Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

LM27222SDX Scheda tecnica(PDF) 8 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Il numero della parte LM27222SDX
Spiegazioni elettronici  High-Speed 4.5A Synchronous MOSFET Driver
Download  11 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  NSC [National Semiconductor (TI)]
Homepage  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM27222SDX Scheda tecnica(HTML) 8 Page - National Semiconductor (TI)

Back Button LM27222SDX Datasheet HTML 3Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 4Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 5Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 6Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 7Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 8Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 9Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 10Page - National Semiconductor (TI) LM27222SDX Datasheet HTML 11Page - National Semiconductor (TI)  
Zoom Inzoom in Zoom Outzoom out
 8 / 11 page
background image
Application Information (Continued)
POWER DISSIPATION
The power dissipated in the driver IC when switching syn-
chronously can be calculated as follows:
where f
SW = switching frequency
V
CC = voltage at the VCC pin,
Q
G_H = total gate charge of the (parallel combination of the)
high-side MOSFET(s)
Q
G_L = total gate charge of the (parallel combination of the)
low-side MOSFET(s)
R
G_H = gate resistance of the (parallel combination of the)
high-side MOSFET(s)
R
G_L = gate resistance of the (parallel combination of the)
low-side MOSFET(S)
R
H_pu = pull-up RDS_ON of the high-side driver
R
H_pd = pull-down RDS_ON of the high-side driver
R
L_pu = pull-up RDS_ON of the low-side driver
R
L_pd = pull-down RDS_ON of the low-side driver
PC BOARD LAYOUT GUIDELINES
1.
Place the driver as close to the MOSFETs as possible.
2.
HG, SW, LG, GND: Run short, thick traces between the
driver and the MOSFETs. To minimize parasitics, the
traces for HG and SW should run parallel and close to
each other. The same is true for LG and GND.
3.
Driver V
CC: Place the decoupling capacitor close to the
V
CC and GND pins.
4.
The high-current loop between the high-side and low-
side MOSFETs and the input capacitors should be as
small as possible.
5.
There should be enough copper area near the MOS-
FETs and the inductor for heat dissipation. Vias may
also be added to carry the heat to other layers.
TYPICAL APPLICATION CIRCUIT DESCRIPITON
The Application Example on the following page shows the
LM27222 being used with National’s LM27212, a 2-phase
hysteretic current mode controller. Although this circuit is
capable of operating from 5V to 28V, the components are
optimized for an input voltage range of 9V to 28V. The
high-side FET is selected for low gate charge to reduce
switching losses. For low duty cycles, the average current
through the high-side FET is relatively small and thus we
trade off higher conduction losses for lower switching losses.
The low-side FET is selected solely on R
DS_ON to minimize
conduction losses. If the input voltage range were 4V to 6V,
the MOSFET selection should be changed. First, much lower
voltage FETs can be used, and secondly, high-side FET
R
DS_ON becomes a larger loss factor than the switching
losses. Of course with a lower input voltage, the input ca-
pacitor voltage rating can be reduced and the inductor value
can be reduced as well. For a 4V to 6V application, the
inductor can be reduced to 200nH to 300nH. The switching
frequency of the LM27212 is determined by the allowed
ripple current in the inductor. This circuit is set for approxi-
mately 300kHz. At lower input voltages, higher frequencies
are possible without suffering a significant efficiency loss.
Although the LM27222 can support operating frequencies up
to 2MHz in many applications, the LM27212 should be lim-
ited to about 1MHz. The control architecture of the LM27212
and the low propagation times of the LM27222 potentially
gives this solution the fastest transient response in the
industry.
www.national.com
8


Codice articolo simile - LM27222SDX

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Texas Instruments
LM27222SD TI-LM27222SD Datasheet
843Kb / 16P
[Old version datasheet]   LM27222 High-Speed 4.5A Synchronous MOSFET Driver
LM27222SD/NOPB TI-LM27222SD/NOPB Datasheet
843Kb / 16P
[Old version datasheet]   LM27222 High-Speed 4.5A Synchronous MOSFET Driver
More results

Descrizione simile - LM27222SDX

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Texas Instruments
LM27222 TI-LM27222_15 Datasheet
843Kb / 16P
[Old version datasheet]   LM27222 High-Speed 4.5A Synchronous MOSFET Driver
logo
Semtech Corporation
SC1218 SEMTECH-SC1218 Datasheet
395Kb / 12P
   High Speed Synchronous MOSFET Driver
logo
National Semiconductor ...
LM2722 NSC-LM2722 Datasheet
162Kb / 8P
   High Speed Synchronous/Asynchronous MOSFET Driver
LM2724A NSC-LM2724A Datasheet
135Kb / 8P
   High Speed 3A Synchronous MOSFET Driver
logo
Semtech Corporation
SC1205 SEMTECH-SC1205 Datasheet
128Kb / 12P
   HIGH SPEED SYNCHRONOUS POWER MOSFET DRIVER
SC1205 SEMTECH-SC1205_04 Datasheet
254Kb / 12P
   High Speed Synchronous Power MOSFET Driver
logo
Samtec, Inc
SC1205CS SAMTEC-SC1205CS Datasheet
255Kb / 12P
   High Speed Synchronous Power MOSFET Driver
logo
Semtech Corporation
SC1405 SEMTECH-SC1405 Datasheet
133Kb / 12P
   HIGH SPEED SYNCHRONOUS POWER MOSFET SMART DRIVER
SC1211 SEMTECH-SC1211 Datasheet
270Kb / 11P
   High Speed, Combi-SenseTM Synchronous MOSFET Driver
SC1405B SEMTECH-SC1405B Datasheet
261Kb / 13P
   High Speed Synchronous Power MOSFET Smart Driver
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11


Scheda tecnica Scarica

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEETIT.COM
Lei ha avuto il aiuto da alldatasheet?  [ DONATE ] 

Di alldatasheet   |   Richest di pubblicita   |   contatti   |   Privacy Policy   |   scambio Link   |   Ricerca produttore
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