BCD AUR9705AGH 1.5mhz, 1a, step down dc-dc converter Datasheet

Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
General Description
Features
The AUR9705 is a high efficiency step-down
DC-DC voltage converter. The chip operation is
optimized using constant frequency, peak-current
mode architecture with built-in synchronous power
MOSFET switchers and internal compensators to
reduce external part counts. It is automatically
switching between the normal PWM mode and LDO
mode to offer improved system power efficiency
covering a wide range of loading conditions.
•
•
•
•
•
•
•
•
•
•
•
•
The oscillator and timing capacitors are all built-in
providing an internal switching frequency of 1.5MHz
that allows the use of small surface mount inductors
and capacitors for portable product implementations.
Additional features included Soft Start (SS), Under
Voltage Lock Out (UVLO) and Thermal Shutdown
Detection (TSD) to provide reliable product
applications.
AUR9705
High Efficiency Buck Power Converter
Low Quiescent Current
Output Current: 1A
Adjustable Output Voltage from 1V to 3.3V
Wide Operating Voltage Range: 2.5V to 5.5V
Built-in Power Switches for Synchronous
Rectification with High Efficiency
Feedback Voltage: 600mV
1.5MHz Constant Frequency Operation
Automatic PWM/LDO Mode Switching Control
Thermal Shutdown Protection
Low Drop-out Operation at 100% Duty Cycle
No Schottky Diode Required
Applications
•
•
•
•
The device is available in adjustable output voltage
versions ranging from 1V to 3.3V, and is able to
deliver up to 1A.
Mobile Phone, Digital Camera and MP3 Player
Headset, Radio and Other Hand-held Instrument
Post DC-DC Voltage Regulation
PDA and Notebook Computer
The AUR9705 is available in WDFN-2×2-6 and
TSOT-23-5 packages.
WDFN-2×2-6
TSOT-23-5
Figure 1. Package Types of AUR9705
Nov. 2011
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
1
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Pin Configuration
D Package
(WDFN-2×2-6)
H Package
(TSOT-23-5)
Pin 1 Mark
NC
1
EN
2
VIN
3
Exposed
Pad
6
FB
1
5
GND
2
4
LX
3
5
4
Figure 2. Pin Configuration of AUR9705 (Top View)
Pin Description
Pin Number
WDFN-2×2-6 TSOT-23-5
1
Nov. 2011
Pin Name
Function
No internal connection (Floating or connected to
GND)
Enable signal input, active high
Power supply input
Connect to inductor
This pin is the GND reference for the NMOS power
stage. It must be connected to the system ground
Feedback voltage from the output of the power
supply
NC
2
3
4
3
1
5
EN
VIN
LX
5
2
GND
6
4
FB
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
2
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Functional Block Diagram
Figure 3. Functional Block Diagram of AUR9705
Ordering Information
AUR9705
Package
D: WDFN-2×2-6
H: TSOT-23-5
Circuit Type
A: Adjustable Output
Package
WDFN-2×2-6
TSOT-23-5
Temperature
Range
-40 to 80°C
G: Green
Part Number
Marking ID
Packing Type
AUR9705AGD
705A
Tape & Reel
AUR9705AGH
9705AG
Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G" in the part number, are RoHS compliant and
green.
Nov. 2011
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
3
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Absolute Maximum Ratings (Note 1)
Parameter
Symbol
Value
Unit
Supply Input Voltage
VIN
0 to 6.0
V
Enable Input Voltage
VEN
-0.3 to VIN+0.3
V
Switch Output Voltage
VLX
-0.3 to VIN+0.3
V
Power Dissipation (On PCB, TA=25°C)
PD
1.89
W
Thermal Resistance (Junction to Ambient, Simulation)
θJA
53
°C/W
Thermal Resistance (Junction to Case, Simulation)
θJC
0.85
°C/W
Operating Junction Temperature
TJ
160
°C
Operating Temperature
TOP
-40 to 85
°C
Storage Temperature
TSTG
-55 to 150
°C
ESD (Human Body Model)
VHBM
2000
V
ESD (Machine Model)
VMM
200
V
Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to
the device. These are stress ratings only, and functional operation of the device at these or any other conditions
beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute
Maximum Ratings” for extended periods may affect device reliability.
