Linear Technology DC1185B-A Demo Manual page 4

DEMO MANUAL
DC1185B-A/-B
RAIL TRACKING
Demonstration circuit 1185 is set up for independent
turn-on of VOUT1 and VOUT2. The ramp-rate for VOUT1 is
determined by the TRK/SS1 capacitor at C2 and the ramp-
rate for VOUT2 is determined by the TRK/SS2 capacitor
at C47. The turn-on of one rail will not affect the other for
the original demo board.
Table 1. VOUT1 Tracking Options for a 1.5V Output
CONFIGURATION
Soft-Start without Tracking (Original Board)
External Coincident Tracking
Table 2. VOUT2 Tracking Options for a 1.2V Output
CONFIGURATION
Soft-Start without Tracking (Original Board)
Coincident Tracking to VOUT1 (1.5V)
External Coincident Tracking
4
This board can be modified on the bench to allow VOUT1
to track an external signal. It can also be modified to
allow VOUT2 to track VOUT1 or to allow VOUT2 to track
an external signal. Tables 2 and 3 cover the rail tracking
options for each rail, with the DC3850B-B version used
as an example.
TRACK 1 DIVIDER
R3 R2
0Ω Not Stuffed
17.8kΩ 20.0kΩ
TRACK 2 DIVIDER
R36 R34
0Ω Not Stuffed
0Ω 10.0kΩ
10.0kΩ Not Stuffed
TRK/SS1 CAPACITOR
C2
0.1µF
Not Stuffed
TRK/SS2 CAPACITOR
R37
Not Stuffed
20.0kΩ Not Stuffed
20.0kΩ Not Stuffed
C47
0.1µF
dc1185b-a/-bf