|
|
PDF LMR24210 Data sheet ( Hoja de datos )
| Número de pieza | LMR24210 | |
| Descripción | 1.0A Step-Down Voltage Regulator | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LMR24210 (archivo pdf) en la parte inferior de esta página. Total 18 Páginas | ||
|
No Preview Available !
LMR24210
October 17, 2011
SIMPLE SWITCHER® 42Vin, 1.0A Step-Down Voltage
Regulator in micro SMD
Features
■ Input voltage range of 4.5V to 42V
■ Output voltage range of 0.8V to 24V
■ Output current up to 1.0A
■ Integrated low RDS(ON) synchronous MOSFETs for high
efficiency
■ Up to 1 MHz switching frequency
■ Low shutdown Iq, 25 µA typical
■ Programmable soft-start
■ No loop compensation required
■ COT architecture with ERM
■ 28 bump micro SMD (2.45 x 3.64 x 0.60 mm) packaging
■ Fully enabled for WEBENCH®™ Power Designer
Performance Benefits
■ Tiny overall solution reduces system cost
■ Integrated synchronous MOSFETs provides high
efficiency at low output voltages
■ COT with ERM architecture requires no loop
compensation, reduces component count, and provides
ultra fast transient response
■ Stable with low ESR capacitors
Applications
■ Point-of-Load Conversions from 5V, 12V and 24V Rails
■ Space Constrained Applications
■ Industrial Distributed Power Applications
■ Power Meters
System Performance
Efficiency vs Load Current
(VOUT = 3.3V)
100
90
80
70
60
50
40
0.0
VIN = 4.5V
VIN = 9V
VIN = 12v
VIN = 24V
VIN = 42v
0.2 0.4 0.6 0.8
LOAD CURRENT (A)
VOUT Regulation vs Load Current
(VOUT = 3.3V)
0.20
0.15
0.10
0.05
0.00
1.0
30173870
-0.05
-0.10
-0.15
-0.20
0.0
VIN = 4.5V
VIN = 9V
VIN = 12V
VIN = 24V
VIN = 42V
0.2 0.4 0.6 0.8
LOAD CURRENT (A)
1.0
30173871
SIMPLE SWITCHER® is a registered trademark of National Semiconductor Corporation
© 2011 National Semiconductor Corporation 301738
www.national.com
Free Datasheet http://www.datasheet4u.com/
1 page  
Symbol
TSD
TSD-HYS
Parameter
Thermal shutdown temperature
Thermal shutdown temperature
hysteresis
Conditions
TJ rising
TJ falling
Min Typ Max Units
165 °C
20 °C
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the
device is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.
Note 3: Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical
Quality Control (SQC) methods. Limits are used to calculate National's Average Outgoing Quality Level (AOQL).
Note 4: VCC provides self bias for the internal gate drive and control circuits. Device thermal limitations limit external loading.
Note 5: θJA calculations were performed in general accordance with JEDEC standards JESD51–1 to JESD51–11.
5 www.national.com
Free Datasheet http://www.datasheet4u.com/
5 Page 
(5)
The LMR24210 can be remotely shutdown by pulling the volt-
age of the EN pin below 1V. In this shutdown mode, the SS
pin is internally grounded, the on-timer is disabled, and bias
currents are reduced. Releasing the EN pin allows normal
operation to resume because the EN pin is internally pulled
up.
30173825
FIGURE 1. Shutdown Implementation
Current Limit
Current limit detection is carried out during the off-time by
monitoring the re-circulating current through the synchronous
MOSFET. Referring to the Functional Block Diagram, when
the main MOSFET is turned off, the inductor current flows
through the load, the PGND pin and the internal synchronous
MOSFET. If this current exceeds 1.8A, the current limit com-
parator toggles, and as a result disabling the start of the next
on-time period. The next switching cycle starts when the re-
circulating current falls back below 1.8A (and the voltage at
the FB pin is below 0.8V). The inductor current is monitored
during the on-time of the synchronous MOSFET. As long as
the inductor current exceeds 1.8A, the main MOSFET will re-
main inhibited to achieve current limit. The operating frequen-
cy is lower during current limit due to a longer off-time.
Figure 2 illustrates an inductor current waveform. On aver-
age, the output current IOUT is the same as the inductor
current IL, which is the average of the rippled inductor current.
In case of current limit (the current limit portion of Figure 2),
the next on-time will not initiate until the current drops below
1.8A (assume the voltage at the FB pin is lower than 0.8V).
During each on-time the current ramps up an amount equal
to:
(6)
During current limit, the LMR24210 operates in a constant
current mode with an average output current IOUT(CL) equal to
1.8A + ILR / 2.
FIGURE 2. Inductor Current - Current Limit Operation
30173826
11
www.national.com
Free Datasheet http://www.datasheet4u.com/
11 Page | ||
| Páginas | Total 18 Páginas | |
| PDF Descargar | [ Datasheet LMR24210.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LMR24210 | LMR24210 SIMPLE SWITCHER 42Vin 1.0A Step-Down Voltage Regulator (Rev. G) |  Texas Instruments |
| LMR24210 | 1.0A Step-Down Voltage Regulator | National Semiconductor |
| 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 |