LT1767 Linear Technology, LT1767 Datasheet - Page 15

• Manufacturer Part Number: LT1767
• Description: Monolithic 1.5A/ 1.25MHz Step-Down Switching Regulators
• Manufacturer: Linear Technology

APPLICATIONS
during switch on time, causing current to flow, and energy
to build in L1B and C4. At switch off, the energy stored in
both L1B and C4 supply the –5V rail. This reduces the
PACKAGE
(0.18)
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
0.007
12V
V
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
IN
Figure 10. Buck Converter with Adjustable Soft-Start
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
D1: UPS120
Q1: 2N3904
+
C3
2.2 F
V
SHDN
IN
SYNC
(0.53 0.015)
0.021 0.006
DESCRIPTION
LT1767-5
BOOST
U
GND
V
C
V
INFORMATION
SW
FB
U
0 – 6 TYP
C
330pF
C
* ONLY REQUIRED IF INPUT CAN SINK >10mA
REMOVABLE
0.1 F
D1
C2
Q1
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
INPUT
Figure 9. Dual Source Supply with 6 A Reverse Leakage
CMDSH-3
R4
47k
5 H
W
D2
L1
SEATING
R3
2k
100 F
U
PLANE
83k
28.5k
UPS120*
C1
15nF
C
SS
+
1767 F10
0.009 – 0.015
(0.22 – 0.38)
(Reference LTC DWG # 05-08-1660)
2.2 F
V
SHDN
IN
U
SYNC
OUTPUT
5V
1A
8-Lead Plastic MSOP
LT1767-3.3
(1.10)
0.043
MAX
BOOST
GND
MS8 Package
0.0256
(0.65)
BSC
V
C
V
4.7k
SW
FB
1.5nF
0.1 F
LT1767-2.5/LT1767-3.3/LT1767-5
current in L1A and changes L1B current waveform from
square to triangular. For details on this circuit, including
maximum output currents, see Design Note 100.
* L1 IS A SINGLE CORE WITH TWO WINDINGS
†
UPS120
BH ELECTRONICS #511-1013
IF LOAD CAN GO TO ZERO,
AN OPTIONAL PRELOAD OF 1k TO 5k
MAY BE USED TO IMPROVE LOAD REGULATION
D1, D3: UPS120
6V TO 15V
CMDSH-3
(0.86)
0.034
5 H
REF
0.005 0.002
GND
(0.13 0.05)
V
IN
Figure 11. Dual Output SEPIC Converter
C3
2.2 F
16V
CERAMIC
3.3V, 1A
2.2 F
V
SHDN
IN
SYNC
(3.00 0.102)
0.193 0.006
0.118 0.004*
(4.90 0.15)
LT1767/LT1767-1.8/
LT1767-5
ALTERNATE
BOOST
1767 F09
GND
SUPPLY
CERAMIC
V
C
V
2.2 F
SW
FB
C
330pF
0.1 F
16V
C
C4
C2
1
8
7 6 5
2 3
D1
CMDSH-3
L1B*
D2
4
L1A*
9 H
D3
10V TANT
100 F
(3.00 0.102)
0.118 0.004**
C5
+
MSOP (MS8) 1100
sn1767 1767fas
+
C1
100 F
10V TANT
15
OUTPUT
5V
OUTPUT
–5V
1767 F11
†