SD3118-2R2 [SKYWORKS]

600mA Voltage-Scaling Step-Down Converter for RF Power Amplifiers with Bypass Switch;
SD3118-2R2
型号: SD3118-2R2
厂家: SKYWORKS SOLUTIONS INC.    SKYWORKS SOLUTIONS INC.
描述:

600mA Voltage-Scaling Step-Down Converter for RF Power Amplifiers with Bypass Switch

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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
General Description  
Features  
The AAT1171 SwitchReg™ dynamically controls the oper-  
ating voltage of a WCDMA or CDMA power amplifier  
inside single-cell, lithium-ion battery-powered systems.  
The AAT1171 outputs a voltage between 0.6V and 3.6V,  
thereby optimizing the amplifier efficiency at both low  
and high transmit levels.  
• VIN Range: 2.7V to 5.5V  
• Variable Output Voltage: 0.6V to 3.6V  
• 600mA Output Current  
• DAC Input: 0.2V to 1.2V  
• High Output Accuracy: ±3%  
• 45μA No Load Quiescent Current  
• Internal Soft Start Limits Startup Current and Output  
Voltage Overshoot  
• Synchronizable to External 19.8MHz System Clock  
• Over-Temperature and Current Limit Protection  
• Integrated 85mΩ Bypass MOSFET  
• 2MHz Operation  
The AAT1171 output voltage is controlled via an analog  
signal from the baseband processor. It can deliver  
600mA of continuous load current while maintaining a  
low 45μA of no load quiescent current. The 2MHz switch-  
ing frequency minimizes the size of external components  
while keeping switching losses low. To further improve  
system efficiency, an 85mΩ bypass MOSFET transistor is  
also included to allow the PA to be powered directly from  
the battery.  
• PWM/LL Control with Override  
• Fast Start-Up:  
50μs (AAT1171-4, AAT1171-5)  
150μs (AAT1171-1)  
• 100% Duty Cycle Operation  
The AAT1171 maintains high efficiency thoughout the  
entire load range in Light Load (LL) mode, and can be  
forced into Pulse Wide Modulation (PWM) mode for low  
noise operation or can be synchronized to an external  
clock.  
• <30μs Output Voltage Response Time  
• 3x3mm 12-Pin TDFN or 1.535x2.235mm 12-Pin  
WLCSP Package  
Temperature Range: -40°C to +85°C  
The AAT1171 is available in a Pb-free, space-saving  
TDFN33-12 or 12-pin wafer-level chip scale package  
(WLCSP) and is rated over the -40°C to +85°C tempera-  
ture range.  
Applications  
• WCDMA or CDMA PA in Cellular Phones, Smartphones,  
Feature Phones, etc.  
• Express Card  
• PCMCIA Data Cards  
Typical Application  
L1  
L1  
4.7μH  
2.2μH  
VIN  
0.6V - 3.6V  
VIN  
0.6V - 3.6V  
LX  
LX  
VCC  
VCC  
AAT1171-1/  
AAT1171-4  
AAT1171-5  
CIN  
4.7μF  
CIN  
4.7μF  
COUT  
10μF  
COUT  
4.7μF  
VOUT  
BYPASS  
MODE/SYNC  
EN  
VOUT  
BYPASS  
MODE/SYNC  
EN  
VCC2  
GNDx2  
DAC  
VCONT  
PA  
VCC2  
GNDx2  
DAC  
VCONT  
PA  
VCC2  
VCC2  
VREF  
VREF  
DAC  
Baseband  
Processor  
DAC  
Baseband  
Processor  
TX  
RX  
TX  
RX  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Pin Descriptions  
Pin #  
TDFN33-12  
WLCSP-12  
Symbol  
Function  
1
N/A  
N/C  
Not connected.  
Feedback input pin. This pin is connected to the converter output. It is used to  
complete the control loop, regulating the output voltage to the desired value.  
When in bypass mode, a low resistance MOSFET is connected between this pin  
and VIN.  
2, 3  
5, 9  
VOUT  
Bias supply. Supply power for the internal circuitry. Connect to input power via  
low pass lter with decoupling to AGND.  
Analog ground. Connect the return of all small signal components to this pin.  
Control voltage input from a DAC. Input voltage between 0.2V and 1.2V to con-  
trol output voltage of the converter. Force pin to 1.3V for bypass switch enable.  
Enable DC/DC converter, active high.  
Enable control to bypass the DC/DC converter when PA transmitting at full  
power from low battery voltage. Active high.  
4
5
6
7
8
7
6
1
2
3
VCC  
AGND  
DAC  
EN  
BYPASS  
This pin is used to program the device between PWM and LL mode:  
HIGH - PWM Mode Only  
LOW - LL Mode: PWM operation for loads above 100mA and variable switching  
frequency for loads below 100mA. Connecting the SYNC pin to the system clock  
(19.8MHz) will override the internal clock and force the switching frequency to  
the external clock frequency divided by 10.  
9
4
MODE/SYNC  
10  
11  
12  
8, 11  
VIN  
PGND  
Input supply voltage for the converter. Must be closely decoupled.  
Main power ground. Connect to the output and input capacitor return.  
Switching node. Connect the inductor to this pin. It is connected internally to  
the drain of both low- and high-side MOSFETs.  
Exposed paddle (bottom). Connect to ground directly beneath the package.  
