LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
Micropower USB Power
Manager with Li-Ion Charger
and Two Step-Down Regulators
DescripTion
The LTC
®
3554 family* are micropower, highly integrated
power management and battery charger ICs for single-cell
Li-Ion/Polymer battery applications. They include a
PowerPath™ manager with automatic load prioritization,
a battery charger, an ideal diode and numerous internal
protection features. Designed specifically for USB applica-
tions, the LTC3554 power managers automatically limit
input current to a maximum of either 100mA or 500mA.
Battery charge current is automatically reduced such that
the sum of the load current and the charge current does
not exceed the selected input current limit.
The LTC3554 also includes two synchronous step-down
switching regulators as well as a pushbutton controller.
With all supplies enabled in standby mode, the quiescent
current drawn from the battery is only 10μA. The LTC3554
family are available in a 3mm
×
3mm
×
0.75mm 20-lead
QFN package.
L,
LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and PowerPath, Hot Swap and Bat-Track are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6522118, 6700364, 5481178, 6304066, 6570372, 6580258, 7511390.
*See table on page 2 for available options.
FeaTures
n
n
n
n
n
n
n
n
n
n
n
10μA Standby Mode Quiescent Current (All Outputs On)
Seamless Transition Between Input Power Sources:
Li-Ion/Polymer Battery and USB
240mΩ Internal Ideal Diode
Dual High Efficiency Step-Down Switching Regulators
(200mA I
OUT
) with Adjustable Output Voltages
Pushbutton On/Off Control with System Reset
Reset Time: 5 sec (LTC3554/LTC3554-1),
14 sec (LTC3554-2/LTC3554-3)
Full Featured Li-Ion/Polymer Battery Charger
Programmable Charge Current with Thermal Limiting
Instant-On Operation with Discharged Battery
Battery Float Voltage: 4.2V (LTC3554/LTC3554-2/
LTC3554-3), 4.1V (LTC3554-1)
3mm
×
3mm
×
0.75mm 20-Lead QFN Package
applicaTions
n
n
n
n
USB-Based Handheld Products
Portable Li-Ion/Polymer Based Electronic Devices
Fitness Computers
Low Power Medical Devices
Typical applicaTion
4.35V TO 5.5V
USB INPUT
100k
10µF
V
BUS
NTC
100k
T
PROG
1.87k
HPWR
SUSP
BVIN
V
OUT
LTC3554
CHRG
BAT
10µF
SYSTEM
LOAD
Battery Drain Current
vs Temperature
14
BATTERY DRAIN CURRENT (µA)
V
BAT
= 3.8V
STBY = 3.8V
12 REGULATORS LOAD = 0mA
BOTH REGULATORS
10 ENABLED
8
6
4
2
HARD RESET
0
–75 –50 –25 0
25 50 75
TEMPERATURE (°C)
100 125
3554 TA01b
+
Li-Ion
BATTERY
2.2µF
4.7µH
PWR_ON1
SW1
10pF
2.05M
649k
10µH
SW2
10pF
FB2
3554 TA01a
3.3V
200mA
10µF
ONE REGULATOR ENABLED
BOTH REGULATORS DISABLED
FSEL
STBY
PGOOD
PWR_ON2
PBSTAT
ON
ON/OFF
FB1
1.2V
200mA
332k
649k
10µF
3554123ff
1
LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
absoluTe MaxiMuM raTings
V
BUS
, V
OUT
, BVIN
t < 1ms and Duty Cycle < 1% ................... –0.3V to 7V
Steady State ............................................ –0.3V to 6V
BAT, NTC,
CHRG,
SUSP, PBSTAT,
ON,
PGOOD, FB1, FB2 .................................. –0.3V to 6V
