NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 3MHz, 1A STEP-DOWN DC-DC CONVERTER Description Pin Assignments The PAM2304 is a step-down current-mode, DC-DC converter. At heavy load, the constant frequency PWM control performs excellent stability and transient response. To ensure the longest battery life in portable applications, the PAM2304 provides a power-saving PulseSkipping Modulation (PSM) mode to reduce quiescent current under light load operation to save power. The PAM2304 supports a range of input voltages from 2.5V to 5.5V, allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH cell, USB and other standard power sources. The output voltage is adjustable from 0.6V to the input voltage. All versions employ internal power switch and synchronous rectifier to minimize external part count and realize high efficiency. During shutdown, the input is disconnected from the output and the shutdown current is less than 1A. Other key features include under-voltage lockout to prevent deep battery discharge. The PAM2304 is available in TSOT25 and U-DFN2020-6 (Type C) packages. Features Efficiency up to 95% Only 40A (typical) Quiescent Current Output Current: up to 1A Internal Synchronous Rectifier 3MHz Switching Frequency Soft Start Under Voltage Lockout Short Circuit Protection Thermal Shutdown Small TSOT25 and U-DFN2020-6 (Type C) Packages Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. "Green" Device (Note 3) Notes: Applications Smart Phone MID Portable Electronics Wireless Devices Cordless Phone Computer Peripherals Battery Powered Widgets Electronic Scales Digital Frame 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant. 2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated's definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green" products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. Typical Applications Circuit R1 V O 0.6 1 R2 PAM2304 Document number: DS36386 Rev. 3 - 3 1 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Pin Descriptions Function Pin Name TSOT25 U-DFN2020-6 (Type C) EN 1 4 GND SW 2 3 6 1 Enable Control Input. Force this pin voltage above 1.5V, enables the chip, and below 0.3V shuts down the device. Ground. The drains of the internal main and synchronous power MOSFET. VIN 4 5 Chip main power supply pin. FB AGND PGND NC 5 -- -- -- 3 -- -- 2 Feedback voltage to internal error amplifier, the threshold voltage is 0.6V. Analog Ground. Main power ground return pin. Not Connected. -- Functional Block Diagram PAM2304 Document number: DS36386 Rev. 3 - 3 2 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Absolute Maximum Ratings (@TA = +25C, unless otherwise specified.) 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. Parameter Input Voltage EN, FB Pin Voltage SW Pin Voltage Junction Temperature Storage Temperature Range Soldering Temperature Rating Unit -0.3 to +6.0 -0.3 to VIN -0.3 to (VIN +0.3) +150 -65 to +150 +300, 5s V V V C C C Recommended Operating Conditions (@TA = +25C, unless otherwise specified.) Parameter Supply Voltage Rating Unit 2.7 to 5.5 V Operation Temperature Range -40 to +85 Junction Temperature Range -40 to +125 C Thermal Information Parameter Thermal Resistance (Junction to Case) Symbol JC Package Max TSOT25 (Note 4) 130 U-DFN2020-6 (Type C) 25 TSOT25 250 Thermal Resistance (Junction to Ambient) JA U-DFN2020-6 (Type C) 68 TSOT25 400 Internal Power Dissipation (TA = +25C) PD U-DFN2020-6 (Type C) 980 Note: Unit C/W mW 4. The maximun output current for TSOT25 package is limited by internal power dissipation capacity as described in Application Information hereinafter. PAM2304 Document number: DS36386 Rev. 3 - 3 3 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Electrical Characteristics (@TA = +25C, VIN = 3.6V, VO = 1.8V, CIN = 10F, COUT = 10F, L = 1H, unless otherwise specified.) Parameter Symbol Test Conditions Min Typ Max Units V Input Voltage Range VIN -- 2.5 -- 5.5 Regulated Feedback Voltage VFB -- 0.588 0.6 0.612 V Reference Voltage Line Regulation VFB -- -- 0.3 -- %/V Regulated Output Voltage Accuracy VO IO = 100mA -3 -- +3 % IPK VIN = 3V, VFB = 0.5V or VO = 90% -- 1.5 -- A Output Voltage Line Regulation LNR VIN = 2.5V to 5V, IO = 10mA -- 0.2 0.5 %/V Output Voltage Load Regulation LDR IO = 1mA to 800mA -- 0.5 1.5 % A Peak Inductor Current Quiescent Current IQ No load -- 40 70 Shutdown Current ISD VEN = 0V -- -- 1 A VO = 100% -- 3 -- MHz Oscillator Frequency Drain-Source On-State Resistance fOSC RDS(ON) VFB = 0V or VO = 0V IDS = 100mA P MOSFET N MOSFET -- 1 -- MHz -- -- 0.30 0.35 0.45 0.50 ILSW -- -- 0.01 1 A -- -- 95 -- % EN Threshold High VEH -- 1.5 -- -- V EN Threshold Low VEL -- -- -- 0.3 V IEN -- -- 0.01 -- A OTP OTH -- -- -- -- +150 +30 -- -- C C SW