POWER LOSS (mW)
LTC4012/
LTC4012-1/LTC4012-2
High Efficiency,
Multi-Chemistry Battery Charger
with PowerPath Control
Fserutae Dnoitpircse
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General Purpose Battery Charger Controller The LTC4012 is a constant-current/constant-volt-
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Efficient 550kHz Synchronous Buck PWM Topology age battery charger controller. It uses a synchronous
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0.5% Output Float Voltage Accuracy quasi-constant frequency PWM control architecture
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Programmable Charge Current: 4% Accuracy that will not generate audible noise with ceramic bulk
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Programmable AC Adapter Current Limit: capacitors. Charge current is set by external resis-
3% Accuracy tors and can be monitored as an output voltage.
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No Audible Noise with Ceramic Capacitors With no built-in termination, the LTC4012 family charges
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INFET Low Loss Ideal Diode PowerPath Control a wide range of batteries under external control.
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Wide Input Voltage Range: 6V to 28V
The LTC4012 features fully adjustable output voltage, while
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Wide Output Voltage Range: 2V to 28V
the LTC4012-1 and LTC4012-2 can be pin-programmed for
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Indicator Outputs for AC Adapter Present, Charging,
Lithium-Ion/Polymer battery packs of 1-, 2-, 3- or 4-series
C/10 Current Detection and Input Current Limiting
cells. The LTC4012-1 provides output voltage of 4.1V/cell
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Analog Charge Current Monitor
and the LTC4012-2 is a 4.2V/cell version.
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Micropower Shutdown
n The device includes AC adapter input current limiting, which
20-Pin 4mm 4mm 0.75mm QFN Package
maximizes charge rate for a fixed input power level. An
external sense resistor programs the input current limit,
a snoitacilpp
and the ICL status pin indicates reduced charge current as
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Notebook Computers
a result of AC adapter current limiting. Ideal diode control
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Portable Instruments
at the adaptor input improves charger efficiency.
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Battery Backup Systems
The CHRG status pin is active during all charging modes,
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
including special indication for low charge current.
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents including 5723970.
t lacipy a noitacilpp
FROM
25m
Efficiency at DCIN = 20V
POWER TO
ADAPTER
SYSTEM
0.1F
13V TO 28V 20F
100 10000
5.1k
INFET CLP
EFFICIENCY
95
CLN
DCIN BOOST
0.1F
90
0.1F
TGATE
ACP
85 POWER LOSS 1000
SW
CHRG INTV
DD
TO/FROM
2F 80
MCU
ICL BGATE 6.8H
V = 12.3V
OUT
R = 33m
SENSE
SHDN GND 75
R = 3.01k
IN
3.01k
R = 26.7k
PROG
ITH
CSP
70 100
6.04k
0 0.5 1 1.5 2 2.5 3
LTC4012 33m
3.01k
CHARGE CURRENT (A)
0.1F
CSN
BAT
PIN NAME
PROG FBDIV
20F
PART INFET DCDIV
301k
+ LTC4009 X
26.7k 4.7nF
12.3V
V LTC4012 X
FB
4012 TA02
Li-Ion
32.8k
BATTERY
4012 TA01
4012fa
EFFICIENCY (%)LTC4012/
LTC4012-1/LTC4012-2
a etulosbMixa Mu M r sgnita
(Note 1)
DCIN ............................................................14V to 30V SHDN, FVS0, FVS1 or V to GND ...............0.3V to 7V
FB
DCIN to CLP ................................................ 32V to 20V ACP, CHRG or ICL to GND .......................... 0.3V to 30V
CLP, CLN or SW to GND ............................. 0.3V to 30V Operating Temperature Range
CLP to CLN ............................................................0.3V (Note 2) ............................................. 40C to 125C
CSP, CSN or BAT to GND ........................... 0.3V to 28V Junction Temperature (Note 3) ............................. 125C
CSP to CSN ............................................................0.3V Storage Temperature Range ..................65C to 150C
BOOST to GND ........................................... 0.3V to 36V
BOOST to SW...............................................0.3V to 7V
p ni c no Fnoitarugi
LTC4012 LTC4012-1
LTC4012-2
TOP VIEW TOP VIEW
20 19 18 17 16 20 19 18 17 16
CLN 1 15 CSP CLN 1 15 CSP
CLP CSN CLP CSN
2 14 2 14
21 21
INFET 3 13 PROG INFET 3 13 PROG
GND GND
DCIN 4 12 ITH DCIN 4 12 ITH
ACP 5 11 BAT ACP 5 11 BAT
6 7 8 9 10 6 7 8 9 10
UF PACKAGE UF PACKAGE
20-LEAD (4mm s 4mm) PLASTIC QFN 20-LEAD (4mm s 4mm) PLASTIC QFN
T = 125C, = 37C/W T = 125C, = 37C/W
JMAX JA JMAX JA
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
o r D re i n Fro Mnoita
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4012CUF#PBF LTC4012CUF#TRPBF 4012 20-Lead (4mm 4mm) Plastic QFN 0C to 85C
LTC4012CUF-1#PBF LTC4012CUF-1#TRPBF 40121 20-Lead (4mm 4mm) Plastic QFN 0C to 85C
LTC4012CUF-2#PBF LTC4012CUF-2#TRPBF 40122 20-Lead (4mm 4mm) Plastic QFN 0C to 85C
LTC4012IUF#PBF LTC4012IUF#TRPBF 4012 40C to 125C
20-Lead (4mm 4mm) Plastic QFN
LTC4012IUF-1#PBF LTC4012IUF-1#TRPBF 40121 40C to 125C
20-Lead (4mm 4mm) Plastic QFN
LTC4012IUF-2#PBF LTC4012IUF-2#TRPBF 40122 20-Lead (4mm 4mm) Plastic QFN 40C to 125C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified 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: