|
|
PDF LT1370HVIR Data sheet ( Hoja de datos )
| Número de pieza | LT1370HVIR | |
| Descripción | 500kHz High Efficiency 6A Switching Regulator | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT1370HVIR (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
LT1370
500kHz High Efficiency
6A Switching Regulator
FEATURES
s Faster Switching with Increased Efficiency
s Uses Small Inductors: 4.7µH
s All Surface Mount Components
s Low Minimum Supply Voltage: 2.7V
s Quiescent Current: 4.5mA Typ
s Current Limited Power Switch: 6A
s Regulates Positive or Negative Outputs
s Shutdown Supply Current: 12µA Typ
s Easy External Synchronization
s Switch Resistance: 0.065Ω Typ
U
APPLICATIONS
s Boost Regulators
s Laptop Computer Supplies
s Multiple Output Flyback Supplies
s Inverting Supplies
DESCRIPTION
The LT®1370 is a monolithic high frequency current mode
switching regulator. It can be operated in all standard
switching configurations including boost, buck, flyback,
forward, inverting and “Cuk.” A 6A high efficiency switch
is included on the die, along with all oscillator, control and
protection circuitry.
The LT1370 typically consumes only 4.5mA quiescent
current and has higher efficiency than previous parts.
High frequency switching allows for very small inductors
to be used.
New design techniques increase flexibility and maintain
ease of use. Switching is easily synchronized to an exter-
nal logic level source. A logic low on the Shutdown pin
reduces supply current to 12µA. Unique error amplifier
circuitry can regulate positive or negative output voltage
while maintaining simple frequency compensation tech-
niques. Nonlinear error amplifier transconductance
reduces output overshoot on start-up or overload recov-
ery. Oscillator frequency shifting protects external com-
ponents during overload conditions.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
ON
OFF
+ C1**
22µF
25V
5V to 12V Boost Converter
5V
L1*
D1
MBRD835L
VOUT†
12V
VIN
S/S VSW
LT1370
FB
GND VC
C2
0.047µF
R3
2k
R1
53.6k
1%
+
R2
6.19k
1%
C3
0.0047µF
C4**
22µF
25V
×2
*COILTRONICS
UP2-4R7 (4.7µH)
UP4-100 (10µH)
**AVX TPSD226M025R0200
†MAX IOUT
L1 IOUT
4.7µH 1.8A
10µH 2A
LT1370 • TA01
12V Output Efficiency
92
VIN = 5V
L = 10µH
90
88
86
84
82
80
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
LT1370 • TA02
1
1 page  
TYPICAL PERFORMANCE CHARACTERISTICS
VC Pin Threshold and High
Clamp Voltage vs Temperature
2.2
2.0
1.8 VC HIGH CLAMP
1.6
1.4
1.2
VC THRESHOLD
1.0
–50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1370 • G10
Feedback Input Current
vs Temperature
800
700 VFB =VREF
600
500
400
300
200
100
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1370 • G11
LT1370
Negative Feedback Input Current
vs Temperature
0
VNFB =VNFR
–10
–20
–30
–40
–50
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
LT1370 • G12
PIN FUNCTIONS
VC: The Compensation pin is used for frequency compen-
sation, current limiting and soft start. It is the output of the
error amplifier and the input of the current comparator.
Loop frequency compensation can be performed with an
RC network connected from the VC pin to ground. See
Applications Information.
FB: The Feedback pin is used for positive output voltage
sensing and oscillator frequency shifting. It is the invert-
ing input to the error amplifier. The noninverting input of
this amplifier is internally tied to a 1.245V reference.
NFB: The Negative Feedback pin is used for negative
output voltage sensing. It is connected to the inverting
input of the negative feedback amplifier through a 100k
source resistor.
S/S: Shutdown and Synchronization Pin. The S/S pin is
logic level compatible. Shutdown is active low and the
shutdown threshold is typically 1.3V. For normal opera-
tion, pull the S/S pin high, tie it to VIN or leave it floating. To
synchronize switching, drive the S/S pin between 600kHz
and 800kHz. See Applications Information.
VIN: Bypass Input Supply Pin with a Low ESR Capacitor,
10µF or More. The regulator goes into undervoltage lock-
out when VIN drops below 2.5V. Undervoltage lockout
stops switching and pulls the VC pin low.
VSW: The Switch pin is the collector of the power switch
and has large currents flowing through it. Keep the traces
to the switching components as short as possible to
minimize radiation and voltage spikes.
GND: Tie all ground pins to a good quality ground plane.
See Applications Information.
5
5 Page 
UU W U
APPLICATIO S I FOR ATIO
Layout Considerations
For maximum efficiency, LT1370 switch rise and fall times
are made as short as possible. To prevent radiation and
high frequency resonance problems, proper layout of the
components connected to the switch node is essential. B
field (magnetic) radiation is minimized by keeping output
diode, switch pin and output bypass capacitor leads as
short as possible. Figure 3 shows recommended posi-
tions for these components. E field radiation is kept low by
minimizing the length and area of all traces connected to
the switch pin. A ground plane should always be used
under the switcher circuitry to prevent interplane
coupling.
LT1370
The high speed switching current path is shown schemati-
cally in Figure 4. Minimum lead length in this path is
essential to ensure clean switching and low EMI. The path
including the switch, output diode and output capacitor is
the only one containing nanosecond rise and fall times.
Keep this path as short as possible.
More Help
For more detailed information on switching regulator
circuits, please see Application Note 19. Linear
Technology also offers a computer software program,
SwitcherCADTM, to assist in designing switching convert-
ers. In addition, our Applications Department is always
ready to lend a helping hand.
SwitcherCAD is a trademark of Linear Technology Corporation.
FB GND NFB
VC S/S VSW VIN
C
C
D KEEP PATH FROM
VSW, OUTPUT DIODE,
OUTPUT CAPACITORS
AND GROUND RETURN
AS SHORT AS POSSIBLE
LT1370 • F03
Figure 3. Layout Considerations— R Package
SWITCH
L1 NODE
HIGH
VIN FREQUENCY
CIRCULATING
PATH
Figure 4
VOUT
LOAD
LT1370 • F04
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LT1370HVIR.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT1370HVIR | 500kHz High Efficiency 6A Switching Regulator | Linear Technology |
| LT1370HVIT7 | 500kHz High Efficiency 6A Switching Regulator | Linear Technology |
| 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 |