Linear Technology LTC4089EDJC-5, LTC4089 Datasheet

LTC4089/LTC4089-5

1

40895fb

HVIN

BOOST

HVEN

IN

SW

4.7µF

10µF

4.7µF

1µF

TIMER

CLPROG

LTC4089

GND PROG

HVOUT

HVPR

OUT

BAT

0.1µF

100k2k

5V (NOM)

FROM USB

CABLE V

BUS

HIGH (6V-36V)

VOLTAGE INPUT

Li-Ion BATTERY

+

1k

TO LDOs
R

EGS

, ETC.

4089 TAO1

VOUT (TYP)

V

BAT

+0.3V
5V
5V

V

BAT

AVAILABLE INPUT

HV INPUT (LTC4089)

HV INPUT (LTC4089-5)

USB ONLY
BAT ONLY

10µH

0.1µF

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other

trademarks are the property of their respective owners.

Burst Mode is a registered trademark

of Linear Technology Corporation.

Protected by U.S. Patents including 6522118 and 6700364.

TYPICAL APPLICATIO

U

USB Power Manager with

High Voltage Switching Charger

The LTC®4089/LTC4089-5 are USB power managers plus
high voltage Li-Ion battery chargers. These devices control
the total current used by the USB peripheral for operation
and battery charging. Battery charge current is automati­cally reduced such that the sum of the load current and
the charge current does not exceed the programmed input
current limit. The LTC4089/LTC4089-5 also accommodate
high voltage power supplies, such as 12V AC-DC wall
adapters, FireWire, or automotive power.

The LTC4089 provides an adaptive output that tracks the
battery voltage for high effi ciency charging from the high
voltage input. The LTC4089-5 provides a fi xed 5V output
from the high voltage input to charge single cell Li-Ion
batteries. The charge current is programmable and an
end-of-charge status output (CHRG) indicates full charge.
Also featured is programmable total charge time, an NTC
thermistor input used to monitor battery temperature while
charging and automatic recharging of the battery.

■

Portable USB Devices—GPS Receivers, Cameras,

MP3 Players, PDAs

■

Seamless Transition Between Power Sources: Li-Ion
Battery, USB, and 6V to 36V External Supply

■

High Effi ciency 1.2A Charger from 6V to 36V Input

with Adaptive Output Control (LTC4089)

■

Load Dependent Charging from USB Input

Guarantees Current Compliance

■

215m Internal Ideal Diode plus Optional External

Ideal Diode Controller Provides Low Loss Power
Path When External Supply/USB Not Present

■

Constant-Current/Constant-Voltage Operation with

Thermal Feedback to Maximize Charging Rate
without Risk of Overheating

■

Selectable 100% or 20% Current Limit (e.g., 500mA/

100mA) from USB Input

■

Preset 4.2V Charge Voltage with 0.8% Accuracy

■

C/10 Charge Current Detection Output

■

NTC Thermistor Input for Temperature Qualifi ed

Charging

■

Tiny (6mm 3mm 0.75mm) 22-Pin DFN Package

APPLICATIO S

U

FEATURES

DESCRIPTIO

U

LTC4089 High Voltage
Battery Charger Effi ciency

BATTERY VOLTAGE (V)

2.5

40

EFFICIENCY (%)

45

55

60

65

90

75

3

3.5

4089 TA01b

50

80

85

70

4

4.5

HVIN = 8V
HVIN = 12V
HVIN = 24V
HVIN = 36V

CC CURRENT = 970mA
NO OUTPUT LOAD
FIGURE 10 SCHEMATIC
WITH R

PROG

= 52k

LTC4089-5

LTC4089

LTC4089/LTC4089-5

2

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Terminal Voltage

BOOST ...................................................... –0.3V to 50V

BOOST above SW .....................................................25V

HVIN, HVEN .............................................. –0.3V to 40V

IN, OUT, HVOUT

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

DC ............................................................ –0.3V to 6V

BAT .............................................................. –0.3V to 6V

NTC, TIMER, PROG, CLPROG .......–0.3V to (V

CC

+ 0.3V)

