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PDF LTM4604 Data sheet ( Hoja de datos )
| Número de pieza | LTM4604 | |
| Descripción | 4A DC/DC uModule | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de LTM4604 (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
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www.DataSheet4U.com
LTM4604
Low Voltage, 4A DC/DC
µModuleTM with Tracking
FEATURES
■ Complete Standalone Power Supply
■ Wide Input Voltage Range: 2.375V to 5.5V
■ 4A DC, 5A Peak Output Current
■ 0.8V to 5V Output
■ Output Voltage Tracking
■ ±2% Total DC Error
■ UltraFastTM Transient Response
■ Power Good Indicator
■ Current Mode Control
■ Current Foldback Protection, Parallel/Current Sharing
■ Up to 95% Efficiency
■ Programmable Soft-Start
■ Micropower Shutdown: IQ ≤ 7μA
■ Overtemperature Protection
■ Small and Very Low Profile Package:
15mm × 9mm × 2.3mm LGA
APPLICATIONS
■ Telecom and Networking Equipment
■ Servers
■ Storage Cards
■ ATCA Cards
■ Industrial Equipment
DESCRIPTION
The LTM®4604 is a complete 4A switch mode DC/DC power
supply. Included in the package are the switching control-
ler, power FETs, inductor and all support components.
Operating over an input voltage range of 2.375V to 5.5V,
the LTM4604 supports an output voltage range of 0.8V
to 5V, set by a single resistor. This high efficiency design
delivers up to 4A continuous current (5A peak). Only bulk
output capacitors are needed to complete the design.
The low profile package (2.3mm) enables utilization of
unused space on the bottom of PC boards for high density
point of load regulation. High switching frequency and
a current mode architecture enable a very fast transient
response to line and load changes without sacrificing
stability. The device supports output voltage tracking for
supply rail sequencing.
Fault protection features include foldback current protec-
tion, thermal shutdown and a programmable soft-start
function. The LTM4604 is offered in a space saving and
thermally enhanced 15mm × 9mm × 2.3mm LGA package
and is Pb free and RoHS compliant.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
μModule and UltraFast are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
3.3V to 2.5V/4A μModule Regulator
VIN
3.3V
10μF
6.3V
VIN
PGOOD VOUT
LTM4604
COMP
FB
RUN/SS TRACK
GND
VIN
2.37k
VOUT
2.5V
4A
22μF
6.3V
×2
4604 TA01a
Efficiency vs Output Current
100
VIN = 3.3V
95 VOUT = 2.5V
90
85
80
75
70
65
01
23
OUTPUT CURRENT (A)
4
"$ " /
4604f
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TYPICAL PERFORMANCE CHARACTERISTICS
Start-Up
Start-Up
LTM4604
VOUT
1V/DIV
IIN
1A/DIV
VOUT
1V/DIV
IIN
1A/DIV
VIN = 5V
VOUT = 2.5V
COUT = 4 × 22μF
NO LOAD
200μs/DIV
(0.01μF SOFT-START CAPACITOR)
4604 G10
VFB vs Temperature
806
804
802
800
798
796
794
-50 -25
0 25 50
Temperature (C)
75 100
"$ " / #
Short-Circuit Protection
1.5V Short, No Load
VIN = 5V
VOUT = 2.5V
COUT = 4 × 22μF
4A LOAD
200μs/DIV
(0.01μF SOFT-START CAPACITOR)
4604 G11
Current Limit Foldback
1.6
1.4
1.2
1.0
0.8
0.6
0.4 VOUT = 1.5V
VIN = 5V
0.2 VIN = 3.3V
VIN = 2.5V
0
345
6
OUTPUT CURRENT (A)
7
8
4604 G12
Short-Circuit Protection
1.5V Short, 4A Load
VOUT
0.5V/DIV
IIN
4A/DIV
VOUT
0.5V/DIV
IIN
1A/DIV
20μs/DIV
4604 G13
100μs/DIV
4604 G14
4604f
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LTM4604
APPLICATIONS INFORMATION
Ratio metric modes of tracking can be achieved by selecting
different resistor values to change the output tracking ratio.
The master output must be greater than the slave output
for the tracking to work. Linear Technology Tracker Cad26
can be used to implement different tracking scenarios. The
Master and Slave data inputs can be used to implement
the correct resistor values for coincident or ratio tracking.
The master and slave regulators require load current for
tracking down.
Power Good
The PGOOD pin is an open-drain pin that can be used to
monitor valid output voltage regulation. This pin monitors
a ±7.5% window around the regulation point.
COMP Pin
The pin is the external compensation pin. The module
has already been internally compensated for all output
voltages. Table 4 is provided for most application require-
ments. A spice model will be provided for other control
loop optimizations.
Parallel Operation
The LTM4604 device is an inherently current mode con-
trolled device. Parallel modules will have very good current
sharing. This will balance the thermals on the design.
Figure 16 shows a schematic of the parallel design. The
voltage feedback changes with the variable N as more
modules are paralleled. The equation:
VOUT
=
0.8V
•
4.99k
N
+
RFB
RFB
N is the number of paralleled modules.
Thermal Considerations and Output Current Derating
The power loss curves in Figures 4 and 5 can be used
in coordination with the load derating curves in Figures
6 through 13 for calculating an approximate θJA for the
module with and without heat sinking methods with vari-
ous airflow conditions. Thermal models are derived from
several temperature measurements at the bench, and are
correlated with thermal analysis software. Tables 2 and
3 provide a summary of the equivalent θJA for the noted
conditions. These equivalent θJA parameters are correlated
to the measured values and improve with air flow. The
maximum junction temperature is monitored while the
derating curves are derived.
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
5V TO 1.2V
POWER LOSS
3.3V TO 1.2V
POWER LOSS
1234
LOAD CURRENT (A)
5
4604 F04
Figure 4. 1.2V Power Loss
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
5V TO 2.5V
POWER LOSS
3.3V TO 2.5V
POWER LOSS
1234
LOAD CURRENT (A)
5
4604 F05
Figure 5. 2.5V Power Loss
4604f
11
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet LTM4604.PDF ] | |
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