LTC3708_15 Datasheet, PDF (9/32 Pages) Linear Technology – Fast 2-Phase, No RSENSE Buck Controller with Output Tracking

FUNCTIONAL DIAGRAM
LTC3708
FCB
EXTLPF
R_EPLL
C_EPLL
INTLPF
CLOCK DETECTOR
FROM CHANNEL 2
TG
ENABLE
PHASE DETECTOR
(PD2)
PHASE DETECTOR
(PD1)
TO CHANNEL 2 OST
OST
t_ON
=
0.7
I_ION
(10pF)
R
Q
S
20k
+
I_CMP
I_REV
–
1.4V
V_RNG
0.7V
s
3.3μA
R_IPLL
C_IPLL
I_{ON RON}
V_CC
0.6V
+
C_IN
V_IN
REF
C_VCC
FCNT
ON
SWITCH
LOGIC
SHDN
OV
BOOST
TG
SW
SENSE⁺
DRV_CC
BG
PGND
SENSE^–
C_B
M1
L1
D_B ⁺
C_OUT
V_OUT
C_DRVCC
M2
0.66V
OV
V_FB
R2
1
240k
I_TH
C_C
R_C
TRACK
Q1 Q2
V_REF
0.6V
DUPLICATE FOR SECOND
CHANNEL CONTROLLER
EA
Q4
R1
SGND
UV
0.54V
1.3V
Q3
RUN
SHDN
ENABLE
>100μs
BLANKING
FROM CHANNEL 2
OV AND UV COMPARATORS
1.2μA _6V
–+
1.3V
RUN/SS
C_SS
NOTE: THE RUN/SS PIN ONLY CLAMPS
V_REF FOR PHASE 1 NOT PHASE 2.
3708 FD
PGOOD
3708fb
9