LTM4614EV#PBF Linear Technology, LTM4614EV#PBF Datasheet - Page 10

• Manufacturer Part Number: LTM4614EV#PBF
• Description: IC UMODULE DC/DC DUAL 4A 144LGA
• Manufacturer: Linear Technology
• Series: µModuler
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LTM4614EV#PBF

• Design Resources: LTM4614 Spice Model
• Output: 0.8 ~ 5 V
• Number Of Outputs: 2
• Power (watts): 12W
• Mounting Type: Surface Mount
• Voltage - Input: 2.38 ~ 5.5 V
• Package / Case: 144-LGA
• 1st Output: 0.8 ~ 5 VDC @ 4A
• 2nd Output: 0.8 ~ 5 VDC @ 4A
• Size / Dimension: 0.59" L x 0.59" W x 0.11" H (15mm x 15mm x 2.8mm)
• Power (watts) - Rated: 12W
• Operating Temperature: -40°C ~ 125°C
• Efficiency: 95%
• Dc To Dc Converter Type: Step Down
• Pin Count: 144
• Input Voltage: 5.5V
• Output Voltage: 1.49V
• Switching Freq: 1250KHz
• Output Current: 4A
• Package Type: LGA
• Output Type: Fixed
• Switching Regulator: Yes
• Load Regulation: 1.5%
• Line Regulation: 0.3%
• Mounting: Surface Mount
• Input Voltage (min): 2.375V
• Operating Temperature Classification: Automotive
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• Lead Free Status / Rohs Status: Compliant

LTM4614
APPLICATIONS INFORMATION
Fault Conditions: Current Limit and Overcurrent
Foldback
The LTM4614 has current mode control, which inher-
ently limits the cycle-by-cycle inductor current not only
in steady-state operation, but also in transient.
Along with foldback current limiting in the event of an
overload condition, the LTM4614 has overtemperature
shutdown protection that inhibits switching operation
around 150°C for each channel.
Run Enable and Soft-Start
The RUN/SS pins provide a dual function of enable and
soft-start control for each channel. The RUN/SS pins are
used to control turn on of the LTM4614. While each enable
pin is below 0.5V, the LTM4614 will be in a low quiescent
current state. At least a 0.8V level applied to the enable
pins will turn on the LTM4614 regulators. This pin can be
used to sequence the regulator channels. The soft-start
control is provided by a 1M pull-up resistor (R
1000pF capacitor (C
each channel. An external capacitor can be applied to the
RUN/SS pin to increase the soft-start time. A typical value
is 0.01μF. The approximate equation for soft-start:
10
t
SOFTSTART
1.2V
4A
=In
⎛
⎝ ⎜
C3
100μF
6.3V
SS
V
IN
) as drawn in the Block Diagram for
V
– 1.8V
IN
C4
22μF
6.3V
⎞
⎠ ⎟
PGOOD1
1.5V
R
10k
• R
FB1
Figure 2. Dual Outputs (1.5V and 1.2V) with Tracking
SS
4.99k
R
TB
• C
SS
R3
10k
R
10k
TA
SS
PGOOD1
V
FB1
COMP1
TRACK1
RUN/SS1
OUT1
) and a
C1
22μF
6.3V
GND1
V
V
IN
IN1
LTM4614
3V TO 5.5V
GND2
V
where R
Figure 1, and 1.8V is the soft-start upper range. The
soft-start function can also be used to control the output
ramp-up time, so that another regulator can be easily
tracked to it.
Output Voltage Tracking
Output voltage tracking can be programmed externally
using the TRACK pins. Either output can be tracked up
or down with another regulator. The master regulator’s
output is divided down with an external resistor divider
that is the same as the slave regulator’s feedback divider to
implement coincident tracking. The LTM4614 uses a very
accurate 4.99k resistor for the internal top feedback resistor.
Figure 2 shows an example of coincident tracking.
Equations:
IN2
RUN/SS2
PGOOD2
TRACK1=
Slave = 1+
TRACK2
COMP2
V
OUT2
FB2
C2
22μF
6.3V
SS
⎛
⎝ ⎜
and C
⎛
⎝ ⎜
V
CONTROL
RAMP
R4
10k
IN
C
4.99k + R
4.99k
SSEXT1
R
OR
SS
PGOOD2
FB1
R
are shown in the Block Diagram of
FB1
⎞
⎠ ⎟
R
5.76k
FB2
• TRACK1
FB1
⎞
⎠ ⎟
C7
100μF
6.3V
• Master
4614 F02
C9
22μF
6.3V
1.5V
4A
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