ACT4012 ETC2 | Alldatasheet
Document overview
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Technical content
Wide Input 2A Step Down Converter
FEATURES
2A Output Current Up to 92% Efficiency Up to 20V Input Range 8µA Shutdown Supply Current 410kHz Switching Frequency Adjustable Output Voltage Cycle-by-Cycle Current Limit Protection Thermal Shutdown Protection Frequency Foldback at Short Circuit Stability with Wide Range of Capacitors, Including Low ESR Ceramic Capacitors SOP-8 Package
APPLICATIONS
TFT LCD Monitors Portable DVDs Car-Powered or Battery-Powered Equipments Set-Top Boxes Telecom Power Supplies DSL and Cable Modems and Routers Termination Supplies GENERAL DESCRIPTION The ACT4012 is a current-mode step-down DC-DC converter that generates up to 2A output current at 410kHz switching frequency. The device utilizes Active-Semi’s proprietary ISOBCD20 process for operation with input voltage up to 20V. Consuming only 8μA in shutdown mode, the ACT4012 is highly efficient with peak efficiency at 92% when in operation. Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency foldback at short circuit. The ACT4012 is available in SOP-8 package and requires very few external devices for operation. Active-Semi, Inc. - 1 - www.active-semi.com Figure 1. Typical Application Circuit
ORDERING INFORMATION
PART NUMBER TEMPERATURE RANGE PACKAGE PINS PACKING ACT4012SH -40°C to 85°C SOP-8 8 TUBE ACT4012SH-T -40°C to 85°C SOP-8 8 TAPE & REEL PIN CONFIGURATION PIN DESCRIPTION PIN NUMBER PIN NAME PIN DESCRIPTION 1 BS Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver. Connect a 10nF between this pin and SW. 2 IN Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor in Application Information section. 3 SW Switch Output. Connect this pin to the switching end of the inductor. 4 G Ground and Heatsink. Connect to a large, uncovered PCB copper area for best heat dissipation. 5 FB Feedback Input. The voltage at this pin is regulated to 1.293V. Connect to the resistor divider between output and ground to set output voltage. 6 COMP Compensation Pin. See Compensation Technique in Application Information section. 7 EN Enable Input. When higher than 1.3V, this pin turns the IC on. When lower than 0.7V, this pin turns the IC off. Output voltage is discharged when the IC is off. This pin has a small internal pull up current to a high level voltage when pin is not connected. Do not allow EN to exceed 6V. 8 N/C Not Connected. Active-Semi, Inc. - 2 - www.active-semi.com 1BS SOP-8 2IN 3SW N/C EN COMP FB ACT4012SH
(Note: Exceeding these limits may damage the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability.) PARAMETER VALUE UNIT IN Supply Voltage -0.3 to 25 V SW Voltage -1 to VIN + 1 V BS Voltage VSW – 0.3 to VSW + 8 V EN, FB, COMP Voltage -0.3 to 6 V Continuous SW Current Internally limited A Junction to Ambient Thermal Resistance (θ JA) 105 °C/W Maximum Power Dissipation 0.76 W Operating Junction Temperature -40 to 150 °C Storage Temperature -55 to 150 °C Lead Temperature (Soldering, 10 sec) 300 °C
ELECTRICAL CHARACTERISTICS
(VIN = 12V, TA= 25°C unless otherwise specified.) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT Input Voltage VIN VOUT = 5V, ILOAD = 0A to 1A 7 20 V High-Side Switch On Resistance RONH 0.4 Ω Low-Side Switch On Resistance RONL 10 Ω SW Leakage VEN = 0 0 10 µA Current Limit ILIM 2.4 2.85 A COMP to Current Limit Transconductance GCOMP 1.8 A/V Error Amplifier Transconductance GEA ΔICOMP = ±10µA 550 µA/V Error Amplifier DC Gain AVEA 4000 V/V Switching Frequency fSW 350 410 470 kHz Short Circuit Switching Frequency VFB = 0 50 kHz Maximum Duty Cycle DMAX VFB = 1.1V 90 % Minimum Duty Cycle VFB = 1.4V 0 % Enable Threshold Voltage Hysteresis = 0.1V 0.7 1 1.3 V Enable Pull Up Current Pin pulled up to 4.5V typically when left unconnected 2 µA Supply Current in Shutdown VEN = 0 8 20 µA IC Supply Current in Operation VEN = 3V, VFB = 1.4V 0.7 mA Thermal Shutdown Temperature Hysteresis = 10°C 160 °C Active-Semi, Inc. - 3 - www.active-semi.com
Figure 2. Functional Block Diagram state continues until the cycle starts again. logic using BS bootstrap pin as the positive rail. The Oscillator normally switches at 410kHz. minimum of 50kHz at VFB = 0.5V. be directly connected to IN. junction temperature exceeds 160°C.
*Heat dissipation copper area required. Leave more than 2 in2 of uncovered PCB area immediately adjacent to the G pin. Figure 5. ACT4012 2.5V/2A Output Application
TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 5, unless otherwise specified .) Active-Semi, Inc. - 8 - www.active-semi.com
SOP-8 PACKAGE OUTLINE AND DIMENSIONS SYMBOL 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 4.780 5.000 0.188 0.197 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. - 9 - www.active-semi.com 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 data sheet, 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 www.active-semi.com. For other inquiries, please send to: