Os motores de busca de Datasheet de Componentes eletrônicos
  Portuguese  ▼
ALLDATASHEETPT.COM

X  

LM2744 Folha de dados(PDF) 11 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Nome de Peças LM2744
Descrição Electrónicos  Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
Download  22 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricante Electrônico  NSC [National Semiconductor (TI)]
Página de início  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM2744 Folha de dados(HTML) 11 Page - National Semiconductor (TI)

Back Button LM2744 Datasheet HTML 7Page - National Semiconductor (TI) LM2744 Datasheet HTML 8Page - National Semiconductor (TI) LM2744 Datasheet HTML 9Page - National Semiconductor (TI) LM2744 Datasheet HTML 10Page - National Semiconductor (TI) LM2744 Datasheet HTML 11Page - National Semiconductor (TI) LM2744 Datasheet HTML 12Page - National Semiconductor (TI) LM2744 Datasheet HTML 13Page - National Semiconductor (TI) LM2744 Datasheet HTML 14Page - National Semiconductor (TI) LM2744 Datasheet HTML 15Page - National Semiconductor (TI) Next Button
Zoom Inzoom in Zoom Outzoom out
 11 / 22 page
background image
Application Information (Continued)
A desired delay time t
DELAY between the startup of the
master supply output voltage and the LM2744 output voltage
can be set based on the SD pin low-to-high threshold V
SD-IH
and the slew rate of the voltage at the SD pin, SR
SD:
t
DELAY =VSD-IH /SRSD
Note again, that in Figure 4, the LM2744’s output voltage
has been represented symbolically as V
OUT2, i.e. without
explicitly showing the power components.
V
SD-IH is typically 1.08V and SRSD is the slew rate of the SD
pin voltage. The values of the sequencing divider resistors
R
S1 and RS2 set the SRSD based on the master supply
output voltage slew rate, SR
OUT1, using the following equa-
tion:
For example, if the master supply output voltage slew rate
was 1V/ms and the desired delay time between the startup
of the master supply and LM2744 output voltage was 5ms,
then the desired SD pin slew rate would be (1.08V/5ms) =
0.216V/ms. Due to the internal impedance of the SD pin, the
maximum recommended value for R
S2 is 1k
Ω. To achieve
the desired slew rate, R
S2 would then be 274
Ω. A timing
diagram for this example is shown in Figure 5.
SD PIN IMPEDANCE
When connecting a resistor divider to the SD pin of the
LM2744 some care has to be taken. Once the SD voltage
goes above V
SD-IH, a 17 µA pull-up current is activated as
shown in Figure 6. This current is used to create the internal
hysteresis ()170mV); however, high external impedances
will affect the SD pin logic thresholds as well. The external
impedance used for the sequencing divider network should
preferably be a small fraction of the impedance of the SD pin
for good performance (around 1k
Ω).
MOSFET GATE DRIVERS
The LM2744 has two gate drivers designed for driving
N-channel MOSFETs in a synchronous mode. Note that
unlike most other synchronous controllers, the bootstrap
capacitor of the LM2744 provides power not only to the
driver of the upper MOSFET, but the lower MOSFET driver
20106014
FIGURE 4. Sequencing Circuit
20106011
FIGURE 5. Delay for Sequencing
20106006
FIGURE 6. SD Pin Logic
www.national.com
11


Nº de peça semelhante - LM2744

Fabricante ElectrônicoNome de PeçasFolha de dadosDescrição Electrónicos
logo
Texas Instruments
LM2744 TI1-LM2744 Datasheet
1Mb / 32P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
LM2744 TI-LM2744 Datasheet
1Mb / 33P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
LM2744MTC/NOPB TI-LM2744MTC/NOPB Datasheet
1Mb / 33P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
LM2744MTCX/NOPB TI-LM2744MTCX/NOPB Datasheet
1Mb / 33P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
LM2744 TI-LM2744_15 Datasheet
1Mb / 33P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
More results

Descrição semelhante - LM2744

Fabricante ElectrônicoNome de PeçasFolha de dadosDescrição Electrónicos
logo
Texas Instruments
LM2744 TI1-LM2744 Datasheet
1Mb / 32P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
LM2744 TI-LM2744_15 Datasheet
1Mb / 33P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference
logo
National Semiconductor ...
LM2746 NSC-LM2746 Datasheet
1Mb / 24P
   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller
logo
Texas Instruments
LM2743 TI1-LM2743_14 Datasheet
1Mb / 37P
[Old version datasheet]   Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller
LM2743 TI-LM2743_15 Datasheet
1Mb / 41P
[Old version datasheet]   LM2743 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller
LM2743MTCX TI-LM2743MTCX Datasheet
1Mb / 37P
[Old version datasheet]   LM2743 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller
LM2743 TI1-LM2743 Datasheet
1Mb / 41P
[Old version datasheet]   LM2743 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller
logo
Feature Integration Tec...
F72815 FINTEK-F72815 Datasheet
637Kb / 18P
   Synchronous Buck PWM DC-DC Controller with External Reference Voltage Input
logo
Winbond
W83321S WINBOND-W83321S Datasheet
795Kb / 18P
   N-Channel FET Synchronous Buck Regulator Controller
logo
Nuvoton Technology Corp...
W83320G NUVOTON-W83320G Datasheet
422Kb / 20P
   N-Channel FET Synchronous Buck Regulator Controller
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22


Folha de dados Download

Go To PDF Page


Ligação URL




Privacy Policy
ALLDATASHEETPT.COM
ALLDATASHEET é útil para você?  [ DONATE ] 

Sobre Alldatasheet   |   Publicidade   |   Contato conosco   |   Privacy Policy   |   roca de Link   |   Lista de Fabricantes
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com