Zakładka z wyszukiwarką danych komponentów
  Polish  ▼
ALLDATASHEET.PL

X  

LM4960 Arkusz danych(PDF) 11 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Numer części LM4960
Szczegółowy opis  Piezoelectric Speaker Driver
Download  12 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Producent  NSC [National Semiconductor (TI)]
Strona internetowa  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM4960 Arkusz danych(HTML) 11 Page - National Semiconductor (TI)

Back Button LM4960 Datasheet HTML 4Page - National Semiconductor (TI) LM4960 Datasheet HTML 5Page - National Semiconductor (TI) LM4960 Datasheet HTML 6Page - National Semiconductor (TI) LM4960 Datasheet HTML 7Page - National Semiconductor (TI) LM4960 Datasheet HTML 8Page - National Semiconductor (TI) LM4960 Datasheet HTML 9Page - National Semiconductor (TI) LM4960 Datasheet HTML 10Page - National Semiconductor (TI) LM4960 Datasheet HTML 11Page - National Semiconductor (TI) LM4960 Datasheet HTML 12Page - National Semiconductor (TI)  
Zoom Inzoom in Zoom Outzoom out
 11 / 12 page
background image
Application Information (Continued)
CALCULATING OUTPUT CURRENT OF BOOST
CONVERTER (I
AMP)
As shown in Figure 2 which depicts inductor current, the load
current is related to the average inductor current by the
relation:
I
LOAD =IIND(AVG) x (1 - DC)
(7)
Where "DC" is the duty cycle of the application. The switch
current can be found by:
I
SW =IIND(AVG) + 1/2 (I
RIPPLE)
(8)
Inductor ripple current is dependent on inductance, duty
cycle, input voltage and frequency:
I
RIPPLE =DCx(VIN-VSW)/(fxL)
(9)
combining all terms, we can develop an expression which
allows the maximum available load current to be calculated:
I
LOAD(max) = (1–DC)x(ISW(max)–DC(VIN-VSW))/fL (10)
The equation shown to calculate maximum load current
takes into account the losses in the inductor or turn-OFF
switching losses of the FET and diode.
DESIGN PARAMETERS V
SW AND ISW
The value of the FET "ON" voltage (referred to as V
SW in
equations 7 thru 10) is dependent on load current. A good
approximation can be obtained by multiplying the "ON Re-
sistance" of the FET times the average inductor current.
FET on resistance increases at V
IN values below 5V, since
the internal N-FET has less gate voltage in this input voltage
range (see Typical Performance Characteristics curves).
Above V
IN = 5V, the FET gate voltage is internally clamped
to 5V.
The maximum peak switch current the device can deliver is
dependent on duty cycle. For higher duty cycles, see Typical
Performance Characteristics curves.
INDUCTOR SUPPLIERS
Recommended suppliers of inductors for the LM4960 in-
clude, but are not limited to Taiyo-Yuden, Sumida, Coilcraft,
Panasonic, TDK and Murata. When selecting an inductor,
make certain that the continuous current rating is high
enough to avoid saturation at peak currents. A suitable core
type must be used to minimize core (switching) losses, and
wire power losses must be considered when selecting the
current rating.
PCB LAYOUT GUIDELINES
High frequency boost converters require very careful layout
of components in order to get stable operation and low
noise. All components must be as close as possible to the
LM4802 device. It is recommended that a 4-layer PCB be
used so that internal ground planes are available.
Some additional guidelines to be observed:
1. Keep the path between L1, D1, and Co extremely short.
Parasitic trace inductance in series with D1 and Co will
increase noise and ringing.
2. The feedback components R1, R2 and C
f 1 must be kept
close to the FB pin of U1 to prevent noise injection on the FB
pin trace.
3. If internal ground planes are available (recommended)
use vias to connect directly to ground at pin 2 of U1, as well
as the negative sides of capacitors C
s1 and Co.
GENERAL MIXED-SIGNAL LAYOUT
RECOMMENDATION
This section provides practical guidelines for mixed signal
PCB layout that involves various digital/analog power and
ground traces. Designers should note that these are only
"rule-of-thumb" recommendations and the actual results will
depend heavily on the final layout.
Power and Ground Circuits
For 2 layer mixed signal design, it is important to isolate the
digital power and ground trace paths from the analog power
and ground trace paths. Star trace routing techniques (bring-
ing individual traces back to a central point rather than daisy
chaining traces together in a serial manner) can have a
major impact on low level signal performance. Star trace
routing refers to using individual traces to feed power and
ground to each circuit or even device. This technique will
take require a greater amount of design time but will not
increase the final price of the board. The only extra parts
required may be some jumpers.
Single-Point Power / Ground Connection
The analog power traces should be connected to the digital
traces through a single point (link). A "Pi-filter" can be helpful
in minimizing high frequency noise coupling between the
analog and digital sections. It is further recommended to
place digital and analog power traces over the correspond-
ing digital and analog ground traces to minimize noise cou-
pling.
Placement of Digital and Analog Components
All digital components and high-speed digital signals traces
should be located as far away as possible from analog
components and circuit traces.
Avoiding Typical Design / Layout Problems
Avoid ground loops or running digital and analog traces
parallel to each other (side-by-side) on the same PCB layer.
When traces must cross over each other do it at 90 degrees.
Running digital and analog traces at 90 degrees to each
other from the top to the bottom side as much as possible will
minimize capacitive noise coupling and crosstalk.
www.national.com
11


