201995A.pdf

DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
General Description
Features
The AAT1157 SwitchReg™ is a step-down switching converter, ideal for applications where fixed frequency and
low ripple are required over the full range of load conditions. The 2.7V to 5.5V input voltage range makes the
AAT1157 ideal for single-cell lithium-ion/polymer battery
applications. Capable of up to 1.2A with internal
MOSFETs, the current-mode controlled IC provides high
efficiency over a wide operating range. Fully integrated
compensation simplifies system design and lowers external parts count. The device operates at a fixed 1MHz
switching frequency across all load conditions.
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The AAT1157 is available in the Pb-free, 16-pin 3x3mm
QFN package and is rated over the -40°C to +85°C temperature range.
VIN Range: 2.7V to 5.5V
Up to 95% Efficiency
110 m RDS(ON) Internal Switches
<1μA Shutdown Current
1MHz Buck Switching Frequency
Fixed or Adjustable VOUT ≥ 0.8V
Integrated Power Switches
Current Mode Operation
Internal Compensation
Stable with Ceramic Capacitors
Constant PWM Operation for Low Output Ripple
Internal Soft Start
Over-Temperature Protection
Current Limit Protection
16-Pin QFN 3x3mm Package
-40°C to +85°C Temperature Range
Applications
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HDD MP3 Players
Notebook Computers
PDAs
Point-of-Load Regulation
Set Top Boxes
Smart Phones
Wireless Notebook Adapters
Typical Application
U1
AAT1157
3.3V
12
R1
100
C1
10μF
11
10
7
9
6
C2
0.1μF
8
5
VP
FB
VP
LX
VP
LX
EN
VCC
LX
N/C
N/C
PGND
N/C
PGND
SGND PGND
2.5V
4
R3
187k
15
14
13
L1
3.0μH
16
3
R4
59k
C3-C4
2x 22μF
2
1
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1
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Pin Descriptions
Pin #
Symbol
1, 2, 3
PGND
4
FB
5
SGND
7
EN
6, 8, 16
N/C
9
VCC
10, 11, 12
VP
13, 14, 15
LX
EP
Function
Main power ground return pin. Connect to the output and input capacitor return. (See board layout
rules.)
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.
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 AAT1157 into shutdown
mode reducing the supply current to less than 1μA. The pin should not be left floating.
Not internally connected.
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 high- and
low-side MOSFETs.
Exposed paddle (bottom); connect to PGND directly beneath package.
Pin Configuration
QFN33-16
(Top View)
LX
LX
LX
N/C
13
14
15
16
PGND
PGND
PGND
FB
1
12
2
11
3
10
4
9
VP
VP
VP
VCC
8
7
6
5
N/C
EN
N/C
SGND
2
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DATA SHEET
AAT1157
1MHz 1.2A 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 to150
3000
V
V
V
V
°C
V
Value
Units
50
4.2
2.0
°C/W
°C/W
W
Value
Units
-40 to 85
°C
Thermal Characteristics
Symbol
JA
JC
PD
Description
Maximum Thermal Resistance (QFN33-16)3
Maximum Thermal Resistance (QFN33-16)
Maximum Power Dissipation (QFN33-16) (TA = 25°C)3, 4
Recommended Operating Conditions
Symbol
T
Description
Ambient Temperature Range
1. Stresses above those listed in Absolute Maximum Ratings may cause 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 100pF capacitor discharged through a 1.5k resistor into each pin.
3. Mounted on a demo board (FR4, in still air). Exposed pad must be mounted to PCB.
4. Derate 20mW/°C above 25°C.
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DATA SHEET
AAT1157
1MHz 1.2A 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
VIN
VOUT
VOUT/VOUT
VOUT
(VOUT*VIN)
IQ
ISHDN
ILIM
VUVLO
VUVLO(HYS)
VIL
VIH
IIL
IIH
RDS(ON)H
RDS(ON)L
Description
Conditions
Input Voltage Range
Output Voltage Tolerance
Load Regulation
VIN = VOUT + 0.2 to 5.5V, IOUT = 0 to 1.2A
VIN = 4.2V, ILOAD = 0 to 1.2A
Line Regulation
Quiescent Supply Current
Shutdown Current
Current Limit
Under-Voltage Lockout
Under-Voltage Lockout Hysteresis
Input Low Voltage
Input High Voltage
Input Low Current
Input High Current
High Side Switch On Resistance
Low Side Switch On Resistance
FOSC
Oscillator Frequency
TSD
THYS
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
Min
Typ
Max
Units
5.5
+4
±2.5
V
%
%
VIN =2.7 to 5.5V
±0.1
%/V
No Load
VEN = 0V, VIN = 5.5V
TA = 25°C
VIN Rising, VEN = VCC
VIN Falling, VEN = VCC
160
2.7
-4
300
1.0
1.7
2.5
1.2
250
0.6
1.4
VIN = VFB = 5.5V
VIN = VFB = 0V
TA = 25°C
TA = 25°C
TA = 25°C, Adjustable Version
TA = 25°C, 3.3V Version
750
600
110
100
1000
850
140
15
1.0
1.0
150
150
1250
1200
μA
μA
A
V
mV
V
V
μA
μA
m
m
kHz
°C
°C
1. The AAT1157 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls.
4
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DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Typical Characteristics
No Load Supply Current vs. Input Voltage
DC Regulation
(VOUT = 2.5V)
2.0
85°C
250
200
150
25°C
-40°C
100
50
0
2.5
VIN = 3.0V
0.0
VIN = 3.3V
-1.0
-2.0
-3.0
-4.0
3
3.5
4
4.5
5
1
5.5
10
100
10000
Output Current (mA)
P-Channel RDSON vs. Input Voltage
N-Channel RDSON vs. Input Voltage
200
180
100°C
160
180
120°C
160
RDSON (mΩ
Ω)
140
120
100
85°C
80
25°C
60
100°C
140
120°C
120
100
80
85°C
60
40
40
20
20
0
2.5
25°C
0
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
Input Voltage (V)
Input Voltage (V)
Output Voltage vs. Temperature
Frequency vs. Input Voltage
(VIN = 3.6V; VOUT = 2.5V; IOUT = 1.0A)
5.5
(VOUT = 1.8V)
0.1
1.3
0
Frequency (MHz)
Output Voltage Error (%)
1000
Input Voltage (V)
200
RDSON (mΩ
Ω)
VIN = 3.6V
1.0
Output Error (%)
Supply Current (μ
μA)
300
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
-40
-20
0
20
40
Temperature (°°C)
60
80
100
1.28
1.26
1.24
1.22
1.2
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
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DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Output Ripple
(VOUT = 2.5V; IOUT = 1.2A; VIN = 3.6V)
3.5
4.0
3.0
2.0
2.5
0.0
2.0
-2.0
1.5
-4.0
1.0
-6.0
0.5
-8.0
0.0
-10.0
-0.5
0.02
0.01
2
-0.01
1.5
-0.02
-0.03
1
-0.04
0.5
-0.05
-0.06
0
Time (500ns/div)
Load Transient Response
(400mA-1.2A; VIN = 3.3V; VOUT = 2.5V)
0.24
4.2
0.20
4.0
0.16
3.8
0.12
3.6
0.08
3.4
0.04
3.2
0.00
3.0
-0.04
-0.08
2.8
Time (25μ
μs/div)
0.08
4.0
0.05
3.5
0.02
3.0
-0.01
2.5
-0.04
2.0
-0.07
1.2A
1.5
-0.10
-0.13
1.0
400mA
-0.16
0.5
0.0
Time (20μ
μs/div)
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Load Current
(A) (bottom)
4.4
Output Voltage (AC Coupled)
(V) (top)
Line Transient
(IOUT = 1.2A; VO = 2.5V)
Output Voltage (AC coupled)
(bottom) (V)
Input Voltage
(top) (V)
2.5
0
Time (250μ
μs/div)
6
3
Inductor Current
(bottom) (A)
6.0
Output Voltage (AC coupled)
(top) (V)
Soft Start
(VOUT = 2.5V; IOUT = 1.2A; VIN = 3.6V)
Inductor Current
(bottom) (A)
Enable and Output Voltage
(top) (V)
Typical Characteristics
DATA SHEET
AAT1157
1MHz 1.2A 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
Applications Information
Control Loop
EN
PGND
nents while providing sufficient DC loop gain for good
load regulation. The voltage loop crossover frequency
and phase margin are set by the output capacitor.
The AAT1157 is a peak current mode buck converter. The
inner wide bandwidth loop controls the inductor peak
current. The inductor current is sensed through the
P-channel MOSFET (high side) and is also used for shortcircuit and overload protection. A fixed slope compensation signal is added to the sensed current to maintain
stability for duty cycles greater than 50%. The loop
appears as a voltage-programmed current source in parallel with the output capacitor.
