PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Features n n n n n n n n n n n n General Description Greater than 90% Efficiency Adjustable Output Voltage Up to 24V Internal 24V Power MOSFET Peak Current 3A,4.5A,5.5A 520kHz Frequency Built-in Over-Voltage Protection (OVP) Open Protection Programmable Soft-Start Function Thermal Shutdowns Under-Voltage-Lockout Over-Current Protection SOP-8(EP) Package The PAM242x devices are high-performance,fixed frequency, current-mode PWM step-up DC/DC converter that incorporate internal power MOSFETs. The PAM242x includes an integrated power MOSFET that supports peak currents of up to 3A/4.5A/5.5A. The PAM2 42x utilizes simple ex ternal loop compensation allowing optimization between component size, cost, and AC performance across a wide range of applications. Additional functions include an externally programmable soft-start function for easy inrush current control, internal over-voltage pr otection (OVP) ,c ycle-by- cyc le current limit protection, under voltage lock-out and thermal shutdown. Applications n n n n TFT LCD Monitors Battery-Powered Equipment Set-Top Boxes DSL and Cable Modems and Routers The PAM242x is available in the small SOP-8(EP) package. Typical Application SS34 L1 VIN 3.6V~5.5V VOUT 12V/800mA 6.8 μH C1 470μF C2 10μF PGND C8 10nF PAM242x EN FB COMP R3 51k C5 470uF R1 85k SS VIN C3 1μF C4 10uF SW AGND C6 47pF R2 10k C7 2.2nF Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 1 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Block Diagram Pin Configuration & Marking Information Top View SOP-8(EP) PGND 1 8 SW VIN 2 7 SS EN 3 6 FB COMP 4 5 AGND PCN: Product Code of PAM242x XXX: Internal Code V: Voltage Code Y: Year W: Week Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 2 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Pin Descriptions Pin Number Name Function 1 PGND Power Ground 2 IN Supply Input. 3 EN 4 COMP Error Amplifier Compensation Node. 5 AGND Analog Ground 6 FB Enable Control. Connect to a logic high level to enable the IC. Connect to a logic low level to disable the IC. When unused, connect EN pin to IN (do not leave pin floating). Feedback Input. Connect this pin a res istor divider from the output to set the output voltage. FB is regulated to 1.262V. Sof t Start Control Input. Connect a capacitor from this pin to Ground to set soft-start 7 SS timing duration. SS is discharged to ground in shutdown. SS may be left unconnected if soft start is not desired. 8 SW E xposed PAD Switch Output. Connec t this pin to the inductor and the schottky diode. To minimize E MI, minimize the PCB trace path between this pin and the input bypass capac itor. Connected to gound Absolute Maximum Ratings These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. All voltages are with respect to ground. SW to Ground...................................–0.3V to 28V VIN, EN, FB, SS, COMP to Ground........................ ...................................................... –0.3V to 6.5V Continuous SW Current..............Internally Limited Operating Temperature Range............................. ................................................... –40 C to 150 C Storage Temperature Range......... –55 C to 150C Lead Temperature (Soldering, 10 sec) .......... 300 C Recommended Operating Conditions Junction Temperature................... - 40℃ to 125℃ Ambient Temperature ..................... - 40℃ to 85 ℃ Thermal Information Parameter Thermal Resistance (Junction to Case) Thermal Resistance (Junction to Ambient) Package Symbol Maximum SOP-8(EP ) θJC 75 Unit ℃/W θJA SOP-8(EP ) 180 Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 3 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Electrical Characteristic At T A =25 C ,V IN=V EN=5V,,unless otherwise specified. CONDITIONS PARAMETER Input Voltage Under Voltage Lockout Thres hold Under Voltage Lockout Hysteresis Quiescent Supply Current Supply Current in S hutdown Switching Frequency MIN 2.7 VIN Rising UNIT 5.5 V 2.5 V 200 mV 0.25 3 0.35 5 EN = Ground 0.1 520 1 1.262 1.287 V 0 0.05 80 0.15 nA %/V 85 FB Feedback Voltage 1.237 VFB from 2.7V to 5.5V PAM2421 Switch Current Limit MAX VFB = 1.4V, Not Switching VFB = 1.0V, Switc hing Maximum Dut y Cyc le FB Input Current FB Volt age Line Regulation TYP PAM2422 PAM2423 VIN=3.2V Duty Cycle = 70% uA kHz % 3 A 4.5 5.5 PAM2421 130 Switch On Res istance PAM2422 100 Switch Leak age Current PAM2423 VSW = 10V, EN = Ground Soft Start Pin Bias Current VSS = 1.2V Logic High Threshold Logic Low Threshold EN Pin EN Pin mΩ 70 2 4.5 15 uA 7 uA 0.4 V V 1.4 EN Pull Down Resistor Thermal Shutdown Temperature Thermal Shutdown Hysteresis mA 1 MΩ 160 ℃ 40 ℃ Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 4 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Typical Operating Characteristics At T A =25C ,VIN =VEN =5V,VFREQ =0V,unless otherwise specified. Efficiency vs Output Current (Vo=12V) Efficiency vs Output Current (Vo=15V) 100 % 100% 90 % 90% 80 % 80% 70 % 70% 60 % 60% 50 % 50% 40 % 40% 30 % 30% 20 % 10 % Vin=3 .6V Vin=4 .2V Vin=5 V 20% Vin=3.6V Vin=4.2V Vin=5V 10% 0% 0% 1 10 100 Lo ad Cu rren t (mA) 10 00 1 Efficiency vs Output Current (Vo=5V) 10 100 Lo ad Current (m A) Efficiency vs Input Voltage (Vo=5V) 100% 1 00% 90% 90% 80% 80% 70% 70% 60% 60% 50% 50% 40% 40% 30% Io=1m A Io=10 mA Io=10 0m A Io=50 0m A Io=1A 30% V in=2. 