Podobny numer części - LM4960

ProducentNumer częściArkusz danychSzczegółowy opis
logo
Texas Instruments
LM4960 TI1-LM4960 Datasheet
783Kb / 20P
[Old version datasheet]   Piezoelectric Speaker Driver
LM4960SQ/NOPB TI1-LM4960SQ/NOPB Datasheet
783Kb / 20P
[Old version datasheet]   Piezoelectric Speaker Driver
More results

Podobny opis - LM4960

ProducentNumer częściArkusz danychSzczegółowy opis
logo
Texas Instruments
LM4960 TI1-LM4960 Datasheet
783Kb / 20P
[Old version datasheet]   Piezoelectric Speaker Driver
logo
Rohm
BU64562GWZ ROHM-BU64562GWZ Datasheet
721Kb / 24P
   Piezoelectric Actuator Driver
logo
R & E International, In...
RE46C100 RANDE-RE46C100 Datasheet
42Kb / 3P
   Piezoelectric Horn Driver Circuit
logo
Microchip Technology
RE46C100 MICROCHIP-RE46C100 Datasheet
124Kb / 4P
   Piezoelectric Horn Driver Circuit
2009
RE46C100 MICROCHIP-RE46C100_14 Datasheet
631Kb / 18P
   Piezoelectric Horn Driver Circuit
03/25/14
logo
Sanyo Semicon Device
LV8071LP SANYO-LV8071LP Datasheet
71Kb / 6P
   Piezoelectric Actuator Driver IC
logo
Texas Instruments
LM4962 TI1-LM4962_14 Datasheet
926Kb / 23P
[Old version datasheet]   Ceramic Speaker Driver
logo
National Semiconductor ...
LM4962 NSC-LM4962 Datasheet
1Mb / 22P
   Ceramic Speaker Driver
logo
Texas Instruments
LM4961 TI1-LM4961_14 Datasheet
1Mb / 23P
[Old version datasheet]   Ceramic Speaker Driver
logo
National Semiconductor ...
LM4961 NSC-LM4961 Datasheet
509Kb / 16P
   Ceramic Speaker Driver
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12


Arkusz danych Pobierz

Go To PDF Page


Link URL




Polityka prywatności
ALLDATASHEET.PL
Czy Alldatasheet okazała się pomocna?  [ DONATE ] 

O Alldatasheet   |   Reklama   |   Kontakt   |   Polityka prywatności   |   Linki   |   Lista producentów
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