|
|
PDF TD6817 Data sheet ( Hoja de datos )
| Número de pieza | TD6817 | |
| Descripción | 1.5MHz 2A Synchronous Step-Down Regulator Dropout | |
| Fabricantes | Techcode | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de TD6817 (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
|
No Preview Available !
Techcode®
1.5MHz 2A Synchronous Step-Down Regulator Dropout
DATASHEET
TD6817
General Description
Features
The TD6817 is a high efficiency monolithic synchronous
buck regulator using a constant frequency, current mode
architecture. The device is available in an adjustable
version and fixed output voltages of 1.5V and 1.8V.
Supply current during operation is only 20mA and drops
to ≤1mA in shutdown. The 2.5V to 5.5V input voltage
range makes the TD6817 ideally suited for single Li-Ion
battery-powered 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
feedback reference voltage. The TD6817 is available in
TSOT23-5 package.
High Efficiency: Up to 96%
High Efficiency at light loads
Very Low Quiescent Current: Only 20uA During
Operation
2A Output Current
2.5V to 5.5V 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 ≤1uA Supply Current
Current Mode Operation for Excellent Line and Load
Transient Response
Overtemperature Protected
TSOT23-5 Package is Available
Applications
Cellular Telephones
Personal Information Appliances
Wireless and DSL Modems
Digital Still Cameras
MP3 Players
Portable Instruments
Package Types
December, 20, 2009
TSOT23-5
Figure 1. Package Types of TD6817
America Techcode Semiconductor, Inc.
1
www.techcodesemi.c
om
1 page  
Techcode®
1.5MHz 2A Synchronous Step-Down Regulator Dropout
DATASHEET
TD6817
Electrical Characteristics(Cont.)
Unless otherwise specified, VIN= 3.6V TA=25 ºC.
Symbol
IPK
VLOADREG
VIN
IS
fOSC
RPFET
RNFET
ILSW
VRUN
IRUN
Parameter
Peak Inductor Current
Output Voltage Load
Regulation
Input Voltage Range
Conditions
Min.
VIN = 3V, VFB = 0.5V or
VOUT = 90%, Duty Cycle < 2.4
35%
2.5
Input DC Bias Current
Active Mode
Sleep Mode
VFB = 0.5V or VOUT =
90%, ILOAD = 0A
VFB = 0.62V or VOUT =
103%, ILOAD = 0A
Shutdown
VRUN = 0V, VIN = 4.2V
Oscillator Frequency
VFB = 0.6V or VOUT =
1
100%
VFB = 0V or VOUT = 0V
RDS(ON) of P-Channel
FET
RDS(ON) of N-Channel
FET
SW Leakage
ISW = 100mA
ISW = -100mA
VRUN = 0V, VSW = 0V or
5V, VIN = 5V
RUN Threshold
0.3
RUN Leakage Current
Typ.
2.5
0.5
300
20
0.1
1.5
400
0.11
0.12
0.01
1
Max.
2.6
5.5
400
35
1
1.8
0.13
0.15
1
1.5
1
Unit
A
%
V
uA
uA
uA
MHz
KHz
Ω
Ω
uA
V
uA
December, 20, 2009
America Techcode Semiconductor, Inc.
5
www.techcodesemi.c
om
5 Page 
Techcode®
1.5MHz 2A Synchronous Step-Down Regulator Dropout
Function Description(Cont.)
DATASHEET
TD6817
Low Supply Operation
The TD6817 will operate with input supply voltages as
low as 2.5V, but the maximum allowable output current is
reduced at this low voltage. Figure 2 shows the reduction
in the maximum output current as a function of input
voltage for various output voltages.
Slope Compensation and Inductor Peak
Current
Slope compensation provides stability in constant
frequency architectures by preventing subharmonic
oscillations at high duty cycles. It is accomplished
internally by adding a compensating ramp to the inductor
current signal at duty cycles in excess of 40%. Normally,
this results in a reduction of maximum inductor peak
current for duty cycles >40%. However, the TD6817 uses
a patent-pending scheme that counteracts this
compensating ramp, which allows the maximum inductor
peak current to remain unaffected throughout all duty
cycles.
The basic TD6817 application circuit is shown in Figure
3. External component selection is driven by the load
requirement and begins with the selection of L followed
by CIN and COUT.
Inductor Selection
For most applications, the value of the inductor will fall in
the range of 1uH to 4.7uH. Its value is chosen based on
the desired ripple current. Large value inductors lower
ripple current and small value inductors result in higher
ripple currents. Higher VIN or VOUT also increases the
ripple current as shown in equation 1. A reasonable
starting point for setting ripple current is DIL = 800mA
(40% of 2000mA).
The DC current rating of the inductor should be at least
equal to the maximum load current plus half the ripple
current to prevent core saturation. Thus, a 2200mA rated
inductor should be enough for most applications
(2000mA + 200mA). For better efficiency, choose a low
DC-resistance
inductor.
The inductor value also has an effect on Burst Mode
operation. The transition to low current operation begins
when the inductor current peaks fall to approximately
200mA. Lower inductor values (higher DIL) will cause
this to occur at lower load currents, which can cause a
dip in efficiency in the upper range of low current
operation. In Burst Mode operation, lower inductance
values will cause the burst frequency to increase.
Maximum Output Current vs Input Voltag
December, 20, 2009
America Techcode Semiconductor, Inc.
11
www.techcodesemi.c
om
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet TD6817.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| TD6810 | 1.5MHz 800mA Synchronous Step-Down Regulator Dropout |  Techcode Semiconductor |
| TD6811 | 1.5MHz 1.2A Synchronous Step-Down Regulator Dropout | Techcode |
| TD6811B | 1.5MHz 1.2A Synchronous Step-Down Regulator Dropout | Techcode |
| TD6814 | 1.5MHz 1.2A Synchronous Step-Down Regulator Dropout | Techcode |
| 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 |