PWR_ON1, PWR_ON2, STBY
HPWR, FSEL (Note 4) ......................–0.3V to V
CC
+ 0.3V
I
BAT
.............................................................................1A
I
SW1
, I
SW2
(Continuous) ...................................... 300mA
I
CHRG
, I
PGOOD,
I
PBSTAT
............................................75mA
Operating Junction Temperature Range ...–40°C to 85°C
Junction Temperature ............................................110°C
Storage Temperature Range .................. –65°C to 125°C
(Notes 1, 2, 3)
pin conFiguraTion
TOP VIEW
PROG
15 NTC
21
GND
14
CHRG
13 SW1
12 BVIN
11 SW2
6
FB1
7
FB2
8
PWR_ON2
9 10
PWR_ON1
STBY
SUSP
V
BUS
V
OUT
BAT
20 19 18 17 16
HPWR 1
FSEL 2
PBSTAT 3
PGOOD 4
ON
5
UD PACKAGE
20-LEAD (3mm
×
3mm) PLASTIC QFN
T
JMAX
= 110°C,
θ
JA
= 58.7°C/W
EXPOSED PAD (PIN 21) IS GND, AND MUST BE SOLDERED TO PCB GND
orDer inForMaTion
LEAD FREE FINISH
LTC3554EUD#PBF
LTC3554EUD-1#PBF
LTC3554EUD-2#PBF
LTC3554EUD-3#PBF
LTC3554EPD#PBF
TAPE AND REEL
LTC3554EUD#TRPBF
LTC3554EUD-1#TRPBF
LTC3554EUD-2#TRPBF
LTC3554EUD-3#TRPBF
LTC3554EPD#TRPBF
PART MARKING
LDYS
LGFG
LFZX
LGHK
FDPT
PACKAGE DESCRIPTION
20-Lead (3mm
×
3mm) Plastic QFN
20-Lead (3mm
×
3mm) Plastic QFN
20-Lead (3mm
×
3mm) Plastic QFN
20-Lead (3mm
×
3mm) Plastic QFN
20-Lead (3mm
×
3mm) Plastic UTQFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
(OBSOLETE)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
LTC3554 Options
PART NUMBER
LTC3554
LTC3554-1
LTC3554-2
LTC3554-3
FLOAT
VOLTAGE
4.2V
4.1V
4.2V
4.2V
HARD
RESET TIME SEQUENCING
5 seconds
5 seconds
Yes (Buck1
→
Buck2)
Yes (Buck1
→
Buck2)
14 seconds Yes (Buck1
→
Buck2)
14 seconds No (Buck1 and Buck2
Together)
2
3554123ff
LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
power Manager elecTrical characTerisTics
SYMBOL
PARAMETER
No-Load Quiescent Currents
Battery Drain Current
I
BATQ
CONDITIONS
I
OUT
= 0 (Note 5)
V
BUS
= 0V (Hard Reset)
V
BUS
= 0V
V
BUS
= 0V, PWR_ON1 = PWR_ON2 = 3.8V
V
BAT
= V
FLOAT
, Timer Timed Out
100mA, 500mA Modes
SUSP = 5V (Suspend Mode)
V
BVIN
= 3.8V, V
BUS
= 0V (Note 8)
PWR_ON1 = STBY = 3.8V
PWR_ON1 = PWR_ON2 = STBY = 3.8V
PWR_ON1 = 3.8V, STBY = 0V
PWR_ON1 = PWR_ON2 = 3.8V, STBY = 0V
4.35
80
400
3.5
0
The
l
denotes specifications that
apply over the full operating junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
BUS
= 5V, V
BAT
= 3.8V,
HPWR = SUSP = PWR_ON1 = PWR_ON2 = 0V, R
PROG
= 1.87k, STBY = High, unless otherwise noted.
MIN
TYP
MAX
UNITS
I
BATQC
I
BUSQ
I
BVINQ
Battery Drain Current, V
BUS
Available
V
BUS
Input Current
0.2
3
6.5
5
300
15
0.01
1.5
3
18
36
2
5
12
8
500
30
1
3
6
35
70
5.5
100
500
3.9
300
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
V
mA
mA
V
V
mV
mV
mΩ
BVIN Input Current
Shutdown Input Current
One Buck Enabled, Standby Mode
Both Bucks Enabled, Standby Mode
One Buck Enabled
Both Bucks Enabled
Input Power Supply
V
BUS
Input Supply Voltage
Total Input Current
I
BUS(LIM)
V
UVLO
V
DUVLO
V
BUS
Undervoltage Lockout
V
BUS
to BAT Differential Undervoltage
Lockout
