SD6039A SHOUDING | Alldatasheet
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The SD6039A requires a minimum number of The SD6039A is a step down switch mode SD6039A 22AA SStteepp--DDoowwnn PPWWMM SSwwiittcchh--MMooddee DDCC//DDCC RReegguullaattoorr FFeeaattuurreess Maximum Output Current: 2A Stable with Low ESR Output Ceramic Capacitors Thermal Shutdown Up to 92% Efficiency Cycle-by-Cycle Over Current Protection Wide 5V to 16V Operating Input Range Programmable Under Voltage Lockout Output Adjustable from 1.2V to 16V Available in 8 pin SO package Frequency: up to 400kHz DDeessccrriippttiioonn converter. It achieves 2A continuous output current over a wide input supply range with excellent load and line regulation. Current mode operation prov ides fast transient response and eases loop stabilization. Fault condition protection includes cycle-by-cycle current limiting and thermal shutdown. readily available standard external components. AApppplliiccaattiioonnss Pre-Regulator for Linear Regulators Distributed Power Systems Battery Charger SD6039A TTyyppiiccaall AApppplliiccaattiioonn CCiirrccuuiitt GND 5V ~ 16V SWVIN FB 5COMP6 EN VOUT L 4.7µH 68µF 330pF 15k 20µF 22pF DC+ 1.2V ~ 16V * The Output Voltage is set by R2 and R3: V OUT www.shouding.net
The SD6039A is guaranteed to meet perfo PPiinn AAssssiiggnnmmeenntt aanndd DDeessccrriippttiioonn 1 2 3 4 TOP VIEW SOP-8L 8 7 6 5 PIN NAME
DESCRIPTION
1,8 N/C No Connect
2 VIN Input
3 SW Switch Node
4 GND Ground
5 FB Feedback
6 COMP Optional External Compensation
7 EN ON/OFF Control (High Enable)
((NNoottee 11)) IN +0.3)V Note 1: Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2: rmance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. EElleeccttrriiccaall CChhaarraacctteerriissttiiccss Operating Conditions: T A =25 , V℃ IN =6V, unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V IN Input Voltage Range 5 16 V V OUT Output Voltage 1.2 16 V I Q Quiescent Current V OUT = 5V, I LOAD = 0A 800 μA I OFF Shutdown Current V EN = 0V, V IN = 12V 50 μA V FB Feedback Voltage T A = 25℃ 0.8 V f OSC Oscillator Frequency V OUT = 5V, I OUT = 100mA 400 kHz EFFI Efficiency When connected to extra components, V IN =9V, V OUT = 5V, I OUT =1A 89 % www.shouding.net
www.shouding.net TTyyppiiccaall PPeerrffoorrmmaannccee CChhaarraacctteerriissttiiccss Operating Conditions: T A =25 , unless otherwise specified.℃ Efficiency vs. Output Current (VOUT=1.2V) 0 400 800 1200 1600 2000 Output Current (mA) Efficiency (%) V IN =9V V IN =12V Efficiency vs. Output Current (VOUT=5V) 100 0 400 800 1200 1600 2000 Output Current (mA) Efficiency (%) V IN =9V V IN =12V Output Voltage vs. Load Current (VIN=9V) 4.7 4.715 4.73 4.745 4.76 4.775 4.79 4.805 4.82 4.835 4.85 0 400 800 1200 1600 2000 Load Current (mA) Output Voltage (V) Output Voltage vs. Load Current (VIN=9V) 1.02 1.04 1.06 1.08 1.1 1.12 1.14 1.16 1.18 1.2 0 400 800 1200 1600 2000 Load Current (mA) Output Voltage (V)
www.shouding.net Output Noise （V IN =9V, V OUT =1.2V, I LOAD =0.5A） S W （（V IN =9V, V OUT =1.2V, I LOAD =0.5A） Output Voltage vs. Load Current (VIN=12V) 1.02 1.04 1.06 1.08 1.1 1.12 1.14 1.16 1.18 1.2 0 400 800 1200 1600 2000 Load Current (mA) Output Voltage (V) Output Voltage vs. Load Current (VIN=12V) 4.7 4.715 4.73 4.745 4.76 4.775 4.79 4.805 4.82 4.835 4.85 0 400 800 1200 1600 2000 Load Current (mA) Output Voltage (V)
www.shouding.net Main Supply Pin. The SD6039A operates from a 5V to 16V unregulated input. It must be PPiinn FFuunnccttiioonnss N/C (Pin 1, 8): No Connect. VIN (Pin 2): closely decoupled to GND, with a 20 μF or greater ceramic capacitor to prevent large voltage spikes from appearing at the input. SW (Pin 3): Switch Node Connection to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. GND (Pin 4): Ground Pin. FB (Pin 5): Feedback Pin. Receive the feedback voltage from an external resistive divider across the output. In the adjustable version, t he output voltage is fixed. The out put voltage is set by R2 and R3: V OUT COMP (Pin 6): This node is the output of the transconductance error amplifier and the input to the current comparator. Frequency co mpensation is done at this node by connecting a series R-C to ground. EN (Pin 7): En Control Input. Forcing this pin above 1V enables the part. Forcing this pin below 0.7V can shuts down the device. Do not leave EN floating.
