Skyworks CDRH5D28-4R2 850khz 700ma synchronous buck dc/dc converter Datasheet

DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
General Description
Features
The AAT1151 SwitchReg™ is a step-down switching converter ideal for applications where high efficiency is
required over the full range of output load conditions.
The 2.7V to 5.5V input voltage range makes the AAT1151
ideal for single-cell lithium-ion/polymer battery applications. Capable of more than 700mA with internal
MOSFETs, the current-mode controlled IC provides high
efficiency using synchronous rectification. Fully integrated compensation simplifies system design and lowers external parts count.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
The device operates at a fixed 850kHz switching frequency and enters Pulse Frequency Modulation (PFM)
mode for light load current to maintain high efficiency
across all load conditions.
The AAT1151 is available in Pb-free MSOP-8 and QFN3316 packages and is rated over the -40°C to +85°C temperature range.
VIN Range: 2.7V to 5.5V
Up to 95% Efficiency
High Initial Accuracy ±1%
110m RDS(ON) Internal Switches
<1μA Shutdown Current
850kHz Switching Frequency
Fixed VOUT or Adjustable VOUT ≥1.0V
Integrated Power Switches
Synchronous Rectification
Current Mode Operation
Internal Compensation
Stable with Ceramic Capacitors
PFM for Optimum Efficiency for All Load Conditions
Internal Soft Start
Over-Temperature Protection
Current Limit Protection
MSOP-8 and QFN33-16 Packages
-40°C to +85°C Temperature Range
Applications
•
•
•
•
•
•
•
Cellular Phones
Digital Cameras
MP3 Players
Notebook Computers
PDAs
USB-Powered Equipment
Wireless Notebook Adapters
Typical Application
INPUT
VP
10μF
FB
AAT1151
3.0μH
LX
ENABLE
100Ω
VCC
OUTPUT
SGND
PGND
2x 22μF
0.1μF
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
1
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Pin Descriptions
Pin #
MSOP-8
QFN33-16
Symbol
1
4
FB
2
5, 6
SGND
3
7
EN
4
9
VCC
5
10, 11, 12
VP
6, 7
13, 14, 15
LX
8
1, 2, 3
PGND
8, 16
EP
NC
Function
Feedback input pin. This pin is connected to the converter output. It is used to set the output
of the converter to regulate to the desired value via an internal resistive divider. For an adjustable output, an external resistive divider is connected to this pin on the 1V model.
Signal ground. Connect the return of all small signal components to this pin. (See board layout rules.)
Enable input pin. A logic high enables the converter; a logic low forces the AAT1151 into shutdown mode reducing the supply current to less than 1μA. The pin should not be left floating.
Bias supply. Supplies power for the internal circuitry. Connect to input power via low pass
filter with decoupling to SGND.
Input supply voltage for the converter power stage. Must be closely decoupled to PGND.
Connect inductor to these pins. Switching node internally connected to the drain of both highand low-side MOSFETs.
Main power ground return pin. Connect to the output and input capacitor return. (See board
layout rules.)
Not internally connected.
Exposed paddle (bottom); connect to PGND directly beneath package
Pin Configuration
MSOP-8
(Top View)
QFN33-16
(Top View)
LX
LX
LX
NC
12
2
11
3
10
4
9
VP
VP
VP
VCC
8
VP
1
7
5
13
4
LX
14
VCC
6
PGND
PGND
PGND
FB
6
3
LX
5
EN
7
15
2
PGND
16
SGND
8
2
1
1
FB
NC
EN
SGND
SGND
2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Absolute Maximum Ratings1
Symbol
VCC, VP
VLX
VFB
VEN
TJ
VESD
Description
VCC, VP to GND
LX to GND
FB to GND
EN to GND
Operating Junction Temperature Range
ESD Rating2 - HBM
Value
Units
6
-0.3 to VP + 0.3
-0.3 to VCC + 0.3
-0.3 to 6
-40 to 150
3000
V
V
V
V
°C
V
Value
Units
Thermal Characteristics3
Symbol
Description
JA
Thermal Resistance
PD
Maximum Power Dissipation (TA = 25°C)
MSOP-8
QFN33-16
MSOP-84
QFN33-165
150
50
667
2.0
°C/W
mW
W
Recommended Operating Conditions
Symbol
T
Description
Ambient Temperature Range
Value
Units
-40 to 85
°C
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Human body model is a 100pF capacitor discharged through a 1.5k resistor into each pin.
3. Mounted on a demo board.
4. Derate 6.7mW/°C above 25°C.
5. Derate 20mW/°C above 25°C.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
3
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Electrical Characteristics1
VIN = VCC = VP = 5V, TA = -40°C to 85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol
Description
VIN
VOUT
Input Voltage Range
Output Voltage Tolerance
VUVLO
Under-Voltage Lockout
VUVLO(HYS)
IIL
IIH
IQ
ISHDN
ILIM
RDS(ON)H
RDS(ON)L

VOUT
(VOUT*VIN)
VOUT/VOUT
FOSC
VEN(L)
VEN(H)
TSD
THYS
Conditions
VIN = VOUT + 0.2 to 5.5V, IOUT = 0 to 700mA
VIN Rising
VIN Falling
Under-Voltage Lockout Hysteresis
Input Low Current
Input High Current
Quiescent Supply Current
Shutdown Current
Current Limit
High Side Switch On Resistance
Low Side Switch On Resistance
Efficiency
VIN = VFB = 5.5V
VIN = VFB = 0V
No Load, VFB = 0V, VIN = 4.2V, TA = 25°C
VEN = 0V, VIN = 5.5V
TA = 25°C
TA = 25°C
TA = 25°C
IOUT = 300mA, VIN = 3.5V
Load Regulation
VIN = 4.2V, ILOAD = 0 to 700mA
Line Regulation
Oscillator Frequency
Enable Threshold Low
Enable Threshold High
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
VIN = 2.7V to 5.5V
TA = 25°C
Min
Typ
2.7
-3.0
Max
Units
5.5
+3.0
2.5
V
%
1.2
250
210
1.0
1.0
300
1.0
1.2
110
100
92
150
150
0.9
600
0.1
850
V
mV
μA
μA
μA
μA
A
m
m
%
%
1200
0.6
1.4
140
15
%/V
kHz
V
V
°C
°C
1. The AAT1151 is guaranteed to meet performance specifications over the -40°C to +85°C operating range and is assured by design, characterization, and correlation with statistical process controls.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Typical Characteristics
Efficiency vs. Load Current
Efficiency vs. Load Current
(VOUT = 2.5V; L = 4.2μ
μH)
(VOUT = 1.8V)
100
Efficiency (%)
Efficiency (%)
100
90
80
70
80
3.6V
70
50
1
10
100
1
1000
10
No Load Supply Current vs. Input Voltage
1000
Frequency vs. Input Voltage
300
890
T = 85°C
250
Frequency (kHz)
Supply Current (μ
μA)
100
Load Current (mA)
Output Current (mA)
200
150
T = -40°C
T = 25°C
100
50
880
870
860
850
0
2.5
3
3.5
4
4.5
5
2.5
5.5
Output Voltage vs. Temperature
3.5
4
4.5
5
5.5
Load and Line Regulation
3.0
1.794
2.0
1.79
1.0
VOUT Error (%)
1.792
1.788
1.786
1.784
1.782
1.78
-40
3
Input Voltage (V)
Input Voltage (V)
Output Voltage (V)
4.2V
60
60
50
2.7V
90
VIN = 4.2V
VIN = 3.6V
0.0
VIN = 2.7V
-1.0
-2.0
-20
0
20
40
60
Temperature (°°C)
80
100
-3.0
1
10
100
1000
Load Current (mA)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
5
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Typical Characteristics
Output Ripple 1.8V, 50mA, VIN = 3.6V
Circuit of Figure 1
Switching Frequency vs. Temperature
Frequency (kHz)
1000
800
600
400
200
0
-40
-20
0
20
40
60
80
100
20
1.4
10
1.2
0
0.8
-20
0.6
-30
0.4
-40
0.2
-50
0
-60
-0.2
Time (2μ
μs/div)
Temperature (°°C)
4
80
3.8
60
3.6
40
3.4
20
3.2
0
3
-20
2.8
-40
Output Voltage
(AC coupled) (top) (mV)
100
20
3.5
10
3
-10
2
-20
1.5
-30
1
-40
0.5
-50
0
Time (2μ
μs/div)
100
4
80
3.8
60
3.6
40
3.4
20
3.2
0
3
-20
2.8
-40
Output Voltage (top) (mV)
(AC coupled)
120
4.2
40
3.5
20
3
2.5
0
-20
2
-40
1.5
-60
1
-80
0.5
-100
0
-120
-0.5
Time (200μs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
Inductor Current
(bottom) (A)
4.4
Load Transient Response 50mA to 0.7A
VIN = 3.6V − Circuit of Figure 1
Output Voltage
(bottom) (mV)
Input Voltage
(top) (V)
Line Transient Response 1.8V, 0.7A
Circuit of Figure 1
6
-0.5
-60
Time (20μ
μs/div)
Time (20μ
μs/div)
2.5
0
Inductor Current
(bottom) (A)
120
4.2
Output Ripple 1.8V, 0.7A, VIN = 3.6V
Circuit of Figure 1
Output Voltage
(bottom) (mV)
Input Voltage
(top) (V)
Line Transient Response 1.8V, 50mA
Circuit of Figure 1
4.4
1
-10
Inductor Current
(bottom) (A)
Output Voltage
(AC coupled) (top) (mV)
1200
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Typical Characteristics
