ACT4523YH-T

Active-Semi FEATURES • • • • • 40V Input Voltage Surge 38V Steady State Operation Up to 3A output current Output Voltage up to 12V Patent Pending Active CC Sensorless Constant Current Control − Integrated Current Control Improves Efficiency, Lowers Cost, and Reduces Component Count • Resistor Programmable ACT4523 Rev 4, 21-Jul-11 Wide-Input Sensorless CC/CV Step-Down DC/DC Converter APPLICATIONS • Car Charger/ Adaptor • Rechargeable Portable Devices • General-Purpose CC/CV Supply GENERAL DESCRIPTION ACT4523 is a wide input voltage, high efficiency Active CC step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. ACT4523 provides up to 3A output current at 225kHz switching frequency. Active CC is a patent-pending control scheme to achieve highest accuracy sensorless constant current control. Active CC eliminates the expensive, high accuracy current sense resistor, making it ideal for battery charging applications and adaptors with accurate current limit. The ACT4523 achieves higher efficiency than traditional constant current switching regulators by eliminating its associated power loss. Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency foldback at short circuit. The devices are available in a SOP8EP package and require very few external devices for operation. − Current Limit from 1.5A to 3A − Patented Cable Compensation from 0Ω to 0.3Ω • ±7.5% CC Accuracy − Compensation of Input /Output Voltage Change − Temperature Compensation − Independent of inductance and Inductor DCR • • • • 2% Feedback Voltage Accuracy Up to 94% Efficiency 225kHz 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-8EP Package CC/CV Curve Input 10V to 40V IN HSB SW C3 22nF 50V L1 30µH 6.0 ACT4523-001 5V 5.0 VIN = 24V ENABLE EN ISET FB GND COMP Output Voltage (V) ACT4523 4.0 3.0 2.0 1.0 0.0 0 R2 52k VIN = 12V C1 47µF C2 R1 11.5k 2.2nF R3 8.2k R4 10k D1 SK34 C4 220µF 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 Output Current (A) Innovative PowerTM -1www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi ORDERING INFORMATION PART NUMBER ACT4523YH-T ACT4523 Rev 4, 21-Jul-11 OPERATION TEMPERATURE RANGE -40°C to 85°C PACKAGE SOP-8EP PINS 8 PACKING TAPE & REEL PIN CONFIGURATION PIN DESCRIPTIONS PIN 1 2 3 4 5 6 7 NAME HSB IN SW GND FB COMP EN DESCRIPTION High Side Bias Pin. This provides power to the internal high-side MOSFET gate driver. Connect a 22nF 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. 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. 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. 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 1.6V 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. Heat Dissipation Pad. Connect this exposed pad to large ground copper area with copper and vias. 8 ISET Exposed Pad Innovative PowerTM -2- www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi ABSOLUTE MAXIMUM RATINGS PARAMETER IN to GND SW to GND HSB to GND FB, EN, ISET, COMP to GND Junction to Ambient Thermal Resistance Operating Junction Temperature Storage Junction Temperature Lead Temperature (Soldering 10 sec.) ACT4523 Rev 4, 21-Jul-11 VALUE -0.3 to 40 -1 to VIN + 1 VSW - 0.3 to VSW + 7 -0.3 to + 6 46 -40 to 150 -55 to 150 300 UNIT V V V V °C/W °C °C °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 © 2011 Active-Semi, Inc. Active-Semi ELECTRICAL CHARACTERISTICS (VIN = 20V, TA = 25°C, unless otherwise specified.) ACT4523 Rev 4, 21-Jul-11 PARAMETER Input Voltage Input Voltage Surge VIN UVLO Turn-On