www.shouding.net rements than on what SD6039A requires to operate. AApppplliiccaattiioonn IInnffoorrmmaattiioonn Inductor Selection For most applications, the value of the inductor will fall in the range of 1μH to 4.7μH. 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 V IN or V OUT also increases the ripple current as shown in equation .A reasonable starting point for setting ripple current is I△ L 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 2.8A rated inductor should be enough for most applications (2A + 0.8A). For better efficiency, choose a low DC-resistance inductor. Different core materials and shapes will change the si ze/current and price/current relationship of an inductor. Toroid or shielded pot cores in ferrite or perm alloy materials are small and don’t radiate much energy, but generally cost more than powdered iron core inductors with similar electrical characteristics. The choice of which style inducto r to use often depends more on the price vs. size requirements and any radiated field/EMI requi Efficiency Considerations The efficiency of a switching regulator is equal to the output power divided by the input power times 100%. It is often useful to analyze individual losses to determine what is limiting the efficiency and which change would produce the most improvement. Efficiency can be expressed as: Efficiency = 100% - (L1+ dissipative elements in the circuit produce losses, tw o main sources usually account for most of the losses: VIN quiescent current and I R losses. The VIN quiescent curr ent loss dominates the efficiency loss at very low load currents whereas the I R loss dominates the efficiency loss at medium to high load currents. In a typical efficiency plot, the efficienc y curve at very low load currents can be misleading since the actual power lost is of no consequence. 1. The VIN quiescent current is due to two components: the DC bias current as given in the electrical characteristics and the internal main switch and synchronous switch gate charge currents. The gate charge current results from switching the gate capacitance of the internal power MOSFET switches. Each time the gate is switched from high to low to high again, a packet of charge △Q moves from VIN to ground. The resulting △Q/△t is the current out of VIN that is typically larger than the DC bias current. In continuous mode, I GATECHG = f (Q T B ) where Q T and Q B are the gate charges of the internal top and bottom switches. Both the DC bias and gate charge losses are proportional to VIN and thus their effects will be more pronounced at higher supply voltages. 2. I R losses are calculated from the resistances of the internal switches, R SW and external inductor R L In continuous mode the average out put current flowing through i nductor L is “chopped” between the main switch and the synchronous sw itch. Thus, the series resistance looking into the SW pin is a function of both top and bottom MOSFET R DS(ON) and the duty cycle (DC) as follows: R SW = R DS(ON)TOP x DC + R DS(ON)BOT x (1-DC) The R DS(ON) for both the top and bottom MOSFETs can be obtained from the
www.shouding.net operation of the SD6039A. Check Typical Performance Characterist ics curves. Thus, to obtain I R losses, simply add R SW to R L and multiply the result by the square of the average output current. Other losses including C IN and C OUT ESR dissipative losses and inductor core losses generally account for less than 2% of the total loss. Board Layout Suggestions When laying out the printed circ uit board, the following checklist should be used to ensure proper the following in your layout: 1. The power traces, consisting of t he GND trace, the SW trace and the V IN trace should be kept short, direct and wide. 2. Put the input capacitor as close as possible to the device pins (VIN and GND). 3. SW node is with high frequency voltage swi ng and should be kept small area. Keep analog components away from SW node to prevent stray capacitive noise pick-up. 4. Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors.
www.shouding.net PPaacckkaaggiinngg IInnffoorrmmaattiioonn Symbol Dimensions In Millimeters Dimensions 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 0.170 0.250 0.006 0.010 D 4.700 5.100 0.185 0.200 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 e 1.270(BSC) 0.050(BSC) L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8°