor, Electrolytic, 47µF/50V, 6.3х7mm Murata, TDK 1 3 C2 Capacitor, Ceramic, 2.2µF/50V, 1206, SMD Murata, TDK 1 4 C3 Capacitor, Ceramic, 2.2nF/6.3V, 0603, SMD Murata, TDK 1 5 C4 Capacitor, Ceramic, 10nF/50V, 0603, SMD Murata, TDK 1 6 C5 Capacitor, Electrolytic, 100µF/10V, 6.3х7mm Murata, TDK 1 7 C6 Capacitor, Ceramic, 1µF/10V, 0603, SMD Murata, TDK 1 8 C7 (Optional) Capacitor, Ceramic, 100pF/6.3V, 0603 Murata, TDK 1 9 L1 82µH, 1.4A, 20%, SMD CDRH125-820M Sumida 1 10 D1 Diode, Schottky, 40V/2A, B240A, SMA Diodes 1 11 D2 Diode, 75V/150mA, LL4148 Good-ARK 1 12 R1 Chip Resistor, 20kΩ, 0603, 1% Murata, TDK 1 13 R2 Chip Resistor, 52kΩ, 0603, 1% Murata, TDK 1 14 R3 Chip Resistor, 25kΩ, 0603, 5% Murata, TDK 1 15 R4 Chip Resistor, 10kΩ, 0603, 1% Murata, TDK 1 Innovative PowerTM DESCRIPTION - 10 - MANUFACTURER QTY www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.) Efficiency vs. Load Current Switching Frequency vs. Input Voltage ACT4501-004 Efficiency (%) VIN = 12V 80 Switching Frequency (kHz) 90 130 VIN = 16V 70 VIN = 24V 60 50 VOUT = 5V 40 1 10 100 1000 ACT4501-005 100 125 120 115 110 105 5 10000 10 Load Current (mA) VIN = 12V RISET = 33kΩ 900 CC Current (mA) Switching Frequency (kHz) 35 CC Current vs. Temperature 80 60 40 800 700 600 500 20 0 0.2 0.4 0.6 0.8 400 -40 1 -25 0 25 50 75 80 Temperature (°C) Feedback Voltage (V) Peak Current Limit vs. Duty Cycle CC Current vs. Input Voltage 900 800 Maximum CC Current (mA) RISET = 33kΩ 700 600 500 400 ACT4501-009 2500 ACT4501-008 1000 CC Current (mA) 30 ACT4501-007 100 25 1000 ACT4501-006 120 20 Input Voltage (V) Switching Frequency vs. Feedback Voltage 140 0 15 100 2250 2000 1750 1500 1250 1000 750 500 250 0 10 12 18 24 30 0 Input Voltage (V) Innovative PowerTM 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Duty Cycle - 11 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.) Standby Supply Current vs. Input Voltage Shutdown Current vs. Input Voltage (EN pulled low) 100 5 4 Input Current (mA) Shutdown Current (µA) 120 ACT4501-011 ACT4501-010 140 80 60 40 3 2 1 20 0 0 5 10 15 20 25 30 5 15 Input Voltage (V) 35 SW vs. Output Voltage Ripples Reverse Leakage Current (VIN Floating) 80 ACT4501-013 ACT4501-012 100 Reverse Leakage Current (µA) 25 Input Voltage (V) VIN = 12V V0UT = 5V I0UT = 1A CH1 60 40 CH2 20 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 CH1: VOUT, 50mV/div CH2: VSW, 5V/div TIME: 4µs/div 5 VOUT (V) SW vs. Output Voltage Ripples ACT4501-015 CH1 ACT4501-014 VIN = 24V V0UT = 5V I0UT = 1A Start up with EN VIN = 12V V0UT = 5V I0UT = 1A CH1 CH2 CH2 CH1: EN, 1V/div CH2: VOUT, 1V/div TIME: 2ms/div CH1: VOUT, 50mV/div CH2: VSW, 10V/div TIME: 4µs/div Innovative PowerTM - 12 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.) Load Step Waveforms Start up with EN CH1 VIN = 12V V0UT = 5V IISET = 1A CH1 ACT4501-017 ACT4501-016 VIN = 24V V0UT = 5V IISET = 1A CH2 CH2 CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 400μs/div CH1: EN, 1V/div CH2: VOUT, 1V/div TIME: 2ms/div Load Step Waveforms CH1 ACT4501-018 VIN = 24V V0UT = 5V IISET = 1A CH2 CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 400μs/div Innovative PowerTM - 13 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, IISET = 1A, L = 82µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified.) Short Circuit Short Circuit Recovery ACT4501-020 VIN = 12V V0UT = 5V IISET = 1A ACT4501-019 CH1 VIN = 12V V0UT = 5V IISET = 1A CH1 CH2 CH2 CH3 CH3 CH1: VOUT, 2V/div CH2: IOUT, 1A/div CH3: VSW, 10V/div TIME: 40µs/div CH1: VOUT, 2V/div CH2: IOUT, 1A/div CH3: VSW, 10V/div TIME: 40µs/div Short Circuit Recovery Short Circuit VIN = 24V V0UT = 5V IISET = 1A ACT4501-022 ACT4501-021 VIN = 24V V0UT = 5V IISET = 1A CH1 CH1 CH2 CH2 CH3 CH3 CH1: VOUT, 2V/div CH2: IOUT, 1A/div CH3: VSW, 20V/div TIME: 40µs/div CH1: VOUT, 2V/div CH2: IOUT, 1A/div CH3: VSW, 20V/div TIME: 40µs/div Innovative PowerTM - 14 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4501 Rev 2, 14-Nov-12 PACKAGE OUTLINE SOP-8 PACKAGE OUTLINE AND DIMENSIONS D L C E1 E SYMBOL ? θ A A2 B A1 e DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 1.350 1.750 0.053 0.069 A1 0.100 0.250 0.004 0.010 A2 1.350 1.550 0.053 0.061 B 0.330 0.510 0.013 0.020 C 0.190 0.250 0.007 0.010 D 4.700 5.100 0.185 0.201 E 3.800 4.000 0.150 0.157 E1 5.800 6.300 0.228 0.248 e 1.270 TYP 0.050 TYP L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8° Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact firstname.lastname@example.org or visit http://www.active-semi.com. is a registered trademark of Active-Semi. Innovative PowerTM - 15 - www.active-semi.com Copyright © 2012 Active-Semi, Inc.