FEATURES
Battery Charger
n
Standalone USB Charger
n
Up to 950mA Charge Current Programmable via
Single Resistor
n
HPWR Input Selects 20% or 100% of Programmed
Charge Current
n
NTC Input for Temperature Qualified Charging
n
Internal Timer Termination
n
Bad Battery Detection
n
CHRG
Indicates C/10 or Timeout
Buck Regulators
n
400mA Output Current
n
2.25MHz Constant Frequency Operation
n
Zero Current in Shutdown
n
Low Noise Pulse Skip Operation or Power Saving
Burst Mode Operation
n
Low No-Load Quiescent Current: 35μA
n
Available in a Low Profile Thermally Enhanced
16-Lead 3mm
×
3mm QFN Package
LTC3559/LTC3559-1
Linear USB Battery Charger
with Dual Buck Regulators
DESCRIPTION
The LTC
®
3559/LTC3559-1 are USB battery chargers with
dual high efficiency buck regulators. The parts are ideally
suited to power single-cell Li-Ion/Polymer based handheld
applications needing multiple supply rails.
Battery charge current is programmed via the PROG pin
and the HPWR pin, with capability up to 950mA at the BAT
pin. The battery charger has an NTC input for temperature
qualified charging. The
CHRG
pin allows battery status to
be monitored continuously during the charging process.
An internal timer controls charger termination.
Each monolithic synchronous buck regulator provides up
to 400mA of output current while operating at efficiencies
greater than 90% over the entire Li-Ion/Polymer range.
A MODE pin provides the flexibility to place both buck
regulators in a power saving Burst Mode
®
operation or a
low noise pulse skip mode.
The LTC3559/LTC3559-1 are offered in a low profile ther-
mally enhanced 16-lead (3mm
×
3mm) QFN package.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIONS
n
n
SD/Flash-Based MP3 Players
Low Power Handheld Applications
TYPICAL APPLICATION
USB Charger Plus Dual Buck Regulators
UP TO 500mA
USB (4.3V TO 5.5V)
OR AC ADAPTOR
V
CC
1μF
NTC
1.74k
PROG
CHRG
SUSP
DIGITAL
CONTROL
HPWR
EN1
EN2
MODE
GND
EXPOSED
PAD
SW2
22pF
FB2
649k
3559 TA01
BAT
PV
IN
2.2μF
LTC3559
SW1
22pF
FB1
4.7μH
+
SINGLE
Li-lon CELL
(2.7V TO 4.2V)
2.5V
400mA
655k
309k
10μF
4.7μH
324k
1.2V
400mA
10μF
3559fb
1
LTC3559/LTC3559-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
CHRG
PROG
NTC
12 HPWR
17
11 SUSP
10 FB2
9
5
EN1
6
SW1
7
PV
IN
8
SW2
EN2
V
CC
GND 1
BAT 2
MODE 3
FB1 4
V
CC
(Transient);
t < 1ms and Duty Cycle < 1%....................... –0.3V to 7V
V
CC
(Static) .................................................. –0.3V to 6V
BAT, CHRG, SUSP ........................................ –0.3V to 6V
HPWR, NTC, PROG ....... –0.3V to Max (V
CC
, BAT) + 0.3V
PROG Pin Current ...............................................1.25mA
BAT Pin Current ..........................................................1A
PV
IN
................................................ –0.3V to BAT + 0.3V
EN1, EN2, MODE.......................................... –0.3V to 6V
FB1, FB2, SW1, SW2 ............–0.3V to PV
IN
+ 0.3V or 6V
I
SW1
, I
SW2
......................................................600mA DC
Junction Temperature (Note 2) ............................. 125°C
Operating Temperature Range (Note 3).... –40°C to 85°C
Storage Temperature.............................. –65°C to 125°C
16 15 14 13
UD PACKAGE
16-LEAD (3mm 3mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 68°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3559EUD#PBF
LTC3559EUD-1#PBF
TAPE AND REEL
LTC3559EUD#TRPBF
LTC3559EUD-1#TRPBF
PART MARKING
LCMB
LDQD
PACKAGE DESCRIPTION
16-Lead (3mm
×
3mm) Plastic QFN
16-Lead (3mm
×
3mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
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/
ELECTRICAL CHARACTERISTICS
range, otherwise specifications are at T
A
= 25°C.
