LINEAR TECHNOLOGY LTC3559, LTC3559-1 Technical data

LTC3559/LTC3559-1

Linear USB Battery Charger

with Dual Buck Regulators

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 Qualifi ed 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 Profi le Thermally Enhanced

16-Lead 3mm × 3mm QFN Package

APPLICATIONS

DESCRIPTION

The LTC®3559/LTC3559-1 are USB battery chargers with
dual high effi ciency 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
qualifi ed 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 effi ciencies
greater than 90% over the entire Li-Ion/Polymer range.
A MODE pin provides the fl exibility to place both buck
regulators in a power saving Burst Mode
low noise pulse skip mode.

The LTC3559/LTC3559-1 are offered in a low profi le ther­mally 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.

®

operation or a

n

SD/Flash-Based MP3 Players

n

Low Power Handheld Applications

TYPICAL APPLICATION

USB Charger Plus Dual Buck Regulators

USB (4.3V TO 5.5V)

OR AC ADAPTOR

DIGITAL

CONTROL

1μF

1.74k

V

CC

NTC

PROG

CHRG

SUSP

HPWR

EN1

EN2

MODE

GND

LTC3559

EXPOSED

PAD

BAT

PV

SW1

FB1

SW2

FB2

IN

UP TO 500mA

4.7μH

22pF

4.7μH

22pF

2.2μF

+

655k

309k

324k

649k

3559 TA01

SINGLE
Li-lon CELL
(2.7V TO 4.2V)

2.5V
400mA

10μF

1.2V
400mA

10μF

3559fb

1

LTC3559/LTC3559-1

ABSOLUTE MAXIMUM RATINGS

PIN CONFIGURATION

(Note 1)

VCC (Transient);

t < 1ms and Duty Cycle < 1% ....................... –0.3V to 7V

(Static) .................................................. –0.3V to 6V

V

CC

BAT, CHRG, SUSP ........................................ –0.3V to 6V

HPWR, NTC, PROG .......–0.3V to Max (V

, BAT) + 0.3V

CC

PROG Pin Current ...............................................1.25mA

BAT Pin Current ..........................................................1A

................................................–0.3V to BAT + 0.3V

PV

IN

EN1, EN2, MODE .......................................... –0.3V to 6V

FB1, FB2, SW1, SW2 ............–0.3V to PV

, I

I

SW1

......................................................600mA DC

SW2

+ 0.3V or 6V

IN

Junction Temperature (Note 2) ............................. 125°C

BAT

MODE

FB1

16-LEAD (3mm s 3mm) PLASTIC QFN

EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB

TOP VIEW

VCCCHRG

16 15 14 13

1GND

2

17

3

4

5 6 7 8

EN1

SW1

UD PACKAGE

T

= 125°C, θJA = 68°C/W

JMAX

PROG

IN

PV

NTC

SW2

12

HPWR

SUSP

11

FB2

10

EN2

9

Operating Temperature Range (Note 3).... –40°C to 85°C

Storage Temperature ..............................–65°C to 125°C

ORDER INFORMATION

LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC3559EUD#PBF LTC3559EUD#TRPBF LCMB

LTC3559EUD-1#PBF LTC3559EUD-1#TRPBF LDQD

Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based fi nish parts.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/

16-Lead (3mm × 3mm) Plastic QFN

16-Lead (3mm × 3mm) Plastic QFN

–40°C to 85°C

–40°C to 85°C

The l denotes specifi cations that apply over the full operating temperature

ELECTRICAL CHARACTERISTICS

range, otherwise specifi cations are at TA = 25°C.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Battery Charger. V

V

CC

I

VCC

V

FLOAT

I

CHG

I

BAT

V

UVLO

ΔV
V

DUVLO

UVLO

Input Supply Voltage
Battery Charger Quiescent Current (Note 4) Standby Mode, Charge Terminated

BAT Regulated Output Voltage LTC3559

Constant-Current Mode Charge Current HPWR = 5V

Battery Drain Current Standby Mode, Charger Terminated

Undervoltage Lockout Threshold BAT = 3.5V, VCC Rising 3.85 4.0 4.125 V
Undervoltage Lockout Hysteresis BAT = 3.5V 200 mV

Differential Undervoltage Lockout
Threshold

= 5V, BAT = PVIN = 3.6V, R

CC

= 1.74k, HPWR = 5V, SUSP = NTC = EN1 = EN2 = 0V

PROG

Suspend Mode, V

0°C ≤ T

≤ 85°C, LTC3559

A

LTC3559-1

≤ 85°C, LTC3559-1

0°C ≤ T

A

HPWR = 0V

Shutdown, V
Suspend Mode, SUSP = 5V, BAT = V

BAT = 4.05V, (VCC – BAT) Falling (LTC3559)
BAT = 3.95V, (V

CC

= 5V

SUSP

< V

, BAT = V

UVLO

– BAT) Falling (LTC3559-1)

CC

FLOAT

FLOAT

l

4.3 5.5 V

4.179

4.165

4.079

4.065

l

4408446092500

30
30

200

8.5

4.200

4.200

4.100

4.100

–3.5
–2.5
–1.5

50
50

400

17

4.221

4.235

4.121

4.135

100

–7
–4
–3

70
70

μA
μA

V
V

V
V

mA
mA

μA
μA
μA

mV
mV

3559fb

2

LTC3559/LTC3559-1

ELECTRICAL CHARACTERISTICS

The l denotes specifi cations that apply over the full operating temperature
range, otherwise specifi cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

ΔV

DUVLO

V

PROG

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

V

HOT

V

DIS

I

NTC

Logic (HPWR, SUSP, CHRG)

V

IL

V

IH

R

DN

V

CHRG

I

CHRG

Buck Switching Regulators, BAT = PV

PV

IN

I

PVIN

PVIN UVLO PVIN Falling

f

OSC

V

IL

V

IH

I

LIMSW

Differential Undervoltage Lockout
Hysteresis

PROG Pin Servo Voltage HPWR = 5V

Ratio of I

to PROG Pin Current 800 mA/mA

BAT

Trickle Charge Current BAT < V
Trickle Charge Threshold Voltage BAT Rising 2.8 2.9 3.0 V
Trickle Charge Hysteresis Voltage 100 mV

Recharge Battery Threshold Voltage Threshold Voltage Relative to V

Recharge Comparator Filter Time BAT Falling 1.7 ms
Safety Timer Termination Period BAT = V
Bad Battery Termination Time BAT < V
End-of-Charge Indication Current Ratio (Note 5) 0.085 0.1 0.11 mA/mA
End-of-Charge Comparator Filter Time I
Battery Charger Power FET On-Resistance

(Between V

and BAT)

CC

Junction Temperature in Constant
Temperature Mode

Cold Temperature Fault Threshold Voltage Rising NTC Voltage

Hot Temperature Fault Threshold Voltage Falling NTC Voltage

NTC Disable Threshold Voltage Falling NTC Voltage

NTC Leakage Current V

Input Low Voltage HPWR, SUSP Pins 0.4 V
Input High Voltage HPWR, SUSP Pins 1.2 V
Logic Pin Pull-Down Resistance HPWR, SUSP Pins

CHRG Pin Output Low Voltage I
CHRG Pin Input Current BAT = 4.5V, V

IN

Input Supply Voltage LTC3559

Pulse Skip Supply Current
Burst Mode Supply Current
Shutdown Supply Current
Supply Current in UVLO

PV

Rising

IN

Switching Frequency MODE = 0V 1.91 2.25 2.59 MHz
Input Low Voltage MODE, EN1, EN2 0.4 V
Input High Voltage MODE, EN1, EN2 1.2 V
Peak PMOS Current Limit MODE = 0V or 3.8V 550 800 1050 mA

= 25°C.

A

BAT = 4.05V (LTC3559)
BAT = 3.95V (LTC3559-1)

HPWR = 0V
BAT < V

Falling 2.2 ms

BAT

= 190mA 500

I

BAT

Hysteresis

Hysteresis

Hysteresis

= VCC = 5V –1 1 μA

NTC

= 5mA 100 250 mV

CHRG

= 3.8V, EN1 = EN2 = 3.8V

LTC3559-1
MODE = 0 (One Buck Enabled) (Note 6)

MODE = 1 (One Buck Enabled) (Note 6)
EN1 = EN2 = 0V
PV

= 2.0V

IN

TRKL

TRKL

FLOAT

TRKL

130
130

1.000

0.200

0.100

36 46 56 mA

FLOAT

–85 –100 –130 mV

3.5 4 4.5 Hour

0.4 0.5 0.6 Hour

105 °C

75 76.5

78 %V

1.6

33.4 34.9

36.4 %V

1.6

l

0.7 1.7

2.7 %V

50

l

1.9 4 6.3

= 5V 0 1 μA

CHRG

l

3

l

3

220

35

l

4.2

4.1

400

50
0
4

2
8

2.45

2.55

%V

%V

mV
mV

V
V
V

mΩ

CC
CC

CC
CC

CC

mV

MΩ

V
V

μA
μA
μA
μA

V
V

3559fb

3

LTC3559/LTC3559-1

ELECTRICAL CHARACTERISTICS

The l denotes specifi cations that apply over the full operating temperature
range, otherwise specifi cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

