Richtek RT8016-10GQW, RT8016-10PQW, RT8016-12GQW, RT8016-12PQW, RT8016-13GQW Schematic [ru]

...
®
RT8016
1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter
General Description
The RT8016 is a high-efficiency Pulse-Width-Modulated
(PWM) step-down DC-DC converter. Capable of delivering
1A output current over a wide input voltage range from
2.5V to 5.5V, the RT8016 is ideally suited for portable
electronic devices that are powered from 1-cell Li-ion
battery or from other power sources such as cellular
phones, PDAs and hand-held devices.
Two operating modes are available including : PWM/Low-
Dropout autoswitch and shut-down modes, the Internal
synchronous rectifier with low R
dramatically reduces
DS(ON)
conduction loss at PWM mode. No external Schottky
diode is required in practical application.
The RT8016 enters Low-Dropout mode when normal PWM
cannot provide regulated output voltage by continuously
turning on the upper PMOS. The RT8016 enters shut-
down mode and consumes less than 0.1uA when EN pin
is pulled low. The RT8016 also offers a range of 1V to
3.3V with 0.1V per step or adjustable output voltage by
two external resistor.
The switching ripple is easily smoothed-out by small
package filtering elements due to a fixed operating
frequency of 1.5MHz. This along with small WDFN-6L 2x2
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.
Pin Configurations
(TOP VIEW)
1
GND
2
EN
3
VIN
WDFN-6L 2x2
7
6
FB/VOUT
5
GND
4
LX
Features