Soft Start/Enable
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 (external for adjustable
output voltage; internal for fixed output voltage) divides
the output voltage to the error amplifier reference voltage of 0.6V. The low-DC gain voltage error amplifier
eliminates the need for external compensation compo-
Power and Signal Source
Soft start increases the inductor current limit point in
discrete steps once 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 AAT1157 into a non-switching shutdown state. The total input current during shutdown is less than 1μA.
Separate small signal ground and power supply pins isolate the internal control circuitry from the noise associated
with the output power MOSFET switching. The low-pass
filter R1 and C2 shown in the Figure 1 schematic filters
the input noise associated with the power switching.
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DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
LX
Enable
12
R1
100
R2
C1
10μF
100K
C2
0.1μF
11
10
7
9
6
8
5
GND
VOUT+
U1
AAT1157
VIN+
VP
FB
VP
LX
VP
LX
EN
LX
VCC
N/C
N/C
PGND
N/C
PGND
SGND PGND
4
R3
15
14
13
L1
3.0μH
16
3
R4
59.0k
C3-C4
2x 22μF
2
1
VOUT(V)
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
2.0
2.5
3.3
R3 (kΩ)
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
137
187
267
GND
C1 Murata 10μF 6.3V X5R GRM42-6X5R106K6.3
C3,C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805
L1 Sumida CDRH5D28-3R0NC
Figure 1: AAT1157 Evaluation Board Schematic
Lithium-Ion to 2.5V Converter.
Current Limit and
Over-Temperature Protection
For overload conditions, the peak input current sensed
through the high-side P-channel MOSFET is limited.
Thermal protection completely disables switching when
internal dissipation becomes excessive, protecting the
device from damage. The junction over-temperature
threshold is 140°C with 15°C of hysteresis. Once the
over-temperature or over-current fault is removed, the
AAT1157 automatically recovers.
Inductor
L=
=
⎛
VOUT
VOUT ⎞
⋅1ΔIPP ⋅ F ⎝ VIN(MAX)⎠
2.5V
⎛ 2.5V ⎞
⋅ 10.33A ⋅ 1MHz ⎝ 4.2V ⎠
= 3.07μH
The output inductor should limit the ripple current to
330mA at the maximum input voltage. This matches the
inductor current downslope with the fixed internal slope
compensation. For a 2.5V output and the ripple set to a
maximum input voltage of 4.2V, the inductance value
required to limit the ripple current to 330mA is 3.0μH.
From this calculated value, a standard value can be
selected.
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
8
appreciable saturation under normal load conditions.
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.
For a maximum ripple current of 330mA, the peak switch
and inductor current at 1.2A is 1.365A. A standard value
of 3.0μH can be used in this example. The 3.0μH Sumida
series CDRH5D28 inductor has a 24m maximum DCR
and a 2.4A DC current rating.
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 AAT1157. A low ESR/ESL ceramic capacitor
is ideal for this function. To minimize stray inductance,
the capacitor should be placed as closely as possible to
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DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
the IC. This keeps the high frequency content of the
input current localized, minimizing radiated and conducted EMI while facilitating optimum performance of
the AAT1157. 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. Values range from 1μF to
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:
VO ⎛
VO ⎞
⋅ 1VIN ⎝
VIN ⎠
IRMS = IO ⋅
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. The proper placement of
the input capacitor can be seen in the evaluation board
layout (C1 in Figure 2).
For an X7R or X5R ceramic capacitor, the ESR is very low
and the 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
The suggested PCB layout for the AAT1157 is shown in
Figures 2 and 3. The following guidelines should be used
to help insure a proper layout.
1.
2.
3.
Output Capacitor
Since there are no external compensation components,
the output capacitor has a strong effect on loop stability.
Larger output capacitance reduces the crossover frequency while increasing the phase margin. For the 2.5V
1.2A design using the 3.0μH inductor, a 40μF capacitor
provides a stable output. Table 1 provides a list of suggested output capacitor values for various output voltages. In addition to assisting in stability, the output
capacitor limits the output ripple and provides holdup
during large load transitions. The output capacitor RMS
ripple current is given by:
IRMS =
1
2⋅
3
⋅
VOUT ⋅ (VIN - VOUT)
L ⋅ F ⋅ VIN
4.
5.
6.
The input capacitor (C1) should connect as closely as
possible to VP (Pins 10, 11, and 12) and PGND (Pins
1, 2, and 3).