Input Current Limit Power FET
R
ON_ILIM
On-Resistance (Between V
BUS
and V
OUT
)
Battery Charger
V
BAT
Regulated Output Voltage
V
FLOAT
HPWR = 0V (100mA)
HPWR = 5V (500mA)
Rising Threshold
Falling Threshold
Rising Threshold
Falling Threshold
l
l
90
450
3.8
3.6
200
50
350
I
CHG
V
PROG
V
PROG,TRKL
h
PROG
I
TRKL
V
TRKL
ΔV
RECHRG
t
TERM
t
BADBAT
h
C/10
R
ON_CHG
T
LIM
NTC
V
COLD
V
HOT
Constant-Current Mode Charge Current
PROG Pin Servo Voltage
PROG Pin Servo Voltage in Trickle Charge
Ratio of I
BAT
to PROG Pin Current
Trickle Charge Current
Trickle Charge Threshold Voltage
Recharge Battery Threshold Voltage
Safety Timer Termination Period
Bad Battery Termination Time
End-of-Charge Indication Current Ratio
Battery Charger Power FET
On-Resistance (Between V
OUT
and BAT)
Junction Temperature in Constant
Temperature Mode
LTC3554/LTC3554-2/LTC3554-3
LTC3554/LTC3554-2/LTC3554-3, 0°C < T
A
< 85°C
LTC3554-1
LTC3554-1, 0°C < T
A
< 85°C
R
PROG
= 1.87k, 0 ≤ T
A
≤ 85°C
V
BAT
< V
TRKL
V
BAT
< V
TRKL
V
BAT
Rising
V
BAT
Falling
Threshold Voltage Relative to V
FLOAT
Timer Starts when V
BAT
= V
FLOAT
– 50mV
V
BAT
< V
TRKL
(Note 6)
I
BAT
= 200mA
4.179
4.165
4.079
4.065
380
30
2.6
–75
3.2
0.4
0.085
4.2
4.2
4.1
4.1
400
1
0.1
750
40
2.9
2.75
–100
4
0.5
0.1
220
110
4.221
4.235
4.121
4.135
420
50
3
–115
5
0.63
0.115
V
V
V
V
mA
V
V
mA/mA
mA
V
V
mV
Hour
Hour
mA/mA
mΩ
°C
Cold Temperature Fault Threshold Voltage Rising NTC Voltage
Hysteresis
Hot Temperature Fault Threshold Voltage Falling NTC Voltage
Hysteresis
75
34
76
1.3
35
1.3
77
36
%V
BUS
%V
BUS
%V
BUS
%V
BUS
3554123ff
3
LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
power Manager elecTrical characTerisTics
SYMBOL
V
DIS
PARAMETER
NTC Disable Threshold Voltage
CONDITIONS
Falling NTC Voltage
Hysteresis
V
NTC
= V
BUS
= 5V
(Note 12)
I
OUT
= 200mA, V
BUS
= 0V
(Note 7)
The
l
denotes specifications that
apply over the full operating junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), V
BUS
= 5V, V
BAT
= 3.8V,
HPWR = SUSP = PWR_ON1 = PWR_ON2 = 0V, R
PROG
= 1.87k, STBY = High, unless otherwise noted.
l
MIN
1.2
–50
TYP
1.7
50
MAX
2.2
50
NTC Leakage Current
I
NTC
Ideal Diode
Forward Voltage Detection
V
FWD
R
DROPOUT
Diode On-Resistance, Dropout
Diode Current Limit
I
MAX
Logic Inputs (HPWR, SUSP)
Input Low Voltage
V
IL
Input High Voltage
V
IH
Internal Pull-Down Resistance
R
PD
Logic Output (CHRG)
Output Low Voltage
V
OL
Output Hi-Z Leakage Current
I
CHRG
UNITS
%V
BUS
mV
nA
mV
mΩ
A
15
240
1
0.4
1.2
4
V
V
MΩ
mV
µA
I
CHRG
= 5mA
V
BAT
= 4.5V, V
CHRG
= 5V
65
0
250
1
swiTching regulaTor elecTrical characTerisTics
SYMBOL
PARAMETER
BVIN
Input Supply Voltage
V
OUT
UVLO V
OUT
Falling
V
OUT
Rising
f
OSC
Oscillator Frequency
CONDITIONS
(Note 9)
BVIN Connected to V
OUT
Through Low
Impedance. V
OUT
UVLO Disables the Switching
Regulators.
FSEL High
FSEL Low
l
The
l
denotes
specifications that apply over the full operating junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2).
V
OUT
= BVIN = 3.8V, PWR_ON1 = PWR_ON2 = 0V, unless otherwise noted.
