LTC3625/LTC3625-1
1A High Efficiency 2-Cell
Supercapacitor Charger
with Automatic Cell
Balancing
Fae Tseru Dpircse Tnoi
n
High Efficiency Step-Up/Step-Down Charging of Two
The LTC 3625/LTC3625-1 are programmable supercapaci-
Series Supercapacitors
tor chargers designed to charge two supercapacitors in
n
Automatic Cell Balancing Prevents Capacitor
series to a fixed output voltage (4.8V/5.3V or 4V/4.5V
Overvoltage During Charging
selectable) from a 2.7V to 5.5V input supply. Automatic
n
Programmable Charging Current Up to 500mA
cell balancing prevents overvoltage damage to either
(Single Inductor), 1A (Dual Inductor)
supercapacitor while maximizing charge rate. No balancing
n
V = 2.7V to 5.5V
resistors are required.
IN
n
Selectable 2.4V/2.65V Regulation per Cell (LTC3625)
High efficiency, high charging current, low quiescent cur-
n
Selectable 2V/2.25V Regulation per Cell (LTC3625-1)
rent and low minimum external parts count (one inductor,
n
Low No-Load Quiescent Current: 23A
one bypass capacitor at V and one programming resistor)
IN
n
I , I < 1A in Shutdown
VOUT VIN
make the LTC3625/LTC3625-1 ideally suited for small form
n
Low Profile 12-lead 3mm 4mm DFN Package
factor backup or high peak power systems.
a acilpp Tsnoi
Charging current/maximum input current level is pro-
grammed with an external resistor. When the input supply is
n
Servers, RAID Systems, Mass Storage, High Current
removed and/or the EN pin is low, the LTC3625/LTC3625-1
Backup Supplies
automatically enter a low current state, drawing less than
n
Solid State Hard Drives
1A from the supercapacitors.
n
Wireless Power Meters
n
High Peak Power Boosted Supplies
The LTC3625/LTC3625-1 are available in a compact
12-lead 3mm 4mm 0.75mm DFN package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
T lacipy a acilpp Tn oi
1A SCAP Charger
Charging Two 2:1 Mismatched Supercapacitors
6
LTC3625
V V
C = 50F
IN OUT TOP
V
V
IN OUT
C = 100F
BOT
2.7V TO 5.5V
4.8V
5
10F R = 61.9k
PROG
3.3H
SW2
CTL = 0
C 0.1F
TOP
V = 0
SEL
3.3H
4
SW1
V
V OUT
MID
PROG
C 0.1F
BOT
3
61.9k
V
MID
2
PFI
PGOOD
EN
PFO
CTL 1
V
SEL
3625 TA01a
0
0 20 40 60 80 100 120 140 160 180 200
TIME (SECONDS)
3625 TA01b
3625f
VOLTAGE (V)LTC3625/LTC3625-1
a ulosb T e Mixa Mu M r a Tsgni p ni c no Farugi Tnoi
(Note 1)
TOP VIEW
V , V (Transient) t < 1ms,
IN OUT
Duty Cycle < 1% .......................................... 0.3V to 7V
SW1 1 12 SW2
V , V , V , PGOOD,
IN OUT MID V 2 11 V
IN OUT
CTL, PROG, PFI, PFO ................................... 0.3V to 6V
CTL 3 10 V
MID
13
GND
EN, V ........................................... 0.3V to V + 0.3V
V 4 9 PGOOD
SEL IN SEL
V Short-Circuit Duration ............................. Indenfi ite
EN 5 8 PFO
OUT
I , I ............................................................50mA
PROG 6 7 PFI
PGOOD PFO
I ........................................................................1mA
PROG
DE PACKAGE
I , I , I , I (Note 2) ...................................3A 12-LEAD (4mm s 3mm) PLASTIC DFN
VIN SW1 SW2 VOUT
T = 125C, = 43C/W
JMAX JA
Operating Junction Temperature Range
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
(Notes 3, 4) ............................................ 40C to 125C
Storage Temperature Range .................. 65C to 125C
o r D re i n Fro Ma Tnoi
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3625EDE#PBF LTC3625EDE#TRPBF 3625 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
LTC3625EDE-1#PBF LTC3625EDE-1#TRPBF 36251 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
LTC3625IDE#PBF LTC3625IDE#TRPBF 3625 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
LTC3625IDE-1#PBF LTC3625IDE-1#TRPBF 36251 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
Consult LTC Marketing for parts speciefi d with wider operating temperature ranges. *The temperature grade is identiefi d by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: