|
|
PDF AAT2146W Data sheet ( Hoja de datos )
| Número de pieza | AAT2146W | |
| Descripción | Fast Transient 600mA Step-Down Converter | |
| Fabricantes | Skyworks | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de AAT2146W (archivo pdf) en la parte inferior de esta página. Total 18 Páginas | ||
|
No Preview Available !
DATA SHEET
AAT2146W
Low-Noise, Fast Transient 600mA Step-Down Converter
General Description
The AAT2146W SwitchReg is a 2MHz fixed frequency
step-down converter with an input voltage range of 2.7V
to 5.5V and output voltage as low as 0.6V. It is optimized
to react quickly to a load variation. The AAT2146W is
ideal for applications where fixed frequency and low rip-
ple voltage are required over the full range of load condi-
tions.
The AAT2146W is programmable with external feedback
resistors. It can deliver 600mA of load current while
maintaining a low 150μA no-load quiescent current. The
2MHz switching frequency minimizes the size of external
components while keeping switching losses low.
The AAT2146W is designed to maintain high efficiency
throughout the operating range, which is critical for por-
table applications.
The AAT2146W is available in the Pb-free, space-saving
2.0x2.2mm SC70JW-8 package and is rated over the
-40°C to +85°C temperature range.
Features
• VIN Range: 2.7V to 5.5V
• Low Ripple Voltage Fixed Frequency PWM Mode
• VOUT Adjustable from 0.6V to VIN
• Efficiency up to 96%
• 600mA Max Output Current
• 2MHz Switching Frequency
• 150μs Soft Start
• Fast Load Transient
• Over-Temperature Protection
• Current Limit Protection
• 100% Duty Cycle Low-Dropout Operation
• <1μA Shutdown Current
• SC70JW-8 Package
• Temperature Range: -40°C to +85°C
Applications
• Cellular Phones
• Digital Cameras
• Handheld Instruments
• Microprocessor / DSP Core / IO Power
• PDAs and Handheld Computers
• USB Devices
Typical Application
VIN
C2
2.2µF
U1
AAT2146W
VIN LX
EN OUT
AGND PGND
PGND PGND
L1
4.7µH
VO
C1
4.7µF
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202008A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 28, 2012
1
1 page  
DATA SHEET
AAT2146W
Low-Noise, Fast Transient 600mA Step-Down Converter
Typical Characteristics1
100
90
80
70
60
50
40
30
20
10
0
0.1
Efficiency vs. Output Current
(VOUT= 1.8V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
Vin=3.6V
Vin=3.0V
Vin=2.7V
1 10 100
Output Current (mA)
1000
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.1
Load Regulation
(VOUT= 1.8V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
Vin=3.6V
Vin=3.0V
Vin=2.7V
1 10 100
Output Current (mA)
1000
100
90
80
70
60
50
40
30
20
10
0
0.1
Efficiency vs. Output Current
(VOUT= 2.5V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
Vin=3.6V
Vin=3.0V
1 10 100
Output Current (mA)
1000
`
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.1
Load Regulation
(VOUT= 2.5V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
Vin=3.6V
Vin=3.0V
1 10 100
Output Current (mA)
1000
100
90
80
70
60
50
40
30
20
10
0
0.1
Efficiency vs. Output Current
(VOUT= 3.3V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
1 10 100
Output Current (mA)
1000
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.1
Load Regulation
(VOUT= 3.3V)
Vin=5.5V
Vin=5.0V
Vin=4.2V
1 10 100
Output Current (mA)
1000
1. See figure 2 for the application test circuit.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202008A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 28, 2012
5
5 Page 
DATA SHEET
AAT2146W
Low-Noise, Fast Transient 600mA Step-Down Converter
The
term
VO
VIN
·
⎛⎝1 -
VO ⎞
VIN ⎠
appears
in
both
the
input
voltage
rip-
ple and input capacitor RMS current equations and is a
maximum when VO is twice VIN. This is why the input
voltage ripple and the input capacitor RMS current ripple
are a maximum at 50% duty cycle.
The input capacitor provides a low impedance loop for
the edges of pulsed current drawn by the AAT2146W.
Low ESR/ESL X7R and X5R ceramic capacitors are ideal
for this function. To minimize stray inductance, the
capacitor 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 rip-
ple.
The proper placement of the input capacitor (C2) can be
seen in the evaluation board layout in Figure 2.
A laboratory test set-up typically consists of two long
wires running from the bench power supply to the evalu-
ation 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. Errors in the loop phase and gain
measurements can also result.
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.
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 should be placed in parallel with the
low ESR, ESL bypass ceramic. This dampens the high Q
network and stabilizes the system.
Output Capacitor
The output capacitor limits the output ripple voltage and
provides holdup during large load transitions. A 4.7μF to
10μF X5R or X7R ceramic capacitor typically provides
sufficient bulk capacitance to stabilize the output during
large load transitions and has the ESR and ESL charac-
teristics necessary for low output voltage ripple.
The output voltage droop due to a load transient is
dominated by the capacitance of the ceramic output
capacitor. During a step increase in load current, the
ceramic output capacitor alone supplies the load current
until the loop responds. Within two or three switching
cycles, the loop responds and the inductor current
increases to match the load current demand. The rela-
tionship of the output voltage droop during the three
switching cycles to the output capacitance can be esti-
mated by:
COUT
=
3 · ΔILOAD
VDROOP · fsw
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 value for the
output capacitor with respect to load transients.
The internal voltage loop compensation also limits the
minimum output capacitor value to 4.7μF. This is due to
its effect on the loop crossover frequency (bandwidth),
phase margin, and gain margin. Increased output capac-
itance will reduce the crossover frequency with greater
phase margin.
The maximum output capacitor RMS ripple current is
given by:
I =RMS(MAX)
1
2·
·
3
VOUT · (VIN(MAX) - VOUT)
L · fsw · VIN(MAX)
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.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202008A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 28, 2012
11
11 Page | ||
| Páginas | Total 18 Páginas | |
| PDF Descargar | [ Datasheet AAT2146W.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| AAT2146 | Fast Transient 600mA Step-Down Converter |  Advanced Analogic Technologies |
| AAT2146W | Fast Transient 600mA Step-Down Converter | Skyworks |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |