ncp3122 ON Semiconductor, ncp3122 Datasheet - Page 19

• Manufacturer Part Number: ncp3122
• Description: Dual 2.0 A, Step-down Dc/dc Switching Regulator
• Manufacturer: ON Semiconductor

Ratiometric Sequencing
ramping at the same time and also reach the regulation level
at the same time. When common EN is pulled down, the
output voltages are going down at the same time. See Figure
33. This functionality is created by using the same capacitor
values as the soft-start capacitors for all outputs and by
In the ratiometric sequencing mode, multiple outputs start
Disable
Enable
R_TRACK
EN1
VOUT1
VOUT2
R_T
Figure 33. Ratiometric Sequencing Configuration
PG1
PG2
EN1
SEQ1
EN2
SEQ2
TRACK1
TRACK2
AVIN
GND
C3
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C13
R13
R23
C23
GND
C22
NCP3122
C12
19
GND
connecting all EN + SEQ pins together. To ensure this
behavior, the soft start capacitors should have values greater
than the time constant of the output inductor and output
capacitor.
soft-start capacitor for both channels is not recommended.
For proper operation in this mode, using a common
SW1
SW2
VIN
VIN
VIN
VIN
VIN
VIN
GND
C1
D11
D21
GND
GND
GND
L21
L11
VIN
C2
GND
R12
R21
R22
R11
GND
GND
C11
C21
GND
GND
OUT1
OUT2