LTM4605IV#PBF Linear Technology, LTM4605IV#PBF Datasheet - Page 9

• Manufacturer Part Number: LTM4605IV#PBF
• Description: IC DC/DC UMODULE 5A 141-LGA
• Manufacturer: Linear Technology
• Series: µModuler
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LTM4605IV#PBF

• Design Resources: LTM4605 Spice Model
• Output: 0.8 ~ 16 V
• Number Of Outputs: 1
• Power (watts): 80W
• Mounting Type: Surface Mount
• Voltage - Input: 4.5 ~ 20V
• Package / Case: 141-LGA
• 1st Output: 0.8 ~ 16 VDC @ 5A
• Size / Dimension: 0.59" L x 0.59" W x 0.11" H (15mm x 15mm x 2.8mm)
• Power (watts) - Rated: 80W
• Operating Temperature: -40°C ~ 85°C
• Efficiency: 98%
• Dc To Dc Converter Type: Non-Inverting/Inverting/Step Up/Step Down
• Pin Count: 141
• Input Voltage: 20V
• Output Voltage: 0.8 to 16V
• Switching Freq: 170 TO 440KHz
• Output Current: 12/5A
• Package Type: LGA
• Output Type: Adjustable
• Switching Regulator: Yes
• Load Regulation: 0.5%
• Line Regulation: 0.02%
• Mounting: Surface Mount
• Input Voltage (min): 4.5V
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• 2nd Output: -
• Lead Free Status / Rohs Status: Compliant

OPERATION
APPLICATIONS INFORMATION
Power Module Description
The LTM4605 is a non-isolated buck-boost DC/DC power
supply. It can deliver a wide range output voltage from
0.8V to 16V over a wide input range from 4.5V to 20V,
by only adding the sensing resistor, inductor and some
external input and output capacitors. It provides precisely
regulated output voltage programmable via one external
resistor. The typical application schematic is shown in
Figure 16.
The LTM4605 has an integrated current mode buck-boost
controller, ultralow R
and integrated Schottky diodes. With current mode control
and internal feedback loop compensation, the LTM4605
module has suffi cient stability margins and good transient
performance under a wide range of operating conditions
and with a wide range of output capacitors. The operating
frequency of the LTM4605 can be adjusted from 200kHz
to 400kHz by setting the voltage on the PLLFLTR pin.
The typical LTM4605 application circuit is shown in
Figure 16. External component selection is primarily
determined by the maximum load current and output
voltage. Refer to Table 3 for specifi c external capacitor
requirements for a particular application.
Output Voltage Programming
The PWM controller has an internal 0.8V reference voltage.
As shown in the Block Diagram, a 100k, internal feedback
resistor connects V
resistor R
the output voltage:
V
OUT
= 0.8V •
FB
from the V
100k + R
OUT
DS(ON)
R
FB
FB
and V
pin to the SGND pin programs
FB
FETs with fast switching speed
FB
pins together. Adding a
Alternatively, its frequency can be synchronized by the
input clock signal from the PLLIN pin. The typical switch-
ing frequency is 400kHz.
The Burst Mode and skip-cycle mode operations can
be enabled at light loads in the LTM4605 to improve its
effi ciency, while the forced continuous mode and discon-
tinuous mode operations are used for constant frequency
applications. Foldback current limiting is activated in an
overcurrent condition as V
and undervoltage comparators pull the open-drain PGOOD
output low if the output feedback voltage exits the ±10%
window around the regulation point. Pulling the RUN pin
below 1.6V forces the controller into its shutdown state.
If an external bias supply is applied on the EXTV
an effi ciency improvement will occur due to the reduced
power loss in the internal linear regulator. This is especially
true at the higher input voltage range.
Table 1. R
Operation Frequency Selection
The LTM4605 uses current mode control architecture at
constant switching frequency, which is determined by the
internal oscillator’s capacitor. This internal capacitor is
charged by a fi xed current plus an additional current that
is proportional to the voltage applied to the PLLFLTR pin.
V
V
R
R
OUT
OUT
FB
FB
FB
Open
0.8V
11k
Resistor (0.5%) vs Various Output Voltages
8V
9.76k
115k
1.5V
9V
47.5k
8.66k
2.5V
FB
10V
drops. Internal overvoltage
32.4k
7.15k
3.3V
12V
LTM4605
5.62k
15V
19k
5V
CC
pin, then
15.4k
5.23k
16V
6V
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