Moteur de recherche de fiches techniques de composants électroniques
  French  ▼
ALLDATASHEET.FR

X  

LM2734-Q1 Fiches technique(PDF) 9 Page - Texas Instruments

Click here to check the latest version.
No de pièce LM2734-Q1
Description  Thin SOT 1-A Load Step-Down DC-DC Regulator
Download  36 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  TI1 [Texas Instruments]
Site Internet  http://www.ti.com
Logo TI1 - Texas Instruments

LM2734-Q1 Fiches technique(HTML) 9 Page - Texas Instruments

Back Button LM2734-Q1 Datasheet HTML 5Page - Texas Instruments LM2734-Q1 Datasheet HTML 6Page - Texas Instruments LM2734-Q1 Datasheet HTML 7Page - Texas Instruments LM2734-Q1 Datasheet HTML 8Page - Texas Instruments LM2734-Q1 Datasheet HTML 9Page - Texas Instruments LM2734-Q1 Datasheet HTML 10Page - Texas Instruments LM2734-Q1 Datasheet HTML 11Page - Texas Instruments LM2734-Q1 Datasheet HTML 12Page - Texas Instruments LM2734-Q1 Datasheet HTML 13Page - Texas Instruments Next Button
Zoom Inzoom in Zoom Outzoom out
 9 / 36 page
background image
LM2734
VIN
BOOST
SW
GND
CBOOST
L
D1
D2
D3
CIN
VIN
COUT
VOUT
VBOOST
LM2734Z, LM2734Z-Q1
www.ti.com
SNVS334F – JANUARY 2005 – REVISED JANUARY 2016
Feature Description (continued)
There are various methods to derive VBOOST:
1. From the input voltage (VIN)
2. From the output voltage (VOUT)
3. From an external distributed voltage rail (VEXT)
4. From a shunt or series zener diode
In Functional Block Diagram, capacitor CBOOST and diode D2 supply the gate-drive current for the NMOS switch.
Capacitor CBOOST is charged through diode D2 by VIN. During a normal switching cycle, when the internal NMOS
control switch is off (TOFF) (refer to Figure 7), VBOOST equals VIN minus the forward voltage of D2 (VFD2), during
which the current in the inductor (L) forward biases the Schottky diode D1 (VFD1). Therefore the voltage stored
across CBOOST is calculated using Equation 1.
VBOOST –VSW = VIN – VFD2 + VFD1
(1)
When the NMOS switch turns on (TON), the switch pin rises to:
VSW = VIN – (RDSON x IL),
(2)
forcing VBOOST to rise thus reverse biasing D2. The voltage at VBOOST is then:
VBOOST = 2 VIN – (RDSON x IL) – VFD2 + VFD1
(3)
which is approximately:
2 VIN – 0.4 V
(4)
for many applications. Thus the gate-drive voltage of the NMOS switch is approximately:
VIN –0.2 V
(5)
An alternate method for charging CBOOST is to connect D2 to the output as shown in Figure 8. The output voltage
must be between 2.5 V and 5.5 V, so that proper gate voltage is applied to the internal switch. In this circuit,
CBOOST provides a gate drive voltage that is slightly less than VOUT.
In applications where both VIN and VOUT are greater than 5.5 V, or less than 3 V, CBOOST cannot be charged
directly from these voltages. If VIN and VOUT are greater than 5.5 V, CBOOST can be charged from VIN or VOUT
minus a Zener voltage by placing a Zener diode D3 in series with D2, as shown in Figure 9. When using a series
Zener diode from the input, ensure that the regulation of the input supply does not create a voltage that falls
outside the recommended VBOOST voltage.
(VINMAX – VD3) < 5.5V
(6)
(VINMIN – VD3) > 1.6V
(7)
Figure 9. Zener Reduces Boost Voltage from VIN
An alternative method is to place the Zener diode D3 in a shunt configuration as shown in Figure 10. A small
350-mW to 500-mW, 5.1-V Zener in a SOT or SOD package can be used for this purpose. A small ceramic
capacitor such as a 6.3-V, 0.1-µF capacitor (C4) must be placed in parallel with the Zener diode. When the
internal NMOS switch turns on, a pulse of current is drawn to charge the internal NMOS gate capacitance. The
0.1-µF parallel shunt capacitor ensures that the VBOOST voltage is maintained during this time.
Copyright © 2005–2016, Texas Instruments Incorporated
Submit Documentation Feedback
9
Product Folder Links: LM2734Z LM2734Z-Q1


Numéro de pièce similaire - LM2734-Q1

FabricantNo de pièceFiches techniqueDescription
logo
National Semiconductor ...
LM2734 NSC-LM2734 Datasheet
459Kb / 22P
   Thin SOT23 1A Load Step-Down DC-DC Regulator
logo
Texas Instruments
LM2734 TI1-LM2734 Datasheet
1Mb / 31P
[Old version datasheet]   LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator
logo
National Semiconductor ...
LM27341 NSC-LM27341 Datasheet
717Kb / 30P
   2 MHz 1.5A/2A Wide Input Range Step-Down DC-DC Regulator with Frequency Synchronization
logo
Texas Instruments
LM27341 TI1-LM27341 Datasheet
1Mb / 42P
[Old version datasheet]   2 MHz 1.5A/2A Wide Input Range Step-Down DC-DC Regulator with Frequency Synchronization
LM27341 TI-LM27341 Datasheet
2Mb / 44P
[Old version datasheet]   LM27341/LM27342/LM27341-Q1/LM27342-Q1 2 MHz 1.5A/2A Wide Input Range Step-Down DC-DC Regulator with Frequency Synchronization
More results

Description similaire - LM2734-Q1

FabricantNo de pièceFiches techniqueDescription
logo
Texas Instruments
LM2734 TI-LM2734_15 Datasheet
1Mb / 37P
[Old version datasheet]   LM2734 Thin SOT 1-A Load Step-Down DC-DC Regulator
LM2734 TI1-LM2734 Datasheet
1Mb / 31P
[Old version datasheet]   LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator
LM2736YMKX TI-LM2736YMKX Datasheet
1Mb / 31P
[Old version datasheet]   LM2736 Thin SOT 750mA Load Step-Down DC-DC Regulator
LM2736XMK TI-LM2736XMK Datasheet
1Mb / 31P
[Old version datasheet]   LM2736 Thin SOT 750mA Load Step-Down DC-DC Regulator
LM2736YMK TI-LM2736YMK Datasheet
1Mb / 31P
[Old version datasheet]   LM2736 Thin SOT 750mA Load Step-Down DC-DC Regulator
LM2736XMK TI1-LM2736XMK Datasheet
1Mb / 31P
[Old version datasheet]   LM2736 Thin SOT 750mA Load Step-Down DC-DC Regulator
LM2736 TI-LM2736_15 Datasheet
1Mb / 36P
[Old version datasheet]   LM2736 Thin SOT 750 mA Load Step-Down DC-DC Regulator
LM2734Z TI-LM2734Z_15 Datasheet
1Mb / 32P
[Old version datasheet]   LM2734Z/LM2734ZQ Thin SOT 1A Load Step-Down DC-DC Regulator
logo
National Semiconductor ...
LM2736 NSC-LM2736 Datasheet
444Kb / 22P
   Thin SOT23 750mA Load Step-Down DC-DC Regulator
LM2734 NSC-LM2734 Datasheet
459Kb / 22P
   Thin SOT23 1A Load Step-Down DC-DC Regulator
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 33 34 35 36


Fiches technique Télécharger

Go To PDF Page


Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
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