Recommended Operating Conditions
Parameter
Symbol
Min
Max
Unit
Supply Input Voltage
VIN
2.5
5.5
V
Junction Temperature Range
TJ
-20
125
°C
Ambient Temperature Range
TA
-40
80
°C
Nov. 2011
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
4
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Electrical Characteristics
VIN=VEN=5V, VFB=0.6V, L=2.2µH, CIN= 4.7µF, COUT=10µF, TA=25°C, unless otherwise specified.
Parameter
Symbol
Conditions
Min Typ Max Unit
Input Voltage Range
VIN
Shutdown Current
Regulated1Feedback
Voltage
Regulated
Output
Voltage Accuracy
Peak
Inductor
Current
IOFF
VEN=0V
VFB
For Adjustable Output Voltage
Oscillator Frequency
∆VOUT/VOUT
IPK
2.5
VIN=2.5V to 5.5V,
IOUT=0 to 1A
0.585
5.5
V
0.1
1
µA
0.6
0.615
V
3
%
-3
VFB=0.5V
1.5
fOSC
1.2
1.5
A
1.8
MHz
PMOSFET RON
RON(P)
IOUT =200mA
0.25
Ω
NMOSFET RON
RON(N)
IOUT =200mA
0.27
Ω
Quiescent Current
IQ
IOUT=0A, VFB=0.7V
100
µA
LX Leakage Current
ILX
VEN=0V, VLX=0V or 5V
0.01
Feedback Current
IFB
EN Leakage Current
EN High-level Input
Voltage
EN Low-level Input
Voltage
Under Voltage Lock
Out
IEN
0.01
VEN_H
VIN=2.5V to 5.5V
VEN_L
VIN=2.5V to 5.5V
VUVLO
Rising
Hysteresis
Thermal Shutdown
Nov. 2011
TSD
Rev. 1. 0
0.1
µA
30
nA
0.1
µA
1.5
V
0.6
V
1.8
V
0.1
V
160
°C
BCD Semiconductor Manufacturing Limited
5
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
100
100
90
90
80
80
70
70
60
60
50
COUT=10µF
40
L=2.2µH
VIN=2.5V
Efficiency (%)
Efficiency (%)
Typical Performance Characteristics
50
COUT=10µF
40
L=2.2µH
VIN=3.3V
30
VIN=3.3V
30
20
VIN=4.2V
20
VIN=5V
10
VIN=5.5V
VIN=4.2V
VIN=5V
10
VIN=5.5V
0
0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0
0.1
0.2
0.3
Output Current (A)
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Output Current (A)
Figure 4. Efficiency vs. Output Current (VOUT=1.2V)
Figure 5. Efficiency vs. Output Current (VOUT=2.5V)
100
1.60
90
1.55
80
1.50
Frequency (MHz)
Efficiency (%)
70
60
50
40
COUT=10µF
30
L=2.2µH
VIN=4.2V
20
VIN=5.0V
10
VIN=5.5V
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.35
VOUT=1.2V
L=2.2µH
COUT=10µF
1.25
1.20
2.5
1.0
Output Current (A)
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Figure 6. Efficiency vs. Output Current (VOUT=3.3V)
Nov. 2011
1.40
1.30
0
0.0
1.45
Figure 7. Frequency vs. Input Voltage
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
6
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Typical Performance Characteristics (Continued)
1.25
L=2.2µH
COUT=10µF
1.24
Output Voltage (V)
1.23
2.5V
3.3V
4.2V
5V
5.5V
1.22
1.21
1.20
1.19
1.18
1.17
1.16
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Output Current (A)
Figure 8. Output Voltage vs. Output Current
(VOUT=1.2±0.03V)
Figure 9. Output Ripple
(VIN=5.0V, VOUT=3.3V, IOUT=1A)
Figure 10. Power Off through VIN
(VIN=VEN=5.0 to 0V, VOUT=3.3V, IOUT=1A)
Nov. 2011
Figure 11. Soft Start (Power Up through EN)
(VIN=5.0V, VOUT=3.3V, IOUT=1A, VEN=0 to 5.0V)
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
7
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Typical Performance Characteristics (Continued)
Figure 12. Load Transient
(VIN=5.0V, VOUT=1.2V, IOUT=0.1 to 1A)
Figure 13. Load Transient
(VIN=5.0V, VOUT=3.3V, IOUT=0.1 to 1A)
Figure 14. Short Circuit
(VIN=5.0V, VOUT=3.3V Short to GND, IOUT=1A)
Nov. 2011
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
8
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Application Information
