LTC3835-1 Linear Technology, LTC3835-1 Datasheet - Page 15

• Manufacturer Part Number: LTC3835-1
• Description: Low IQ Synchronous Step-Down Controller
• Manufacturer: Linear Technology

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APPLICATIONS INFORMATION
Alternatively, the TRACK/SS pin can be used to track two
(or more) supplies during start-up, as shown qualitatively
in Figures 4a and 4b. To do this, a resistor divider should
be connected from the master supply (V
SS pin of the slave supply (V
During start-up V
set by the resistor divider:
For coincident tracking (V
R
R
V
A
B
V
OUT
X
= R
= R
=
TRACKA
TRACKB
R
TRACKA
R
A
OUT
(4a) Coincident Tracking
•
will track V
R
TIME
TRACKA
OUT
R
OUT
= V
A
+
+
), as shown in Figure 5.
X
X
Figure 4. Two Different Modes of Output Voltage Tracking
R
R
according to the ratio
during start-up),
TRACKB
B
3835-1 F04A
Figure 5. Using the TRACK/SS Pin for Tracking
V
V
X
X
OUT
) to the TRACK/
(MASTER)
(SLAVE)
V
x
R
R
TRACKB
TRACKA
V
OUT
RB
RA
INTV
The LTC3835-1 features an internal P-channel low dropout
linear regulator (LDO) that supplies power at the INTV
pin from the V
drivers and much of the LTC3835-1’s internal circuitry.
The V
5.25V. It can supply a peak current of 50mA and must be
bypassed to ground with a minimum of 4.7μF tantalum,
10μF special polymer, or low ESR electrolytic capacitor.
A ceramic capacitor with a minimum value of 4.7μF can
also be used if a 1Ω resistor is added in series with the
capacitor. No matter what type of bulk capacitor is used, an
additional 1μF ceramic capacitor placed directly adjacent
to the INTV
Good bypassing is needed to supply the high transient
currents required by the MOSFET gate drivers and to
prevent interaction between the channels.
V
TRACK/SS
LTC3835-1
FB
CC
IN
38351 F05
Regulators
LDO regulates the voltage at the INTV
CC
and PGND IC pins is highly recommended.
IN
(4b) Ratiometric Tracking
supply pin. INTV
TIME
LTC3835-1
3835-1 F04B
CC
V
V
powers the gate
X
OUT
(MASTER)
(SLAVE)
CC
15
pin to
38351fc
CC