12  
EP  
10  
LX  
N/A  
Pin Configuration  
TDFN33-12  
(Top View)  
WLCSP-5  
(Top View)  
11: PGND  
8: PGND  
1
2
3
4
5
6
12  
N/C  
VOUT  
VOUT  
VCC  
LX  
10  
9
11  
8
12  
7
LX  
VOUT  
VIN  
11  
10  
9
PGND  
VIN  
VCC  
AGND  
DAC  
MODE/SYNC  
BYPASS  
EN  
4
5
6
MODE/SYNC  
BYPASS  
8
AGND  
DAC  
3
2
1
7
5: VOUT  
2: EN  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Absolute Maximum Ratings1  
Symbol  
Description  
Value  
Units  
VCC, VIN  
VLX  
VOUT  
VN  
TJ  
TLEAD  
Input Voltage and Bias Power to GND  
LX to GND  
VOUT to GND  
EN, DAC, BYPASS, MODE/SYNC to GND  
Operating Junction Temperature Range  
Maximum Soldering Temperature (at leads, 10 sec)  
6.0  
V
V
V
V
°C  
°C  
-0.3 to VIN + 0.3  
-0.3 to VIN + 0.3  
-0.3 to 6.0  
-40 to 150  
300  
Thermal Information2  
Symbol  
Description  
Value  
Units  
TDFN33-122, 3  
WLCSP-122, 4  
TDFN33-12  
WLCSP-12  
2.0  
0.88  
50  
PD  
Maximum Power Dissipation, TA = 25°C  
W
θJA  
Thermal Resistance, TA = 25°C  
°C/W  
114  
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. Mounted on FR4 board; for the WLCSP package, use the NSMD (none-solder mask defined) pad style for tighter control on the copper etch process.  
3. Derate 20mW/°C above 25°C ambient.  
4. Derate 8.8mW/°C above 25°C ambient.  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Electrical Characteristics1  
TA = -40°C to +85°C, unless otherwise noted. VIN = VCC = 3.6V; typical values are TA = 25°C.  
Symbol Description  
Conditions  
Min Typ Max Units  
VIN  
Input Voltage  
UVLO Threshold  
UVLO Hysteresis  
VOUT Programmable Range  
Input Voltage Range from DAC  
2.7  
5.5  
V
V
mV  
V
VIN Rising  
2.6  
200  
VUVLO  
VOUT  
VDACIN  
0.6  
0.2  
3.6  
1.2  
70  
V
No Load, Light Load  
No Load, PWM, VCC Bias Current  
EN = AGND = PGND, MODE/SYNC = VIN or  
GND  
45  
420  
IQ  
Quiescent Current  
Shutdown Current  
μA  
μA  
ISHDN  
1.0  
ILIM  
P-Channel Current Limit  
High Side Switch On Resistance  
Low Side Switch On Resistance  
Bypass Switch Resistance  
LX Leakage Current  
TA = 25°C  
1.2  
1.6  
230  
230  
85  
A
RDS(ON)H  
RDS(ON)L  
RDS(ON)BP  
ILXLEAK  
mΩ  
mΩ  
mΩ  
μA  
VDAC = 1.3V or BYPASS = VIN  
VCC = 5.5V, VLX = 0 to VCC, EN = 0V  
1
VOUT  
VOUT  
VOUT  
VOUT/VIN  
ROUT  
VOUT  
FOSC  
TSD  
THYS  
ILL  
tVOUTS  
/
Load Regulation  
Line Regulation  
ILOAD = 0 to 500mA  
0.5  
%
/
0.2  
%/V  
Feedback Impedance  
Output Voltage Accuracy  
Oscillator Frequency  
Over-Temperature Shutdown Threshold  
Over-Temperature Shutdown Hysteresis  
Light Load Load Current Threshold  
Output Voltage Settling Time  
170  
1.8  
2.0  
140  
15  
kΩ  
V
MHz  
°C  
°C  
mA  
μs  
VDAC = 0.6V, ILOAD = 0  
1.746  
1.854  
100  
VOUT = 0.6V to VOUT(MAX), MODE/SYNC = VIN  
30  
0.6  
1.0  
PWM/Light Load/EN  
VEN(L)  
VEN(H)  
IEN  
Enable Threshold Low  
Enable Threshold High  
Input Low Current  
V
V
μA  
1.4  
-1.0  
VCC = 5.5V  
AAT1171-1: EN = Low to High, MODE/SYNC  
= High, VDAC = 1.2V  
AAT1171-4/AAT1171-5: EN = Low to High,  
MODE/SYNC = High, VDAC = 1.2V  
150  
50  
tEN  
Turn-On Enable Response Time  
μs  
MODE/SYNC  
FMODE/SYNC Synchronization Frequency  
Sync to 19.8MHz2  
19.8  
MHz  
V
VMODE/  
SYNC(H)  
VIN-  
0.4  
MODE/SYNC High Level Threshold  
VMODE/  
SYNC(L)  
MODE/SYNC Low Level Threshold  
0.4  
1.0  
V
IMODE/SYNC MODE/SYNC Low Current  
VSYNC = GND or VCC  
-1.0  
μA  
DAC Input  
Gain  
Output Voltage/DAC Voltage3  
3
V/V  
1. The AAT1171 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-  
tion with statistical process controls.  
