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RT8020
Dual High-Efficiency PWM Step-Down DC-DC Converter
General Description
The RT8020 is a dual high-efficiency Pulse-WidthModulated (PWM) step-down DC-DC converter. It is capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V, the RT8020 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and other handheld devices. Two operational modes are available : PWM/Low-Dropout auto-switch and shutdown modes. Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application. The RT8020 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper PMOS. The RT8020 enter shutdown mode and consumes less than 0.1A when EN pin is pulled low. The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation f requency of 1.5MHz. This along wit h sm all WDFN-12L 3x3 package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection.
Features
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+2.5V to +5.5V Input Range Adjustable Output From 0.6V to VIN 1.2V, 1.3V, 1.8V, 2.5V and 3.3V Fixed/ Adjustable Output Voltage 1A Output Current 95% Efficiency No Schottky Diode Required 50uA Quiescent Current per Channel 1.5MHz Fixed-Frequency PWM Operation Small 12-Lead WDFN Package RoHS Compliant and 100% Lead (Pb)-Free
Applications
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Mobile Phones Personal Information Appliances Wireless and DSL Modems MP3 Players Portable Instruments
Ordering Information
RT8020 Package Type QW : WDFN-12L 3x3 (W-Type) Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Output Voltage : VOUT1/VOUT2 Default : Adjustable A : 3.3V/1.8V B : 3.3V/1.3V C : 3.3V/1.2V D : 2.5V/1.8V
Note : Richtek Pb-free and Green products are :
Pin Configurations
(TOP VIEW)
VIN2 LX2 GND FB1 NC1 EN1
1 2 3 4 5 6 12 11 10 9 8 7
GND 13
EN2 NC2 FB2 GND LX1 VIN1
WDFN-12L 3x3
}RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
Marking Information
For marking information, contact our sales representative directly or through a Richtek distributor located in your area, otherwise visit our website for detail.
}Suitable for use in SnPb or Pb-free soldering processes. }100% matte tin (Sn) plating.
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RT8020
Typical Application Circuit
C OUT2 4.7uF V OUT2 V IN2 1 VIN2 CIN2 4.7uF R12 2 3, Exposed Pad (13) 4 LX2 GND FB1 RT8020 EN2 12 NC2 11 FB2 10 GND LX1 9 8 R22 C IN1 4.7uF V IN1 R21 850k C21 22pF
L2 2.2uH
5 NC1 C11 22pF R11 850k 6 EN1 L1 2.2uH C OUT1 4.7uF
VIN1 7
V OUT1
VOUTx = VREF x 1 + Rx1 Rx2
(
)
Figure 1. Adjustable Voltage Regulator
L2 2.2uH V OUT2 V IN2 1 VIN2 C IN2 4.7uF 2 LX2 GND FB1 RT8020 EN2 12 NC2 11 FB2 10 GND LX1 9 8 C IN1 4.7uF V IN1 C OUT2 4.7uF
3, Exposed Pad (13) 4
5 NC1 6 EN1 L1 2.2uH V OUT1 C OUT1 4.7uF
VIN1 7
VOUTx = 1.2V, 1.3V, 1.8V, 2.5V or 3.3V Figure 2. Fixed Voltage Regulator
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Functional Pin Description
Pin No. 1 2 Pin Name VIN2 LX2 Power Input of Channel 2. Pin for Switching of Channel 2. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Feedback of Channel 1. No Connection or Connect to VIN. Chip Enable of Channel 1 (Active High). VEN1 VIN1. Power Input of Channel 1. Pin for Switching of Channel 1. Feedback of Channel 2. Chip Enable of Channel 2 (Active High). VEN2 VIN2. Pin Function
3, 9, GND Exposed Pad (13) 4 5, 11 6 7 8 10 12 FB1 NC1, NC2 EN1 VIN1 LX1 FB2 EN2
Function Block Diagram
ENx VINx
RS1 OSC and Shutdown Control Slope Compensation Current Sense PWM Comparator Current Limit Detector
Control Logic
Driver
LXx
Error Amplifier FBx RC COMP UVLO and Power Good Detector V REF
RS2 GND
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RT8020
Absolute Maximum Ratings
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(Note 1)
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Supply Input Voltage, VIN1, VIN2 ---------------------------------------------------------------------------------- -0.3V to 6.5V EN1, FB1, LX1, EN2, FB2 and LX2 Pin Voltage -------------------------------------------------------------- -0.3V to VIN + 0.3V Power Dissipation, PD @ TA = 25C WDFN-12L 3x3 ------------------------------------------------------------------------------------------------------- 1.667W Package Thermal Resistance (Note 4) WDFN-12L 3x3, JA -------------------------------------------------------------------------------------------------- 60C/W WDFN-12L 3x3, JC ------------------------------------------------------------------------------------------------- 8.2C/W Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 260C Junction Temperature ----------------------------------------------------------------------------------------------- 150C Storage Temperature Range --------------------------------------------------------------------------------------- -65C to 150C ESD Susceptibility (Note 2) HBM (Human Body Mode) ----------------------------------------------------------------------------------------- 2kV MM (Machine Mode) ------------------------------------------------------------------------------------------------ 200V (Note 3)
Recommended Operating Conditions
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Supply Input Voltage ------------------------------------------------------------------------------------------------ 2.5V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------- -40C to 125C Ambient Temperature Range -------------------------------------------------------------------------------------- -40C to 85C
Electrical Characteristics
(VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2uH, CIN = 4.7uF, COUT = 10uF, TA = 25 C, IMAX= 1A unless otherwise specified)
Parameter Channel 1 and Channel 2 Input Voltage Range Under Voltage Lock Out threshold Hysteresis Quiescent Current Shutdown Current Reference Voltage Adjustable Output Voltage Range
Symbol
Test Conditions
Min
Typ
Max
Units
VIN UVLO
2.5 ---
-1.8 0.1 50 0.1 0.6 -------
5.5 --70 1 0.612 VIN -V +3 +3 +3 +3 +3
V V V A A V V % % % % %
IQ ISHDN VREF VOUT VOUT VOUT
IOUT = 0mA, VFB = VREF + 5% EN = GND For Adjustable Output Voltage (Note 6) VIN = 2.5V to 5.5V, V OUT = 1.2V 0A < IOUT < 1A VIN = 2.5V to 5.5V, V OUT = 1.3V 0A < IOUT < 1A VIN = 2.5 to 5.5V, V OUT = 1.8V 0A < IOUT < 1A VIN = VOUT + V to 5.5V (Note 5) VOUT = 2.5V, 0A < IOUT < 1A VIN = VOUT + V to 5.5V (Note 5) VOUT = 3.3V, 0A < IOUT < 1A
--0.588 VREF -3 -3 -3 -3 -3
Output Voltage Accuracy
Fix
VOUT VOUT VOUT
To be continued
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Parameter Output Voltage Accuracy FB Input Current RDS(ON) of P-MOSFET Adjustable Symbol VOUT IFB Test Conditions VIN = VOUT + V to 5.5V 0A < IOUT < 1A VFB = VIN VIN = 2.5V VIN = 3.6V VIN = 2.5V VIN = 3.6V (Note 5) Min Typ --0.38 0.28 0.35 0.25 1.5 --1.5 160 --Max +3 50 ----2 VIN 0.4 1.8 --1 MHz C % A Units % nA A V
-3
-50 ----1.4 1.5 -1.2 -100
RDS(ON)_P IOUT = 200mA
RDS(ON) of N-MOSFET P-Channel Current Limit EN High-Level Input Voltage EN Low-Level Input Voltage Oscillator Frequency Thermal Shutdown Temperature Maximum Duty Cycle LX Leakage Current
RDS(ON)_N IOUT = 200mA ILIM_P VEN_H VEN_L fOSC TSD VIN = 2.5V to 5.5 V VIN = 2.5V to 5.5V VIN = 2.5V to 5.5V
VIN = 3.6V, IOUT = 100mA
ILX
VIN = 3.6V, VLX = 0V or VLX = 3.6V
-1
Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. JA is measured in the natural convection at TA = 25C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. Note 5. V = IOUT x PRDS(ON) Note 6. Guarantee by design.
