SC46166S [SILAN]
300mA ,500KHZ HIGH EFFICIENCY STEP-UP DC/DC CONVERTER; 300毫安， 500KHZ高效率，升压型DC / DC转换器
| 型号： | SC46166S |
| 厂家： | 
SILAN MICROELECTRONICS JOINT-STOCK |
| 描述： | 300mA ,500KHZ HIGH EFFICIENCY STEP-UP DC/DC CONVERTER |
| 文件： | 总10页 (文件大小：480K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC46166
300mA ,500KHZ HIGH EFFICIENCY STEP-UP DC/DC CONVERTER
DESCRIPTION
The SC46166 is a compact, high efficiency, and low voltage
step-up DC/DC converter, includes an error amplifier, ramp
generator, current comparator, slope compensation, current sense
and driver. Peak current mode PWM control with internal
compensation reduces external parts count and provides a stable
and high efficient operation over a wide range of load currents.
The low start-up input voltage below 0.85V makes SC46166
suitable for 1 to 4 battery cells applications. A high switching
frequency of 500kHz minimizes overall solution footprint by allowing
the use of tiny, low profile inductors and ceramic capacitors. The
SC46166 shifts automatically to Power Saving Mode operation at
light loads, the 20uA low quiescent current together with high
efficiency maintains long battery lifetime. The device also features
low shutdown current of under 1μA.
SOT-23-6
SOT-89-5
FEATURES
APPLICATIONS
* 0.85V Low Start-up Input Voltage
* High Supply Capability to Deliver 3.3V 100mA with 1 Alkaline
Cell
* MP3 Players
* Digital Cameras
* PDA
* Automatic Power Saving Mode Operation with 20μA Quiescent
Supply Current
* LCD Bias Supplies
* Portable Instrument
* Wireless Equipment
* Up to 90% Efficiency
* Output Range: 2.5V to 6V
* Shutdown Mode Supply Current : <1uA
* 500kHz Fixed Switching Frequency
* Over Temperature Protection
* 4KV HBM ESD
* Small SOT-23-6 & SOT-89-5 Package
ORDERING INFORMATION
Device
SC46166
SC46166S
Package
SOT-23-6
SOT-89-5
Seal
46166
46166S
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 1 of 11
SC46166
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS (Tamb=25°C)
Characteristics
VDD Supply Voltage
LX Voltage
Rating
-0.3~+6
Unit
V
-0.3~+6
V
-0.3~+6
V
EN Voltage
-0.3~+6
V
FB Voltage
-40 ~ + 85
-65 ~ +125
°C
°C
Operating Temperature
Storage Temperature
ELECTRICAL CHARACTERISTICS (Tamb=25°C, VIN=1.5V,VDD=3.3V,Load Current=0 Unless otherwise
specified)
Characteristics
Minimum Start-Up Voltage
Operating VDD Range
Symbol
Test condition
I =1mA, Measured On V
DD
Min.
--
Typ.
0.85
--
Max.
0.9
Unit
V
V
ST
L
V
V
DD
pin voltage
2.5
1.2
6
V
DD
Feedback Reference Voltage
V
FB
1.23
1.26
V
Quiescent Current (Power
Saving Mode)
I
FB=1.4V
EN=0V
--
--
--
20
0.1
300
30
1
μA
μA
μA
switch off
I
st
I
Q
Quiescent Current (Shutdown)
Quiescent Current (PWM active
Mode)
Measured On V , Nonswitching
360
DD
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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REV:1.2
2008.07.04
Page 2 of 11
SC46166
Characteristics
Symbol
Test condition
L=4.7μH
1V≤V ≤3 V
Min.
Typ.
Max.
Unit
Power Saving Mode Current
Threshold
I
--
7.5
--
mA
load
Line Regulation
Load Regulation
Switching Frequency
Max Duty Cycle
△V
--
--
2
0.1
500
95
0.4
0.1
1
10
1
mV/V
mV/mA
KHz
%
LINE
IN
△V
1mA≤ I ≤100mA
LOAD
L
Fs
--
450
90
--
550
--
D
FB=1.2V
MAX
R
ON
V =3.3V
DD
0.5
1
Ω
NMOS Switch On Resistance
NMOS Switch Leakage
NMOS Current Limit
I
V ＝5V
LX
--
μA
leak
I
0.75
1
1.25
--
A
LIMIT
V
H
--
--
--
--
--
V
EN Input High
EN Input Low
V
L
--
--
0.35
--
V
Thermal Shutdown Temperature
Thermal Shutdown Hysterises
T
--
150
20
°C
j(sd)
T
--
--
°C
hyst
PIN CONFIGURATION
PIN DESCRIPTION
Pin No.
Pin Name
I/O
Pin Description
Chip Enable (Active High)
SC46166
SC46166S
1
1
EN
NC
I
—
5
—
2
3
4
5
6
Not connect
Ground
GND
LX
G
I/O
P
4
Switch Pin. Connect inductor between LX and VIN
Power Supply Pin of SC46166
Feedback Input Pin
2
VDD
FB
3
I
FUNCTION DESCRIPTION
The SC46166 is a 500kHz, asynchronous boost converter housed in a compact package, includes a voltage
reference, error amplifier, ramp generator, current comparator, slope compensation, current sense and driver.
