поискавой системы для электроныых деталей
  Russian  ▼
ALLDATASHEETRU.COM

X  

LM22670 датащи(PDF) 10 Page - Texas Instruments

номер детали LM22670
подробное описание детали  LM22670/-Q1 42 V, 3 A SIMPLE SWITCHER짰, Step-Down Voltage Regulator with Features
Download  32 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
производитель  TI [Texas Instruments]
домашняя страница  http://www.ti.com
Logo TI - Texas Instruments

LM22670 датащи(HTML) 10 Page - Texas Instruments

Back Button LM22670_15 Datasheet HTML 6Page - Texas Instruments LM22670_15 Datasheet HTML 7Page - Texas Instruments LM22670_15 Datasheet HTML 8Page - Texas Instruments LM22670_15 Datasheet HTML 9Page - Texas Instruments LM22670_15 Datasheet HTML 10Page - Texas Instruments LM22670_15 Datasheet HTML 11Page - Texas Instruments LM22670_15 Datasheet HTML 12Page - Texas Instruments LM22670_15 Datasheet HTML 13Page - Texas Instruments LM22670_15 Datasheet HTML 14Page - Texas Instruments Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 32 page
background image
LM22670, LM22670-Q1
SNVS584P – SEPTEMBER 2008 – REVISED NOVEMBER 2014
www.ti.com
Feature Description (continued)
7.3.3 Switching Frequency Adjustment and Synchronization
The LM22670 device will operate in three different modes, depending on the condition of the RT/SYNC pin. With
the RT/SYNC pin floating, the regulator will switch at the internally set frequency of 500 kHz (typ). With a resistor
in the range of 25 k
Ω to 200 kΩ, connected from RT/SYNC to ground, the internal switching frequency can be
adjusted from 1 MHz to 200 kHz. Figure 12 shows the typical curve for switching frequency versus the external
resistance connected to the RT/SYNC pin. The accuracy of the switching frequency in this mode is slightly worse
than that of the internal oscillator; about ±25% is to be expected. Finally, an external clock can be applied to the
RT/SYNC pin to allow the regulator to synchronize to a system clock or another LM22670 device. The mode is
set during start up of the regulator. When the LM22670 device is enabled, or after VIN is applied, a weak pullup is
connected to the RT/SYNC pin and, after approximately 100 µs, the voltage on the pin is checked against a
threshold of about 0.8 V. With the RT/SYNC pin open, the voltage floats above this threshold and the mode is
set to run with the internal clock. With a frequency set resistor present, an internal reference holds the pin
voltage at 0.8 V; therefore, the resulting current sets the mode to allow the resistor to control the clock frequency.
If the external circuit forces the RT/SYNC pin to a voltage much greater or less than 0.8 V, the mode is set to
allow external synchronization. The mode is latched until either the EN or the input supply is cycled.
The choice of switching frequency is governed by several considerations. For example, lower frequencies may
be desirable to reduce switching losses or improve duty cycle limits. Higher frequencies, or a specific frequency,
may be desirable to avoid problems with EMI or reduce the physical size of external components. The flexibility
of increasing the switching frequency above 500 kHz can also be used to operate outside a critical signal
frequency band for a given application. Keep in mind that the values of inductors and output capacitors cannot
be reduced dramatically by operating above 500 kHz. This is true because the design of the internal loop
compensation restricts the range of these components.
Frequency synchronization requires some care. First, the external clock frequency must be greater than the
internal clock frequency and less than 1 MHz. The maximum internal switching frequency is ensured in the
Electrical Characteristics table.
NOTE
The frequency adjust feature and the synchronization feature cannot be used
simultaneously.
The synchronizing frequency must always be greater than the internal clock frequency. Secondly, the RT/SYNC
pin must see a valid high or low voltage during start up in order for the regulator to go into the synchronizing
mode. Also, the amplitude of the synchronizing pulses must comport with VSYNC levels found in the Electrical
Characteristics table. The regulator will synchronize on the rising edge of the external clock. If the external clock
is lost during normal operation, the regulator will revert to the 500 kHz (typ) internal clock.
If the frequency synchronization feature is used, current limit foldback is not operational (see Current Limit for
details).
Figure 12. Switching Frequency vs RT/SYNC Resistor
10
Submit Documentation Feedback
Copyright © 2008–2014, Texas Instruments Incorporated
Product Folder Links: LM22670 LM22670-Q1


Аналогичный номер детали - LM22670_15

производительномер деталидатащиподробное описание детали
logo
Texas Instruments
LM22670 TI1-LM22670_17 Datasheet
1Mb / 32P
[Old version datasheet]   42-V, 3-A SIMPLE SWITCHER, Step-Down Voltage Regulator With Features
More results

Аналогичное описание - LM22670_15

производительномер деталидатащиподробное описание детали
logo
Texas Instruments
LM22676 TI-LM22676_15 Datasheet
1Mb / 29P
[Old version datasheet]   LM22676/-Q1 42 V, 3 A SIMPLE SWITCHER짰 Step-Down Voltage Regulator with Features
LM22673 TI-LM22673_15 Datasheet
1Mb / 29P
[Old version datasheet]   LM22673/-Q1 42 V, 3 A SIMPLE SWITCHER짰, Step-Down Voltage Regulator with Features
LM22675 TI-LM22675_15 Datasheet
1Mb / 26P
[Old version datasheet]   LM22675/-Q1 42 V, 1 A SIMPLE SWITCHER짰 Step-Down Voltage Regulator with Features
LM22677 TI-LM22677_15 Datasheet
1Mb / 28P
[Old version datasheet]   LM22677/-Q1 42-V, 5-A SIMPLE SWITCHER짰, Step-Down Voltage Regulator With Features
LM22679 TI-LM22679_15 Datasheet
1Mb / 27P
[Old version datasheet]   LM22679/-Q1 42-V, 5-A SIMPLE SWITCHER짰 Step-Down Voltage Regulator With Features
LM22674 TI-LM22674_15 Datasheet
1Mb / 26P
[Old version datasheet]   LM22674/-Q1 42 V, 500 mA SIMPLE SWITCHER짰 Step-Down Voltage Regulator with Features
LM22671 TI-LM22671_15 Datasheet
1Mb / 29P
[Old version datasheet]   LM22671/-Q1 42 V, 500 mA SIMPLE SWITCHER짰 Step-Down Voltage Regulator with Features
LM22670 TI1-LM22670_17 Datasheet
1Mb / 32P
[Old version datasheet]   42-V, 3-A SIMPLE SWITCHER, Step-Down Voltage Regulator With Features
LM22672 TI-LM22672_15 Datasheet
1Mb / 30P
[Old version datasheet]   SIMPLE SWITCHER짰 Step-Down Voltage Regulator with Features
logo
National Semiconductor ...
LM22680 NSC-LM22680 Datasheet
568Kb / 16P
   2A SIMPLE SWITCHER짰, Step-Down Voltage Regulator with Features
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 23 24 25 26 27 28 29 30 31 32


датащи скачать

Go To PDF Page


ссылки URL




Конфиденциальность
ALLDATASHEETRU.COM
Вашему бизинису помогли Аллдатащит?  [ DONATE ] 

Что такое Аллдатащит   |   реклама   |   контакт   |   Конфиденциальность   |   обмен ссыками   |   поиск по производителю
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