LTC3610EWP LINER [Linear Technology], LTC3610EWP Datasheet - Page 15

• Manufacturer Part Number: LTC3610EWP
• Description: 24V, 12A Monolithic Synchronous Step-Down DC/DC Converter
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
INTV
An internal P-channel low dropout regulator produces the
5V supply that powers the drivers and internal circuitry
within the LTC3610. The INTV
RMS and must be bypassed to ground with a minimum of
4.7μF tantalum or ceramic capacitor. Good bypassing is
necessary to supply the high transient currents required
by the MOSFET gate drivers.
The EXTV
and control power from the output or another external
source during normal operation. Whenever the EXTV
pin is above 4.7V the internal 5V regulator is shut off and
an internal 50mA P-channel switch connects the EXTV
pin to INTV
until this pin drops below 4.5V. Do not apply more than
7V to the EXTV
following list summarizes the possible connections for
EXTV
1. EXTV
internal 5V regulator.
CC
CC
:
Regulator and EXTV
CC
CC
grounded. INTV
CC
pin can be used to provide MOSFET gate drive
V
. INTV
OUT1
CC
C
C
V
pin and ensure that EXTV
1μF
OUT
SEC
OUT2
+
+
CC
power is supplied from EXTV
IN4148
CC
C
1:N
T1
IN
CC
CC
is always powered from the
+
pin can supply up to 50mA
GND
V
Connection
IN
Figure 4. Secondary Output Loop and EXTV
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
PGND
PGND
PGND
SW
SW
SW
SW
SW
SW
SW
SW
PV
PV
PV
PV
PV
IN
IN
IN
IN
IN
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
17 18 19 20 21 22 23 24 25
CC
≤ V
IN
. The
CC
CC
CC
LTC3610
2. EXTV
3. EXTV
Soft-Start and Latchoff with the RUN/SS Pin
The RUN/SS pin provides a means to shut down the
LTC3610 as well as a timer for soft-start and overcurrent
latchoff. Pulling the RUN/SS pin below 0.8V puts the
LTC3610 into a low quiescent current shutdown (I
30μA). Releasing the pin allows an internal 1.2μA current
source to charge up the external timing capacitor C
RUN/SS has been pulled all the way to ground, there is a
delay before starting of about:
26 27 28 29 30 31 32
SW
SW
supply compatible with the MOSFET gate drive require-
ments (typically 5V) can improve overall effi ciency.
The low voltage output can be boosted using a charge
pump or fl yback winding to greater than 4.7V. The
system will start-up using the internal linear regulator
until the boosted output supply is available.
t
DELAY
CC
CC
connected to an external supply. A high effi ciency
=
CC
connected to an output derived boost network.
1.2μA
Connection
1.5V
EXTV
PGOOD
SGND
SGND
SGND
SGND
SGND
SGND
SGND
SGND
V
SGND
V
FCB
RNG
V
I
I
ON
ON
CC
FB
TH
C
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
SS
= 1.3s/μF
3610 F04
(
R4
R3
OPTIONAL EXTV
CONNECTION
5V < V
OUT2
< 7V
)
C
CC
SS
LTC3610
15
SS
3610fd
Q
. If
<