The low start-up function allows SC46166 operating from an input voltage below 1V, 0.85V typically at VDD. In
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 3 of 11
SC46166
current mode PWM operation,SC46166 automatically detects the output, if the output load current falls below an
internally programmed threshold (The threshold has an dependence on the input voltage, output voltage and also
the value of the external inductor.), it shifts to Power Saving Mode operation, in which the IC consumes only 20μA,
the efficiency is increased. However, the output ripple typically increases. Power Saving Mode ripple can be
reduced, by placing a small feed-forward capacitor (An empirical suggestion is around 0.1~10nF) between VOUT
and FB pins.
Operating at heavy loads for a long time, the die temperature will rise, if the die temperature continues to rise and
reaches 150°C, the device shuts off entirely, the part will be enabled again when the die temperature drops by about
20°C.
APPLICATIONS INFORMATION
Output Voltage Setting
Referring to the figure1, the output voltage of the switching regulator (VOUT) can be set with Equation following:
R1
VOUT = (1+
)X1.23V
R2
Feedback Loop Design
Referring to Application Circuit of figure1, the selection of R1 and R2 are based on the trade-off between
quiescent current consumption and interference immunity. Higher R reduces the quiescent current (Path current =
1.23V/R2), however resistors beyond 5MΩ , are not recommended. Lower R gives better noise immunity, and is
less sensitive to interference, layout parasitics, FB node leakage, and improper probing to FB pins. A proper value
of feed-forward capacitor C1 parallel with R1 can improve the noise immunity of the feedback loops, especially in
an improper layout. An empirical suggestion is around 100pF~1nF for feedback resistors of MΩ, and 10nF~100nF
for feedback resistors of hundreds kΩ.
COMPONENT SELECTION
Inductor Selection
The SC46166 can utilize small surface mount and chip inductors due to its fast 500kHz switching frequency.
Typically, a 4.7μH inductor is recommended for most applications. Larger values of inductance will allow greater
output current capability by reducing the inductor ripple current. Increasing the inductance above will also increase
size .
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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2008.07.04
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SC46166
The inductor current ripple is typically set for 20% to 40% of the maximum inductor current (IP). The inductor
should have low ESR (series resistance of the windings) to reduce the power losses, and must be able to handle the
peak inductor current without saturating. To minimize radiated noise, use a shielded bobbin inductor.
Output and Input Capacitor Selection
Low ESR (equivalent series resistance) capacitors should be used to minimize the output voltage ripple.
Multilayer ceramic capacitors are an excellent choice as they have extremely low ESR and are available in small
footprints. A 10μF to 22μF output capacitor is sufficient for most applications. Larger values may be used to obtain
extremely low output voltage ripple and improve transient response.
Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. It
follows that ceramic capacitors are also a good choice for input decoupling, and should be located as close as
possible to the device. A 4.7μF input capacitor is sufficient for virtually any application.
Operating at light loads, a additional feed forward capacitor may be required (for example C1 in the Figure 1)to
maintain acceptable output voltage ripple.
For all the three capacitors above, X5R and X7R dielectric materials are preferred, for their ability to maintain
capacitance over wide voltage and temperature ranges.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
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SC46166
TYPICAL ELECTRICAL CHARACTERISTICS CURVES (Tamb=25°C, Unless otherwise specified)
(To be continued)
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REV:1.2
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SC46166
(Continued)
TYPICAL ELECTRICAL CHARACTERISTICS CURVES (Tamb=25°C, Unless otherwise specified)
Output ripple & LX
Output ripple & LX
Time (1us/Div)
Time (1us/Div)
VIN=1.5V，VOUT=3.3V@100mA
VIN=3V，VOUT=5V@100mA
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 7 of 11
SC46166
TYPICAL APPLICATION CIRCUIT
Figure 1. Application Circuit for 2-Cell to 3.3V Boost Converter
Note: The circuit and parameters are reference only, please set the parameters of the real application circuit based
on the real test .
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 8 of 11
SC46166
PACKAGE OUTLINE
SOT-23-6
UNIT: mm
SOT-89-5
UNIT: mm
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 9 of 11
SC46166
HANDLING MOS DEVICES:
Electrostatic charges can exist in many things. All of our MOS devices are internally protected against
electrostatic discharge but they can be damaged if the following precautions are not taken:
• Persons at a work bench should be earthed via a wrist strap.
• Equipment cases should be earthed.
• All tools used during assembly, including soldering tools and solder baths, must be earthed.
• MOS devices should be packed for dispatch in antistatic/conductive containers.
Note: Silan reserves the right to make changes without notice in this specification for the improvement of the design and performance.
Silan will supply the best possible product for customers.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2
2008.07.04
Page 10 of 11
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