+2.5V to +5.5V Input Range


Adjustable Output From 0.6V to V


1A Output Current


95% Efficiency


No Schottky Diode Required


1.5MHz Fixed Frequency PWM Operation


Small 6-Lead WDFN Package


RoHS Compliant and 100% Lead (Pb)-Free

IN
Applications
Mobile Phones
Personal Information Appliances
Wireless and DSL Modems
MP3 Players
Portable Instruments
Ordering Information
RT8016-
Package Type QW : WDFN-6L 2x2 (W-Type)
Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free)
Output Voltage Default : Adjustable 10 : 1.0V 11 : 1.1V : 32 : 3.2V 33 : 3.3V
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
DS8016-04 February 2012 www.richtek.com
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1
RT8016
Typical Application Circuit
V
IN
2.5V to 5.5V
V
IN
2.5V to 5.5V
L
C
IN
4.7µF
3
2
VIN
EN
RT8016
VOUT
GND
1, 5
LX
4
6
2.2µH
Figure 1. Fixed Voltage Regulator
L
C
IN
4.7µF
3
VIN
RT8016
2
EN FB
GND
1, 5
LX
4
6
2.2µH
C1
I
R2
R1
R2
V
C
OUT
10µF
C
10µF
OUT
V
OUT
OUT
R1
REFOUT
1 x VV
+=
R2
with R2 = 300kΩ to 60kΩ so the IR2 = 2μA to 10μA,
and (R1 x C1) should be in the range between 3x10
Figure 2. Adjustable Voltage Regulator
Layout Guide
RT8016_FIX
GND
1
2
EN
34
VIN
C
IN
C
IN
between V GND as close as possible
Layout note:
1. The distance that C
2. C
should be placed near RT8016.
OUT
6
VOUT
5
GND
LX
must be placed
and
DD
connects to VIN is as close as possible (Under 2mm).
IN
Output capacitor must be near RT8016
L1
C
OUT
LX should be connected to Inductor by wide and short trace, keep sensitive compontents away from this trace
-6
and 6x10
-6
for component selection.
RT8016_ADJ
GND
1
EN
2
VIN
3
C
IN
CIN must be placed
between V GND as close as possible
DD
and
FB
6
GND
5
LX
4
LX should be connected to Inductor by wide and short trace, keep sensitive compontents away from this trace
L1
Output capacitor must be near RT8016
C
OUT
R1
R2
Figure 3. Layout Guide for RT8016
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DS8016-04 February 2012www.richtek.com
Functional Pin Description
Pin No. Pin Name Pin Function
2 EN Chip Enable (Active High).
3 VIN Power Input.
4 LX Pin for Switching.
1, 5 GND Ground Pin.
6 FB/VOUT Feedback/Output Voltage Pin.
7 (Exposed Pad) NC
No Internal Connection. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
Function Block Diagram
EN VIN
RT8016
FB/VOUT
Slope
Compensation
Error
Amplifier
RC
COMP
OSC &
Shutdown
Control
Current
Sense
PWM
Comparator
UVLO &
Power Good
Detector
RS1
Current
Limit
Detector
Control
Logic
V
REF
Controller
GND
Driver
Current
Source
Current
Detector
LX
Mux
RS2
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RT8016
Absolute Maximum Ratings (Note 1)
Supply Input Voltage ------------------------------------------------------------------------------------------------------ 6.5V
EN, FB Pin Voltage ------------------------------------------------------------------------------------------------------- 0.3V to V
Power Dissipation, P
@ TA = 25°C
D
WDFN-6L 2x2 -------------------------------------------------------------------------------------------------------------- 0.606W
Package Thermal Resistance (Note 2)
WDFN-6L 2x2, θJA--------------------------------------------------------------------------------------------------------- 165°C/W
WDFN-6L 2x2, θJC-------------------------------------------------------------------------------------------------------- 20°C/W
Lead Temperature (Soldering, 10 sec.)------------------------------------------------------------------------------- 260°C
Storage Temperature Range -------------------------------------------------------------------------------------------- 65°C to 150°C
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions (Note 4)
Supply Input Voltage ------------------------------------------------------------------------------------------------------ 2.5V to 5.5V
Junction Temperature Range --------------------------------------------------------------------------------------------
Ambient Temperature Range --------------------------------------------------------------------------------------------
40°C to 125°C
40°C to 85°C
IN
Electrical Characteristics
(V
= 3.6V, V
IN