7V V in=3. 6V V in=4. 2V 20% 10% 1 000 20% 10% 0% 0% 1 10 100 1000 O ut put Current (mA ) 10000 2. 5 3 3 .5 4 4.5 5 Inp ut Vo lt ag e(V ) Efficiency vs Input Voltage (Vo=12V) Efficiency vs Input Voltage (Vo=15V) 100% 1 00 % 90% 90 % 80% 80 % 70% 70 % 60% 60 % 50% 50 % 40% 40 % 1mA 10mA 100mA 500mA 1A 30% 20% 10% 30 % 1mA 10mA 100m A 500m A 20 % 10 % 0% 0% 3 3.5 4 4.5 5 5. 5 3 Inpu t Voltage (V) 3 .5 4 4 .5 Inp ut Vo lta ge (V) 5 5 .5 Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 5 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Typical Operating Characteristics At T A =25C ,VIN =VEN =5V,VFREQ =0V,unless otherwise specified. Output Voltage vs Output Current (Vo=12V) Output Voltage vs Output Current (Vo=15V) 12.5 15.5 12 15 11.5 14.5 11 14 10.5 Vin= 3. 6V Vin= 4. 2V Vin= 5V 13.5 V in= 4. 2V V in= 5V 13 10 0 200 400 600 Load Current (mA ) 800 0 1000 20 0 400 600 800 1000 L oad C urre nt (mA) Quiescent Current (V FB=1.0V) Quiescent Current (V FB=1.4V) 4 0.25 3. 5 0.2 3 2. 5 0.15 2 0.1 1. 5 1 0.05 0. 5 0 0 2 3 4 In put Voltage(V) 5 2 6 3 4 Inp u t Vo lta ge (V) 5 6 Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 6 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Application Information The PAM242x are highly efficient step -up DC/DC converters that employ a currentmode,fixed frequency pulse-width modulation (PWM) architecture with excellent line and load regulation.The PAM242x operate at constant switching frequency under medium to high load current conditions. At light loads, these devices operate in a pulse-skipping mode in order to improve light-load efficiency. Open Protection Soft-Start Drive EN low to disable the IC and reduce the su pply c urr ent to j ust 0.1 μA . As wi th al l nonsynchronous step-up DC/DC converters, the external Schottky diode provides a DC path from the input to the output in shutdown. As a result, the output drops to one diode voltage drop below the input in shutdown. Once the outputs achieve regulation, if the voltage at FB falls below 0.2V the controller will automatically disable, preventing the controller from running open-loop and potentially damaging the IC and load. Shutdown The PAM242x both offer a programmable softstart function which minimizes inrush current during startup. The soft-start period is programmed by connecting a 10nF capacitor between SS and Ground. Operation of the softstart function is as follows: when the IC is disabled, SS is actively discharged to Ground. Upon enabling the IC, CSS is charged with a 4.5 μA current so that the voltage at SS increases in a controlled manner. The peak inductor current is limited by the voltage at SS, so that the input current is limited until the soft-start period expires, and the regulator can achieve its full output current rating. Thermal Shutdown The PAM242x both feature integrated thermal overload protection. Both devices are automatically disabled when their junction temperatures exceed 160°C, and automatically re-enable when the die temperature decreases by 40°C. Setting the Output Voltage The PAM242x both feature external adjustable output voltages of up to 24V. To program the output voltage, simply connect a resistive voltage divider between the output, FB, and G ND, wi th r es istor s s et acc ordi ng to the following equation: Where VFB is 1.262V. Rectifier Selection For optimal performance, the rectifier should be a Schottky rectifier that is rated to handle both the output voltage as well as the peak switch current. Over Voltage Protection The PAM242x features internal automatic overvoltage protection, when feedback voltage is higher than 115%. Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 7 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Ordering Information PAM 242x X X X xxx X Shipping Package Output Voltage Number of Pins Package Type Pin Configuration Pin Configuration A Type Package Type Number of Pins E: SO P-8(EP) C: 8 Output Voltage ADJ: Adjustable Part Number Peak Current Package Type Shipping Package PAM2421AECADJR 3A SOP-8(EP) 2,500 Units/Tape & Reel PAM2422AECADJR 4.5A SOP-8(EP) 2,500 Units/Tape & Reel PAM2423AECADJR 5.5A SOP-8(EP) 2,500 Units/Tape & Reel Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 8 PAM2421,PAM2422,PAM2423 3A,4.5A,5.5A PWM Step-Up DC/DC Converter Outline Dimension SOP-8(EP) Power Analog Microelectronics, Inc www.poweranalog.com 02/2012 Rev1.1 9