Voltage VIN UVLO Hysteresis Standby Supply Current Shutdown Supply Current Feedback Voltage Internal Soft-Start Time Error Amplifier Transconductance Error Amplifier DC Gain Switching Frequency Foldback Switching Frequency Maximum Duty Cycle Minimum On-Time COMP to Current Limit Transconductance Secondary Cycle-by-Cycle Current Limit Slope Compensation ISET Voltage ISET to IOUT DC Room Temp Current Gain CC Controller DC Accuracy EN Threshold Voltage EN Hysteresis EN Internal Pull-up Current High-Side Switch ON-Resistance SW Off Leakage Current Thermal Shutdown Temperature Thermal Shutdown Temperature Hysteresis TEST CONDITIONS MIN 10 TYP MAX 38 40 UNIT V V V V Input Voltage Rising Input Voltage Falling VEN = 3V, VFB = 1V VEN = 3V, VOUT = 5V, No load VEN = 0V 9.0 9.4 1.1 0.9 3.0 75 9.7 1.4 mA mA 115 824 µA mV µs µA/V V/V 792 808 400 VFB = VCOMP = 0.8V, ∆ICOMP = ± 10µA 650 4000 VFB = 0.808V VFB = 0V 200 225 30 250 kHz kHz 85 88 200 91 % ns A/V A A V A/A VCOMP = 1.2V Duty = DMAX Duty = DMAX 5.25 4.5 1.2 1 IOUT / ISET, RISET = 19.6kΩ RISET = 19.6kΩ, VOUT = 3.5V Open-Loop DC Test EN Pin Rising EN Pin Falling 1175 1.47 25000 1190 1.6 125 4 0.16 1205 1.73 mA V mV µA Ω VEN = VSW = 0V Temperature Rising Temperature Falling 1 150 20 10 µA °C °C Innovative PowerTM -4- www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi FUNCTIONAL BLOCK DIAGRAM IN AVIN PVIN ACT4523 Rev 4, 21-Jul-11 EN BANDGAP, REGULATOR, & SHUTDOWN CONTROL OSCILLATOR VREF = 0.808V EMI CONTROL HSB Σ PWM CONTROLLER SW VREF = 0.808V + FB - CC CONTROL COMP ISET FUNCTIONAL DESCRIPTION CV/CC Loop Regulation As seen in Functional Block Diagram, the ACT4523 is a peak current mode pulse width modulation (PWM) converter with CC and CV control. The converter operates as follows: 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. 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 -5- regulating output voltage to regulating output current, and the output voltage will drop with increasing load. The Oscillator normally switches at 225kHz. However, if FB voltage is less than 0.6V, then the switching frequency decreases until it reaches a typical value of 30kHz at VFB = 0.15V. Enable Pin The ACT4523 has an enable input EN for turning the IC on or off. The EN pin contains a precision 1.6V comparator with 125mV 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. 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 1.6V, or driven with open-drain logic to provide digital on/off control. Thermal Shutdown The ACT4523 disables switching when its junction temperature exceeds 150°C and resumes when the temperature has dropped by 20°C. www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi APPLICATIONS INFORMATION Output Voltage Setting Figure 1: Output Voltage Setting ACT4523 Rev 4, 21-Jul-11 CC Current Line Compensation When operating at constant current mode, the current limit increase slightly with input voltage. For wide input voltage applications, a resistor RC is added to compensate line change and keep output high CC accuracy, as shown in Figure 3. Figure 3: Iutput Line Compensation VOUT ACT4523 FB RFB2 RFB1 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 ⎞ R FB1 = R FB 2 ⎜ OUT − 1 ⎟ 0 .808 V ⎝ ⎠ the two the and (1) Inductor Selection The inductor maintains a continuous current to the output load. This inductor current has a ripple that is dependent on the inductance value: 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: CC Current Setting ACT4523 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. Figure 2: Curve for Programming Output CC Current L= VOUT × (VIN _VOUT ) VIN fSW ILOADMAX K RIPPLE (2) Output Current vs. RISET 3500 3000 ACT4523-002 Output Current (mA) 2500 2000 1500 1000 500 VIN = 24V, VOUT = 4V 0 8 11 14 17 20 23 26 29 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. With a selected inductor value the peak-to-peak inductor current is estimated as: ILPK _ PK = VOUT × (VIN _VOUT ) L × VIN × fSW (3) The peak inductor current is estimated as: 32 RISET (kΩ) 1 ILPK = ILOADMAX + ILPK _ PK 2 (4) Innovative PowerTM -6- www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi APPLICATIONS INFORMATION CONT’D The selected inductor should not saturate at ILPK. The maximum output current is calculated as: IOUTMAX = ILIM _ ACT4523 Rev 4, 21-Jul-11 Output Capacitor (5) 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 + 1 I_ 2 LPK PK LLIM is the internal current limit, which is typically 3.2A, as shown in Electrical Characteristics Table. VIN 28 × fSW LC OUT 2 (6) External High Voltage Bias Diode 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. Figure 4: External High Voltage Bias Diode 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 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. 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 This diode is also recommended for high duty cycle operation and high output voltage applications. 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. 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. Innovative PowerTM -7- www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi STABILITY COMPENSATION Figure 5: Stability Compensation ACT4523 Rev 4, 21-Jul-11 If RCOMP is limited to 15kΩ, then the actual cross over frequency is 6.58 / (VOUTCOUT). Therefore: C COMP = 6 . 45 × 10 _ 6 VOUT C OUT (F) (14) 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: R ESRCOUT ≥ (Min : CCOMP2 is needed only for high ESR output capacitor 1 . 77 × 10 C OUT _6 ,0 . 006 × VOUT ) (Ω) (15) The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 5. The DC loop gain of the system is determined by the following equation: A VDC = 0 . 808 V A VEA G COMP I OUT And the proper value for CCOMP2 is: C COMP 2 = C OUT R ESRCOUT R COMP (16) (7) The dominant pole P1 is due to CCOMP: fP 1 = G EA COMP 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. Table 1 shows some calculated results based on the compensation method above. Table 1: 2 π A VEA C (8) 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: fZ 1 = 1 2 π R COMP C COMP (9) Typical Compensation for Different Output Voltages and Output Capacitors VOUT 2.5V COUT 47μF Ceramic CAP 47μF Ceramic CAP 47μF Ceramic CAP 470μF/6.3V/30mΩ 470μF/6.3V/30mΩ 470μF/6.3V/30mΩ RCOMP CCOMP CCOMP2 5.6kΩ 6.2kΩ 8.2kΩ 39kΩ 45kΩ 51kΩ 3.3nF 3.3nF 3.3nF 22nF 22nF 22nF None None None 47pF 47pF 47pF (10) 3.3V 5V 2.5V 3.3V 5V And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used): fP 3 = 1 2πR COMP C COMP2 (11) The following steps should be used to compensate the IC: STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP: R COMP = 2 π V OUT C OUT f SW 10 G EA G COMP × 0 . 808 V : CCOMP2 is needed for high ESR output capacitor. CCOMP2 ≤ 47pF is recommended. CC Loop Stability The constant-current control loop is internally compensated over the 1500mA-3000mA output range. No additional external compensation is required to stabilize the CC current. = 5 . 