2. Please contact Sales for other synchronization frequencies.  
3. Please contact Sales for other output voltage/DAC voltage gains.  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
Efficiency vs. Output Current  
(LL Mode; VOUT = 3.3V)  
Load Regulation  
(LL Mode; VOUT = 3.3V)  
100  
1.0  
VIN = 3.9V  
90  
0.5  
VIN = 5.0V  
80  
VIN = 4.2V  
70  
0.0  
VIN = 3.6V  
VIN = 5.0V  
60  
VIN = 4.2V  
-0.5  
-1.0  
50  
40  
0.1  
1
10  
100  
1000  
0.1  
1
10  
100  
1000  
Output Current (mA)  
Output Current (mA)  
Efficiency vs. Output Current  
(PWM Mode; VOUT = 3.3V)  
Load Regulation  
(PWM Mode; VOUT = 3.3V)  
1.0  
0.5  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
VIN = 5.0V  
VIN = 4.2V  
VIN = 3.6V  
0.0  
VIN = 3.6V  
VIN = 4.2V  
VIN = 5.0V  
-0.5  
-1.0  
0.1  
1
10  
100  
1000  
0.1  
1
10  
100  
1000  
Output Current (mA)  
Output Current (mA)  
Efficiency vs. Output Current  
(LL Mode; VOUT = 2.5V)  
Load Regulation  
(LL Mode; VOUT = 2.5V)  
1.0  
0.5  
100  
VIN = 3.0V  
90  
80  
70  
60  
50  
40  
VIN = 5.0V  
VIN = 4.2V  
VIN = 4.2V  
0.0  
VIN = 5.0V  
VIN = 3.0V  
-0.5  
-1.0  
0.1  
1
10  
100  
1000  
0.1  
1
10  
100  
1000  
Output Current (mA)  
Output Current (mA)  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
Efficiency vs. Output Current  
(PWM Mode; VOUT = 2.5V)  
Load Regulation  
(PWM Mode; VOUT = 2.5V)  
1.0  
100  
90  
80  
VIN = 5.0V  
VIN = 3.0V  
0.5  
70  
VIN = 3.0V  
60  
VIN = 4.2V  
50  
40  
0.0  
VIN = 4.2V  
30  
VIN = 5.0V  
-0.5  
20  
10  
0
-1.0  
0.1  
1
10  
100  
1000  
1000  
1000  
0.1  
1
10  
100  
1000  
Output Current (mA)  
Output Current (mA)  
Efficiency vs. Output Current  
(LL Mode; VOUT = 1.8V)  
Load Regulation  
(LL Mode; VOUT = 1.8V)  
100  
1.0  
0.5  
0.0  
VIN = 2.7V  
90  
80  
70  
60  
50  
40  
30  
VIN = 3.6V  
VIN = 4.2V  
VIN = 4.2V  
VIN = 3.6V  
VIN = 2.7V  
-0.5  
-1.0  
0.1  
1
10  
100  
1000  
0
1
10  
100  
Output Current (mA)  
Output Current (mA)  
Efficiency vs. Output Current  
(PWM Mode; VOUT = 1.8V)  
Load Regulation  
(PWM Mode; VOUT = 1.8V)  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
1.0  
0.5  
VIN = 2.7V  
VIN = 3.6V  
VIN = 4.2V  
VIN = 3.6V  
0.0  
VIN = 2.7V  
VIN = 4.2V  
-0.5  
-1.0  
0.1  
1
10  
100  
1000.  
0.1  
1
10  
100  
Output Current (mA)  
Output Current (mA)  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
Output Voltage vs. Supply Voltage  
(LL Mode; VOUT = 1.5V)  
Output Voltage vs. Supply Voltage  
(PWM Mode; VOUT = 1.5V)  
1.514  
1.514  
1.510  
1.510  
IOUT = 50mA  
IOUT = 50mA  
1.506  
1.506  
IOUT = 300mA  
IOUT = 300mA  
1.502  
1.502  
IOUT = 600mA  
1.498  
1.498  
IOUT = 600mA  
1.494  
1.494  
2.7 2.9 3.1 3.3 3..5 3.7 3..9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5  
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5  
Supply Voltage (V)  
Supply Voltage (V)  
Output Voltage vs. Temperature  
(VIN = 3.6V; VOUT = 1.8V; VDAC = 0.6V; RL = 10)  
Bypass Mode Dropout Voltage  
vs. Load Current  
0.05  
1.0  
0.5  
0.00  
-0.05  
-0.10  
-0.15  
-0.20  
-0.25  
-0.30  
0.0  
-0.5  
-1.0  
-1.5  
-40  
-15  
10  
35  
60  
85  
0.1  
1
10  
100  
1000  
Temperature (°°C)  
Load Current (mA)  
Supply Current vs. Supply Voltage  
(No Load; LL Mode)  
Supply Current vs. Supply Voltage  
(No Load; PWM Mode)  
7.0  
6.5  
6.0  
5.5  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
70  
65  
60  
55  
50  
45  
40  
35  
30  
VOUT = 1.8V  
VOUT = 1.8V  
VOUT = 0.6V  
VOUT = 0.6V  
2.7  
3.1  
3.5  
3.9  
4.3  
4.7  
5.1  
5.5  
2.7  
3.1  
3.5  
3.9  
4.3  
4.7  
5.1  
5.5  
Supply Voltage (V)  
Supply Voltage (V)  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
P-Channel RDS(ON) vs. Input Voltage  
400  
Bypass RDS(ON) vs. Input Voltage  
140  
TJ = 120°C  
TJ = 85°C  
TJ = 120°C  
350  
120  
100  
80  
60  
40  
20  
0
TJ = 85°C  
300  
250  
TJ = 25°C  
200  
150  
100  
50  
TJ = 25°C  
0
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5  
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5  
Input Voltage (V)  
Input Voltage (V)  
Switching Frequency vs. Temperature  
(VIN = 3.6V; VOUT = 1.8V; RL = 10)  
Output Voltage vs. DAC Voltage  
(VIN = 4.2V; LL Mode)  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0.0  
2.06  
2.04  
2.02  
2.00  
1.98  
1.96  
1.94  
1.92  
1.90  
25°C  
85°C  
PWM  
LL  
-40°C  
-40.0  
-20.0  
0.0  
20.0  
40.0  
60.0  
80.0  
0.2  
0.4  
0.6  
0.8  
1.0  
1.2  
1.4  
Temperature (°C)  
DAC Voltage (V)  
Heavy Load Switching Waveform  
(VIN = 3.6V; VOUT = 1.8V; RL = 3Ω; COUT = 4.7µF; L = 2.2µH)  
VOUT  
(AC coupled)  
20mV/div  
IL  
200mA/div  
0
VLX  
2V/div  
0
Time (200ns/div)  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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201999B  
• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
Light Load Switching Waveform  
(PWM Mode; VIN = 4.2V; VOUT = 0.6V; RL = 10Ω;  
COUT = 4.7µF; L = 2.2µH)  
Light Load Switching Waveform  
(LL Mode; VIN = 4.2V; VOUT = 0.6V; RL = 10Ω;  
COUT = 4.7µF; L = 2.2µH)  
VOUT  
(AC coupled)  
20mV/div  
VOUT  
(AC coupled)  
20mV/div  
IL  
100mA/div  
IL  
200mA/div  
0
0
VLX  
2V/div  
VLX  
2V/div  
0
0
Time (200ns/div)  
Time (1µs/div)  
DAC Transient Response in PWM Mode  
(VIN = 3.6V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
DAC Transient Response in LL Mode  
(VIN = 3.6V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
VOUT  
1V/div  
VOUT  
1V/div  
3.3V  
3.3V  
0.6V  
0.6V  
0
0
1.2V  
1.2V  
VDAC  
0.5V/div  
0
VDAC  
0.5V/div  
0.2V  
0.2V  
0
Time (25µs/div)  
Time (25µs/div)  
Bypass Transient Response  
(PWM Mode; VIN = 3.6V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
Bypass Transient Response  
(LL Mode; VIN = 3.6V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
3.5V  
3.5V  
VOUT  
1V/div  
VOUT  
1V/div  
0.6V  
0.6V  
0
0
VBYP  
1V/div  
0
VBYP  
1V/div  
0
Time (25µs/div)  
Time (25µs/div)  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Typical Characteristics  
Enable Soft Start  
(VIN = 3.6V; VOUT = 1.8V; RL = 3.9Ω;  
COUT = 4.7µF; L = 2.2µH)  
DAC to Bypass Transient Response  
(LL Mode; VIN = 4.2V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
4.2V  
VOUT  
1.8V  
1V/div  
0V  
VOUT  
1V/div  
Enable  
2V/div  
0V  
0.6V  
0
1.3V  
IIN  
VDAC  
0.5V/div  
200mA/div  
0.2V  
0
0A  
Time (20µs/div)  
Time (25µs/div)  
Load Transient Response  
(VIN = 4.2V; VOUT = 3.3V; COUT = 4.7µF; L = 2.2µH)  
Load Transient Response  
(VIN = 3.6V; VOUT = 1.8V; COUT = 4.7µF; L = 2.2µH)  
VOUT  
(AC coupled)  
20mV/div  
VOUT  
(AC coupled)  
20mV/div  
3.51V  
1.914V  
3.26V  
1.798V  
500mA  
525mA  
IOUT  
200mA/div  
IOUT  
100mA/div  
250mA  
200mA  
Time (20µs/div)  
Time (20µs/div)  
Line Transient Response  
(VOUT = 1.5V; RL = 10Ω; COUT = 4.7µF; L = 2.2µH)  
VIN  
0.5V/div  
3.6V  
3.0V  
1.56V  
VOUT  
(AC coupled)  
50mV/div  
1.44V  
Time (50µs/div)  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Functional Block Diagram  
VOUT  
VCC  
VIN  
DH  
Comp  
Error  
Amp  
DAC  
EN  
Logic  
LX  
DL  
BYPASS  
MODE/SYNC  
Interface  
MODE/SYNC  
AGND PGND  
In addition to the converter output, an additional low  
resistance bypass MOSFET (85mΩ) can be connected  
between the battery input and the converter output (VIN  
to VOUT), bypassing the converter and output inductor to  
improve headroom and extend the WCDMA PA full power  
range. This reduces the battery voltage necessary for a  
WCDMA RF power amplifier to meet linearity require-  
ments, thus extending operating time. In dual mode  
systems, the bypass mode may also be used when the  
WCDMA RF power amplifier is in GSM mode. Bypass  
mode is activated by setting the bypass input high or by  
forcing the baseband DAC output voltage to 1.3V.  
Functional Description  
The AAT1171 is a 600mA 2MHz peak current mode syn-  
chronous step-down (buck) converter designed to oper-  
ate from a single-cell lithium-ion battery with a 2.7V to  
4.2V input range. The output voltage is dynamically  
programmed by the DAC input voltage.  
To maximize converter efficiency over all load conditions,  
the converter automatically transitions to a variable fre-  
quency light load (LL) mode when the load is less than  
100mA. When combined with the very low quiescent  
current, the LL mode maintains a high efficiency over the  
complete load range. For noise sensitive applications,  
the converter can be forced into a fixed frequency PWM  
mode. Provisions are also made for synchronization of  
the converter to an external system clock.  
The AAT1171 requires only three external components  
for operation (CIN, COUT, LX). The high 2MHz switching  
frequency reduces the inductor size required to 2.2μH  
for the AAT1171-1/AAT1171-4 and 4.7μH for the  
AAT1171-5. This reduces the DC resistance and improves  
the converter efficiency while minimizing the inductor  
The synchronous buck converter power output devices  
are sized at 230mΩ for a 600mA full load output current.  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
footprint and height. The output voltage of the converter  
is regulated to within 0.5% and will settle in less than  
30μs (according to WCDMA specifications) in response to  
any step change in the DAC input.  
LL/PWM Control  
Two control modes are available with the AAT1171: LL  
mode and PWM mode. PWM mode maintains a fixed  
switching frequency regardless of load. The fixed switch-  
ing frequency gives the advantage of lower output ripple  
and simplified output and input noise filtering. PWM  
mode also provides a faster output voltage response to  
changes in the DAC voltage.  