FB

I

FB

D

MAX

R

PMOS

R

NMOS

R

SW(PD)

Feedback Voltage
FB Input Current FB1, FB2 = 0.82V –0.05 0.05 μA
Maximum Duty Cycle FB1, FB2 = 0V 100 %
R

of PMOS ISW = 150mA 0.65

DS(ON)

R

of NMOS ISW = –150mA 0.75

DS(ON)

SW Pull-Down in Shutdown 13

= 25°C.

A

l

780 800 820 mV

Ω

Ω

kΩ

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
dissipation P

T

is calculated from the ambient temperature TA and power

J

according to the following formula:

D

= TA + (PD • θJA°C/W)

J

Note 3: The LTC3559/LTC3559-1 are guaranteed to meet specifi cations

temperature range are assured by design, characterization and correlation
with statistical process controls.

Note 4: V

CC

or any current delivered to the BAT pin. Total input current is equal to this
specifi cation plus 1.00125 • I

Note 5: I

C/10

with indicated PROG resistor.
Note 6: FB high, regulator not switching.

from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating

TYPICAL PERFORMANCE CHARACTERISTICS

Suspend State Supply and BAT
Currents vs Temperature

10

9

8

7

6

VCC = 5V

5

BAT = 4.2V
SUSP = 5V

4

CURRENT (μA)

EN1 = EN2 = 0V

3

2

1

0

–55

–35

I

VCC

I

BAT

25

5

–15

TEMPERATURE (°C)

65

85

3559 G01

45

Battery Regulation (Float)
Voltage vs Temperature

4.250
VCC = 5V

4.225

4.200

4.175

(V)

4.150

FLOAT

V

4.125

4.100

4.075

4.050

–35 –15 25

–55

LTC3559

LTC3559-1

TEMPERATURE (°C)

5

45 65 85

supply current does not include current through the PROG pin

BAT

where I

is the charge current.

BAT

is expressed as a fraction of measured full charge current

Battery Regulation (Float) Voltage
vs Battery Charge Current,
Constant-Voltage Charging

4.205

4.200

4.195

4.190

4.185

4.180

(V)

BAT

4.175

V

4.170

4.165
VCC = 5V

4.160

HPWR = 5V

= 845Ω

R

PROG

4.155
EN1 = EN2 = 0V

4.150

3559 G02

100

300

400

2000

I

BAT

500

(mA)

600

700

800

900

3559 G03

1000

4

3559fb

TYPICAL PERFORMANCE CHARACTERISTICS

Battery Charge Current
vs Supply Voltage

500

VCC = 5V

495

HPWR = 5V

490

485

480

475

(mA)

470

BAT

I

465

460

455

450

445

440

= 1.74k

R

PROG

EN1 = EN2 = 0V

4.3

4.5

4.6 4.9 5.1

4.8 5.0 5.2 5.4 5.5

4.7
VCC (V)

Battery Charger Undervoltage
Lockout Threshold vs Temperature

4.2
BAT = 3.5V

(V)

CC

V

4.1

4.0

3.9

3.8

3.7

3.6

RISING

FALLING

5.34.4

3559 G04

Battery Charge Current
vs Battery Voltage (LTC3559)

500

450

400

350

300

(mA)

250

BAT

I

200

150

100

50

0

2

VCC = 5V
R

PROG

= 1.74k

2.5

HPWR = 5V

HPWR = 0V

3

V

BAT

Battery Drain Current in
Undervoltage Lockout
vs Temperature

3.0
EN1 = EN2 = 0V

(μA)

BAT

I

2.5

2.0

1.5

1.0

0.5

BAT = 4.2

(LTC3559)

3.5

(V)

BAT = 3.6

LTC3559/LTC3559-1

Battery Charge Current
vs Ambient Temperature in
Thermal Regulation

500

450

400

350

300

(mA)

250

BAT

I

200

150

VCC = 5V

100

HPWR = 5V

= 1.74k

R

PROG

50

EN1 = EN2 = 0

0

–35 5

–55

4

4.5

3559 G05

–15

25

TEMPERATURE (°C)