The
l
denotes specifications that apply over the full operating temperature
MIN
l
SYMBOL
PARAMETER
CONDITIONS
Battery Charger. V
CC
= 5V, BAT = PV
IN
= 3.6V, R
PROG
= 1.74k, HPWR = 5V, SUSP = NTC = EN1 = EN2 = 0V
Input Supply Voltage
V
CC
Battery Charger Quiescent Current (Note 4) Standby Mode, Charge Terminated
I
VCC
Suspend Mode, V
SUSP
= 5V
BAT Regulated Output Voltage
LTC3559
V
FLOAT
0°C ≤ T
A
≤ 85°C, LTC3559
LTC3559-1
0°C ≤ T
A
≤ 85°C, LTC3559-1
Constant-Current Mode Charge Current
HPWR = 5V
I
CHG
HPWR = 0V
Battery Drain Current
Standby Mode, Charger Terminated
I
BAT
Shutdown, V
CC
< V
UVLO
, BAT = V
FLOAT
Suspend Mode, SUSP = 5V, BAT = V
FLOAT
V
UVLO
Undervoltage Lockout Threshold
BAT = 3.5V, V
CC
Rising
Undervoltage Lockout Hysteresis
BAT = 3.5V
ΔV
UVLO
V
DUVLO
Differential Undervoltage Lockout
Threshold
BAT = 4.05V, (V
CC
– BAT) Falling (LTC3559)
BAT = 3.95V, (V
CC
– BAT) Falling (LTC3559-1)
TYP
MAX
5.5
400
17
4.221
4.235
4.121
4.135
500
100
–7
–4
–3
4.125
70
70
UNITS
V
μA
μA
V
V
V
V
mA
mA
μA
μA
μA
V
mV
mV
mV
3559fb
4.3
200
8.5
4.200
4.200
4.100
4.100
460
92
–3.5
–2.5
–1.5
4.0
200
50
50
l
4.179
4.165
4.079
4.065
440
84
3.85
30
30
2
LTC3559/LTC3559-1
ELECTRICAL CHARACTERISTICS
range, otherwise specifications are at T
A
= 25°C.
PARAMETER
Differential Undervoltage Lockout
Hysteresis
PROG Pin Servo Voltage
SYMBOL
ΔV
DUVLO
V
PROG
The
l
denotes specifications that apply over the full operating temperature
MIN
TYP
130
130
1.000
0.200
0.100
800
46
2.9
100
–100
1.7
4
0.5
0.1
2.2
500
105
MAX
UNITS
mV
mV
V
V
V
mA/mA
mA
V
mV
mV
ms
Hour
Hour
mA/mA
ms
mΩ
°C
CONDITIONS
BAT = 4.05V (LTC3559)
BAT = 3.95V (LTC3559-1)
HPWR = 5V
HPWR = 0V
BAT < V
TRKL
BAT < V
TRKL
BAT Rising
Threshold Voltage Relative to V
FLOAT
BAT Falling
BAT = V
FLOAT
BAT < V
TRKL
(Note 5)
I
BAT
Falling
I
BAT
= 190mA
h
PROG
I
TRKL
V
TRKL
ΔV
TRKL
ΔV
RECHRG
t
RECHRG
t
TERM
t
BADBAT
h
C/10
t
C/10
R
ON(CHG)
T
LIM
NTC
V
COLD
Ratio of I
BAT
to PROG Pin Current
Trickle Charge Current
Trickle Charge Threshold Voltage
Trickle Charge Hysteresis Voltage
Recharge Battery Threshold Voltage
Recharge Comparator Filter Time
Safety Timer Termination Period
Bad Battery Termination Time
End-of-Charge Indication Current Ratio
End-of-Charge Comparator Filter Time
Battery Charger Power FET On-Resistance
(Between V
CC
and BAT)
Junction Temperature in Constant
Temperature Mode
36
2.8
–85