Under-voltage lockout, internal compensation, soft-start,  
over-current, and over-temperature protection are also  
included.  
DAC Output Voltage Control  
In LL mode, the converter transitions to a variable  
switching frequency as the load decreases below 100mA.  
Above 100mA, where switching losses no longer domi-  
nate, the switching frequency is fixed. The LL mode’s  
effect on the DAC to output voltage response time is  
most notable when transitioning from a high output volt-  
age to a low voltage. When the converter is in PWM  
mode, the inductor current can be reversed and the out-  
put voltage actively discharged by the synchronous  
MOSFET. While in LL mode, the output voltage is dis-  
charged by the load only, resulting in a slower response  
to a DAC transition from a high to a low voltage.  
The output voltage is programmed by way of the DAC  
input voltage. The DAC to output gain for the AAT1171  
is 3.  
VOUT = 3 · VDAC  
The DAC input voltage range is 0.2V to 1.2V, which cor-  
responds to an output voltage range of 0.6V to 3.6V (see  
Figure 1). For a 1.3V DAC level, the bypass switch is  
activated and the output voltage level is equivalent to  
the input voltage minus the bypass MOSFET (RDS(ON)(bp)  
drop.  
)
For PWM mode, apply a logic level high to the MODE/  
SYNC pin; for LL mode, apply a logic level low to the  
MODE/SYNC pin.  
Bypass Mode  
In bypass mode, the AAT1171 bypasses the output  
inductor, connecting the input directly to the output  
through a low RDS(ON) 85mΩ MOSFET. Bypass mode is  
initiated by applying 1.3V to the DAC input or by apply-  
ing a logic high to the bypass input. When not activated,  
a logic level low must be applied to the bypass input pin.  
The bypass MOSFET current is limited to 600mA.  
Soft Start/Enable  
The AAT1171 soft-start control prevents output voltage  
overshoot and limits inrush current when either the input  
power or the enable input is applied. When pulled low,  
the enable input forces the converter into a low-power,  
non-switching state with less than 1μA bias current.  
VIN  
4V  
3.6V  
3V  
2V  
1V  
0.6V  
0.2V  
1V 1.2V1.3V  
DAC Output  
Figure 1: VOUT vs. VDAC  
.
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Low Dropout Operation  
Applications Information  
For conditions where the input voltage drops to the out-  
put voltage level, the converter duty cycle increases to  
100%. As 100% duty cycle is approached, the minimum  
off-time initially forces the high-side on-time to exceed  
the 2MHz clock period, reducing the converter switching  
frequency. Once the input drops to the level where the  
output can no longer be regulated, the high-side P-channel  
MOSFET is enabled continuously for 100% duty cycle. The  
output voltage then tracks the input voltage minus the IR  
Inductor Selection  
The step-down converter uses peak current mode con-  
trol with slope compensation to maintain stability for  
duty cycles greater than 50%. Because the required  
slope compensation varies with output voltage, the  
AAT1171 varies the slope compensation to match the  
output voltage. This allows the use of a single inductor  
value for all output voltage levels. The inductor value is  
2.2μH for the AAT1171-1/AAT1171-4 and 4.7μH for the  
AAT1171-5.  
drop of the high side P-channel MOSFET RDS(ON)  
.
UVLO Shutdown  
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 satura-  
tion characteristics.  
Under-voltage lockout (UVLO) circuitry monitors the input  
voltage and disables the converter when the input voltage  
drops to 2.4V, guaranteeing sufficient operating input  
voltage to maintain output voltage regulation and control.  
For a rising input voltage, the UVLO circuitry enables the  
converter 200mV above the shutdown level at 2.6V.  
The inductor should not show any appreciable saturation  
under normal load conditions. The inductor ripple cur-  
rent varies with both the input voltage and the output  
voltage and peaks at the maximum input voltage with  
the output at one half of the input voltage. For the typi-  
cal AAT1171, this corresponds to a 4.2V input voltage  
and a 2.1V output voltage. With the suggested 2.2μH  
inductor, this corresponds to 239mA peak-to-peak ripple  
current. For a 600mA DC load current, the peak inductor  
current would be 718mA. In order to prevent saturation  
under normal load conditions, the peak inductor current  
should be less than the inductor saturation current.  
Current Limit and  
Short-Circuit Protection  
The high-side P-channel MOSFET current limit compara-  
tor limits the peak inductor current to 1.6A. In PWM  
mode, the synchronous MOSFET current limit compara-  
tor limits the peak negative inductor current, and output  
capacitor discharge current is limited to 1A. In bypass  
mode, the bypass MOSFET current is limited to 600mA.  
In the event of an overload or short-circuit condition, the  
current limit protects the load and the AAT1171 power  
devices. Upon removal of the short-circuit or fault condi-  
tion, the AAT1171 output automatically recovers to the  
regulated level.  
VIN(MAX)  
IPK(MAX) = IO +  
8 ∙ L ∙ FS  
4.2V  
8 ∙ 2.2μH ∙ 2MHz  
= 0.6A +  
= 0.6A + 0.12A  
= 0.72A  
Thermal Overload Protection  
The maximum junction temperature is limited by the  
AAT1171 over-temperature shutdown protection circuit-  
ry. Both the step-down converter and the bypass  
MOSFET are disabled when the junction temperature  
reaches 140°C. Normal operation resumes once the  
junction temperature drops to 125°C.  
Some inductors may meet peak and average current  
requirements 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. The inductor losses can be esti-  
mated by using the full load output current. The output  
inductor losses can then be calculated to estimate their  
effect on overall device efficiency.  