Leakage Current High Efficiency EN Leakage Current Over Temperature Protection OTP Hysteresis PAM2304 Document number: DS36386 Rev. 3 - 3 4 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Typical Performance Characteristics (@TA = +25C, CIN = 10F, COUT = 10F, L = 1H, unless otherwise specified.) PAM2304 Document number: DS36386 Rev. 3 - 3 5 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Typical Performance Characteristics (continued) (@TA = +25C, CIN = 10F, COUT = 10F, L = 1H, unless otherwise specified.) PAM2304 Document number: DS36386 Rev. 3 - 3 6 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Typical Performance Characteristics (continued) (@TA = +25C, CIN = 10F, COUT = 10F, L = 1H, unless otherwise specified.) PAM2304 Document number: DS36386 Rev. 3 - 3 7 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Application Information The basic PAM2304 application circuit is shown on Page 2. External component selection is determined by the load requirement, selecting L first and then CIN and COUT. Inductor Selection For most applications, the value of the inductor will fall in the range of 1H. Its value is chosen based on the desired ripple current. Large value inductors lower ripple current and small value inductors result in higher ripple currents. Higher VIN or VOUT also increases the ripple current as shown in Equation 1. A reasonable starting point for setting ripple current is IL = 400mA (40% of 1A). IL 1 VOUT VIN 1 Equation (1) f L VOUT The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation. Thus, a 1.4A rated inductor should be enough for most applications (1A + 400mA). For better efficiency, choose a low DC-resistance inductor. CIN and COUT Selection In continuous mode, the source current of the top MOSFET is a square wave of duty cycle VOUT/VIN. To prevent large voltage transients, a low ESR input capacitor sized for the maximum RMS current must be used. The maximum RMS capacitor current is given by: CIN required IRMS IOMAX VOUT VIN VOUT 1/ 2 VIN This formula has a maximum at V = 2VOUT, where IRMS =IOUT/2. This simple worst-case condition is commonly used for design because even significant deviations do not offer much relief. Note that the capacitor manufacturer's ripple current ratings are often based on 2000 hours of life. This makes it advisable to further derate the capacitor, or choose a capacitor rated at a higher temperature than required. Consult the manufacturer if there is any question. The selection of COUT is driven by the required effective series resistance (ESR). Typically, once the ESR requirement for COUT has been met, the RMS current rating generally far exceeds the IRIPPLE(P-P) requirement. The output ripple VOUT is determined by: 1 VOUT IL ESR 8 f C OUT Where f = operating frequency, COUT = output capacitance and IL = ripple current in the inductor. For a fixed output voltage, the output ripple is highest at maximum input voltage since IL increases with input voltage. Using Ceramic Input and Output Capacitors Higher values, lower cost ceramic capacitors are now becoming available in smaller case sizes. Their high ripple current, high voltage rating and low ESR make them ideal for switching regulator applications. Using ceramic capacitors can achieve very low output ripple and small circuit size. When choosing the input and output ceramic capacitors, choose the X5R or X7R dielectric formulations. These dielectrics have the best temperature and voltage characteristics of all the ceramics for a given value and size. Thermal Consideration Thermal protection limits power dissipation in the PAM2304. When the junction temperature exceeds +150C, the OTP (Over Temperature Protection) starts the thermal shutdown and turns the pass transistor off. The pass transistor resumes operation after the junction temperature drops below +120C. For continuous operation, the junction temperature should be maintained below +125C. The power dissipation is defined as: PD IO 2 VO DS(ON )H VIN VORDS(ON)L VIN tSW FS IO IQ VIN IQ is the step-down converter quiescent current. The term tsw is used to estimate the full load step-down converter switching losses. PAM2304 Document number: DS36386 Rev. 3 - 3 8 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Application Information (continued) Thermal Consideration (continued) For the condition where the step-down converter is in dropout at 100% duty cycle, the total device dissipation reduces to: PD IO 2 RDS(ON)H IQ VIN Since RDS(ON), quiescent current and switching losses all vary with input voltage, the total losses should be investigated over the complete input voltage range. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surrounding airflow and temperature difference between junction and ambient. The maximum power dissipation can be calculated by the following formula: PD TJ(MAX ) T A JA Where TJ(max) is the maximum allowable junction temperature +125C. TA is the ambient temperature and JA is the thermal resistance from the junction to the ambient. Based on the standard JEDEC for a two layers thermal test board, the thermal resistance of TSOT25 package is 250C/W. The maximum power dissipation at TA = +25C can be calculated by following formula: PD = (125C-25C)/250C/W = 0.4W Setting the Output Voltage The internal reference is 0.6V (Typical). The output voltage is calculated as below: R1 VO 0.6 1 R2 The output voltage is given by Table 1. Table 1: Resistor selection for output voltage setting VO R1 R2 1.2V 1.5V 1.8V 2.5V 3.3V 100k 150k 200k 380k 540k 100k 100k 100k 120k 120k 100% Duty Cycle Operation As the input voltage approaches the output voltage, the converter turns the P-Channel transistor continuously on. In this mode the output voltage is equal to the input voltage minus the voltage drop across the P-Channel transistor: VOUT = VIN - ILOAD (RDS(ON) + RL ) where RDS(ON) = P-Channel Switch ON Resistance, ILOAD = Output Current, R = Inductor DC Resistance UVLO and Soft-Start The reference and the circuit remain reset until the VIN crosses its UVLO threshold. The PAM2304 has an internal soft-start circuit that limits the in-rush current during start-up. This prevents possible voltage drops of the input voltage and eliminates the output voltage overshoot. The soft-start acts as a digital circuit to increase the switch current in several steps to the P-Channel current limit (1500mA). Short Circuit Protection The switch peak current is limited cycle-by-cycle to a typical value of 1500mA. In the event of an output voltage short circuit, the device operates with a frequency of 1MHz and minimum duty cycle, therefore the average input current is typically 200mA. Thermal Shoutdown When the die temperature exceeds +150C, a reset occurs and the reset remains until the temperature decrease to +120C, at which time the circuit can be restarted. PAM2304 Document number: DS36386 Rev. 3 - 3 9 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Application Information (continued) PCB Layout Check List When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the PAM2304. These items are also illustrated graphically in Figure 1. Check the following in your layout: 1. The power traces, consisting of the GND trace, the SW trace and the VIN trace should be kept short, direct and wide. 2. Does the VFB pin connect directly to the feedback resistors? The resistive divider R1/R2 must be connected between the (+) plate of COUT and ground. 3. Does the (+) plate of CIN connect to VIN as closely as possible? This capacitor provides the AC current to the internal power MOSFETs. 4. Keep the switching node, SW, away from the sensitive VFB node. 5. Keep the (-) plates of CIN and COUT as close as possible. Ordering Information Part Number Output Voltage Package Packaging PAM2304AABADJ PAM2304BKFADJ ADJ ADJ TSOT25 U-DFN2020-6 (Type C) 3000 Units/Tape & Reel 3000 Units/Tape & Reel Marking Information PAM2304 Document number: DS36386 Rev. 3 - 3 10 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Package Outline Dimensions (All dimensions in mm.) Please see http://www.diodes.com/package-outlines.html for the latest version. TSOT25 D e1 E E1 L2 c 4x1 e L 5x b A A2 A1 TSOT25 Dim Min Max Typ A 1.00 A1 0.01 0.10 A2 0.84 0.90 D 2.90 E 2.80 E1 1.60 b 0.30 0.45 c 0.12 0.20 e 0.95 e1 1.90 L 0.30 0.50 L2 0.25 0 8 4 1 4 12 All Dimensions in mm U-DFN2020-6 (Type C) A A3 A1 Seating Plane D D2 Pin #1 ID E E2 Z (4x) L e PAM2304 Document number: DS36386 Rev. 3 - 3 U-DFN2020-6 Type C Dim Min Max Typ A 0.57 0.63 0.60 A1 0.00 0.05 0.02 A3 -- -- 0.15 b 0.25 0.35 0.30 D 1.95 2.075 2.00 D2 1.55 1.75 1.65 E 1.95 2.075 2.00 E2 0.86 1.06 0.96 e -- -- 0.65 L 0.25 0.35 0.30 Z -- -- 0.20 All Dimensions in mm b 11 of 13 www.diodes.com September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. TSOT25 C C Dimensions Value (in mm) C 0.950 X 0.700 Y 1.000 Y1 3.199 Y1 Y (5x) X (5x) U-DFN2020-6 (Type C) X2 X1 Y (6x) Dimensions Y2 X (6x) PAM2304 Document number: DS36386 Rev. 3 - 3 C X X1 X2 Y Y1 Y2 Y1 C 12 of 13 www.diodes.com Value (in mm) 0.650 0.350 1.650 1.700 0.525 1.010 2.400 September 2019 (c) Diodes Incorporated NOT RECOMMENDED FOR NEW DESIGN Use AP61100 PAM2304 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. 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LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright (c) 2019, Diodes Incorporated www.diodes.com PAM2304 Document number: DS36386 Rev. 3 - 3 13 of 13 www.diodes.com September 2019 (c) Diodes Incorporated