ltc3770 Linear Technology Corporation, ltc3770 Datasheet - Page 9

• Manufacturer Part Number: ltc3770
• Description: Fast No Rsense Step-down Synchronous Controller With Margining, Tracking And Pll
• Manufacturer: Linear Technology Corporation

V
this pin to the output voltage makes the on-time propor-
tional to V
the pin is grounded and defaults to 4.8V when the pin is
tied to INTV
PGOOD (Pin 32/Pin 3): Power Good Output. Open drain
PI FU CTIO S
FU CTIO AL DIAGRA
ON
U
U
(Pin 31/Pin 2): On-Time Voltage Input. Connecting
OUT
U
0.6V
REF
MARGIN0
MARGIN1
V
CC
IN
MPGM
PLLIN
PLLFLTR
. The comparator input defaults to 0.6V when
6
5
.
U
12
12K
PLL-SYNC
–
13
10
–
R4
9
U
1.18V
+
V
+
REFOUT
0.6V
V
(UH Package/G Package)
RNG
1
R3
240k
V
2.0V
0.5V
OUT
31
t
1
ON
4.8V
=
V
I
THB
ON
I
V
CMP
I
VON
ION
V
+
–
Q1
REFIN
(10pF)
(0.5~2)
W
7
+
8
I
ON
20k
Q2
EA
+
3.3µA
(UH Package)
R
ON
Q4
R
R
–
R
Q6
R
S
+
–
V
3
INSNS
Q
15
I
REV
I
TH
80% • V
FOLDBACK
DISABLED
AT START-UP*
R
29 FCB
–
–
C
REFIN
SS
C
F
C1
0.6V
+
+
logic output that is pulled to ground when the output
voltage is not within ±10% of the regulation point, after the
internal 25µs power bad mask timer expires.
Exposed Pad (Pin 33) UH Package: Signal Ground. Must
be soldered to the PCB ground for electrical contact and
optimum thermal performance.
0.25V
1.5V
Z0
Z1
Z2
–
INTV
RUN
RUN
1µA
FCNT
RUN
CC
ON
OV
28
17
18
+
30
THROUGH
SWITCH
LOGIC
SHOOT
ANTI-
AND
INTV
11
CC
REG
TRACK/SS
5V
OV
UV
1.4µA
–
+
–
+
SENSE
SENSE
PGOOD
BOOST
DRV
PGND
C
SW
BG
27
TG
26
25
24
23
20
21
22
32
VCC
C
SS
CC
+
–
14 V
10K
10K
90K
C
D
B
INTV
IN
B
SENSE
SENSE
+
*CONNECTION W/O
CC
SENSE RESISTOR
19
BG
C
+
–
IN
+
–
M1
M2
C
R
(OPTIONAL)*
OUT
PGND
SENSE
Z
SW
16
VIN
V
SGND
L1
V
IN
+
M2
2
4
FB
LTC3770
R2
R1
V
OUT
3770fb
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