LTC3101
TYPICAL APPLICATIONS
Sequenced Start-Up, Buck-Boost Followed by Buck Converters
V
= 3.3V
OUT3
300mA FOR V ≥ 1.8V
IN
+
C4
10μF
C3
10μF
800mA FOR V ≥ 3V
IN
2 AA
CELLS
R3
1M
4.7μH
R5
100k
R4
221k
BAT1 BAT2 SW3A SW3B OUT3
USB POWER
4.3V TO 5.5V
USB1
USB2
FB3
ENA2
ENA3
HSO
C5
Power-Up Waveforms
C2
10μF
0.1μF
Hot Swap OUTPUT
3.3V
PWRKEY 5V/DIV
PBSTAT 2V/DIV
C6
100mA
4.7μF
V
C1
0.033μF
OUT2
TRACKING OUTPUT
200mA
MAX
PWM
ENA1
OUTPUT
VOLTAGES
1V/DIV
C7
4.7μF
V
OUT3
C
RS
V
OUT1
1.8V
50mA
LDO
C
2V/DIV
RS
LTC3101
C8
4.7μF
ON/OFF
RESET 2V/DIV
4.7μH
V
OUT2
SW2
FB2
1.8V
PWRKEY
3101 TA05b
C10
10μF
R6
C9
350mA
10ms/DIV
221k
22pF
V
OUT1
μP
R7
110k
4.7μH
R1
50k
R2
50k
V
OUT1
1.2V
SW1
FB1
PBSTAT
PWRON
RESET
C12
10μF
R8
221k
C11
22pF
350mA
R9
221k
GND
3101 TA05a
PACKAGE DESCRIPTION
UF Package
24-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1697)
BOTTOM VIEW—EXPOSED PAD
R = 0.115
PIN 1 NOTCH
R = 0.20 TYP
OR 0.35 s 45o
CHAMFER
0.75 p 0.05
4.00 p 0.10
(4 SIDES)
TYP
23 24
0.70 p0.05
PIN 1
TOP MARK
(NOTE 6)
0.40 p 0.10
1
4.50 p 0.05
3.10 p 0.05
2.45 p 0.05
(4 SIDES)
2
2.45 p 0.10
(4-SIDES)
PACKAGE
OUTLINE
(UF24) QFN 0105
0.200 REF
0.25 p 0.05
0.25 p0.05
0.50 BSC
0.00 – 0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGD-X)—TO BE APPROVED
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, IF PRESENT
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
3101f
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
31
Linear [ Linear ]