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Typical Operating Characteristics
Efficiency vs. Output Current
100 90 80 100
Efficiency vs. Output Current
90 80
Efficiency (%)
Efficiency (%)
70 60 50 40 30 20 10 0 0
VIN = 3.6V VIN = 4.2V VIN = 5.0V
70 60 50 40 30 20
VIN VIN VIN VIN
= = = =
5.0V 3.6V 3.3V 2.5V
VOUT = 3.3V, L = 4.7H, COUT = 4.7F
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
10 0 0 0.1 0.2
VOUT = 1.2V, L = 4.7H, COUT = 4.7F
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Output Current (A)
Output Current (A)
Efficiency vs. Output Current
100 90 2.00 1.90
UVLO Threshold vs. Temperature
UVLO Threshold (V)
80
Rising
Efficiency (%)
70 60 50 40 30 20 10 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
1.80 1.70 1.60 1.50 1.40 1.30
VIN VIN VIN VIN
= = = =
5.0V 3.6V 3.3V 2.5V
Falling
VOUT = 1.2V, L = 2.2H, COUT = 10F
1.20 0.8 0.9 1 -40 -25 -10 5 20 35
VOUT = 1.2V, IOUT = 0A
50 65 80 95 110 125
Output Current (A) EN Pin Threshold vs. Input Voltage
1.20 1.15 1.10 1.6 1.5 1.4
Temperature (C)
EN Pin Threshold vs. Temperature
EN Pin Threshold (V)
EN Pin Threshold (V)
1.05 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5
1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 -40 -25 -10 5 20 35 50 65 80 95 110 125
Rising
Rising Falling
Falling
VOUT = 1.2V, IOUT = 0A
VIN = 3.6V, VOUT = 1.2V, IOUT = 0A
Input Voltage (V)
Temperature (C)
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Output Voltage vs. Loading Current
1.230 1.225 1.220 1.25 1.24 1.23
Output Voltage vs. Temperature
Output Voltage (V)
1.215 1.210 1.205 1.200 1.195 1.190 1.185
Output Voltage (V)
VIN = 5.0V
1.22 1.21 1.20 1.19 1.18 1.17 1.16
VIN = 3.6V
1.180 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.15 -40 -25 -10 5 20 35 50
VIN = 3.6V, IOUT = 0A
65 80 95 110 125
Loading Current (A)
Temperature (C)
Switching Frequency vs. Input Voltage
1.60 1.55 1.6 1.55 1.5
Switching Frequency vs. Temperature
Frequency(kHz)
Frequency(kHz)
1.50 1.45 1.40 1.35 1.30 1.25
1.45 1.4 1.35 1.3 1.25
VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA
1.20 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5 1.2 -40 -25 -10
VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA
5 20 35 50 65 80 95 110 125
Input Voltage (V)
Temperature (C)
Output Current Limit vs. Input Voltage
2.4 2.3 2.4 2.3
Output Current Limit vs. Temperature
VOUT = 1.2V VIN = 5.0V
Output Current Limit (A)
2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5
Output Current Limit (A)
2.2
2.2 2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 -40 -25 -10 5 20 35 50 65 80 95 110 125
VIN = 3.6V
VIN = 3.3V
VOUT = 1.2V @ TA = 25C
Input Voltage (V)
Temperature (C)
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RT8020
Power On from EN
VIN = 3.6V, VOUT = 1.2V, IOUT = 10mA
Power On from EN
VIN = 3.6V, VOUT = 1.2V, IOUT = 1A
VEN (2V/Div) VOUT (1V/Div) II N (500mA/Div) Time (100s/Div)
VEN (2V/Div) VOUT (1V/Div) II N (500mA/Div) Time (100s/Div)
Power On from VIN
VIN = 3.6V, VOUT = 1.2V, IOUT = 10mA
Power Off from EN
VIN = 3.6V, VOUT = 1.2V, IOUT = 10mA
VIN (2V/Div) VOUT (1V/Div) ILX (1A/Div) Time (250s/Div)
VEN (2V/Div) VOUT (1V/Div) ILX (1A/Div) Time (100s/Div)
Load Transient Response
VIN = 3.6V, VOUT = 1.2V, IOUT = 50mA to 1A
Load Transient Response
VIN = 3.6V, VOUT = 1.2V, IOUT = 50mA to 0.5A
VOUT (50mV/Div)
VOUT (50mV/Div)
IOUT (500mA/Div) Time (50s/Div)
IOUT (500mA/Div) Time (50s/Div)
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Load Transient Response
VIN = 5.0V, VOUT = 1.2V, IOUT = 50mA to 1A
Load Transient Response
VIN = 5.0V, VOUT = 1.2V, IOUT = 50mA to 0.5A
VOUT (50mV/Div)
VOUT (50mV/Div)
IOUT (500mA/Div) Time (50s/Div)
IOUT (500mA/Div) Time (50s/Div)
Ripple
VIN = 3.6V, VOUT = 1.2V, IOUT = 1A
Ripple
VIN = 5.0V, VOUT = 1.2V, IOUT = 1A
VOUT (10mV/Div)
VOUT (10mV/Div)
VLX (2V/Div)
VLX (2V/Div)
Time (500ns/Div)
Time (500ns/Div)
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RT8020
Applications Information
The basic RT8020 application circuit is shown in Typical Application Circuit. External component selection is determined by the maximum load current and begins with the selection of the inductor value and operating frequency followed by CIN and COUT. Inductor Selection For a given input and output voltage, the inductor value and operating frequency determine the ripple current. The ripple current IL increases with higher VIN and decreases with higher inductance. V V IL = OUT x 1 - OUT f xL VIN Having a lower ripple current reduces the ESR losses in the output capacitors and the output voltage ripple. Highest efficiency operation is achieved at low frequency with small ripple current. This, however, requires a large inductor. A reasonable starting point for selecting the ripple current is IL = 0.4(IMAX). The largest ripple current occurs at the highest VIN. To guarantee that the ripple current stays below a specified maximum, the inductor value should be chosen according to the following equation :
