LTC3785_15 Datasheet, PDF (18/20 Pages) Linear Technology – 10V, High Efficiency, Synchronous, No RSENSE Buck-Boost Controller

LTC3785
Typical Application
1nF
121k ^205k
V_IN
RUN/SS
V_SENSE
V_CC
I_SVIN
TG1
R1
205k
R2
121k
270pF
V_BST1
1.3k
1nF
12k
SW1
I_SSW1
V_DRV
FB
BG1
LTC3785
V_C
RT
I_SVOUT
R_T
59k
TG2
R_ILSET
42.2k
MODE
V_BST2
I_LSET
SW2
I_SSW2
CCM
BG2
GND
V_IN
2.7V TO 10V
C_VCC
4.7µF
9V REGULATED
WALL ADAPTER
+ _Li-Ion
2.7V TO 4.2V
CMDSH-3
C_A
0.22µF
C_IN
MA
22µF
MA = MB = MC = MD = 1/2 Si7940DY
L1 = WÜRTH ELECTRONICS 744311470
D1 = D2 = PMEG2020EJ
OPTIONAL
L1
MB
D1
4.7µH
CMDSH-3
C_B
0.22µF
OPTIONAL
MD
D2
V_OUT
3.3V
3A
C_OUT
100µF
MC
3785 TA02
Package Description
UF Package
24-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1697)
4.50 ± 0.05 2.45 ± 0.05
(4 SIDES)
3.10 ± 0.05
0.70 ±0.05
4.00 ± 0.10
(4 SIDES)
PIN 1
TOP MARK
(NOTE 6)
0.75 ± 0.05
2.45 ± 0.10
(4-SIDES)
BOTTOM VIEW—EXPOSED PAD
R = 0.115
TYP
23 24
PIN 1 NOTCH
R = 0.20 TYP OR
0.35 s 45° CHAMFER
0.40 ± 0.10
1
2
PACKAGE
OUTLINE
(UF24) QFN 0105
0.25 ±0.05
0.50 BSC
0.200 REF
0.00 – 0.05
0.25 ± 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
3785fc
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