Datasheet

LTC3838-1
47
38381f
For more information www.linear.com3838-1
TYPICAL APPLICATIONS
Figure 19. 3.3V to 14V Power Input, 1.2V/20A and 0.9V/20A Dual Output, 300kHz, R
SENSE
, Step-Down Converter
(with Externally-Available 5V to 5.5V Supply)
100k
17.4k23.2k
470pF470pF
47pF47pF
38381 F19
1nF
0.1µF
L2
0.47µH
C
OUT4
100µF
×2
C
OUT3
330µF
×2
DB2
M2
+
LTC3838-1
2.2Ω
2.2Ω
10k
100k
137k
V
IN
1µF
1nF
4.7µF
0.1µF
0.01µF 0.01µF
L1
0.47µH
R
S1
0.0015Ω
R
S2
0.0015Ω
C
OUT2
330µF
×2
C
OUT1
100µF
×2
V
OUT1
1.2V
20A
V
OUT2
0.9V
20A
V
IN
3.3V TO 14V
20k//10k
10k
20k
10k
SENSE1
–
SENSE1
+
BOOST1
TG1
SW1
SENSE2
+
BOOST2
TG2
SW2
DRV
CC1
INTV
CC
DRV
CC2
EXTV
CC
DB1
SENSE2
–
BG1 BG2
V
DFB2
+
V
DFB2
–
PGND
V
OUTSENSE1
+
V
OUTSENSE1
–
PGOOD1 PGOOD2
TRACK/SS1
ITH1
DTR1
V
RNG
TRACK/SS2
ITH2
DTR2
PHASMD
MODE/PLLIN
CLKOUT
RUN2
SGND
RUN1
RT
PGOOD1 PGOOD2
M1
5V TO 5.5V EXTERNAL
1µF
C
IN2
22µF
×4
+
C
IN1
180µF
+
100Ω
100Ω
100Ω
100Ω
C
IN1
: SANYO 16SVP180MX
C
IN2
: MURATA GRM32ER61C226KE20L
C
OUT1
, C
OUT4
: MURATA GRM31CR60J107ME39L
C
OUT2
, C
OUT3
: SANYO 2R5TPE330M9
DB1, DB2: CENTRAL SEMI CMDSH-4ETR
L1, L2: WÜRTH 7443330047
M1, M2: INFINEON BSC0911ND
SGND
Note: When operating with the power V
IN
supply below 5.5V, this applicatoin requires the 5V to 5.5V external supply
to be present at EXTV
CC
in order to maintain DRV
CC
, INTV
CC
and V
IN
pin voltages needed for the IC to function
properly. The EXTV
CC
supply is optional when the power V
IN
supply is at or above 5.5V.
Power input voltage range of this application
cannot be generalized for other frequency and/or output voltage. Each
application that needs a power input voltage different from the V
IN
pin voltage shall be tested individually for margin
of range in which the switching nodes (SW1, SW2) phase-lock to the clock output (CLKOUT).