deviations do not much relieve. The selection of COUT
is determined by the Effective Series Resistance
(ESR) that is required to minimize output voltage
ripple and load step transients, as well as the amount
of bulk capacitor that is necessary to ensure that the
control loop is stable. Loop stability can be also
checked by viewing the load step transient response
as described in the following section. The output
ripple, △VOUT, is determined by:
The basic AUR9705 application circuit is shown in
Figure 16, external components selection is determined
by the load current and is critical with the selection of
inductor and capacitor values.
1. Inductor Selection
For most applications, the value of inductor is chosen
based on the required ripple current with the range of
2.2µH to 4.7µH.
∆VOUT ≤ ∆I L [ ESR +
V
1
∆I L =
VOUT (1 − OUT )
f ×L
VIN
The output ripple is the highest at the maximum input
voltage since △IL increases with input voltage.
The largest ripple current occurs at the highest input
voltage. Having a small ripple current reduces the ESR
loss in the output capacitor and improves the efficiency.
The highest efficiency is realized at low operating
frequency with small ripple current. However, larger
value inductors will be required. A reasonable starting
point for ripple current setting is △IL=40%IMAX . For a
maximum ripple current stays below a specified
value, the inductor should be chosen according to the
following equation:
L =[
3. Load Transient
A switching regulator typically takes several cycles to
respond to the load current step. When a load step
occurs, VOUT immediately shifts by an amount equal
to △ILOAD×ESR, where ESR is the effective series
resistance of output capacitor. △ILOAD also begins to
charge or discharge COUT generating a feedback error
signal used by the regulator to return VOUT to its
steady-state value. During the recovery time, VOUT
can be monitored for overshoot or ringing that would
indicate a stability problem.
VOUT
VOUT
][1 −
]
f × ∆I L ( MAX )
VIN ( MAX )
4. Output Voltage Setting
The DC current rating of the inductor should be at
least equal to the maximum output current plus half
the highest ripple current to prevent inductor core
saturation. For better efficiency, a lower
DC-resistance inductor should be selected.
The output voltage of AUR9705 can be adjusted by a
resistive divider according to the following formula:
VOUT = VFB × (1 +
2. Capacitor Selection
I RMS = I OMAX
VOUT
R1
FB
1
2
AUR9705
R2
GND
It indicates a maximum value at VIN=2VOUT, where
IRMS=IOUT/2. This simple worse-case condition is
commonly used for design because even significant
Nov. 2011
R1
R
) = 0.6V × (1 + 1 )
R2
R2
The resistive divider senses the fraction of the output
voltage as shown in Figure 15.
The input capacitance, CIN, is needed to filter the
trapezoidal current at the source of the top MOSFET.
To prevent large ripple voltage, a low ESR input
capacitor sized for the maximum RMS current must
be used. The maximum RMS capacitor current is
given by:
[V (V − VOUT )]
× OUT IN
VIN
1
]
8 × f × COUT
Figure 15. Setting the Output Voltage
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
9
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Application Information (Continued)
the VIN and this effect will be more serious at higher
input voltages.
5. Efficiency Considerations
The efficiency of switching regulator is equal to the
output power divided by the input power times 100%.
It is usually useful to analyze the individual losses to
determine what is limiting efficiency and which
change could produce the largest improvement.
Efficiency can be expressed as:
5.2 I2R losses are calculated from internal switch
resistance, RSW and external inductor resistance RL.
In continuous mode, the average output current
flowing through the inductor is chopped between
power PMOSFET switch and NMOSFET switch.
Then, the series resistance looking into the LX pin is
a function of both PMOSFET RDS(ON) and NMOSFET
Efficiency=100%-L1-L2-…..
Where L1, L2, etc. are the individual losses as a
percentage of input power.
RDS(ON) resistance and the duty cycle (D):
RSW = RDS (ON )P × D + RDS (ON ) N × (1 − D )
Although all dissipative elements in the regulator
produce losses, two major sources usually account for
most of the power losses: VIN quiescent current and
I2R losses. The VIN quiescent current loss dominates
the efficiency loss at very light load currents and the
I2R loss dominates the efficiency loss at medium to
heavy load current.
Therefore, to obtain the I2R losses, simply add RSW to
RL and multiply the result by the square of the
average output current.
Other losses including CIN and COUT ESR dissipative
losses and inductor core losses generally account for
less than 2 % of total additional loss.
5.1 The VIN quiescent current loss comprises two
parts: the DC bias current as given in the electrical
characteristics and the internal MOSFET switch gate
charge currents. The gate charge current results from
switching the gate capacitance of the internal power
MOSFET switches. Each cycle the gate is switched
from high to low, then to high again, and the packet
of charge, dQ moves from VIN to ground. The
resulting dQ/dt is the current out of VIN that is
typically larger than the internal DC bias current. In
continuous mode,
6. Thermal Characteristics
In most applications, the part does not dissipate much
heat due to its high efficiency. However, in some
conditions when the part is operating in high ambient
temperature with high RDS(ON) resistance and high
duty cycles, such as in LDO mode, the heat
dissipated may exceed the maximum junction
temperature. To avoid the part from exceeding
maximum junction temperature, the user should do
some thermal analysis. The maximum power
dissipation depends on the layout of PCB, the thermal
resistance of IC package, the rate of surrounding
airflow and the temperature difference between
junction and ambient.
I GATE = f × (Q P + Q N )
Where QP and QN are the gate charge of power
PMOSFET and NMOSFET switches. Both the DC
bias current and gate charge losses are proportional to
Nov. 2011
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
10
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Typical Application
For WDFN-2×2-6
For TSOT-23-5
Note 2: VOUT = VFB × (1 +
R1
).
R2
When R2=300kΩ to 60kΩ, the IR2=2µA to 10µA, and R1×C1 should be in the range between 3×10-6 and 6×10-6 for
component selection.
Figure 16. Typical Application Circuits of AUR9705
Table 1. Component Guide
VOUT
(V)
3.3
2.5
1.8
1.2
1.0
Nov. 2011
R1
(kΩ)
453
320
200
100
68
R2
(kΩ)
100
100
100
100
100
Rev. 1. 0
C1
(pF)
13
18
30
56
82
L1
(µH)
2.2
2.2
2.2
2.2
2.2
BCD Semiconductor Manufacturing Limited
11
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Mechanical Dimensions
WDFN-2×2-6
Nov. 2011
Rev. 1. 0
Unit: mm(inch)
BCD Semiconductor Manufacturing Limited
12
Data Sheet
1.5MHz, 1A, STEP DOWN DC-DC CONVERTER
AUR9705
Mechanical Dimensions (Continued)
TSOT-23-5
Unit: mm(inch)
2.800(0.110)
3.000(0.118)
5
0°
8°
R0.100(0.004)
MIN
4
0.600(0.024)
REF
2.600(0.102)
3.000(0.118)
1.500(0.059)
1.700(0.067)
0.370(0.015)
MIN
1
2
3
0.950(0.037)
TYP
0.100(0.004)
0.250(0.010)
0.350(0.014)
0.510(0.020)
0.250(0.010)
TYP
0.700(0.028)
0.900(0.035)
GAUGE PLANE
1.900(0.075)
TYP
5°
1.000(0.039)
MAX
0.000(0.000)
0.100(0.004)
Nov. 2011
4X7
°
Rev. 1. 0
BCD Semiconductor Manufacturing Limited
13
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
IMPORTANT NOTICE
IMPORTANT
NOTICE
BCD Semiconductor
BCD
Semiconductor Manufacturing
Manufacturing Limited
Limited reserves
reserves the
the right
right to
to make
make changes
changes without
without further
further notice
notice to
to any
any products
products or
or specifispecifications herein.
cations
herein. BCD
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited does
does not
not assume
assume any
any responsibility
responsibility for
for use
use of
of any
any its
its products
products for
for any
any
particular purpose,
particular
purpose, nor
nor does
does BCD
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited assume
assume any
any liability
liability arising
arising out
out of
of the
the application
application or
or use
use
of any
of
any its
its products
products or
or circuits.
circuits. BCD
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited does
does not
not convey
convey any
any license
license under
under its
its patent
patent rights
rights or
or
other rights
other
rights nor
nor the
the rights
rights of
of others.
others.
MAIN SITE
SITE
MAIN
- Headquarters
BCD
Semiconductor Manufacturing Limited
BCD
Semiconductor
Manufacturing Limited
- Wafer
Fab
No.
1600, Zi
Xing Road,
Shanghai ZiZhu
Science-basedLimited
Industrial Park, 200241, China
Shanghai
SIM-BCD
Semiconductor
Manufacturing
Tel:
Fax: +86-21-24162277
800,+86-21-24162266,
Yi Shan Road, Shanghai
200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
REGIONAL SALES OFFICE
Shenzhen OfficeSALES OFFICE
REGIONAL
- Wafer
FabSemiconductor Manufacturing Limited
BCD
Shanghai
SIM-BCD
Semiconductor Manufacturing Co., Ltd.
- IC Design
Group
800 Yi
Shan Road,
Shanghai
200233,
China Corporation
Advanced
Analog
Circuits
(Shanghai)
Tel: +86-21-6485
1491,YiFax:
0008200233, China
8F, Zone B, 900,
Shan+86-21-5450
Road, Shanghai
Tel: +86-21-6495 9539, Fax: +86-21-6485 9673
Taiwan Office
Shanghai
Semiconductor Manufacturing Co., Ltd., Shenzhen Office
BCD Taiwan
Semiconductor
Shenzhen SIM-BCD
Office
Office (Taiwan) Company Limited
Unit
A Room
1203, Skyworth
Bldg., Gaoxin
Ave.1.S., Nanshan
Shenzhen,
4F, 298-1,
Guang Road,(Taiwan)
Nei-Hu District,
Taipei,
Shanghai
SIM-BCD
Semiconductor
Manufacturing
Co., Ltd.District,
Shenzhen
Office
BCDRui
Semiconductor
Company
Limited
China
Taiwan
Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Tel:
+86-755-8826
Tel: +886-2-2656
2808
Room
E, 5F, Noble 7951
Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China
Taiwan
Fax:
+86-755-88267951
7865
Fax: +886-2-2656
28062808
Tel: +86-755-8826
Tel: +886-2-2656
Fax: +86-755-8826 7865
Fax: +886-2-2656 2806
USA Office
BCD Office
Semiconductor Corp.
USA
30920Semiconductor
Huntwood Ave.Corporation
Hayward,
BCD
CA 94544,
USA Ave. Hayward,
30920
Huntwood
Tel :94544,
+1-510-324-2988
CA
U.S.A
Fax:: +1-510-324-2988
+1-510-324-2788
Tel
Fax: +1-510-324-2788
Similar pages