LTM4604AEV#PBF Linear Technology, LTM4604AEV#PBF Datasheet - Page 10

• Manufacturer Part Number: LTM4604AEV#PBF
• Description: IC UMODULE DC/DC LV 4A 66-LGA
• Manufacturer: Linear Technology
• Series: µModuler
• Type: Point of Load (POL) Non-Isolatedr

Specifications of LTM4604AEV#PBF

• Design Resources: LTM4604A Spice Model
• Output: 0.8 ~ 5 V
• Number Of Outputs: 1
• Power (watts): 20W
• Mounting Type: Surface Mount
• Voltage - Input: 2.38 ~ 5.5 V
• Package / Case: 66-LGA
• 1st Output: 0.8 ~ 5 VDC @ 4A
• Size / Dimension: 0.59" L x 0.35" W x 0.09" H (15mm x 9mm x 2.3mm)
• Power (watts) - Rated: 20W
• Operating Temperature: -40°C ~ 125°C
• Efficiency: 95%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• 3rd Output: -
• 2nd Output: -

LTM4604A
Run Enable and Soft-Start
The RUN/SS pin provides dual functions of enable and
soft-start control. The RUN/SS pin is used to control turn
on of the LTM4604A. While this pin is below 0.5V, the
LTM4604A will be in a 7μA low quiescent current state.
A 0.8V threshold will enable the LTM4604A. This pin can
be used to sequence LTM4604A devices. The soft-start
control is provided by a 1M pull-up resistor (R
1000pF capacitor (C
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 is:
where R
Figure 1, 1.8V is the soft-start upper range, and C
is the additional capacitance for further soft-start contol.
The soft-start function can also be used to control the
output ramp-up time, so that another regulator can be
easily tracked. An independent ramp control signal can
be applied to the master ramp, otherwise, connect the
TRACK pin to V
Output Voltage Tracking
Output voltage tracking can be programmed externally
using the TRACK pin. The output can be tracked up and
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 LTM4604A uses a
very accurate 4.99k resistor for the top feedback resistor.
Figure 2 shows an example of coincident tracking.
V
V
to the point of the programmed value at which V
proceeds beyond the 0.8V reference value. The V
APPLICATIONS INFORMATION
10
TRACK
TRACK
t
V
SOFTSTART
TRACK
is the track ramp applied to the slave’s TRACK pin.
applies the track reference for the slave output up
SS
=
and C
4 99
= ln
.
IN
SS
R
to disable tracking.
k R
FB
+
V
SS
are shown in the Block Diagram of
2
IN
) as drawn in the Block Diagram.
FB
V
– 1.8V
IN
2
•
V
MASTER
• R
SS
(
C
SS
+ C
SSEXT
SS
) and a
TRACK
TRACK
SSEXT
)
pin must go beyond 0.8V to ensure the slave output has
reached its fi nal value. Load current must be present for
proper tracking.
C
SSEXT
X5R OR X7R
X5R OR X7R
Figure 2. Dual Outputs (3.3V and 1.5V) with Tracking
10μF
10μF
C
6.3V
C
6.3V
Figure 3. Output Voltage Coincident Tracking
IN1
IN2
PGOOD
COMP
RUN/SS
PGOOD
COMP
RUN/SS
LTM4604A
LTM4604A
GND
GND
V
V
V
V
5V
5V
IN
IN
IN
IN
TRACK
TRACK
V
V
OUT
OUT
FB
FB
R
5.76k
TIME
RAMP
CONTROL
OR V
FB2
IN
MASTER OUTPUT
R
4.99k
FB1
SLAVE OUTPUT
R
1.62k
R
5.76k
FB3
FB
4604A F03
C
22μF
6.3V ×3
X5R OR
X7R
C
22μF
6.3V ×3
X5R OR
X7R
OUT1
OUT2
4604A F02
V
3.3V
4A
V
1.5V
4A
MASTER
SLAVE
4604af