Output Ripple
Circuit of Figure 1
3.5
3
3
2
2.5
1
2
0
1.5
-1
1
-2
0.5
-3
0
-4
-0.5
Time (200μ
μs/div)
20
15
Ripple (mV)
4
Inductor Current
(bottom) (A)
Enable (top)
Output (middle) (V)
Soft Start 1.8V, 0.7A, VIN = 3.6V
Circuit of Figure 1
VIN = 2.7V
VIN = 3.6V
10
5
VIN = 4.2V
0
1
10
100
1000
Output Current (mA)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
7
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Functional Block Diagram
VCC
VP = 2.7V to 5.5V
1.0V REF
FB
OP. AMP
CMP
DH
LOGIC
1MΩ
LX
DL
Temp.
Sensing
OSC
SGND
Operation
Control Loop
The AAT1151 is a peak current mode buck converter. The
inner wide bandwidth loop controls the peak current of
the output inductor. The output inductor current is
sensed through the P-channel MOSFET (high side) and is
also used for short-circuit and overload protection. A
fixed slope compensation signal is added to the sensed
current to maintain stability. The loop appears as a voltage programmed current source in parallel with the output capacitor.
The voltage error amplifier output programs the current
loop for the necessary inductor current to force a constant output voltage for all load and line conditions. The
voltage feedback resistive divider is internal, dividing the
output voltage to the error amplifier reference voltage of
1.0V. The voltage error amplifier does not have the large
DC gain typical of most error amplifiers. This eliminates
the need for external compensation components, while
still providing sufficient DC loop gain for load regulation.
8
EN
PGND
The voltage loop crossover frequency and phase margin
are set by the output capacitor value only.
PFM/PWM Operation
Light load efficiency is maintained by way of PFM control.
The AAT1151 PFM control forces the peak inductor current to a minimum level regardless of load demand. At
medium to high load demand, this has no effect on circuit operation and normal PWM controls take over. PFM
reduces the switching frequency at light loads, thus
reducing the associated switching losses.
Soft Start/Enable
Soft start increases the inductor current limit point in
discrete steps when the input voltage or enable input is
applied. It limits the current surge seen at the input and
eliminates output voltage overshoot. When pulled low,
the enable input forces the AAT1151 into a low-power,
non-switching state. The total input current during shutdown is less than 1μA.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Power and Signal Source
current in the inductor can meet or exceed the current
limit point of the AAT1151. These conditions can tolerate
greater saturation in the inductor without degradation in
converter performance. Some inductors may meet the
peak and average current ratings yet result in excessive
losses due to a high DCR. Always consider the losses
associated with the DCR and its effect on the total converter efficiency when selecting an inductor.
Separate small signal ground and power supply pins
isolate the internal control circuitry from the noise associated with the output MOSFET switching. The low pass
filter R1 and C2 in schematic Figure 1 filters the noise
associated with the power switching.
Current Limit and
Over-Temperature Protection
For a 1.0A load and the ripple set to 40% at the maximum input voltage, the maximum peak-to-peak ripple
current is 280mA. The inductance value required is
2.84μH.
For overload conditions, the peak input current is limited. As load impedance decreases and the output voltage
falls closer to zero, more power is dissipated internally,
raising the device temperature. Thermal protection completely disables switching when internal dissipation
becomes excessive, protecting the device from damage.
The junction over-temperature threshold is 140°C with
10°C of hysteresis.
VOUT
⎛ VOUT⎞
L=I •k•F • 1- V
⎝
O
S
IN ⎠
=
1.5V
⎞
⎛
⎞⎛
• 1 - 1.5V
4.2V ⎠
⎝ 1A • 0.4 • 850kHz ⎠ ⎝
= 2.84μH
Inductor
The output inductor is selected to limit the ripple current
to some predetermined value, typically 20% to 40% of
the full load current at the maximum input voltage.
Manufacturer’s specifications list both the inductor DC
current rating, which is a thermal limitation, and the
peak current rating, which is determined by the saturation characteristics. The inductor should not show any
appreciable saturation under normal load conditions.
During overload and transient conditions, the average
Efficiency vs. Load Current
U1
AAT1151-MSOP
2.7V-4.2V
5
VP
FB
The factor “k” is the fraction of full load selected for the
ripple current at the maximum input voltage. For ripple
current at 40% of the full load current, the peak current
will be 120% of full load. Selecting a standard value of
3.0μH gives 38% ripple current. A 3.0μH inductor selected from the Sumida CDRH5D28 series has a 24m DCR
and a 2.4A DC current rating. At full load, the inductor
DC loss is 24mW, which amounts to a 1.6% loss in efficiency.
(VOUT = 1.8V)
1.8V
1
100
R1
100
4
VCC
LX
7
3
EN
LX
6
C3, C4
2x22µF
C2
0.1µF
2
C1
C3-C4
L1
L1
3.3µH
SGND PGND
8
Murata 10µF 6.3V X5R GRM42-6X5R106K6.3
Murata 22µF 6.3V GRM21BR60J226ME39L X5R 0805
Sumida CDRH3D16-4R7NC or CDRH3D16-3R3NC
Efficiency (%)
C1
10µF
R2
100k
2.7V
90
80
3.6V
4.2V
70
60
50
1
10
100
1000
Load Current (mA)
Figure 1: AAT1151 Evaluation Board.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
9
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Input Capacitor
The primary function of the input capacitor is to provide
a low impedance loop for the edges of pulsed current
drawn by the AAT1151. A low ESR/ESL ceramic capacitor
is ideal for this function. To minimize stray inductance,
the capacitor should be placed as close as possible to the
IC. This keeps the high frequency content of the input
current localized, minimizing radiated and conducted
EMI while facilitating optimum performance of the
AAT1151. Ceramic X5R or X7R capacitors are ideal for
this function. The size required will vary depending on
the load, output voltage, and input voltage source
impedance characteristics. A typical value is around
10μF. The input capacitor RMS current varies with the
input voltage and the output voltage. The equation for
the RMS current in the input capacitor is:
IRMS = IO •
VO ⎛
V ⎞
• 1- O
VIN ⎝
VIN ⎠
The input capacitor RMS ripple current reaches a maximum when VIN is two times the output voltage where it
is approximately one half of the load current. Losses
associated with the input ceramic capacitor are typically
minimal and are not an issue. Proper placement of the
input capacitor can be seen in the reference design layout in Figures 2 and 4.
Output Capacitor
Since there are no external compensation components,
the output capacitor has a strong effect on loop stability.
Lager output capacitance will reduce the crossover frequency with greater phase margin. For the 1.5V 1A
design using the 4.1μH inductor, two 22μF capacitors
provide a stable output. In addition to assisting stability,
the output capacitor limits the output ripple and provides
10
holdup during large load transitions. The output capacitor RMS ripple current is given by:
IRMS =
1
VOUT · (VIN - VOUT)
L · FS · VIN
2· 3
·
For a ceramic capacitor, the ESR is so low that dissipation
due to the RMS current of the capacitor is not a concern.
Tantalum capacitors with sufficiently low ESR to meet
output voltage ripple requirements also have an RMS
current rating well beyond that actually seen in this
application.
Layout
Figures 2 through 5 display the suggested PCB layout for
the AAT1151. The following guidelines should be used to
help ensure a proper layout.
• The input capacitor (C1) should connect as closely as
possible to VP (Pin 5) and PGND (Pin 8).
• C2 and L1 should be connected as closely as possible.
The connection L1 to the LX node should be as short
as possible.
• The feedback trace (Pin 1) should be separate from
any power trace and connect as closely as possible to
the load point. Sensing along a high-current load trace
will degrade DC load regulation.
• The resistance of the trace from the load return to the
PGND (Pin 8) should be kept to a minimum. This will
help to minimize any error in DC regulation due to differences in the potential of the internal signal ground
and the power ground.
• Low pass filter R1 and C3 provide a cleaner bias
source for the AAT1151 active circuitry. C3 should be
placed as closely as possible to SGND (Pin 2) and VCC
(Pin 4). See Figures 2 and 7.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Figure 2: MSOP Evaluation
Board Top Layer.
Figure 3: MSOP Evaluation
Board Bottom Layer.
Figure 4: QFN Evaluation Board Top Side.
Figure 5: QFN Evaluation Board Bottom Side.
45
R4=10kΩ
40
2.7V - 5.5V
AAT1151-1.0
10,11,12
35
R1 100
R3 (kΩ)
30
25
R2
20
100k
C1
10μF
15
10
5
C3
0.1μF
9
7
5,6
VP
FB
VCC
LX
4
13,14,15
L1
3.3μH
EN
SGND PGND
VO+ 1.25V 0.7A
R3
2.55k 1%
1,2,3
R4
10kΩ 1%
C2, C4
2x 22μF
GND
0
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
Output Voltage (V)
Figure 6: R3 vs. VOUT for Adjustable Output
C1 Murata 10μF 6.3V X5R GRM42-6X5R106K6.3
C2, C4 Murata 22μF 6.3V GRM21BR60J226ME39L X5R 0805
L1 Sumida CDRH3D16-3R3 NC
Figure 7: Adjustable Output Schematic.
Using the AAT1151-1.0V.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
11
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Thermal Calculations
There are two types of losses associated with the
AAT1151 output switching MOSFET: switching losses and
conduction losses. Conduction losses are associated with
the RDS(ON) characteristics of the output switching device.
At the full load condition, assuming continuous conduction mode (CCM), a simplified form of the total losses is
given by:
P=
IO2 · (RDS(ON)H · VO + RDS(ON)L · (VIN · VO))
V IN
+ (t SW · FS · I O · VIN + IQ) · VIN
where Iq is the AAT1151 quiescent current.
12
Once the total losses have been determined, the junction
temperature can be derived from the JA for the MSOP-8
package.
TJ = P · θJA + TAMB
Adjustable Output
For applications requiring an output other than the fixed
available, the 1V version can be programmed externally.
Resistors R3 and R4 of Figure 7 force the output to regulate higher than 1V. R4 should be 100 times less than the
1M internal resistance of the FB pin (recommended
10k). Once R4 is selected, R3 can be calculated. For a
1.25 volt output with R4 set to 10.0k, R3 is 2.55k.
R3 = (VO - 1) · R4 = 0.25 · 10kΩ = 2.55kΩ
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Design Example
Specifications
IOUT = 0.7A
IRIPPLE = 40% of Full Load at Max VIN
VOUT = 1.5V
VIN = 2.7V to 4.2V (3.6V nominal)
FS = 850kHz
TAM = 85°C
Maximum Input Capacitor Ripple
IRMS = I O ·
VO ⎛
V ⎞
· 1 - O = 0.35Arms, VIN = 2 · VO
VIN ⎝ VIN ⎠
P = esr · IRMS2 = 5mΩ · 0.352 A = 0.6mW
Inductor Selection
L=
⎛ V ⎞
VOUT
1.5V
⎛ 1.5V⎞
⋅ 1 - OUT =
⋅1= 4.05μH
IO ⋅ k ⋅ FS ⎝
VIN ⎠ 0.7A ⋅ 0.4 ⋅ 850kHz ⎝ 4.2V⎠
Select Sumida inductor CDRH3D16, 3.3μH, 63m, 1.8mm height.