External Synchronization  
The AAT1171 switching frequency can be synchronized to  
an external square wave clock via the MODE/SYNC input.  
The external clock frequency range and logic levels for  
which the AAT1171 will remain synchronized are listed in  
the Electrical Characteristics table of this datasheet.  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Input Capacitor Selection  
PL = IO DCR = 0.6A2 0.14Ω = 50mW  
PO  
3.4 0.6A  
= 97%  
2
A 10V X5R or X7R ceramic capacitor is suggested for the  
input capacitor with typical values ranging from 4.7μF to  
10μF. To estimate the required input capacitance size,  
determine the acceptable input ripple level (VPP) and solve  
for C, as shown below. The calculated value varies with  
input voltage and is a maximum when VIN is double the  
output voltage. Always examine the ceramic capacitor DC  
voltage coefficient characteristics when selecting the  
proper value. For example, due to the voltage coefficient  
of a 10μF 6.3V X5R ceramic capacitor, with an applied  
voltage of 5V DC the capacitance decreases to 6μF.  
η =  
=
PO + PL 3.4V 0.6A + 50mW  
The 2.2μH inductor selected for the AAT1171 evaluation  
board has a 140mΩ DCR and a 0.91A DC current rating.  
At 600mA load current, the inductor loss is 50mW which  
gives 2.4% loss in efficiency for a 600mA 3.4V output  
voltage with an inductor that measures 3.2x3.2x1.2mm.  
Output Capacitor Selection  
VO  
VO ⎞  
VIN ⎠  
The AAT1171-1/AAT1171-4 are designed for use with  
4.7μF 10V X5R ceramic output capacitors, while the  
AAT1171-5 is designed for use with 10μF 10V X5R  
ceramic output capacitors. Although a larger output  
capacitor provides improved response to large load tran-  
sients, it also limits the output voltage rise and fall time  
in response to the DAC input. For stable operation, with  
sufficient phase and gain margin, the internal voltage  
loop compensation limits the minimum output capacitor  
value to 4.7μF. Increased output capacitance will reduce  
the crossover frequency with greater phase margin.  
· 1 -  
VIN  
CIN =  
VPP  
IO  
- ESR ·FS  
VO  
VO ⎞  
VIN ⎠  
1
· 1 -  
=
VIN  
4
1
CIN(MIN)  
=
VPP  
IO  
- ESR · 4 · FS  
The output voltage droop due to load transients is dom-  
inated by the output capacitor. During a step increase in  
load current, the output capacitor supplies the load cur-  
rent while the control loop responds. Within two or three  
switching cycles, the inductor current increases to match  
the load current demand. The relationship of the output  
voltage droop during the three switching cycles to the  
output capacitance can be estimated by:  
The maximum input capacitor RMS current is:  
VO  
VO ⎞  
VIN ⎠  
IRMS = IO ·  
· 1 -  
VIN  
The input capacitor RMS ripple current varies with the  
input and output voltage and will always be less than or  
equal to half of the total DC load current.  
3 · ∆ILOAD  
COUT  
=
V
DROOP · FS  
VO  
VO ⎞  
VIN ⎠  
1
· 1 -  
=
D · (1 - D) = 0.52 =  
VIN  
2
Once the average inductor current increases to the DC  
load level, the output voltage recovers. The above equa-  
tion establishes a limit on the minimum output capacitor  
value necessary to meet a given output voltage droop  
requirement (VDROOP) for a given load transient.  
for VIN = 2 · VO  
IO  
IRMS(MAX)  
=
The maximum output capacitor RMS ripple current is:  
2
1
V
OUT · (VIN(MAX) - VOUT  
)
IRMS(MAX)  
=
·
L · FS · VIN(MAX)  
VO  
2 · 3  
VO  
·
1 -  
VIN  
VIN  
The term  
appears in both the input voltage  
Dissipation due to the RMS current in the ceramic output  
capacitor ESR is typically minimal, resulting in less than  
a few degrees rise in hot-spot temperature.  
ripple and input capacitor RMS current equations and is  
a maximum when VIN is twice Vo; therefore, the input  
voltage ripple and the input capacitor RMS current ripple  
are a maximum at 50% duty cycle.  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
The input capacitor provides a low impedance loop for  
the edges of pulsed current drawn by the AAT1171. Low  
ESR/ESL X7R and X5R ceramic capacitors are ideal for  
this function. To minimize stray inductance, the capaci-  
tor should be placed as closely as possible to the IC. This  
keeps the high frequency content of the input current  
localized, minimizing EMI and input voltage ripple.  
Thermal Calculations  
There are three types of losses associated with the  
AAT1171 step-down converter: switching losses, con-  
duction losses, and quiescent current losses. Conduction  
losses are associated with the RDS(ON) characteristics of  
the power MOSFET devices. Switching losses are domi-  
nated by the gate charge of the power MOSFET devices.  
The AAT1171 main and synchronous power MOSFETs are  
sized to have similar RDS(ON) values that track with the  
input voltage. At full load, assuming continuous conduc-  
tion mode (CCM), a simplified form of the step-down  
converter losses is given by:  
The proper placement of the input capacitor (C1) can be  
seen in the evaluation board layout in Figure 4.  
A laboratory test set-up typically consists of two long  
wires running from the bench power supply to the eval-  
uation board input voltage pins. The inductance of these  
wires, along with the low-ESR ceramic input capacitor,  
can create a high Q network that may affect converter  
performance. This problem often becomes apparent in  
the form of excessive ringing in the output voltage dur-  
ing load transients with errors in loop phase and gain  
measurements.  
PTOTAL = IO2 · RDS(ON) + (tSW · FS · IO + IQ) · VIN  
IQ is the step-down converter quiescent current. The  
term tsw is used to estimate the full load switching loss-  
es, which are dominated by the gate charge losses.  