C3-C4 and L1 should be connected as closely as possible. The connection from L1 to the LX node should
be as short as possible.
The trace connecting the FB pin to resistors R3 and
R4 should be as short as possible by placing R3 and
R4 immediately next to the AAT1157. The sense
trace connection R3 to the output voltage should be
separate from any power trace and connect as closely as possible to the load point. Sensing along a highcurrent load trace will degrade DC load regulation.
The resistance of the trace from the load return to
the PGND (Pins 1, 2, and 3) and SGND (Pin 5) 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. SGND (Pin 5) can also be used to remotely
sense the output ground at the point of load to
improve regulation.
A low pass filter (R1 and C2) provides a cleaner bias
source for the AAT1157 active circuitry. C2 should be
placed as closely as possible to SGND (Pin 5) and VCC
(Pin 9).
For good heat transfer, four 15 mil vias spaced on a
26 mil grid connect the QFN central paddle to the bottom side ground plane, as shown in Figures 2 and 3.
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9
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Figure 2: AAT1157 Evaluation Board Top Side.
Figure 3: AAT1157 Evaluation Board Bottom Side.
Thermal Calculations
Adjustable Output
There are three types of losses associated with the
AAT1157: MOSFET switching losses, conduction losses,
and quiescent current losses. The conduction losses are
due to the RDSON characteristics of the internal P- and
N-channel MOSFET power devices. At full load, assuming
continuous conduction mode (CCM), a simplified form of
the total losses is given by:
Resistors R3 and R4, as shown in Figure 1, force the
output to regulate higher than the 0.6V reference voltage level. The optimum value for R4 is 59k. Values
higher than this can cause stability problems, while
lower values can degrade light load efficiency. For a 2.5V
output with R4 set to 59k, R3 is 187k.
P=
2
O
I
⋅ (RDSON(HS) ⋅ VO + RDSON(LS) ⋅ (VIN - VO))
VIN
+ (tsw ⋅ F ⋅ IO ⋅ VIN + IQ) ⋅ VIN
Where IQ is the AAT1157 quiescent current.
Once the total losses have been determined, the junction
temperature can be derived from the JA for the QFN
package. Close attention should be paid to the proper
layout for the QFN package. Proper size and placement
of thermal routing vias below the central paddle is necessary for good heat transfer to other PCB layers and
their ground planes. The JA for the QFN package with no
connection to the central paddle is 50°C/W. The actual
JA will vary with the number and type of vias. The PCB
board size, number of board layers, and ground plane
characteristics also influence the JA. A good thermal
connection from the paddle to the PCB ground plane layers can significantly reduce JA.
TJ = P • ΘJA + TAMB
10
⎛ VO ⎞
⎛ 2.5V ⎞
R3 = V -1 · R4 = 0.6V - 1 · 59kΩ = 187kΩ
⎝ REF ⎠
⎝
⎠
Output
Voltage
(V)
0.8
1.0
1.2
1.5
1.8
2.5
3.3
L1 (μH)
1.5
1.5
2.2
2.2
3.0
3.0
2.2
-
Output
Capacitor
(C3-C4) (μF)
R3 for
R4 = 59kΩ
(kΩ)
3x 22
2x 22
2x 22
2x 22
2x 22
2x 22
22
19.6
39.2
59
88.7
118
187
267
2.6
3.3
3.3
4.7
4.7
4.7
4.7
Table 1: Suggested Component Values.
Buck-Boost Output
Figure 4 shows how to configure the AAT1157 in a buck
boost configuration with an external MOSFET and
Schottky diode. The converter has a 3.3V 600mA output
with an input voltage ranging from 2.7V to 5.5V.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201995A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 29, 2012
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
VIN 2.7V to 5.5V
U1
AAT1157
R1
100
C1
22μF
C2
0.1μF
R2
267k
12
VP
OUT
11
VP
LX
15
10
VP
LX
14
7
EN
LX
13
9
VCC
N/C
16
6
N/C
PGND
8
N/C
PGND
5
SGND
PGND
VO 3.3V/600mA
4
3
L1
3.0μH
D1
MBRM120L
Q1
Si2302ADS
R3
59.0k
C3,C4
2x 22μF
2
1
L1 Sumida CDRH5D28-3R0
C1 Murata 22μF 10V X7R 1210 GRM32ER71A226KE20L
C3,C4 MuRata 22μF 6.3V X5R 0805 GRM21BR60J226ME39L
Figure 4: AAT1157 Buck Boost Converter.
