LTC3731 Linear Technology, LTC3731 Datasheet - Page 9

• Manufacturer Part Number: LTC3731
• Description: Synchronous Buck Switching Regulator Controller
• Manufacturer: Linear Technology

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FU CTIO AL DIAGRA
PGOOD**
*THE LTC3731CUH USES THE EXPOSED DIE ATTACH PAD FOR THE SGND CONNECTIONS
**THE PHASMD AND PGOOD PIN FUNCTIONS ARE TIED TOGETHER IN THE LTC3731CUH PACKAGE
***LTC3731CG/HG ONLY
R1
U
F
IN
R
C
R2
LP
LP
PHASMD**
PLLFLTR
DIFFOUT
CLKOUT
R
UVADJ
PLLIN
EAIN
C
DELAY
C
100µs
FCB
IN
IN
I
1.2V
TH
C
–
+
0.600V
0.660V
U
PROTECTION
0.6V
50k
–
+
V
FB
+
–
40k
40k
OSCILLATOR
PHASE DET
–
+
+
–
EA
OV
40k
40k
FCB
–
+
A1
–
+
–
+
CLK1
CLK2
CLK3
0.66V
0.54V
EAIN
W
DUPLICATE FOR SECOND AND THIRD
CONTROLLER CHANNELS
LATCH
RS
V
CC
6V
1.5µA
5(V
0.86V
FB
SLOPE
COMP
)
CLAMP
S
R
SS
I
1
Figure 2
5(V
–
+
SHDN
0.55V
Q
Q
RST
FB
–
2.4V
FCB
)
DROP
OUT
DET
+
+
START
SOFT-
54k
SHED
B
RUN
3mV
BOT
FORCE BOT
–
SHDN
FCB
54k
UV RESET
–
+
I
2
INTERNAL
SWITCH
SUPPLY
LOGIC
0.600V
1.2V
TOP
BOT
V
CC
V
CC
36k
36k
V
(VDR)***
REF
SENSE
SENSE
RUN/SS
BOOST
SGND*
PGND
V
SW
TG
BG
CC
+
–
+
V
R
CC
V
SENSE
CC
C
C
D
CC
SS
C
B
B
LTC3731
L
V
IN
+
3731fa
9
C
IN