LTM4603HVEV#PBF Linear Technology, LTM4603HVEV#PBF Datasheet - Page 11

• Manufacturer Part Number: LTM4603HVEV#PBF
• Description: IC DC/DC UMODULE 6A 118-LGA
• Manufacturer: Linear Technology
• Series: µModuler
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LTM4603HVEV#PBF

• Design Resources: LTM4603HV Spice Model
• Output: 0.6 ~ 5 V
• Number Of Outputs: 1
• Power (watts): 30W
• Mounting Type: Surface Mount
• Voltage - Input: 4.5 ~ 28 V
• Package / Case: 118-LGA
• 1st Output: 0.6 ~ 5 VDC @ 6A
• Size / Dimension: 0.59" L x 0.59" W x 0.11" H (15mm x 15mm x 2.8mm)
• Power (watts) - Rated: 30W
• Operating Temperature: -40°C ~ 85°C
• Efficiency: 93%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• 2nd Output: -

APPLICATIO S I FOR ATIO
or choose a capacitor rated at a higher temperature than
required. Always contact the capacitor manufacturer for
derating requirements.
In Figure 20, the 10μF ceramic capacitors are together
used as a high frequency input decoupling capacitor. In a
typical 6A output application, two very low ESR, X5R or
X7R, 10μF ceramic capacitors are recommended. These
decoupling capacitors should be placed directly adjacent
to the module input pins in the PCB layout to minimize
the trace inductance and high frequency AC noise. Each
10μF ceramic is typically good for 2A to 3A of RMS ripple
current. Refer to your ceramics capacitor catalog for the
RMS current ratings.
Multiphase operation with multiple LTM4603HV devices in
parallel will lower the effective input RMS ripple current due
to the interleaving operation of the regulators. Application
Note 77 provides a detailed explanation. Refer to Figure 2
for the input capacitor ripple current requirement as a func-
tion of the number of phases. The fi gure provides a ratio
of RMS ripple current to DC load current as a function of
duty cycle and the number of paralleled phases. Pick the
corresponding duty cycle and the number of phases to
arrive at the correct ripple current value. For example, the
2-phase parallel LTM4603HV design provides 10A at 2.5V
output from a 12V input. The duty cycle is DC = 2.5V/12V
= 0.21. The 2-phase curve has a ratio of ~0.25 for a duty
cycle of 0.21. This 0.25 ratio of RMS ripple current to a
DC load current of 10A equals ~2.5A of input RMS ripple
current for the external input capacitors.
Figure 2. Normalized Input RMS Ripple Current
vs Duty Factor for One to Six Modules (Phases)
0.6
0.5
0.4
0.3
0.2
0.1
0
0.1
0.2
U
0.3
DUTY FACTOR (V
0.4
U
1-PHASE
2-PHASE
3-PHASE
4-PHASE
6-PHASE
0.5
OUT
0.6
/V
IN
0.7
W
)
0.8
4603HV F02
0.9
U
Output Capacitors
The LTM4603HV is designed for low output voltage ripple.
The bulk output capacitors defi ned as C
with low enough effective series resistance (ESR) to meet
the output voltage ripple and transient requirements. C
can be a low ESR tantalum capacitor, a low ESR polymer
capacitor or a ceramic capacitor. The typical capacitance is
200μF if all ceramic output capacitors are used. Additional
output fi ltering may be required by the system designer,
if further reduction of output ripple or dynamic transient
spike is required. Table 2 shows a matrix of different output
voltages and output capacitors to minimize the voltage
droop and overshoot during a 3A/μs transient. The table
optimizes total equivalent ESR and total bulk capacitance
to maximize transient performance.
Multiphase operation with multiple LTM4603HV devices
in parallel will lower the effective output ripple current
due to the interleaving operation of the regulators. For
example, each LTM4603HV’s inductor current of a 12V to
2.5V multiphase design can be read from the “Inductor
Ripple vs Duty Cycle” (Figure 3). The large ripple current
at low duty cycle and high output voltage can be reduced
by adding an external resistor from f
increases the frequency. If we choose the duty cycle of
DC = 2.5V/12V = 0.21, the inductor ripple current for 2.5V
output at 21% duty cycle is ~2A in Figure 3.
4
3
2
1
0
0
Figure 3. Inductor Ripple Current vs Duty Cycle
20
DUTY CYCLE (V
40
OUT
/V
IN
60
)
4603HV F03
LTM4603HV
80
SET
to ground which
OUT
2.5V OUTPUT
5V OUTPUT
1.8V OUTPUT
1.5V OUTPUT
1.2V OUTPUT
3.3V OUTPUT WITH
82.5k ADDED FROM
V
5V OUTPUT WITH
150k ADDED FROM
f
SET
OUT
are chosen
TO GND
TO f
SET
11
4603hvf
OUT