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

X  

LTM4633 Fiches technique(PDF) 13 Page - Linear Technology

No de pièce LTM4633
Description  Triple 10A Step-DownDC/DC 關Module Regulator
Download  32 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  LINER [Linear Technology]
Site Internet  http://www.linear.com
Logo LINER - Linear Technology

LTM4633 Fiches technique(HTML) 13 Page - Linear Technology

Back Button LTM4633 Datasheet HTML 9Page - Linear Technology LTM4633 Datasheet HTML 10Page - Linear Technology LTM4633 Datasheet HTML 11Page - Linear Technology LTM4633 Datasheet HTML 12Page - Linear Technology LTM4633 Datasheet HTML 13Page - Linear Technology LTM4633 Datasheet HTML 14Page - Linear Technology LTM4633 Datasheet HTML 15Page - Linear Technology LTM4633 Datasheet HTML 16Page - Linear Technology LTM4633 Datasheet HTML 17Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 13 / 32 page
background image
LTM4633
13
4633f
For more information www.linear.com/LTM4633
applicaTions inForMaTion
PLL, Frequency Synchronization
The LTM4633 device operates up to 750kHz. It can also be
synchronizedwithaninputclockthathasahighlevelabove
2V and a low level below 0.8V at the MODE/PLLIN pin. The
FREQ/PLLLPF pin must be floating when synchronized to
an incoming clock. Once the LTM4633 is synchronized to
an external clock frequency, it will always be running in
forced continuous operation. The synchronizing range is
from 600kHz to 750kHz. For VOUT1,2,3 ≤ 1.5V use 600kHz,
and for VOUT1,2,3 ≥ 1.5V use ≥700kHz. These frequencies
optimize efficiency, eliminate minimum on-time issues
for less than 1V output, and control the inductor ripple
currents over the input and output voltage ranges.
A DC voltage should be applied to the FREQ/PLLLPF pin
to set the operating frequency when clock synchronization
is not used. A voltage divider from the INTVCC pin (5V) to
ground can be used to set the frequency to 600kHz (set
to 1.4V), 700kHz (set to 1.6V), or tie the FREQ/PLLLPF
pin to the INTVCC pin for 750kHz. The top resistor in the
voltage divider should be 50k, and the bottom resistor
should be 19.6k for 600kHz (set to 1.4V), or 23.7k for
700kHz (set to 1.6V). In most cases the FREQ/PLLLPF
pin can be tied to the INTVCC pin for 750kHz operation
as long as the minimum on-time is not below 100ns. See
Figure 18 for an example.
Parallel Channel Operation
For outputs that demand more than 10A of load current,
the LTM4633 device can parallel VOUT1 and VOUT2 to sup-
ply 20A of load current. The two channels will operate at
120° of phase shift. The input RMS ripple current can be
calculated using Equation 1. For example, 12V to 1.2V at
20A equates to duty cycle D = 0.1.
ICIN(RMS) =
20A
0.84
• 0.1• 1– 0.1
(
)
ICIN(RMS) = 7.14ARMS, use 4 × 22µF 16V X5R or X7R
ceramic capacitors rated at 2ARMS each.
The LTM4633 regulators are inherently current mode
controlled devices, so the paralleling of VOUT1 and VOUT2
channels will have good current sharing. This will balance
the thermals in the design. Tie the COMP, VFB, TK/SS
and RUN pins together for these two channels to share
the current evenly. Figure 18 shows a schematic of the
parallel design.
Minimum On-Time
Minimum on-time, tON, is the smallest time duration that
any of the three regulator channels is capable of turning on
the top MOSFET. It is determined by internal timing delays,
and the gate charge required to turn-on the top MOSFET.
Low duty cycle applications may approach this minimum
on-time limit and care should be taken to ensure that:
VOUT
VIN •FREQ
> tON(MIN)
If the duty cycle falls below what can be accommodated
by the minimum on-time, the controller will begin to skip
cycles.Theoutputvoltagewillcontinuetoberegulated,but
the output ripple and inductor ripple current will increase.
The minimum on-time can be increased by lowering the
switching frequency. A good rule of thumb is to use 100ns
for the minimum on-time.
Output Voltage Tracking
Output voltage tracking can be programmed externally
using the TK/SS pins. The output can be tracked up and
downwithanotherregulator.Themasterregulator’soutput
is divided down with an external resistor divider that is the
same as the slave regulator’s feedback divider to imple-
ment coincident tracking. The LTM4633 uses an accurate
60.4k resistor internally for the top feedback resistor for
each channel. Figure 2 shows an example of coincident
tracking for VOUT1 and VOUT2. VOUT1 is the master and
VOUT2 is the slave:
VSLAVE = 1+
60.4k
RTA


VTRACK


Numéro de pièce similaire - LTM4633

FabricantNo de pièceFiches techniqueDescription
logo
Linear Technology
LTM4633 LINER-LTM4633 Datasheet
746Kb / 32P
   Triple Output 5A/5A/4A Step-Down DC/DC 關Module짰 Regulator
logo
Analog Devices
LTM4633 AD-LTM4633 Datasheet
1Mb / 36P
   Quad DC/DC 關Module Regulator with Configurable Dual 12A, Dual 5A Output Array
Rev. B
logo
Linear Technology
LTM4633 LINER-LTM4633_15 Datasheet
519Kb / 32P
   Triple 10A Step-Down DC/DC Module Regulator
More results

Description similaire - LTM4633

FabricantNo de pièceFiches techniqueDescription
logo
Linear Technology
LTM4633 LINER-LTM4633_15 Datasheet
519Kb / 32P
   Triple 10A Step-Down DC/DC Module Regulator
LTM4649 LINER-LTM4649 Datasheet
1Mb / 30P
   10A Step-Down DC/DC 關Module Regulator
LTM4649 LINER-LTM4649_15 Datasheet
1Mb / 30P
   10A Step-Down DC/DC Module Regulator
logo
Analog Devices
LTM4658 AD-LTM4658 Datasheet
1Mb / 26P
   Low VIN, High Efficiency 10A Step-Down DC/DC 關Module Regulator
Rev. 0
logo
Linear Technology
LTM4649EY LINER-LTM4649EY Datasheet
667Kb / 8P
   High Efficiency 10A Step-Down 關Module Regulator
LTM4648 LINER-LTM4648 Datasheet
380Kb / 28P
   Low VIN, 10A Step-Down 關Module Regulator
logo
Analog Devices
LTM4705 AD-LTM4705 Datasheet
1Mb / 24P
   20VIN, Dual 5A or Single 10A Step-Down DC/DC 關Module Regulator
logo
Linear Technology
LTM4637 LINER-LTM4637 Datasheet
585Kb / 28P
   20A DC/DC 關Module Step-Down Regulator
LTM4647 LINER-LTM4647 Datasheet
1Mb / 34P
   30A DC/DC Step-Down 關Module Regulator
LTM4645 LINER-LTM4645 Datasheet
695Kb / 34P
   25A DC/DC Step-Down 關Module 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


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