MIN
2.7
2.5
1.91
0.955
–0.05
–0.05
TYP
2.6
2.8
2.25
1.125
MAX
5.5
2.9
2.59
1.295
0.05
0.05
UNITS
V
V
V
MHz
MHz
µA
µA
kΩ
kΩ
V
V
µA
mA
mV
%
Ω
Ω
mV
mA
mV
FB1 Input Current (Note 8)
I
FB1
I
FB2
FB2 Input Current (Note 8)
SW1 Pull-Down in Shutdown
PWR_ON1 = 0V
R
SW1_PD
R
SW2_PD
SW2 Pull-Down in Shutdown
PWR_ON2 = 0V
Logic Input Pins (FSEL, STBY)
Input High Voltage
Input Low Voltage
Input Current
Switching Regulator 1 in Normal Operation (STBY Low)
Peak PMOS Current Limit
PWR_ON1 = 3.8V (Note 7)
I
LIM1
Regulated Feedback Voltage
PWR_ON1 = 3.8V
V
FB1
D1
Max Duty Cycle
R
DS(ON)
of PMOS
I
SW1
= 100mA
R
P1
R
DS(ON)
of NMOS
I
SW1
= –100mA
R
N1
Switching Regulator 1 in Standby Mode (STBY High)
PWR_ON1 = 3.8V, V
FB1
Falling
V
FB1_LOW
Feedback Voltage Threshold
I
SHORT1_SB
Short-Circuit Current
PWR_ON1 = 2.9V, I
SW1
= 5mA, V
FB1
= 0.77V,
V
DROP1_SB
Standby Mode Dropout Voltage
V
OUT
= 2.9V, BVIN = 2.9V
10
10
1.2
–1
300
780
100
450
800
1.1
0.7
l
0.4
1
600
820
l
770
10
800
21
25
820
50
60
4
3554123ff
LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
swiTching regulaTor elecTrical characTerisTics
SYMBOL
PARAMETER
CONDITIONS
Switching Regulator 2 in Normal Operation (STBY Low)
Peak PMOS Current Limit
PWR_ON2 = 3.8V (Note 7)
I
LIM2
l
Regulated Feedback Voltage
PWR_ON2 = 3.8V
V
FB2
D2
Max Duty Cycle
R
DS(ON)
of PMOS
I
SW2
= 100mA
R
P2
R
DS(ON)
of NMOS
I
SW2
= –100mA
R
N2
Switching Regulator 2 in Standby Mode (STBY High)
l
PWR_ON2 = 3.8V, V
FB2
Falling
V
FB2_LOW
Feedback Voltage Threshold
I
SHORT2_SB
Short-Circuit Current
PWR_ON2 = 2.9V, I
SW2
= 5mA, V
FB2
= 0.77V, V
OUT
V
DROP2_SB
Standby Mode Dropout Voltage
= 2.9V, BVIN = 2.9V
MIN
300
780
100
The
l
denotes
specifications that apply over the full operating junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2).
V
OUT
= BVIN = 3.8V, PWR_ON1 = PWR_ON2 = 0V, unless otherwise noted.
TYP
450
800
1.1
0.7
770
10
800
21
25
820
50
60
MAX
600
820
UNITS
mA
mV
%
Ω
Ω
mV
mA
mV
pushbuTTon inTerFace elecTrical characTerisTics
SYMBOL
PARAMETER
Pushbutton Pin (ON)
Pushbutton Operating Supply Range
V
CC_PB
ON
Threshold Rising
V
ON_TH
ON
Threshold Falling
ON
Input Current
I
ON
Pushbutton Pull-Up Resistance
R
PB_PU
Logic Input Pins (PWR_ON1, PWR_ON2)
V
PWR_ONx
PWR_ONx Threshold Rising
PWR_ONx Threshold Falling
PWR_ONx Input Current
I
PWR_ONx
Status Output Pins (PBSTAT, PGOOD)
PBSTAT Output High Leakage Current
I
PBSTAT
PBSTAT Output Low Voltage
V
PBSTAT
PGOOD Output High Leakage Current
I
PGOOD
PGOOD Output Low Voltage
V
PGOOD
V
THPGOOD
PGOOD Threshold Voltage
Pushbutton Timing Parameters (Note 11)
t
ON_PBSTATL
Minimum
ON
Low Time to Cause PBSTAT
Low
Delay from
ON
High to PBSTAT High
t
ON_
PBSTATH
The
l
denotes
specifications that apply over the full operating junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2).
V
BAT
= 3.8V, unless otherwise noted.
CONDITIONS
(Notes 4 , 9)
l
MIN
2.7
0.4
–1
200
TYP
MAX
5.5
1.2
1
650
1.2
1
1
0.4
1
0.4
UNITS
V
V
V
µA
kΩ
V
V
µA
µA
V
µA
V
%
ms
µs
ms
V
ON
= V
CC
(Note 4)
Pull-Up to V
CC
(Note 4)
400
0.4
–1
V
PBSTAT
= 3V
I
PBSTAT
= 3mA
V
PGOOD
= 3V
I
PGOOD
= 3mA
(Note 10)
ON
Brought Low During Power-On (PON) or
Power-Up (PUP1, PUP2) States
Power-On (PON) State, After PBSTAT Has Been
Low for at Least t
PBSTAT_PW
Starting in the Hard Reset (HR) or Power-Off
(POFF) States
ON
Brought Low During the Power-On (PON)or
Power-Up (PUP1, PUP2) States
LTC3554/LTC3554-1
LTC3554-2/LTC3554-3
Power-On (PON) or Power-Up (PUP1, PUP2)
States
–1
0.1
–1
0.1
–8
50
900
400
t
ON_PUP
t
ON_HR
Minimum
ON
Low Time to Enter
Power-Up (PUP1 or PUP2) State
Minimum
ON
Low Time to Hard Reset
t
PBSTAT_PW
PBSTAT Minimum Pulse Width
4
11
40
5
14
50
6
17
s
s
ms
3554123ff
5
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