ltc3858-2 Linear Technology Corporation, ltc3858-2 Datasheet - Page 22

• Manufacturer Part Number: ltc3858-2
• Description: Ltc3858-2 - Low Iq, Dual 2-phase Synchronous Step-down Controller
• Manufacturer: Linear Technology Corporation

LTC3858-2
APPLICATIONS INFORMATION
Alternatively, the SS pin can be used to track two (or
more) supplies during start-up, as shown qualitatively in
Figures 7a and 7b. To do this, a resistor divider should
be connected from the master supply (V
pin of the slave supply (V
ing start-up, V
by the resistor divider:
22
V
V
OUT
X
=
R
TRACKA
R
OUT
(7a) Coincident Tracking
A
will track V
•
TIME
R
TRACKA
OUT
), as shown in Figure 8. Dur-
R
X
A
according to the ratio set
Figure 7. Two Different Modes of Output Voltage Tracking
+ R
+ R
38582 F07a
B
TRACKB
V
V
X(MASTER)
OUT(SLAVE)
Figure 8. Using the SS Pin for Tracking
X
) to the SS
R
R
TRACKB
TRACKA
V
x
V
OUT
R
R
B
A
For coincident tracking (V
1/2 LTC3858-2
V
SS
FB
R
R
A
B
= R
= R
38582 F08
TRACKA
TRACKB
(7b) Ratiometric Tracking
TIME
OUT
= V
X
38582 F07b
during start-up):
V
V
X(MASTER)
OUT(SLAVE)
38582f