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PDF LTM4644 Data sheet ( Hoja de datos )
| Número de pieza | LTM4644 | |
| Descripción | Quad DC/DC uModule Regulator | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de LTM4644 (archivo pdf) en la parte inferior de esta página. Total 30 Páginas | ||
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LTM4644
FEATURES
Quad DC/DC µModule
Regulator with Configurable
4A Output Array
DESCRIPTION
n Quad Output Step-Down µModule® Regulator with 4A
per Output
n Wide Input Voltage Range: 4V to 14V
n 2.375V to 14V with External Bias
n 0.6V to 5.5V Output Voltage
n 4A DC, 5A Peak Output Current Each Channel
n Up to 5.5W Power Dissipation (TA = 60°C, 200 LFM,
No Heat Sink)
n ±1.5% Total Output Voltage Regulation
n Current Mode Control, Fast Transient Response
n Parallelable for Higher Output Current
n Output Voltage Tracking
n Internal Temperature Sensing Diode Output
n External Frequency Synchronization
n Overvoltage, Current and Temperature Protection
n 9mm × 15mm × 5.01mm BGA Package
APPLICATIONS
n Multirail Point of Load Regulation
n FPGAs, DSPs and ASICs Applications
L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule and PolyPhase are registered
trademarks and LTpowerCAD is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
The LTM®4644 is a quad DC/DC step-down µModule (mi-
cromodule) regulator with 4A per output. Outputs can be
paralleled in an array for up to 16A capability. Included
in the package are the switching controllers, power FETs,
inductors and support components. Operating over an
input voltage range of 4V to 14V or 2.375V to 14V with
an external bias supply, the LTM4644 supports an output
voltage range of 0.6V to 5.5V each set by a single external
resistor. Its high efficiency design delivers 4A continuous
(5A peak) output current per channel. Only bulk input and
output capacitors are needed.
Fault protection features include overvoltage, overcurrent
and overtemperature protection. The LTM4644 is offered
in 9mm ×15mm × 5.01mm BGA package. The LTM4644
is available with SnPb (BGA) or RoHS compliant terminal
finish.
Configurable Output Array*
4A
4A
4A
8A
4A
12A 16A
4A 4A 4A
* Note 4
Click to view associated TechClip Videos.
TYPICAL APPLICATION
4V to 14V Input, Quad 0.9V, 1V, 1.2V and
1.5V Output DC/DC µModule Regulator*
4V to 14V
22µF
×2
16V
CLKIN
VIN1
SVIN1
CLKOUT
VOUT1
FB1
RUN1
PGOOD1
LTM4644
VIN2
SVIN2
VOUT2
FB2
RUN2
PGOOD2
40.2k
60.4k
1.5V/4A
47µF
4V
1.2V/4A
47µF
4V
VIN3
SVIN3
RUN3
VOUT3
FB3
PGOOD3
90.9k
1V/4A
47µF
4V
VIN4
SVIN4
RUN4
TEMP
SGND
VOUT4
FB4
PGOOD4
GND
4644 TA01a
121k
0.9V/4A
47µF
4V
*TA = 60°C, 200LFM, NO HEAT SINK
For more information www.linear.com/LTM4644
1.5V Output Efficiency and
Power Loss (Each Channel)
95 2
90
85 1.5
80
75 1
70
65 0.5
60
55
0
VIN = 5V
VIN = 12V
0
1234
LOAD CURRENT (A)
4644 TA01b
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1 page  
TYPICAL PERFORMANCE CHARACTERISTICS
LTM4644
3.3V Output Transient Response
5V Output Transient Response
Start-Up with No Load
VOUT
50mV/DIV
AC-COUPLED
VOUT
50mV/DIV
AC-COUPLED
IIN
0.1A/DIV
LOAD STEP
1A/DIV
LOAD STEP
1A/DIV
VOUT
0.5V/DIV
20µs/DIV
4644 G07
VIN = 12V, VOUT = 3.3V, IOUT = 3A TO 4A, 1A/µs
OUTPUT CAPACITOR = 47µF CERAMIC
20µs/DIV
4644 G08
VIN = 12V, VOUT = 5V, IOUT = 3A TO 4A, 1A/µs
OUTPUT CAPACITOR = 47µF CERAMIC
5ms/DIV
4644 G09
VIN = 12V, VOUT = 1.5V
INPUT CAPACITOR = 150µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 22µF CERAMIC CAPACITOR
OUTPUT CAPACITOR = 47µF CERAMIC CAPACITOR
SOFT-START CAPACITOR = 0.1µF
Start-Up with 4A Load
Short-Circuit with No Load
Short-Circuit with 4A Load
IIN
0.2A/DIV
IIN
0.5A/DIV
IIN
0.5A/DIV
VOUT
0.5V/DIV
VOUT
0.5V/DIV
VOUT
0.5V/DIV
5ms/DIV
4644 G10
VIN = 12V, VOUT = 1.5V
INPUT CAPACITOR = 150µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 22µF CERAMIC CAPACITOR
OUTPUT CAPACITOR = 47µF CERAMIC CAPACITOR
SOFT-START CAPACITOR = 0.1µF
20µs/DIV
4644 G11
VIN = 12V, VOUT = 1.5V
INPUT CAPACITOR = 150µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 22µF CERAMIC CAPACITOR
OUTPUT CAPACITOR = 47µF CERAMIC CAPACITOR
20µs/DIV
4644 G12
VIN = 12V, VOUT = 1.5V
INPUT CAPACITOR = 150µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 22µF CERAMIC CAPACITOR
OUTPUT CAPACITOR = 47µF CERAMIC CAPACITOR
Recovery to No Load from
Short-Circuit
VOUT
200mV/DIV
IOUT
20A/DIV
Output Ripple
5mV/DIV
AC-COUPLED
Start Into Pre-Biased Output
VIN
2V/DIV
VOUT
1V/DIV
VIN = 12V
5µs/DIV
4644 G13
VOUT = 1V
INPUT CAPACITOR = 22µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 2× 22µF CERAMIC CAP.
OUTPUT CAPACITOR = 2× 47µF CERAMIC CAP.
SOFT-START CAPACITOR = 0.1µF
VIN = 12V
500µs/DIV
4644 G14
VOUT = 1.5V
INPUT CAPACITOR = 22µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 2× 22µF CERAMIC CAP.
OUTPUT CAPACITOR = 2× 47µF CERAMIC CAP.
SOFT-START CAPACITOR = 0.1µF
20MHz MEASUREMENT BANDWIDTH
VIN = 12V
1µs/DIV
4644 G15
VOUT = 5V
INPUT CAPACITOR = 22µF SANYO ELECTROLYTIC
CAPACITOR (OPTIONAL) + 2× 22µF CERAMIC CAP.
OUTPUT CAPACITOR = 2× 47µF CERAMIC CAP.
SOFT-START CAPACITOR = 0.1µF
For more information www.linear.com/LTM4644
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5 Page 
LTM4644
APPLICATIONS INFORMATION
Discontinuous Conduction Mode (DCM)
In applications where low output ripple and high efficiency
at intermediate current are desired, discontinuous con-
duction mode (DCM) should be used by connecting the
MODE pin to SGND. At light loads the internal current
comparator may remain tripped for several cycles and
force the top MOSFET to stay off for several cycles, thus
skipping cycles. The inductor current does not reverse
in this mode.
Force Continuous Conduction Mode (CCM)
In applications where fixed frequency operation is more
critical than low current efficiency, and where the lowest
output ripple is desired, forced continuous conduction
mode operation should be used. Forced continuous opera-
tion can be enabled by tying the MODE pin to INTVCC. In
this mode, inductor current is allowed to reverse during
low output loads, the COMP voltage is in control of the
current comparator threshold throughout, and the top
MOSFET always turns on with each oscillator pulse. During
start-up, forced continuous mode is disabled and inductor
current is prevented from reversing until the LTM4644’s
output voltage is in regulation.
be at least 400ns. The clock high level must be above 2V
and clock low level below 0.3V. During the start-up of
the regulator, the phase-locked loop function is disabled.
Multichannel Parallel Operation
For loads that demand more than 4A of output current,
the LTM4644 multiple regulator channels can be easily
paralleled to provide more output current without increas-
ing input and output voltage ripples. The LTM4644 has
preset built-in phase shift between each two of the four
regulator channels which is suitable to employ a 2+2, 3+1
or 4 channels parallel operation. Table 2 gives the phase
difference between regulator channels.
Table 2. Phase Difference Between Regulator Channels
CHANNEL
CH1 CH2 CH3 CH4
Phase Difference
180° 90° 180°
Figure 2 shows a 2+2 and a 4-channels parallel concept
schematic for clock phasing.
Operating Frequency
The operating frequency of the LTM4644 is optimized to
achieve the compact package size and the minimum output
ripplevoltage while still keeping high efficiency. The default
operating frequency is internally set to 1MHz. In most ap-
plications, no additional frequency adjusting is required.
If any operating frequency other than 1MHz is required
by application, the µModule regulator can be externally
synchronized to a clock from 700kHz to 1.3MHz.
CH1 180° CH2
(0°) (180°)
CH3 180° CH4
(0°) (180°)
VOUT1
VOUT2
LTM4644
VOUT3
VOUT4
8A 8A
Frequency Synchronization and Clock In
The power module has a phase-locked loop comprised
of an internal voltage controlled oscillator and a phase
detector. This allows all internal top MOSFET turn-on to
be locked to the rising edge of the same external clock.
The external clock frequency range must be within ±30%
around the 1MHz set frequency. A pulse detection circuit
is used to detect a clock on the CLKIN pin to turn on the
phase-locked loop. The pulse width of the clock has to
CH1 180° CH2 90° CH3 180° CH4
(0°)
(180°)
(270°)
(90°)
VOUT1
VOUT2
LTM4644
VOUT3
VOUT4
4644 F02
16A
Figure 2. 2+2 and 4 Channels Parallel Concept Schematic
For more information www.linear.com/LTM4644
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11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet LTM4644.PDF ] | |
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