LTC3857 Datasheet, PDF (10/38 Pages) Linear Technology – Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

LTC3857
FUNCTIONAL Diagram
PGOOD1
27
PGOOD2
14
FREQ
2
20µA
0.88V
V_FB1
PHASMD
3
CLKOUT
4
0.72V
0.88V
V_FB2
0.72V
VCO
CLK2
CLK1
C_LP
PFD
PLLIN/MODE
5
I_LIM
28
V_IN
22
EXTV_CC
20
+
4.7V ^–
SYNC
DET
100k
CURRENT
LIMIT
5.1V
LDO
EN
5.1V
LDO
EN
33 SGND
19 INTV_CC
DUPLICATE FOR SECOND
CONTROLLER CHANNEL
BOOST
24, 17
INTV_CC V_IN
D_B
DROP
OUT
DET
BOT
SQ
TOP ON
TG
26, 15
TOP
SW
25, 16
RQ
SHDN
SWITCH
LOGIC
BOT
INTV_CC
BG
23, 18
0.425V ⁺
–
SLEEP
PGND
21
ICMP
–+
2.7V
0.55V
+ ^IR
–
3mV
SENSE⁺
32, 10
SENSE^–
1, 9
C_B
D
C_IN
C_OUT
L
R_SENSE
SLOPE COMP
V_FB
31, 11
EA 0.80V
TRACK/SS
R_B
R_A
11V
SHDN
RST
2(V_FB)
0.5µA
OV
0.88V
I_TH
30, 12
FOLDBACK
SHDN
TRACK/SS
1µA _{29, 13}
C_C
C_C2 R_C
C_SS
RUN
7, 8
3857 FD
V_OUT
3857fa
10