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DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Design Example
Specifications
IOUT = 1.2A
IRIPPLE = 330mA
VOUT = 2.5V
VIN = 3.0V to 4.2V
FS = 1MHz
TAMB = 85°C
Maximum Input Capacitor Ripple
IRMS = I O ·
VO ⎛
V ⎞
· 1 - O = 0.59Arms
VIN ⎝ VIN ⎠
P = esr · IRMS2 = 5mΩ · 0.592 A = 1.7mW
Inductor Selection
L=
⎛ V ⎞
VOUT
2.5V
2.5V⎞
⎛
⋅ 1 - OUT =
⋅ 1= 3.07μH
ΔIPP ⋅ F ⎝
VIN ⎠
0.33A ⋅ 1MHz ⎝
4.2V⎠
Select Sumida inductor CDRH5D28 3.0μH.
ΔI =
⎛ 2.5V⎞
VO ⎛
V ⎞
2.5V
⋅ 1- O =
⋅ 1= 340mA
L ⋅ F ⎝ VIN ⎠ 3.0μH ⋅ 1MHz ⎝ 4.2V⎠
IPK = IOUT +
ΔI
= 1.2A + 0.17A = 1.37A
2
P = IO2 ⋅ DCR = (1.2A)2 ⋅ 31mΩ = 45mW
Output Capacitor Ripple Current
IRMS =
1
2· 3
·
(VOUT) · (VIN - VOUT)
1
2.5V · (4.2V - 2.5V)
·
= 97.4mArms
=
L · F · VIN
2 · 3 3.0μH · 1MHz · 4.2V
Pesr = esr · IRMS2 = 5mΩ · (97.4mA)2 = 47.4μW
12
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201995A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 29, 2012
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
AAT1157 Dissipation and Junction Temperature Estimate
PTOTAL =
=
IO2 • (RDSON(HS) • VO + RDSON(LS) • (VIN -VO))
VIN
+ (tsw • F • IO + IQ) • VIN
1.2A2 • (0.17Ω • 2.5V + 0.16Ω • (4.2V - 2.5V))
4.2V
+ (20nsec • 1MHz • 1.2A + 275μA) • 4.2V
= 341mW
TJ(MAX) = TAMB + ΘJA • PTOTAL = 85°C + 50°C/W • 0.341W = 102°C
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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13
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Manufacturer
Part Number
Value
(μH)
Max DC
Current (A)
DCR
(mΩ)
Size (mm)
LxWxH
Type
Sumida
Sumida
Sumida
Taiyo Yuden
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Murata
Murata
CDRH5D28-2R6
CDRH5D28-3R0
CDRH5D28-4R2
NPO5DB4R7M
CDRH4D28-2R2
CDRH4D28-2R7
CDRH4D28-3R3
CDRH5D18-4R1
CDRH3D16/HP-2R2
CDRH3D16/HP-3R3
LQH55DN4R7M03
LQH66SN4R7M03
2.6
3.0
4.2
4.7
2.2
2.7
3.3
4.1
2.2
3.3
4.7
4.7
2.6
2.4
2.2
1.4
2.04
1.6
1.57
1.95
2.3
1.8
2.7
2.2
18
24
31
38
31
43
49
57
59
85
41
25
5.7x5.7x3.0
5.7x5.7x3.0
5.7x5.7x3.0
5.9x6.1x2.8
5.0x5.0x3.0
5.0x5.0x3.0
5.0x5.0x3.0
5.7x5.7x2.0
4.0x4.0x1.8
4.0x4.0x1.8
5.0x5.0x4.7
6.3x6.3x4.7
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Non-Shielded
Shielded
Table 2: Surface Mount Inductors.
Manufacturer
Part Number
Value (μF)
Voltage (V)
Temp. Co.
Case
Murata
Murata
Murata
GRM21BR60J106ME01L
GRM21BR60J226ME01L
GRM31CR60J106KA01L
10
22
10
6.3
6.3
6.3
X5R
X5R
X5R
0805
0805
1206
Table 3: Surface Mount Capacitors.
14
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201995A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 29, 2012
DATA SHEET
AAT1157
1MHz 1.2A Buck DC/DC Converter
Ordering Information
Output Voltage
Package
Marking1
Part Number (Tape and Reel)2
FB = 0.6V, Adjustable ≥ 0.8V
3.3V
QFN33-16
QFN33-16
OEXYY
OZXYY
AAT1157IVN-T1
AAT1157IVN-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 Information3
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.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. 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.
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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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
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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
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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15