3.5
0.4
0.085
56
3.0
–130
4.5
0.6
0.11
Cold Temperature Fault Threshold Voltage Rising NTC Voltage
Hysteresis
V
HOT
Hot Temperature Fault Threshold Voltage Falling NTC Voltage
Hysteresis
V
DIS
NTC Disable Threshold Voltage
Falling NTC Voltage
Hysteresis
NTC Leakage Current
V
NTC
= V
CC
= 5V
I
NTC
Logic (HPWR, SUSP
CHRG)
,
Input Low Voltage
HPWR, SUSP Pins
V
IL
Input High Voltage
HPWR, SUSP Pins
V
IH
Logic Pin Pull-Down Resistance
HPWR, SUSP Pins
R
DN
CHRG
Pin Output Low Voltage
I
CHRG
= 5mA
V
CHRG
CHRG
Pin Input Current
BAT = 4.5V, V
CHRG
= 5V
I
CHRG
Buck Switching Regulators, BAT = PV
IN
= 3.8V, EN1 = EN2 = 3.8V
Input Supply Voltage
LTC3559
PV
IN
LTC3559-1
Pulse Skip Supply Current
MODE = 0 (One Buck Enabled) (Note 6)
I
PVIN
Burst Mode Supply Current
MODE = 1 (One Buck Enabled) (Note 6)
Shutdown Supply Current
EN1 = EN2 = 0V
Supply Current in UVLO
PV
IN
= 2.0V
PV
IN
UVLO PV
IN
Falling
PV
IN
Rising
Switching Frequency
MODE = 0V
f
OSC
Input Low Voltage
MODE, EN1, EN2
V
IL
Input High Voltage
MODE, EN1, EN2
V
IH
Peak PMOS Current Limit
MODE = 0V or 3.8V
I
LIMSW
75
33.4
l
0.7
–1
76.5
1.6
34.9
1.6
1.7
50
78
36.4
2.7
1
0.4
%V
CC
%V
CC
%V
CC
%V
CC
%V
CC
mV
μA
V
V
MΩ
mV
μA
V
V
μA
μA
μA
μA
V
V
MHz
V
V
mA
l
1.2
1.9
4
100
0
6.3
250
1
4.2
4.1
400
50
2
8
l
l
3
3
220
35
0
4
2.45
2.55
2.25
l
1.91
1.2
550
2.59
0.4
1050
800
3559fb
3
LTC3559/LTC3559-1
ELECTRICAL CHARACTERISTICS
range, otherwise specifications are at T
A
= 25°C.
PARAMETER
Feedback Voltage
FB Input Current
Maximum Duty Cycle
R
DS(ON)
of PMOS
R
DS(ON)
of NMOS
SW Pull-Down in Shutdown
SYMBOL
V
FB
I
FB
D
MAX
R
PMOS
R
NMOS
R
SW(PD)
The
l
denotes specifications that apply over the full operating temperature
MIN
780
–0.05
100
TYP
800
MAX
820
0.05
UNITS
mV
μA
%
Ω
Ω
kΩ
CONDITIONS
l
FB1, FB2 = 0.82V
FB1, FB2 = 0V
I
SW
= 150mA
I
SW
= –150mA
0.65
0.75
13
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
•
θ
JA
°C/W)
Note 3:
The LTC3559/LTC3559-1 are guaranteed to meet specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 4:
V
CC
supply current does not include current through the PROG pin
or any current delivered to the BAT pin. Total input current is equal to this
specification plus 1.00125 • I
BAT
where I
BAT
is the charge current.
Note 5:
I
C/10
is expressed as a fraction of measured full charge current
with indicated PROG resistor.
Note 6:
FB high, regulator not switching.