12 × 10 7 VOUT C OUT (Ω) (12) Output Cable Resistance Compensation To compensate for resistive voltage drop across the charger's output cable, the ACT4523 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. Use the curve in Figure 6 to choose the proper feedback resistance values for cable compensation. -8www.active-semi.com Copyright © 2011 Active-Semi, Inc. 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 = 2 . 83 × 10 R COMP 5 (F) (13) Innovative PowerTM Active-Semi STABILITY COMPENSATION CONT’D RFB1 is the high side resistor of voltage divider. In the case of high RFB1 used, the frequency compensation needs to be adjusted correspondingly. As show in Figure 7, adding a capacitor in paralled with RFB1 or increasing the compensation capacitance at COMP pin helps the system stability. Figure 6: Cable Compensation at Various Resistor Divider Values Delta Output Voltage vs. Output Current ACT4523-003 350 43 0k 60 k ACT4523 Rev 4, 21-Jul-11 power GND with vias or short and wide path. 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. Connect exposed pad to power ground copper area with copper and vias. 4) Use copper plane for power GND for best heat dissipation and noise immunity. 5) Place feedback resistor close to FB pin. 6) Use short trace connecting HSB-CHSB-SW loop Figure 8 shows an example of PCB layout. Delta Output Voltage (mV) 300 250 200 150 100 50 0 0 0.4 0.8 1.2 B1 RF = 1 R FB =3 R 1 FB R FB 1 k 00 =3 k 40 =2 R FB1 R FB1 RFB1 00k =2 0k = 15 R FB1 k = 100 1k =5 1.6 2 Output Current (A) Figure 7: Frequency Compensation for High RFB1 Figure 8: PCB Layout 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. 2) Place input decoupling ceramic capacitor CIN as close to IN pin as possible. CIN is connected Innovative PowerTM -9- Figure 9 gives one typical car charger application schematic and associated BOM list. www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi Figure 9: Typical Application Circuit for 5V/2.1A Car Charger ACT4523 Rev 4, 21-Jul-11 Table 2: BOM List for 5V/2.1A Car Charger ITEM REFERENCE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 U1 C1 C2 C3 C4 C5 C6 L1 D1 D2 R1 R2 R3 R4 DESCRIPTION IC, ACT4523YH, SOP-8EP Capacitor, Electrolytic, 47µF/50V, 6.3х7mm Capacitor, Ceramic, 10µF/50V, 1206, SMD Capacitor, Ceramic, 2.2nF/6.3V, 0603, SMD Capacitor, Ceramic, 22nF/50V, 1206, SMD Capacitor, Electrolytic, 220µF/10V, 6.3х7mm Capacitor, Ceramic, 1µF/10V, 0603, SMD Inductor,33µH, 3A, 20%, SMD Diode, Schottky, 40V/3A, SK34 Diode, 75V/150mA, LL4148 Chip Resistor, 11.5kΩ, 0603, 1% Chip Resistor, 52kΩ, 0603, 1% Chip Resistor, 8.2kΩ, 0603, 5% Chip Resistor, 10kΩ, 0603, 1% MANUFACTURER Active-Semi Murata, TDK Murata, TDK Murata, TDK Murata, TDK Murata, TDK Murata, TDK Tyco Electronics Diodes Good-ARK Murata, TDK Murata, TDK Murata, TDK Murata, TDK QTY 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Innovative PowerTM - 10 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi TYPICAL PERFORMANCE CHARACTERISTICS (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) ACT4523 Rev 4, 21-Jul-11 100 95 90 85 80 75 70 65 60 200 Efficiency vs. Load current 250 ACT4523-004 VIN = 12V 230 210 190 170 150 130 110 600 1000 1400 1800 2200 10 Switching Frequency vs. Input Voltage ACT4523-005 VIN = 24V VOUT = 5V Switching Frequency (kHz) Efficiency (%) 15 20 25 30 35 40 Load Current (mA) Input Voltage (V) Switching Frequency vs. Feedback Voltage 260 2700 2600 ACT4523-006 CC Current vs. Temperature ACT4523-007 Switching Frequency (kHz) CC Current (mA) 210 2500 2400 2300 2200 2100 160 110 60 10 0 100 200 300 400 500 600 700 800 900 2000 25 45 65 85 105 125 145 Feedback Voltage (mV) Temperature (°C) CC Current vs. Input Voltage 2600 4.2 ACT4523-008 4.05 3.9 3.75 3.6 3.45 3.3 3.15 3 14 18 22 26 30 34 38 Maximum Peak Current vs. Duty Cycle ACT4523-009 2400 2200 2000 1800 1600 10 Maximum CC Current (A) CC Current (mA) 20 30 40 50 60 70 Input Voltage (V) Duty Cycle Innovative PowerTM - 11 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) ACT4523 Rev 4, 21-Jul-11 175 160 Shutdown Current vs. Input Voltage Standby Supply Current (mA) ACT4523-010 3 2.5 2 1.5 1 0.5 0 0 4 Standby Current vs. Input Voltage ACT4523-011 Shutdown Current (µA) 145 130 115 100 85 70 10 15 20 25 30 35 40 8 12 16 20 24 28 32 36 40 Input Voltage (V) Input Voltage (V) Reverse Leakage Current (VIN Floating) 160 ACT4523-012 Start up into CC mode ACT4523-013 VOUT = 5V RLORD = 1.5Ω IISET = 2A VIN = 12V CH1 Reverse Leakage Current (µA) 120 80 40 CH2 0 0 1 2 3 4 5 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 200µs/div VOUT (V) Start up into CC mode ACT4523-014 VOUT = 5V RLORD = 1.5Ω IISET = 2A VIN = 24V CH1 SW vs. Output Voltage Ripples ACT4523-015 VIN = 12V VOUT = 5V IOUT = 2.1A CH1 CH2 CH2 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 200µs/div CH1: VOUT Ripple, 20mV/div CH2: SW, 5V/div TIME: 2µs/div Innovative PowerTM - 12 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) ACT4523 Rev 4, 21-Jul-11 SW vs. Output Voltage Ripple ACT4523-016 VIN = 24V VOUT = 5V IOUT = 2.1A CH1 VIN = 12V VOUT = 5V IOUT = 2.1A Start up with EN ACT4523-017 CH1 CH2 CH2 CH1: VRIPPLE, 20mV/div CH2: SW, 10V/div TIME: 2µs/div CH1: EN, 2V/div CH2: VOUT, 2V/div TIME: 400µs//div Start up with EN ACT4523-018 VIN = 24V VOUT = 5V IISET = 2.1A Load Step Waveforms ACT4523-019 VIN = 12V VOUT = 5V IISET = 2.1A CH1 CH1 CH2 CH2 CH1: EN, 2V/div CH2: VOUT, 2V/div TIME: 400µs//div CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 200µs//div Load Step Waveforms ACT4523-020 VIN = 24V VOUT = 5V IISET = 2.1A CH1 Short Circuit ACT4523-021 VIN = 12V VOUT = 5V IISET = 2.1A CH1 CH2 CH2 CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 200µs//div CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 100µs//div Innovative PowerTM - 13 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) ACT4523 Rev 4, 21-Jul-11 Short Circuit ACT4523-022 CH1 VIN = 24V VOUT = 5V IISET = 2.1A VIN = 12V VOUT = 5V IISET = 2.1A Short Circuit Recovery ACT4523-023 CH1 CH2 CH2 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 100µs//div CH1: VOUT, 2V/div CH2: IOUT, 2A/div TIME: 1ms/div Short Circuit Recovery ACT4523-024 VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH2 CH1: VOUT, 2V/div CH2: IOUT, 2A/div TIME: 1ms/div Innovative PowerTM - 14 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. Active-Semi PACKAGE OUTLINE SOP-8EP PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILLIMETERS MIN MAX ACT4523 Rev 4, 21-Jul-11 DIMENSION IN INCHES MIN MAX A A1 A2 b c D D1 E E1 E2 e L θ 1.350 0.000 1.350 0.330 0.170 4.700 3.202 3.800 5.800 2.313 1.700 0.100 1.550 0.510 0.250 5.100 3.402 4.000 6.200 2.513 0.053 0.000 0.053 0.013 0.007 0.185 0.126 0.150 0.228 0.091 0.067 0.004 0.061 0.020 0.010 0.200 0.134 0.157 0.244 0.099 1.270 TYP 0.400 0° 1.270 8° 0.050 TYP 0.016 0° 0.050 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 sales@active-semi.com or visit http://www.active-semi.com. ® is a registered trademark of Active-Semi. - 15 www.active-semi.com Copyright © 2011 Active-Semi, Inc. Innovative PowerTM