PROG Voltage
vs Battery Charge Current

1.2
VCC = 5V

HPWR = 5V

(V)

PROG

V

1.0

0.8

0.6

0.4

0.2

= 1.74k

R

PROG

EN1 = EN2 = 0V

85

45 125

105

65

3.5
–55

–35 –15

TEMPERATURE (°C)

Recharge Threshold
vs Temperature

115

VCC = 5V

111

107

103

99

(mV)

95

91

RECHARGE

V

87

83

79

75

–55

–35

–15

TEMPERATURE (°C)

25 65 85

545

3559 G07

25

5

45

65

3559 G10

0

–55

–35 –15

TEMPERATURE (°C)

25 65 85

545

3559 G08

Battery Charger FET
On-Resistance vs Temperature

700

VCC = 4V

= 200mA

I

BAT

650

EN1 = EN2 = 0V

600

550

(mΩ)

500

ON

R

450

400

350

300

85

–55

–15 5 25 45 65

–35

TEMPERATURE (°C)

85

3559 G11

0

100 200 300 400

I

BAT

SUSP/HPWR Pin Rising
Thresholds vs Temperature

1.2
VCC = 5V

1.1

1.0

0.9

0.8

0.7

THRESHOLD (V)

0.6

0.5

0.4

–35 –15 25

–55

5

TEMPERATURE (°C)

(mA)

500500 150 250 350 450

3559 G09

45 65 85

3559 G12

3559fb

5

LTC3559/LTC3559-1

TYPICAL PERFORMANCE CHARACTERISTICS

CHRG Pin Output Low Voltage
vs Temperature

140

VCC = 5V
I

CHRG

120

100

80

(mV)

60

CHRG

V

40

20

= 5mA

CHRG Pin I-V Curve

70

VCC = 5V
BAT = 3.8V

60

50

40

(mA)

30

CHRG

I

20

10

Timer Accuracy vs Supply Voltage

2.0

1.5

1.0

0.5

0

PERCENT ERROR (%)

–0.5

0

–55

–35 –15

TEMPERATURE (°C)

25 65 85

545

Timer Accuracy vs Temperature

7

VCC = 5V

6

5

4

3

2

1

PERCENT ERROR (%)

0

–1

–2

–55

–15

–35

TEMPERATURE (°C)

585

25

Buck Regulator Input Current vs
Temperature, Pulse Skip Mode
(LTC3559)

400

VFB = 0.82V

350

300

250

200

INPUT CURRENT (μA)

150

100

–35 5

–55

PVIN = 4.2V

–15

25

TEMPERATURE (°C)

PVIN = 2.7V

45 125

65

45 65

85

3559 G13

3559 G16

105

3559 G19

0

0

12

CHRG (V)

Complete Charge Cycle
2400mAh Battery (LTC3559)

1000

800
600

(mA)BAT (V)CHRG (V)

400

BAT

I

200

0

5.0

4.5

4.0

3.5

3.0

5.0

4.0

3.0

2.0

1.0
0

0

12 4 6

TIME (HOUR)

46

35

3559 G14

VCC = 5V

= 0.845k

R

PROG

HPWR = 5V

35

3559 G17

–1.0

4.3

4.7 4.9 5.1

4.5

Buck Regulator Input Current vs
Temperature, Burst Mode Operation

50

VFB = 0.82V

45

40

PVIN = 4.2V

35

30

INPUT CURRENT (μA)

25

20

–35 5

–55

–15

TEMPERATURE (°C)

Buck Regulator PVIN Undervoltage
Thresholds vs Temperature Frequency vs Temperature

2.5

2.4

2.3

2.2

2.1

2.0

(MHz)

OSC

1.9

f

1.8

1.7

1.6

1.5
–55

PVIN = 3.8V

–35 –15 25

TEMPERATURE (°C)

5

(V)

IN

PV

2.85

2.75

2.65

2.55

2.45

2.35

2.25
–35 5

–55

RISING

FALLING

–15

25

TEMPERATURE (°C)

85

45 125

105

65

3559 G20

VCC (V)

PVIN = 2.7V

85

45 125

65

25

85

45

65

5.3 5.5

3559 G15

105

3559 G18

105

125

3559 G21

3559fb

6

TYPICAL PERFORMANCE CHARACTERISTICS

5

5

0

0

LTC3559/LTC3559-1

Buck Regulator Enable
Thresholds vs Temperature

1200

PVIN = 3.8V

1100

1000

900

(mV)