Since the inductance of a short PCB trace feeding the  
input voltage is significantly lower than the power leads  
from the bench power supply, most applications do not  
exhibit this problem.  
For the condition where the buck converter is at 100%  
duty cycle dropout, the total device dissipation reduces  
to:  
PTOTAL = IO2 · RDS(ON) + IQ · VIN  
In applications where the input power source lead induc-  
tance cannot be reduced to a level that does not affect  
the converter performance, a high ESR tantalum or alu-  
minum electrolytic capacitor (C3 of Figure 5) should be  
placed in parallel with the low ESR, ESL bypass ceramic  
capacitor. This dampens the high Q network and stabi-  
lizes the system.  
In bypass mode, the bypass MOSFET RDS(ON)(bp) is used to  
determine the losses. The power MOSFET RDS(ON) increas-  
es with decreasing input voltage and the associated  
losses are a maximum at the minimum input voltage  
(2.7V).  
PTOTAL = IO2 · RDS(ON)(bp) + IQ · VIN  
DAC Programming Gain  
Since the RDS(ON), quiescent current, and switching losses  
all vary with input voltage, the total losses should be  
investigated over the complete input voltage range.  
The output voltage is dynamically controlled by the DAC  
input voltage. The DAC to output gain is fixed at 3. The  
typical response time for a 0.2V to 1.2V pulsed signal on  
the DAC input is less than 30μs. The DAC gain can be  
reduced by an external resistive divider at the DAC  
input, as shown in the evaluation board schematic in  
Figures 2 and 3. For a DAC to output gain of 2 and R2  
at 10kΩ, R1 is 4.99kΩ.  
After calculating the total losses, the maximum junction  
temperature can be derived from the θJA for the TDFN33-  
12 package which is typically 50°C/W.  
TJ(MAX) = PTOTAL · ΘJA + TAMB  
(3- GDAC)R2  
(3 - 2)10kΩ  
R1 =  
=
= 4.99kΩ  
GDAC  
2
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
U1  
L1  
AAT1171-1/AAT1171-4  
2.2μH  
1
2
3
4
5
6
12  
11  
10  
9
VOUT  
N/C  
LX  
PGND  
VOUT  
VOUT  
VCC  
C2  
4.7μF  
VIN  
GND  
C1  
MODE/SYNC  
BYPASS  
EN  
4.7μF  
8
AGND  
DAC  
7
VIN  
GND  
DAC  
R1  
R2  
1
2
3
3
2
1
1 2 3  
ENABLE  
Off On  
BYPASS  
SYNC  
On Off LL PWM  
Figure 2: AAT1171-1/AAT1171-4 Evaluation Board Schematic.  
U2  
L1  
AAT1171-5  
4.7μH  
1
2
3
4
5
6
12  
11  
10  
9
VOUT  
N/C  
LX  
PGND  
VIN  
VOUT  
VOUT  
C2  
10μF  
GND  
VCC  
MODE/SYNC  
BYPASS  
EN  
C1  
4.7μF  
8
AGND  
DAC  
7
VIN  
GND  
DAC  
R1  
R2  
1
2
3
3
2
1
1 2 3  
ENABLE  
Off On  
BYPASS  
SYNC  
On Off LL PWM  
Figure 3: AAT1171-5 Evaluation Board Schematic.  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
3. The PCB trace connected to VOUT (Pins 2 and 3) is  
tied to the bypass path, as well as the feedback path  
for the control loop. In bypass mode, the full load  
current is delivered directly from the battery input;  
therefore, this trace should be sufficient to handle  
current up to the bypass current limit level.  
4. The resistance of the trace from the load return to  
PGND (Pin 11) should be kept to a minimum. This  
minimizes any error in DC regulation due to differ-  
ences in the potential of the internal signal ground  
and the power ground.  
WLCSP Package Light Sensitivity  
The electrical performance of the WLCSP package can be  
adversely affected by exposing the device to certain light  
sources such as direct sunlight or a halogen lamp whose  
wavelengths are red and infra-reds. However, fluores-  
cent lighting has very little effect on the electrical per-  
formance of the WLCSP package.  
Layout  
The suggested PCB layout for the AAT1171 is shown in  
Figures 4 and 5. The following guidelines should be used  
to ensure a proper layout.  
5. For good thermal coupling, PCB vias are required  
from the pad for the TDFN exposed paddle to the  
ground plane. The via diameter should be 0.3mm to  
0.33mm and positioned on a 1.2mm grid.  
1. The input capacitor (C1) should connect as closely  
as possible to VIN (Pin 10) and PGND (Pin 11).  
2. C2 and L1 should be connected as closely as possi-  
ble. The connection of L1 to the LX pin should be as  
short as possible.  
Figure 4: AAT1171 Evaluation Board  
Top Side Layout.  
Figure 5: AAT1171 Evaluation Board  
Bottom Side Layout.  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
PA Step-Down Converter Design Example  
Specifications  
VO(BUCK) 0.6V to 3.4V with RL =10Ω  
VIN  
FS  
TAMB  
2.7V to 4.2V (3.6V nominal)  
2.0MHz  
85°C  
Output Inductor  
L1 = 2.2μH  
For Copper Electronics SD3112, 2.2μH, DCR = 140mΩ.  
VO  
VO  
2.1  
V
2.1V  
ΔIL1(MAX)  
=
1 -  
=
1 -  
= 239mA  
L FS  
VIN  
2.2µH 2.0MHz  
4.2V  
The maximum inductor ripple current occurs at 50% duty cycle at the maximum input voltage.  