ΔI =
⎛ 1.5V⎞
VO ⎛
V ⎞
1.5V
⋅ 1- O =
⋅ 1= 340mA
L ⋅ FS ⎝
VIN⎠ 3.3μH ⋅ 850kHz ⎝ 4.2V⎠
IPK = IOUT +
ΔI
= 0.7A + 0.17A = 0.87A
2
P = IO2 ⋅ DCR = (0.7)2 ⋅ 63mΩ = 31mW
Output Capacitor Ripple Current
IRMS =
VOUT · (VIN - VOUT)
1
1.5V · (4.2V - 1.5V)
·
= 99mArms
=
L · FS · VIN
2 · 3 3.3μH · 850kHz · 4.2V
2· 3
1
·
Pesr = esr · IRMS2 = 5mΩ · 992 mA = 50μW
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
13
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
AAT1151 Dissipation
PTOTAL =
=
IO2 • (RDS(ON)H • VO + RDS(ON)L • (VIN -VO))
VIN
+ (tsw • FS • IO + IQ) • VIN
(0.7A)2 • (0.2Ω • 1.5V + 0.187Ω • (4.2V - 1.5V))
4.2V
+ (20nsec • 850kHz • 0.7A + 0.3mA) • 4.2V = 0.145W
TJ(MAX) = TAMB + ΘJA • PLOSS = 85°C + 150°C/W • 0.145W = 107°C (MSOP-8)
= 85°C + 50°C/W • 0.145W = 92°C (QFN33-16)
Manufacturer
Part Number
Value
Max DC
Current
DCR (Ω)
Taiyo Yuden
Toko
Sumida
Sumida
Sumida
Murata
Murata
Murata
NPO5DB4R7M
A914BYW-3R5M-D52LC
CDRH5D28-3R0
CDRH5D28-4R2
CDRH5D18-4R1
LQH55DN4R7M03
LQH66SN4R7M03
CDRH3D16-3R3
4.7μH
3.5μH
3.0μH
4.2μH
4.1μH
4.7μH
4.7μH
3.3μH
1.4A
1.34A
2.4A
2.2A
1.95A
2.7A
2.2A
1.1A
0.038
0.073
0.024
0.031
0.057
0.041
0.025
0.063
Size (mm)
LxWxH
5.9
5.0
5.7
5.7
5.7
5.0
6.3
3.8
x
x
x
x
x
x
x
x
6.1
5.0
5.7
5.7
5.7
5.0
6.3
3.8
x
x
x
x
x
x
x
x
2.8
2.0
3.0
3.0
2.0
4.7
4.7
1.8
Type
Shielded
Shielded
Shielded
Shielded
Shielded
Non-Shielded
Shielded
Shielded
Table 1: Surface Mount Inductors.
Manufacturer
Part Number
Value
Voltage
Temp. Co.
Case
Murata
Murata
Murata
Murata
GRM40 X5R 106K 6.3
GRM42-6 X5R 106K 6.3
GRM21BR60J226ME39L
GRM21BR60J106ME39L
10μF
10μF
22μF
10μF
6.3V
6.3V
6.3V
6.3V
X5R
X5R
X5R
X5R
0805
1206
0805
0805
Table 2: Surface Mount Capacitors.
14
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
Ordering Information
Output Voltage1
Package
Marking2
Part Number (Tape and Reel)3
1.0V (Adj. VOUT ≥ 1.0V)
1.8V
2.5V
3.3V
QFN33-16
MSOP-8
QFN33-16
MSOP-8
JHXYY
JIXYY
JJXYY
NKXYY
AAT1151IVN-1.0-T1
AAT1151IKS-1.8-T1
AAT1151IVN-2.5-T1
AAT1151IKS-3.3-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information4
MSOP-8
4° ± 4°
4.90 ± 0.10
3.00 ± 0.10
1.95 BSC
0.95 REF
0.60 ± 0.20
PIN 1
3.00 ± 0.10
0.85 ± 0.10
0.95 ± 0.15
10° ± 5°
GAUGE PLANE
0.254 BSC
0.155 ± 0.075
0.075 ± 0.075
0.65 BSC
0.30 ± 0.08
All dimensions in millimeters.
1.
2.
3.
4.
Contact local sales office for custom options.
XYY = assembly and date code.
Sample stock is generally held on part numbers listed in BOLD.
The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing
process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013
15
DATA SHEET
AAT1151
850kHz 700mA Synchronous Buck DC/DC Converter
QFN33-16
Pin 1 Dot By Marking
0.230 ± 0.050
Pin 1 Identification
0.500 ± 0.050
1.250 ± 0.050
5
C0.3
13
9
1.250 ± 0.050
Top View
0.025 ± 0.025
Bottom View
0.214 ± 0.036
0.900 ± 0.100
3.000 ± 0.050
0.400 ± 0.100
3.000 ± 0.050
1
Side View
All dimensions in millimeters.
Copyright © 2012, 2013 Skyworks Solutions, Inc. All Rights Reserved.
Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a
service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no
responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes.
No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.
THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR
PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES
NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM
THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper
use or sale.
Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product
design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.
16
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
201991B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 18, 2013