Datasheet

LTC3459
10
3459fc
TYPICAL APPLICATIONS
Figure 5. Charging a SuperCap from a 3.3V Source
SW
L1
V
IN
1M
V
OUT
5V
C
OUT
2F
1
μF
1μF
LTC3459
SHDN
V
OUT
FB
3.3V
OFF ON
GND
332k
3459 F05
C
OUT
: MAXWELL TECHNOLOGIES ULTRACAP PC5-5, 2F, 5V
L1: 33
μH, 1.7Ω TAIYO YUDEN LB2016
+
controlled, preventing any damaging effects of inrush
current. Proper heat sinking of the package is required in
this application as the die may dissipate 100mW to 200mW
during initial charging. When V
OUT
is greater than ~3.5V,
normal boost mode operation and effi ciency begin, with
the P-channel MOSFET acting as a synchronous switch.
Average input current is a constant 50mA during charg-
ing, where the current delivered to the SuperCap varies
somewhat with duty cycle. Once the SuperCap is charged
to 5V, the LTC3459 begins to regulate and the input cur-
rent is reduced to the amount required to support the load
and/or self discharge of the SuperCap.
PACKAGE DESCRIPTION
2.00 p0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.38 p 0.05
BOTTOM VIEW—EXPOSED PAD
0.56 p 0.05
(2 SIDES)
0.75 p0.05
R = 0.115
TYP
1.37 p0.05
(2 SIDES)
1
3
64
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DC6) DFN 1103
0.25 p 0.05
1.42 p0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
0.61 p0.05
(2 SIDES)
1.15 p0.05
0.675 p0.05
2.50 p0.05
PACKAGE
OUTLINE
0.25 p 0.05
0.50 BSC
0.50 BSC
PIN 1
CHAMFER OF
EXPOSED PAD
DC Package
6-Lead Plastic DFN (2mm × 2mm)
(Reference LTC DWG # 05-08-1703)