ΔI  
IPKL1 = IO + L1(MAX) = 0.6A + 0.118A = 0.718A  
2
PL1 = IO2 DCR = 0.6A2 140mΩ = 50mW  
Output Capacitor  
Specify that VDROOP = 0.2V for a 600mA load pulse.  
3 · ΔILOAD  
VDROOP · FS  
3 · 0.6A  
COUT  
=
=
= 4.5µF  
0.2V · 2.0MHz  
(VO) · (VIN(MAX) - VO)  
L1 · FS · VIN(MAX)  
1
3.4V · (4.2V - 3.4V)  
1
·
= 69mArms  
IRMS  
=
·
=
4.7µH · 2.0MHz · 4.2V  
2· 3  
2· 3  
PESR = ESR · IRMS2 = 5mΩ · (69mA)2 = 24µW  
Input Capacitor  
Specify a maximum input voltage ripple of VPP = 25mV.  
1
1
CIN(MIN)  
=
=
= 3.4µF  
VPP  
IO  
25mV  
0.6A  
- ESR · 4 · FS  
- 5mΩ · 4 · 2.0MHz  
IO  
2
IRMS  
=
= 0.3Arms  
P = ESR · IRMS2 = 5mΩ · (0.3A)2 = 0.45mW  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
AAT1171 Losses  
PTOTAL = IO2 · RDS(ON) + (tsw · FS · IO + IQ) · VIN  
= 0.62 · 0.29Ω + (5ns · 2.0MHz · 0.6A + 60µA) · 4.2V = 104mW  
TJ(MAX) = PTOTAL · ΘJA + TAMB = 104mW · 50°C/W = 5.2°C + 70°C = 75.2°C  
AAT1171 Dropout Losses  
P
TOTAL = IO2 · RDS(ON)(HS) + IQ · VIN  
= 0.62 · 310mΩ + 100µA · 3.5V = 112mW  
TJ(MAX) = PTOTAL · ΘJA + TAMB = 112mW · 50°C/W = 5.6°C + 70°C = 75.6°C  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Manufacturer  
Value  
Device  
Voltage  
Case Size  
Part Number  
AVX  
10μF  
Output Capacitor  
10V  
0805  
0805ZD106KAT  
www.avxcorp.com  
Output or Input Capacitor  
Input Capacitor  
Output Capacitor  
Output or Input Capacitor  
Input Capacitor  
Output Capacitor  
10V  
6.3V  
10V  
10V  
6.3V  
10V  
10V  
6.3V  
0805  
0603  
0805  
0805  
0603  
0805  
0805  
0603  
GRM21BR61A475KA73L  
GRM188R60J475KE19D  
GRM21BR61A106K  
C2012X5R1A475K  
C1608X5ROJ475K  
C2012X5R1A106K  
LMK212BJ475MG  
4.7μF  
10μF  
4.7μF  
10μF  
4.7μF  
Murata  
www.murata.com  
TDK  
www.tdk.com  
Output or Input Capacitor  
Input Capacitor  
Taiyo Yuden  
www.t-yuden.com  
JMK107BJ475MA  
Case Size  
(mm)  
Manufacturer  
Value  
ISAT  
IRMS  
DCR  
Part Number  
2.2μH  
4.7μH  
2.2μH  
4.7μH  
2.2μH  
2.2μH  
1.12A  
0.8A  
1.1A  
0.91A  
0.74A  
1.3A  
0.85A  
0.52A  
0.55A  
140mꢀ  
246mꢀ  
96mꢀ  
238mꢀ  
200mꢀ  
110mꢀ  
3.1x3.1x1.2  
3.1x3.1x1.2  
3.2x3.2x1.2  
3.2x3.2x1.2  
2.0x2.0x1.0  
2.0x2.0x1.4  
SD3118-2R2  
Cooper Electronics  
www.cooperet.com  
SD3112-4R7-R  
CDRH2D11/HP  
CDRH2D11/HP  
LPF2010-2R2M  
LPF2010-2R2M  
Sumida  
www.sumida.com  
0.75A  
ABCO Electronics  
www.abco.co.kr  
Table 1: Suggested Component Selection.  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
Ordering Information  
Package  
Marking1  
Part Number (Tape and Reel)2  
TDFN33-12  
TDFN33-12  
TDFN33-12  
WLCSP-12  
RXXYY  
XCXYY  
XDXYY  
UGYW3  
AAT1171IWP-1-T1  
AAT1171IWP-4-T1  
AAT1171IWP-5-T1  
AAT1171IUP-1-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  
TDFN33-12  
Index Area  
Detail "A"  
0.43 0.05  
0.1 REF  
C0.3  
Pin 1 Indicator  
(optional)  
3.00 0.05  
1.70 0.05  
Top View  
Bottom View  
Detail "A"  
0.05 0.05  
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. YW = data code (year, week) for WLCSP-12 package.  
4. 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.  
WLCSP-12  
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com  
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• Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013  
DATA SHEET  
AAT1171  
600mA Voltage-Scaling Step-Down Converter  
for RF Power Amplifiers with Bypass Switch  
1.535 0.035  
0.300  
0.200  
Line 1:  
Part Code  
Line 2:  
Year Code and  
Bi-Week Code  
(laser marking)  
0.500 BSC  
0.250  
ø
0.2 (Ref.)  
Pin 1 indication  
1.000  
Bottom View  
Top View  
0.310 0.025  
0.245 0.025  
0.330 0.025  
0.070 0.035  
2.235 0.035  
End View  
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. Sky-  
works may change its documentation, products, services, specications 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 conicts, incompatibilities, or other difculties arising from any future changes.  
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CLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM  
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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 en-  
vironmental 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 specications as a result of design defects, errors, or operation of products outside of pub-  
lished parameters or design specications. 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 specications or parameters.  
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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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