VOUT VOUT L= x 1- f x IL(MAX) VIN(MAX)
This results in an abrupt increase in inductor ripple current and consequent output voltage ripple. Do not allow the core to saturate! Different core materials and shapes will change the size/ current and price/current relationship of an inductor. Toroid or shielded pot cores in ferrite or permalloy materials are small and don't radiate energy but generally cost more than powdered iron core inductors with similar characteristics. The choice of which style inductor to use mainly depend on the price vs. size requirements and any radiated field/EMI requirements. CIN and COUT Selection The input capacitance, CIN, is needed to filter the trapezoidal current at the source of the top MOSFET. To prevent large ripple voltage, a low ESR input capacitor sized for the maximum RMS current should be used. RMS current is given by :
IRMS = IOUT(MAX) VOUT VIN VIN -1 VOUT
Inductor Core Selection Once the value for L is known, the type of inductor must be selected. High efficiency converters generally cannot afford the core loss found in low cost powdered iron cores, forcing the use of more expensive ferrite or permalloy cores. Actual core loss is independent of core size for a fixed inductor value but it is very dependent on the inductance selected. As the inductance increases, core losses decrease. However, increased inductance requires more turns of wire and therefore copper losses will increase. Ferrite designs have very low core losses and are preferred at high switching frequencies, so design goals can concentrate on copper loss and preventing saturation. Ferrite core material saturates "hard", which means that inductance collapses abruptly when the peak design current is exceeded.
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This formula has a maximum at VIN = 2VOUT , where I RMS = I OUT /2. This simple worst-case condition is commonly used for design because even significant deviations do not offer much relief. Note that ripple current ratings from capacitor manufacturers are often based on only 2000 hours of life which makes it advisable to further de-rate the capacitor, or choose a capacitor rated at a higher temperature than required. Several capacitors may also be paralleled to meet size or height requirements in the design. The selection of COUT is determined by the effective series resistance (ESR) that is required to minimize voltage ripple and load step transients, as well as the amount of bulk capacitance that is necessary to ensure that the control loop is stable. Loop stability can be checked by viewing the load transient response as described in a later section. The output ripple, VOUT , is determined by : 1 VOUT IL ESR + 8fCOUT
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RT8020
The output ripple is highest at maximum input voltage since IL increases with input voltage. Multiple capacitors placed in parallel may be needed to meet the ESR and RMS current handling requirements. Dry tantalum, special polymer, aluminum electrolytic and ceramic capacitors are all available in surface mount packages. Special polymer capacitors offer very low ESR but have lower capacitance density than other types. Tantalum capacitors have the highest capacitance density but it is important to only use types that have been surge tested for use in switching power supplies. Aluminum electrolytic capacitors have significantly higher ESR but can be used in cost-sensitive applications provided that consideration is given to ripple current ratings and long-term reliability. Ceramic capacitors have excellent low ESR characteristics but can have a high voltage coefficient and audible piezoelectric effects. The high Q of ceramic capacitors with trace inductance can also lead to significant ringing. 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. However, care must be taken when these capacitors are used at the input and output. When a ceramic capacitor is used at the input and the power is supplied by a wall adapter through long wires, a load step at the output can induce ringing at the input, VIN. At best, this ringing can couple to the output and be mistaken as loop instability. At worst, a sudden inrush of current through the long wires can potentially cause a voltage spike at VIN large enough to damage the part. Output Voltage Programming The resistive divider allows the FB pin to sense a fraction of the output voltage as shown in Figure 3.
VOUT R1 FB RT8020 GND R2
For adjustable voltage mode, the output voltage is set by an external resistive divider according to the following equation : VOUT = VREF x (1+ R1/R2) Where VREF is the internal reference voltage (0.6V typical) 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+ L2+ L3+...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, two main sources usually account for most of the losses: VIN quiescent current and I2R losses. The VIN quiescent current loss dominates the efficiency loss at very low load currents whereas the I 2R loss dominates the efficiency loss at medium to high load currents. In a typical efficiency plot, the efficiency curve at very low load currents can be misleading since the actual power lost is of no consequence. 1.The V IN quiescent current oppears due to two components : the DC bias current and the 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, IGATECHG = f(QT + QB) where QT and QB 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. I2R losses are calculated from the resistances of the internal switches, RSW and external inductor RL. In continuous mode the average output current flowing through inductor L is "chopped" between the main switch
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Figure 3. Setting the Output Voltage
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RT8020
Maximum Power Dissipation (W)
and the synchronous switch. Thus, the series resistance looking into the LX pin is a function of both top and bottom MOSFET RDS(ON) and the duty cycle (DC) is shown as follows : RSW = RDS(ON)TOP x DC + RDS(ON)BOT x (1 - DC) The RDS(ON) for both the top and bottom MOSFETs can be obtained from the Typical Performance Characteristics curves. Thus, to obtain I2R losses, simply add RSW to RL and multiply the result by the square of the average output current. Other losses including CIN and COUT ESR dissipative losses and inductor core losses generally account for less than 2% of the total loss. Thermal Considerations The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = ( TJ(MAX) - TA ) / JA Where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT8020 DC/DC converter, where TJ(MAX) is the maximum junction temperature of the die and TA is the ambient temperature. The junction to ambient thermal resistance JA is layout dependent. For WDFN-12L 3x3 packages, the thermal resistance JA is 60C/W on the standard JEDEC 51-7 four-layers thermal test board. The maximum power dissipation at TA = 25C can be calculated by following formula : PD(MAX) = (125C - 25C) / (60C/W) = 1.667W for WDFN-12L 3x3 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance JA. For RT8020 packages, the Figure 4 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed.
1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 25 50 75 100 125
Ambient Temperature (C)
Figure 4. De-rating Curves for RT8020 Package Checking Transient Response The regulator loop response can be checked by looking at the load transient response. Switching regulators take several cycles to respond to a step in load current. When a load step occurs, VOUT immediately shifts by an amount equal to ILOAD (ESR), where ESR is the effective series resistance of COUT . ILOAD also begins to charge or discharge COUT generating a feedback error signal used by the regulator to return VOUT to its steady-state value. During this recovery time, VOUT can be monitored for overshoot or ringing that would indicate a stability problem. Layout Considerations Follow the PCB layout guidelines for optimal performance of RT8020. } For the main current paths, keep their traces short and wide. } Put the input capacitor as close as possible to the device pins (VIN and GND). } LX node is with high frequency voltage swing and should be kept small area. Keep analog components away from LX node to prevent stray capacitive noise pick-up. } Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8020. } Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors.
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RT8020
Table 1. Recommended Inductors
Component Supplier TAIYO YUDEN TAIYO YUDEN Sumida Sumida GOTREND GOTREND Series NR 3015 NR 3015 CDRH2D14 CDRH2D14 GTSD32 GTSD32 Inductance (H) 2.2 4.7 2.2 4.7 2.2 4.7 DCR (m) 60 120 75 135 58 146 Current Rating (mA) 1480 1020 1500 1000 1500 1100 Dimensions (mm) 3 x 3 x 1.5 3 x 3 x 1.5 4.5 x 3.2 x 1.55 4.5 x 3.2 x 1.55 3.85 x 3.85 x 1.8 3.85 x 3.85 x 1.8
Table 2. Recommended Capacitors for CIN and COUT
Component Supplier TDK TDK MURATA MURATA TAIYO YUDEN TAIYO YUDEN TAIYO YUDEN Part No. C1608JB0J475M C2012JB0J106M GRM188R60J475KE19 GRM219R60J106ME19 JMK107BJ475RA JMK107BJ106MA JMK212BJ106RD Capacitance (F) 4.7 10 4.7 10 4.7 10 10 Case Size 0603 0805 0603 0805 0603 0603 0805
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RT8020
Outline Dimension
2
1
2
1
DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated.
Symbol A A1 A3 b D D2 E E2 e L
Dimensions In Millimeters Min 0.700 0.000 0.175 0.150 2.950 2.300 2.950 1.400 0.450 0.350 0.450 Max 0.800 0.050 0.250 0.250 3.050 2.650 3.050 1.750
Dimensions In Inches Min 0.028 0.000 0.007 0.006 0.116 0.091 0.116 0.055 0.018 0.014 0.018 Max 0.031 0.002 0.010 0.010 0.120 0.104 0.120 0.069
W-Type 12L DFN 3x3 Package
Richtek Technology Corporation
Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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