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Número de pieza | KB3408 | |
Descripción | 350mA Synchronous Step-Down Regulator | |
Fabricantes | Kingbor Technology | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de KB3408 (archivo pdf) en la parte inferior de esta página. Total 6 Páginas | ||
No Preview Available ! Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
KB3408
1.5MHz, 350mA
Synchronous Step-Down
Regulator in SOT23-5
FEATURES
■ High Efficiency: Up to 96%
■ Very Low Quiescent Current: Only 20µA
www.DataSheetD4Uu.rcionmg Operation
■ 350mA Output Current
■ 2.5V to 7.4V Input Voltage Range
■ 1.5MHz Constant Frequency Operation
■ No Schottky Diode Required
■ Low Dropout Operation: 100% Duty Cycle
■ 0.6V Reference Allows Low Output Voltages
■ Shutdown Mode Draws ) 1µA Supply Current
■ Current Mode Operation for Excellent Line and
Load Transient Response
■ Overtemperature Protected
■ Low Profile (1mm) SOT23-5 Package
APPLICATIONS
■ Cellular Telephones
■ Personal Information Appliances
■ Wireless and DSL Modems
■ Digital Still Cameras
■ MP3 Players
■ Portable Instruments
DESCRIPTION
The KB3408 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. The device is available in an adjustable
version and fixed output voltages of 1.8V and 3.3V. Supply
current during operation is only 20µA and drops to )1µA
in shutdown. The 2.5V to 7.4V input voltage range makes
the KB3408 ideally suited for single Li-Ion battery-pow-
ered applications. 100% duty cycle provides low dropout
operation, extending battery life in portable systems.
Automatic Burst Mode operation increases efficiency at
light loads, further extending battery life.
Switching frequency is internally set at 1.5MHz, allowing
the use of small surface mount inductors and capacitors.
The internal synchronous switch increases efficiency and
eliminates the need for an external Schottky diode. Low
output voltages are easily supported with the 0.6V feed-
back reference voltage. The KB3408 is available in a low
profile (1mm) SOT23-5 package.
TYPICAL APPLICATION
VIN
2.7V
TO 7.4V
+ CIN
4.7µF
Tan
4
VIN
4.7µH
3
SW
KB3408-1.8
15
RUN VOUT
GND
2
COUT
10µF
CER
VOUT
1.8V
350mA
Figure 1a. High Efficiency Step-Down Converter
95
VIN = 2.7V
90
85
VIN = 3.6V
80
VIN = 4.2V
75
70
65
60
0.1
VOUT = 1.8V
1 10 100
OUTPUT CURRENT (mA)
500
Figure 1b. Efficiency vs Load Current
March 2007
1
KB3408
1 page Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
SIMPLIFIED BLOC DIAGRAM
KB3408
SLOPE
COMP
OSC
OSC
www.DataSheet4U.com
VFB/VOUT
FREQ
SHIFT
5 R1 0.6V +
FB – EA
R2
–
+
VIN
RUN
1 0.6V REF
SHUTDOWN
0.65V
– SLEEP
0.4V +
BURST
–ICOM+P
SQ
RQ
RS LATCH
SWITCHING
LOGIC
AND
BLANKING
CIRCUIT
ANTI-
SHOOT-
THRU
IRCMP
TYPICAL APPLICATION
Tiny 3.3V/350mA Buck Regulator
VIN
3.6V
to 7.4V
+ CIN
4.7µF
4
VIN
3
SW
KB3408
1
RUN
5
VFB
GND
2
4.7µH
22pF
VOUT
3.3V
350mA
COUT**
10µF
CER
450k
100k
** TAIYO YUDEN JMK316BJ106ML
100
VIN = 5V
95 VOUT = 3.3V
90
85
80
75
70
65
60
0.1
1 10 100
OUTPUT CURRENT (mA)
500
VOUT
100mV/DIV
AC COUPLED
IL
500mA/DIV
ILOAD
500mA/DIV
VIN = 5V
20µs/DIV
VOUT = 3.3V
ILOAD = 200mA TO 350mA
March 2007
5
4 VIN
51
3 SW
2 GND
5 Page |
Páginas | Total 6 Páginas | |
PDF Descargar | [ Datasheet KB3408.PDF ] |
Número de pieza | Descripción | Fabricantes |
KB3408 | 350mA Synchronous Step-Down Regulator | Kingbor Technology |
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