Input Voltage Range
Quiescent Current IQ I
Shutdown Current
Reference Voltage
Adjustable Output Range
Output Voltage Acc uracy
FB Input Current
P-MOSFET RON R
N-MOSFET RON R
P-Channel Current Limit
EN High-Level Input Voltage
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OUT
= 2.5V, V
= 0.6V, L = 2.2μH, C
REF
= 4.7μF, C
IN
OUT
= 10uF, T
= 25°C, I
A
= 1A unless otherwise specified)
MAX
Parameter Symbol Test Conditions Min Typ Max Unit
2.5 -- 5.5 V
= 0mA, VFB = V
OUT
EN = GND -- 0.1 1
+ 5% -- 50 70 μA
REF
For Adjustable Output Voltage 0.588 0.600 0.612 V
(Note 6 )
= (V
V
IN
V
> 2.5V which ever is larger.
IN
+ ΔV) to 5.5V or
OUT
V
REF
3
--
V
IN
0.2V
-- 3 %
Fix
V
IN
I
SHDN
V
REF
V
OUT
ΔV
OUT
(Note 5)
Adjustable
V
ΔV
OUT
V
I
FB
DS(ON)_P
DS(ON)_N
V
I
LIM_P
V
EN_H
IN
0A < I
FB
I
OUT
I
OUT
IN
1.5 --
= V
= 2.5V to 5.5 V
+ ΔV to 5.5V (Note 5)
OUT
OU T
< 1A
3
= VIN 50
= 200mA
= 200mA
V
IN
V
IN
V
IN
V
IN
= 3.6V
= 2.5V
= 3.6V
= 2.5V
-- 0.28 --
-- 0.38 --
-- 0.25 --
-- 0.35 --
1.4 2 2.6 A
-- 3 %
-- 50 nA
VIN
DS8016-04 February 2012www.richtek.com
μA
V
Ω
Ω
V
RT8016
Parameter Symbol Test Conditions Min Typ Max Unit
EN Low-Level Input Voltage V
-- -- 0.4 V
EN_L
Under Voltage Lock Out threshold UVLO -- 1.8 -- V
Hyster es i s -- 0.1 -- V
Oscillator Frequency
Thermal Shutdown Temperature
f
V
OSC
T
SD
= 3.6V, I
IN
OU T
= 100mA
-- 160 -- °C
1.2 1.5 1.8 MHz
Max. Duty Cycl e 100 -- -- %
LX Current Source
V
= 3.6V, V
IN
= 0V or V
LX
= 3.6V
LX
1 -- 100
μA
Minimum On-Time tON -- 120 140 ns
Note 1. Stresses beyond those listed Absolute Maximum Ratings may cause permanent damage to the device. These are
stress ratings only, and 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 may
affect device reliability.
Note 2. θ
Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. ΔV = I Note 6. Guarantee by design. Note 7. The start up time is about 300μs.
is measured at T
JA
is on the lead of the package.
of θ
JC
x P
OUT
RDS(ON)
= 25°C on a single-layer and four-layer test board of JEDEC 51. The measurement case position
A
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RT8016
Typical Operating Characteristics
Effic iency vs. Output Current
100
90
80
70
60
50
40
Efficiency (%)
30
20
10
0
0.001 0.01 0.1 1
VIN = 3.6V
VIN = 5V
V
= 1.2V, C
OUT
= 10uF, L = 2.2H
OUT
Output Current (A)
Output Voltage vs. Temperature
1.25
1.24
1.23
1.22
1.21
1.20
1.19
1.18
Output Voltage (V)
1.17
1.16
1.15
-50 -25 0 25 50 75 100 125
Temperature
VIN = 3.6V, I
(°C)
OUT
= 0A
Output Voltage vs. Output Current
1.220
1.218
Output Voltage (V)
1.216
1.214
1.212
1.210
1.208
1.206
1.204
1.202
1.200 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
VIN = 3.6V
VIN = 5V
Output Current (A)
UVLO Threshold vs . Te m perature
2.1
2.0
1.9
1.8
1.7
1.6
Input Voltage (V)
1.5
1.4
1.3
-50 -25 0 25 50 75 100 125
Rising
Falling
V
OUT
Temperature
= 1.2V, I
(°C)
OUT
= 0A
EN Threshold vs. Input Voltage
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
EN Voltage (V)
0.7
0.6
0.5
0.4
2.52.83.13.43.7 4 4.34.64.95.25.5
Rising
Falling
V
OUT
= 1.2V, I
OUT
= 0A
Input Voltage (V)
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1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
EN Voltage (V)
0.7
0.6
0.5
0.4
EN Threshold vs . Temperature
Rising
Falling
VIN = 3.6V, V
-40 -15 10 35 60 85 110 135
Temperature
= 1.2V, I
OUT
(°C)
DS8016-04 February 2012www.richtek.com
6
OUT
= 0A
RT8016
Frequency vs. Input Voltage
1.60
1.55
1.50
1.45
1.40
1.35
Frequency (MHz)
1.30
1.25
1.20
VIN = 3.6V, V
2.5 2.8 3.1 3.4 3 .7 4 4.3 4.6 4.9 5.2 5.5
= 1.2V, I
OUT
Input Voltage (V)
Current Limit vs. Input Voltage
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
Output Current (A)
1.4
1.3
1.2
2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5
Input Voltage (V)
= 300mA
OUT
V
OUT
= 1.2V
Frequency vs. Temperature
1.60
1.55
1.50
1.45
1.40
1.35
Frequency (MHz)
1.30
1.25
1.20
-40 -15 10 35 60 85 110 135
VIN = 3.6V, V
Temperature
= 1.2V, I
OUT
OUT
(°C)
Current Limit vs. Temperature
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
Output Current (A)
1.4
1.3
1.2
-40 -15 10 35 60 85 110 135
VIN = 3.6V
Temperature
VIN = 3.3V
(°C)
= 300mA
VIN = 5V
V
= 1.2V
OUT
Output Ripple Voltage
VIN = 3.6V, V
V
OUT
(10mV/Div)
V
LX
(5V/Div)
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= 1.2V, I
OUT
OUT
Time (500ns/Div)
= 1A
V
OUT
(10mV/Div)
V
LX
(5V/Div)
VIN = 5V, V
Output Ripple Voltage
= 1.2V, I
OUT
Time (500ns/Div)
OUT
= 1A
DS8016-04 February 2012 www.richtek.com
7
RT8016
V
EN
(2V/Div)
V
OUT
(1V/Div)
I
IN
(500mA/Div)
V
IN
(2V/Div)
VIN = 3.6V, V
VEN = 3.6V, V
Power On from EN
= 1.2V, I
OUT
Time (100μs/Div)
OUT
= 10mA
Power On from VIN
= 1.2V, I
OUT
OUT
= 1A
V
EN
(2V/Div)
V
OUT
(1V/Div)
I
IN
(500mA/Div)
V
EN
(2V/Div)
VIN = 3.6V, V
Power On from EN
= 1.2V, I
OUT
Time (100μs/Div)
OUT
= 1A
Power Off from EN
VIN = 3.6V, V
= 1.2V, I
OUT
OUT
= 1A
V
OUT
(1V/Div)
I
IN
(500mA/Div)
V
OUT
(50mV/Div)
I
OUT
(500mA/Div)
Time (250μs/Div)
Load Transient Response
VIN = 3.6V, V
= 50mA to 1A
I
OUT
OUT
= 1.2V
V
OUT
(1V/Div)
I
IN
(500mA/Div)
V
OUT
(50mV/Div)
I
OUT
(500mA/Div)
Time (100μs/Div)
Load Transient Response
VIN = 3.6V, V I
= 50mA to 0.5A
OUT
OUT
= 1.2V
Time (50μs/Div)
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Time (50μs/Div)
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RT8016
V
OUT
(50mV/Div)
I
OUT
(500mA/Div)
Load Transient Response
VIN = 5V, V I
= 50mA to 1A
OUT
= 1.2V
OUT
Time (50μs/Div)
V
OUT
(50mV/Div)
I
OUT
(500mA/Div)
Load Transient Response
VIN = 5V, V I
= 50mA to 0.5A
OUT
= 1.2V
OUT
Time (50μs/Div)
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RT8016
Applications Information
The basic RT8016 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 C
OUT
.
Inductor Selection
For a given input and output voltage, the inductor value
and operating frequency determine the ripple current. The
ripple current ΔIL increases with higher VIN and decreases
with higher inductance.
ΔI
V
=
L
⎤ ⎥
Lf
×
V
1
×
OUTOUT
V
IN
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 ΔIL = 0.4(I
). The largest ripple current occurs at the
MAX
highest VIN. To guarantee that the ripple current stays
below a specified maximum, the inductor value should be
chosen according to the following equation :
V
L
=
OUT
If
Δ×
L(MAX)
⎤ ⎥
V
1
×
V
IN(MAX)
OUT
⎤ ⎥
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 mollypermalloy
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. Unfortunately, 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. 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 depends on the price vs size requirements and
any radiated field/EMI requirements.
CIN and C
Selection
OUT
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 :
V
II
OUT(MAX)RMS
OUT
V
This formula has a maximum at VIN = 2V
I
RMS
= I
/2. This simple worst-case condition is
OUT
V
IN
1
=
V
OUT
IN
, where
OUT
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
derate 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 C
is determined by the effective series
OUT
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, ΔV
ESR ΔIΔV
LOUT
, is determined by :
OUT
1
+
8fC
OUT
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RT8016
The output ripple is highest at maximum input voltage
since ΔIL 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 In put 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 4.
V
OUT
R1
FB
RT8016
GND
R2
For adjustable voltage mode, the output voltage is set by
an external resistive divider according to the following
equation :
R1
)
+=
R2
where V
(1VV
REFOUT
is the internal reference voltage (0.6V typ.)
REF
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 I2R 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 VIN quiescent current appears due to two factors
including : 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
ΔQ moves from VIN to ground.
The resulting ΔQ/Δt is the current out of VIN that is typically
larger than the DC bias current. In continuous mode,
I
GATECHG
= 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.
Figure 4. Setting the Output Voltage
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11
RT8016
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
and the synchronous switch. Thus, the series resistance
looking into the LX pin is a function of both top and bottom
MOSFET R
RSW = R
The R
DS(ON)TOP
DS(ON)
and the duty cycle (DC) as follows :
DS(ON)
x DC + R
DS(ON)BOT
x (1−DC)
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 R
and multiply the result by the square of the average output
current.
Other losses including CIN and C
ESR dissipative
OUT
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 :
P
Where T
temperature, T
D(MAX)
= ( T
J(MAX)
- TA ) / θ
J(MAX)
JA
is the maximum operation junction
is the ambient temperature and the θ
A
is
JA
the junction to ambient thermal resistance.
For recommended operating conditions specification of
RT8016 DC/DC converter, where T
is the maximum
J(MAX)
junction temperature of the die and TA is the maximum
ambient temperature. The junction to ambient thermal
resistance θJA is layout dependent. For WDFN-6L 2x2
packages, the thermal resistance θJA is 165°C/W on the
standard JEDEC 51-7 four layers thermal test board.
The maximum power dissipation at TA = 25°C can be
calculated by following formula :
P
= (125°C − 25°C) / 165°C/W = 0.606W for
D(MAX)
WDFN-6L 2x2 packages
The maximum power dissipation depends on operating
ambient temperature for fixed T
and thermal
J(MAX)
resistance θJA.
For RT8016 packages, the Figure 5 of derating curves
allows the designer to see the effect of rising ambient
temperature on the maximum power allowed.
700
600
500
400
300
200
L
100
Maximum Power Dissipation (mW)
0
0 20 40 60 80 100 120 140
WDFN-6L 2x2
Ambient Temperature (°C)
Single Layer PCB
Figure 5. Derating Curves for RT8016 Package
Checking Tra n sient Re spon se
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, V
equal to ΔI
resistance of C
discharge C
(ESR), where ESR is the effective series
LOAD
OUT
generating a feedback error signal used
OUT
by the regulator to return V
During this recovery time, V
immediately shifts by an amount
OUT
. ΔI
also begins to charge or
LOAD
to its steady-state value.
OUT
can be monitored for
OUT
overshoot or ringing that would indicate a stability problem.
Layout Considerations
Follow the PCB layout guidelines for optimal performance
of RT8016.
` For the main current paths as indicated in bold lines in
Figure 6, 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 RT8016.
Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
12
©
DS8016-04 February 2012www.richtek.com
` Connect all analog grounds to a common node and then
connect the common node to the power ground behind
the output capacitors.
` An example of 2-layer PCB layout is shown in Figure 7
to Figure 8 for reference.
RT8016
V
IN
RT8016
C1
R3
3
VIN
2
EN
LX
FB/VOUT
GND
V
IN
L1
4
C2
6
1, 5
R1
R2
V
OUT
Figure 7. Top Layer
C3
Figure 6. EVB Schematic
Figure 8. Bottom Layer
Table 1. Recommended Inductors
Supplier
Inductance
(μH)
Current Rating (mA)
DCR (mΩ)
Dimensions
(mm)
TAIY O YUDEN 2.2 1480 60 3.00 x 3.00 x 1.50 NR 3015
GOTREND 2.2 1500 58 3.85 x 3.85 x 1.80 GTSD32
Sumida 2.2 1500 75 4.50 x 3.20 x 1.55 CDRH2D14 Sumida 4.7 1000 135 4.50 x 3.20 x 1.55 CDRH2D14
TAIY O YUDEN 4.7 1020 120 3.00 x 3.00 x 1.50 NR 3015
GOTREND 4.7 1100 146 3.85 x 3.85 x 1.80 GTSD32
Series
Supplier
Table 2. Recommended Capacitors for C
Capacitance
(μF)
Package Part Number
and C
IN
OUT
TDK 4.7 603 C1608JB0J475M
MURATA 4.7 603 GRM188R60J475KE19 TAIYO YUDEN 4.7 603 JMK107BJ475RA TAIYO YUDEN 10 603 JMK107BJ106MA
TDK 10 805 C2012JB0J106M MURATA 10 805 GRM219R60J106ME19 MURATA 10 805 GRM219R60J106KE19
TAIYO YUDEN 10 805 JMK212BJ106RD
Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
DS8016-04 February 2012 www.richtek.com
©
13
RT8016
Outline Dimension
D
E
A
A3
A1
D2
L
E2
SEE DETAIL A
1
e
b
2
1
DETAIL A
1
2
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.
Dimensions In Millimeters Dimensions In Inches
Symbol
Min Max Min Max
A 0.700 0.800 0.028 0.031
A1 0.000 0.050 0.000 0.002
A3 0.175 0.250
0.007 0.010
b 0.200 0.350 0.008 0.014
D 1.950 2.050 0.077 0.081
D2 1.000 1.450 0.039 0.057
E 1.950 2.050 0.077 0.081
E2 0.500 0.850 0.020 0.033
e 0.650 0.026
L 0.300 0.400
W-Type 6L DFN 2x2 Package
0.012 0.016
Richtek Technology Corporation
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
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