TYPICAL PERFORMANCE CHARACTERISTICS
Suspend State Supply and BAT
Currents vs Temperature
10
9
8
7
CURRENT (μA)
V
FLOAT
(V)
6
5
4
3
2
1
0
–55
–35
25
5
–15
45
TEMPERATURE (°C)
65
85
I
BAT
4.100
4.075
4.050
–55 –35
–15
45
25
5
TEMPERATURE (°C)
65
85
3559 G02
Battery Regulation (Float)
Voltage vs Temperature
4.250
V
CC
= 5V
LTC3559
4.200
4.175
4.150
4.125
LTC3559-1
4.205
4.200
4.195
4.190
4.185
V
BAT
(V)
4.180
4.175
4.170
4.165
4.160
4.155
4.150
4.225
Battery Regulation (Float) Voltage
vs Battery Charge Current,
Constant-Voltage Charging
I
VCC
V
CC
= 5V
BAT = 4.2V
SUSP = 5V
EN1 = EN2 = 0V
V
CC
= 5V
HPWR = 5V
R
PROG
= 845Ω
EN1 = EN2 = 0V
0 100 200 300 400 500 600 700 800 900 1000
I
BAT
(mA)
3559 G03
3559 G01
3559fb
4
LTC3559/LTC3559-1
TYPICAL PERFORMANCE CHARACTERISTICS
Battery Charge Current
vs Supply Voltage
500
V
CC
= 5V
495 HPWR = 5V
490 R
PROG
= 1.74k
485 EN1 = EN2 = 0V
480
I
BAT
(mA)
475
470
465
460
455
450
445
440
4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
V
CC
(V)
3559 G04
Battery Charge Current
vs Battery Voltage (LTC3559)
500
450
400
350
I
BAT
(mA)
I
BAT
(mA)
300
250
200
150
100
50
0
2
2.5
3.5
3
V
BAT
(V)
4
4.5
3559 G05
Battery Charge Current
vs Ambient Temperature in
Thermal Regulation
500
450
400
350
300
250
200
150
V
CC
= 5V
HPWR = 5V
R
PROG
= 1.74k
EN1 = EN2 = 0
5 25 45 65 85 105 125
TEMPERATURE (°C)
3559 G06
V
CC
= 5V
R
PROG
= 1.74k
HPWR = 5V
HPWR = 0V
100
50
0
–55 –35 –15
Battery Charger Undervoltage
Lockout Threshold vs Temperature
4.2
4.1
4.0
I
BAT
(μA)
V
CC
(V)
3.9
3.8
3.7
3.6
3.5
–55 –35
BAT = 3.5V
RISING
3.0
2.5
2.0
FALLING
Battery Drain Current in
Undervoltage Lockout
vs Temperature
EN1 = EN2 = 0V
BAT = 4.2
(LTC3559)
V
PROG
(V)
1.2
1.0
0.8
BAT = 3.6
1.5
1.0
0.5
0
–55 –35
0.6
0.4
0.2
0
PROG Voltage
vs Battery Charge Current
V
CC
= 5V
HPWR = 5V
R
PROG
= 1.74k
EN1 = EN2 = 0V
25
5
45
–15
TEMPERATURE (°C)
65
85
3559 G07
25
5
45
–15
TEMPERATURE (°C)
65
85
3559 G08
0
50 100 150 200 250 300 350 400 450 500
I
BAT
(mA)
3559 G09
Recharge Threshold
vs Temperature
115
111
107
V
RECHARGE
(mV)
103
R
ON
(mΩ)
99
95
91
87
83
79
75
–55
–35
25
5
–15
45
TEMPERATURE (°C)
65
85
400
350
600
550
500
450
V
CC
= 5V
700
650
Battery Charger FET
On-Resistance vs Temperature
V
CC
= 4V
I
BAT
= 200mA
EN1 = EN2 = 0V
THRESHOLD (V)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
–35
–15
5
25
45
65
85
SUSP/HPWR Pin Rising
Thresholds vs Temperature
V
CC
= 5V
300
–55
0.4
–55 –35
–15
TEMPERATURE (°C)
3559 G10
3559 G11
45
25
5
TEMPERATURE (°C)
65
85
3559 G12
3559fb
5