LTM4611EV#PBF Linear Technology, LTM4611EV#PBF Datasheet - Page 13

• Manufacturer Part Number: LTM4611EV#PBF
• Description: IC UMODULE DC/DC LV 15A 133-LGA
• Manufacturer: Linear Technology
• Series: µModuler
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LTM4611EV#PBF

• Output: 0.8 ~ 5 V
• Number Of Outputs: 1
• Power (watts): 75W
• Mounting Type: Surface Mount
• Voltage - Input: 1.5 ~ 5.5 V
• Package / Case: 133-LGA
• 1st Output: 0.8 ~ 5 VDC @ 15A
• Size / Dimension: 0.59" L x 0.59" W x 0.17" H (15mm x 15mm x 4.32mm)
• Power (watts) - Rated: 75W
• Operating Temperature: -40°C ~ 125°C
• Efficiency: 94%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• 2nd Output: -

applicaTions inForMaTion
enabled by tying the MODE_PLLIN pin to GND. In this
mode, inductor current is allowed to reverse during low
output loads, the I
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 LTM4611’s output
voltage is in regulation.
Multiphase Operation
For outputs that demand more than 15A of load current,
multiple LTM4611 devices can be paralleled to provide
more output current without increasing input and output
voltage ripples. The MODE_PLLIN pin allows the LTM4611
to be synchronized to an external clock (between 360kHz
to 710kHz) and the internal phase-locked loop allows the
LTM4611 to lock onto input clock phase as well. The PLL-
FLTR/f
Figures 18 and 19 for a synchronizing example circuit.
A multiphase power supply significantly reduces the
amount of ripple current in both the input and output ca-
pacitors. The RMS input ripple current is reduced by, and
SET
pin has the onboard loop filter for the PLL. See
TH
Figure 2. Normalized Input RMS Ripple Current vs Duty Factor for One to Six µModules (Phases)
voltage is in control of the current
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
0.1
0.15
1 PHASE
2 PHASE
3 PHASE
4 PHASE
6 PHASE
0.2
0.25
0.3
0.35
0.4
DUTY FACTOR (V
0.45
the effective ripple frequency is multiplied by, the number
of phases used (assuming that the input voltage is greater
than the number of phases used times the output voltage).
The output ripple amplitude is also reduced by the number
of phases used. See Application Note 77.
The LTM4611 device is an inherently current mode con-
trolled device, so parallel modules will have good current
sharing. This will balance the thermals on the design.
Tie the COMP, V
together to share the current evenly. In addition, tie the
respective TRACK/SS and RUN pins of paralleled LTM4611
devices together, to ensure proper start-up and shutdown
behavior. Figures 18 and 19 show schematics of LTM4611
devices operating in parallel.
Input RMS Ripple Current Cancellation
Application Note 77 provides a detailed explanation of
multiphase operation. The input RMS ripple current can-
cellation mathematical derivations are presented, and a
graph is displayed representing the RMS ripple current
reduction as a function of the number of interleaved phases
(see Figure 2).
0.5
0.55
OUT
/V
0.6
IN
)
0.65
0.7
OUT_LCL
0.75 0.8
4617#3EM
0.85 0.9
and V
F02
FB
pins of each LTM4611
LTM4611

4611f