800

EN

V

700

600

500

400

–35 125

–55

–15

RISING

FALLING

25

45

5

TEMPERATURE (°C)

Buck Regulator Effi ciency vs I

105

65

85

3559 G22

LOAD

Buck Regulator PMOS R
vs Temperature (LTC3559)

1300

1200

1100

1000

900

(mΩ)

800

DS(ON)

R

700

600

500

400

–55

–35

–15

PVIN = 2.7V

5

TEMPERATURE (°C)

PVIN = 4.2V

25

45 12

(LTC3559) Buck Regulator Load Regulation

100

Burst Mode

90

OPERATION

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

0.1 10 100 1000

1

I

LOAD

PULSE SKIP
MODE

(mA)

V

OUT

PV

= 2.5V

= 4.2V

IN

3559 G25

(V)

OUT

V

2.60

2.58

2.56

2.54

2.52

2.50

2.48

2.46

2.44

PVIN = 3.8V

= 2.5V

V

OUT

1

Burst Mode

OPERATION

PULSE SKIP

MODE

10 100 100

I

(mA)

LOAD

65

DS(0N)

85

105

3559 G23

3559 G26

Buck Regulator NMOS R
vs Temperature (LTC3559)

1300

1200

1100

1000

900

(mΩ)

800

DS(ON)

R

700

600

500

400

–55

PVIN = 2.7V

–35

–15

PVIN = 4.2V

5

25

TEMPERATURE (°C)

45 12

Buck Regulator Line Regulation

2.60
V

= 2.5V

OUT

= 200mA

I

LOAD

2.58

2.56

2.54

(V)

2.52

OUT

V

2.50

2.48

2.46

2.44

3.0 3.3 3.9

2.7

3.6

PVIN (V)

65

DS(0N)

85

105

3559 G24

4.2

3559 G27

Buck Regulator Effi ciency vs I
(LTC3559)

100

Burst Mode

90

OPERATION

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

0.1 10 100 1000

PULSE SKIP

MODE

V

OUT

PVIN = 2.7V
PV

1

I

(mA)

LOAD

= 1.2V

= 4.2V

IN

LOAD

3559 G28

Buck Regulator Load Regulation

1.25
PVIN = 3.8V

(V)

OUT

V

1.24

1.23

1.22

1.21

1.20

1.19

1.18

1.17

1.16

1.15

= 1.2V

V

OUT

Burst Mode

OPERATION

PULSE SKIP

MODE

1

10 100 100

I

(mA)

LOAD

3559 G29

Buck Regulator Line Regulation

1.25
V

= 1.2V

OUT

(V)

OUT

V

1.24

1.23

1.22

1.21

1.20

1.19

1.18

1.17

1.16

1.15

2.7

I

LOAD

= 200mA

3.0

3.3
PVIN (V)

3.6

3.9

4.2

3559 G30

3559fb

7

LTC3559/LTC3559-1

TYPICAL PERFORMANCE CHARACTERISTICS

Buck Regulator Start-Up Transient

Buck Regulator Pulse Skip Mode
Operation

V

500mV/DIV

INDUCTOR

CURRENT

= 200mA/DIV

I

L

2V/DIV

V

20mV/DIV (AC)

2V/DIV

INDUCTOR

CURRENT

= 60mA/DIV

I

L

OUT

EN

= 3.8V

PV

IN

PULSE SKIP MODE
LOAD = 6Ω

50μs/DIV

Buck Regulator Burst Mode
Operation

OUT

SW

= 3.8V

PV

IN

LOAD = 60mA

2μs/DIV

3559 G33

3559 G35

V

SW

2V/DIV

INDUCTOR

CURRENT

= 50mA/DIV

I

L

INDUCTOR

CURRENT

= 200mA/DIV

V

LOAD STEP

OUT

OUT

20mV/DIV (AC)

I

L

50mV/DIV (AC)

5mA TO 290mA

= 3.8V

PV

IN

LOAD = 10mA

200ns/DIV

Buck Regulator Transient
Response, Pulse Skip Mode

= 3.8V 50μs/DIV

PV

IN

3559 G34

3559 G36

8

INDUCTOR

CURRENT

= 200mA/DIV

I

L

V

50mV/DIV (AC)

5mA TO 290mA

OUT

LOAD STEP

Buck Regulator Transient
Response, Burst Mode Operation

= 3.8V 50μs/DIV

PV

IN

3559 G37

3559fb