CHRG, HPWR, SUSP, HVPR ......................... –0.3V to 6V

Pin Current, DC

IN, OUT, BAT (Note 6) ..............................................2.5A

Operating Temperature Range

LTC4089E ................................................. –40°C to 85°C

Maximum Operating Junction Temperature .......... 110°C

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

(Notes 1, 2, 3, 4, 5)

The

● denotes the specifi cations which apply over the full operating

temperature range, otherwise specifi cations are at TA = 25°C. HVIN = 12V, BOOST = 17V, VIN = 5V, V

BAT

= 3.7V, HVEN = 12V,

HPWR = 5V, R

PROG

= 100k, R

CLPROG

= 2k, SUSP = 0V, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

USB Input Current Limit

V

IN

USB Input Supply Voltage IN

●

4.35 5.5 V

I

IN

Input Bias Current I

BAT

= 0 (Note 7)

Suspend Mode; SUSP = 5V

●

●

0.5
50

1

100

mA

µA

I

LIM

Current Limit R

CLPROG

= 2k, HPWR = 5V

R

CLPROG

= 2k, HPWR = 0V

●

●

475

90

500
100

525
110

mA
mA

I

IN(MAX)

Maximum Input Current Limit (Note 8) 2.4 A

R

ON

ON Resistance VIN to V

OUT

I

OUT

= 80mA Load 0.215

V

CLPROG

CLPROG Pin Voltage R

CLPROG

= 2k

R

CLPROG

= 1k

●

●

0.98

0.98

1.00

1.00

1.02

1.02

V
V

I

SS

Soft-Start Inrush Current IN 5 mA/µs

V

CLEN

Input Current Limit Enable
Threshold Voltage (V

IN

– V

OUT

)

(V

IN

– V

OUT

) VIN Rising

(V

IN

– V

OUT

) VIN Falling

20

–80

50

–50

80

–20

mV
mV

ELECTRICAL CHARACTERISTICS

ABSOLUTE AXI U RATI GS

W

WW

U

PACKAGE/ORDER I FOR ATIO

UUW

22

21

20

19

18

17

16

15

14

13

12

1

2

3

4

5

6

7

8

9

10

11

HVEN

HVIN

BOOST

SW

HVOUT

TIMER

SUSP

HPWR

CLPROG

OUT

IN

TOP VIEW

23

DJC PACKAGE

22-LEAD (6mm × 3mm) PLASTIC DFN

GND

GND

HVOUT

V

C

NTC

VNTC

HVPR

CHRG

PROG

GATE

BAT

EXPOSED PAD (PIN 23) IS GND
(MUST BE SOLDERED TO PCB)

T

JMAX

= 110°C, JA = 40°C/W

ORDER PART NUMBER DJC PART MARKING

LTC4089EDJC
LTC4089EDJC-5

4089

40895

Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/

Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.

LTC4089/LTC4089-5

3

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SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

UVLO

Input Undervoltage Lockout VIN Powers Part, Rising Threshold

●

3.6 3.8 4 V

dV

UVLO

Input Undervoltage Lockout
Hysteresis

VIN Rising – VIN Falling 130 mV

High Voltage Regulator

V

HVIN

HVIN Supply Voltage 6 36 V

I

HVIN

HVIN Bias Current Not Switching

Shutdown; HVEN = 0V

1.9

0.01

2.5
2

mA

µA

V

OUT

Output Voltage with HVIN Present Assumes HVOUT to OUT Connection (LTC4089)

Assumes HVOUT to OUT Connection (LTC4089-5)

●

3.45

4.85

V

BAT

+0.354.6

5.15

V
V

V

HVUVLO

High Voltage Input Undervoltage
Lockout

V

HVIN

Rising 4.7 5 V

f

SW

Switching Frequency V

HVOUT

> 3.95V

V

HVOUT

= 0V

685 750

35

815 kHz

kHz

DC

MAX

Maximum Duty Cycle

●

88 95 %

I

SW(MAX)

Switch Current Limit (Note 9) 1.5 1.95 2.3 A

V

SAT

Switch V

CESAT

ISW = 1A 330 mV

I

LK

Switch Leakage Current 2µA

V

SWD

Minimum Boost Voltage Above SW ISW = 1A 1.85 2.2 V

I

BST

BOOST Pin Current ISW = 1A 30 50 mA

Battery Management

V

BAT

Input Voltage BAT 4.3 V

I

BAT

Battery Drain Current V

BAT

= 4.3V, Charging Stopped
Suspend Mode; SUSP = 5V
V

HVIN

= VIN = 0V, BAT Powers OUT, No Load

●

●

●

15
22
60

27
35

100

µA
µA
µA

V

FLOAT

Regulated Output Voltage I

BAT

= 2mA

I

BAT

= 2mA; (0°C – 85°C)

4.165

4.158

4.200

4.200

4.235

4.242

V
V

I

CHG

Current Mode Charge Current R

PROG

= 100k, No Load

R

PROG

= 50k, No Load; (0°C – 85°C)

●

465
900

500

1000

535

1080

mA
mA

I

CHG(MAX)

Maximum Charge Current (Note 8) 1.2 A

V

PROG

PROG Pin Voltage R

PROG

= 100k

R

PROG

= 50k

●

●

0.98

0.98

1.00

1.00

1.02

1.02

V
V

k

EOC

Ratio of End-of-Charge Current to
Charge Current

V

BAT

= V

FLOAT

(4.2V)

●

0.085 0.1 0.11 mA/mA

I

TRIKL

Trickle Charge Current V

BAT

= 2V, R

PROG

= 100k 35 50 60 mA

V

TRIKL

Trickle Charge Threshold Voltage

●

2.75 2.9 3 V

V

CEN

Charger Enable Threshold Voltage (V

OUT

– V

BAT

) Falling; V

BAT

= 4V

(V

OUT

– V

BAT

) Rising; V

BAT

= 4V

55
80

mV
mV

V

RECHRG

Recharge Battery Threshold Voltage V

FLOAT

- V

RECHRG

●

65 100 135 mV

t

TIMER

TIMER Accuracy V

BAT

= 4.3V –10 10 %

Recharge Time Percent of Total Charge Time 50 %

Low Battery Trickle Charge Time Percent of Total Charge Time, V

BAT

< 2.8V 25 %

T

LIM

Junction Temperature in Constant
Temperature Mode

105 °C

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

A

= 25°C. HVIN = 12V, BOOST = 17V, VIN = 5V, V

BAT

= 3.7V, HVEN = 12V,

HPWR = 5V, R

PROG

= 100k, R

CLPROG

= 2k, SUSP = 0V, unless otherwise noted.

ELECTRICAL CHARACTERISTICS

LTC4089/LTC4089-5

4

40895fb

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Internal Ideal Diode

R

FWD

Incremental Resistance, VON
Regulation

I

BAT

= 100mA 125

m

R

DIO,ON

ON Resistance V

BAT

to V

OUT

I

BAT

= 600mA 215

m

V

FWD

Voltage Forward Drop (V

BAT

- V

OUT

)I

BAT

= 5mA

I

BAT

= 100mA

I

BAT

= 600mA

●

10 30

55

160

50 mV

mV
mV

V

OFF

Diode Disable Battery Voltage 2.8 V

I

FWD

Load Current Limit, for VON
Regulation

550 mA

I

D(MAX)

Diode Current Limit 2.2 A

External Ideal Diode

V

FWD, EXT

External Diode Forward Voltage 20 mV

Logic

V

OL

Output Low Voltage (CHRG, HVPR) I

SINK

= 5mA

●

0.1 0.4 V

V

IH

Input High Voltage HVEN, SUSP, HPWR Pin Low to High 2.3 V

V

IL

Input Low Voltage HVEN, SUSP, HPWR Pin High to Low 0.3 V

I

PULLDN

Logic Input Pull Down Current SUSP, HPWR 2 µA

I

HVEN

HVEN Pin Bias Current V

HVEN

= 2.3V

V

HVEN

= 0V

6

0.01

20

0.1

µA
µA

V

CHG,SD

Charger Shutdown Threshold
Voltage on TIMER

●

0.14 0.4 V

I

CHG,SD

Charger Shutdown Pull-Up Current
on TIMER

V

TIMER

= 0V

●

514 µA

NTC

I

VNTC

VNTC Pin Current V

VNTC

= 2.5V

●

1.4 2.5 3.5 mA

V

VNTC

VNTC Bias Voltage I

VNTC

= 500µA

●

4.4 4.85 V

I

NTC

NTC Input Leakage Current V

NTC

= 1V 0

±1

µA

V

COLD

Cold Temperature Fault Threshold
Voltage

Rising Threshold
Hysteresis

0.74•V

VNTC

0.02•V

VNTC

V
V

V

HOT

Hot Temperature Fault Threshold
Voltage

Falling Threshold
Hysteresis

0.29•V

VNTC

0.01•V

VNTC

V
V

V

DIS

NTC Disable Voltage NTC Input Voltage to GND (Falling)

Hysteresis

●

75 100

35

125 mV

mV

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

A

= 25°C. HVIN = 12V, BOOST = 17V, VIN = 5V, V

BAT

= 3.7V, HVEN = 12V,

HPWR = 5V, R

PROG

= 100k, R

CLPROG

= 2k, SUSP = 0V, unless otherwise noted.

ELECTRICAL CHARACTERISTICS

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: V

CC

is the greater of VIN, V

OUT

or V

BAT

Note 3: All voltage values are with respect to GND.
Note 4: This IC includes over-temperature protection that is intended

to protect the device during momentary overload conditions. Junction
temperatures will exceed 110°C when over-temperature protection is
active. Continuous operation above the specifi ed maximum operating
junction temperature may result in device degradation or failure.

Note 5: The LTC4089/LTC4089-5 are guaranteed to meet specifi ed
performance from 0°C to 85°C and are designed, characterized and
expected to meet these extended temperature limits, but are not tested
at –40°C and 85°C.

Note 6: Guaranteed by long term current density limitations.
Note 7: Total input current is equal to this specifi cation plus 1.002 • I

BAT

where I

BAT

is the charge current.

Note 8: Accuracy of programmed current may degrade for currents greater
than 1.5A.

Note 9: Current limit guaranteed by design and/or correlation to static test.
Slope compensation reduces current limit at high duty cycle.

LTC4089/LTC4089-5

5

40895fb

TIME (MIN)

0

V

BAT

, V

OUT

, V

CHRGB

(V)

I

BAT

(mA)

2

3

200

40895 G03

1

0

50

100

150

5

4

600

900

300

0

1500

1200

V

BAT

V

OUT

V

CHRGB

I

BAT

1250mAh
CELL
HVIN = 12V
R

PROG

= 50k

C/10

TERMINATION

I

BAT

(mA)

0

4.00

V

FLOAT

(V)

4.05

4.10

4.15

4.20

4.25

4.30

200 400 600 800

40895 G01

1000

R

PROG

= 34k

TEMPERATURE (°C)

–50

V

FLOAT

(V)

4.195

4.200

4.205

25

75

40895 G02

4.190

4.185

4.180
–25 0 50

4.210

4.215

4.220

100

VIN = 5V
I

BAT

= 2mA

V

BAT

(V)

0

0

I

BAT

(mA)

100

300

400

500

1

2

2.5 4.5

40895 G04

200

0.5 1.5

3

3.5

4

600

VIN = 5V
V

OUT

= NO LOAD

R

PROG

= 100k

R

CLPROG

= 2k

HPWR = 5V

HPWR = 0V

TEMPERATURE (°C)

–50

I

BAT

(mA)

400

500

600

25 75

40895 G05

300

200

–25 0

50 100 125

100

0

VIN = 5V
V

BAT

= 3.5V

θ

JA

= 50°C/W

V

FWD

(mV)

0

0

I

OUT

(mA)

100

300

400

500

1000

700

50

100

40895 G06

200

800

900

600

150

200

V

BAT

= 3.7V

V

IN

= 0V

–50°C

0°C

50°C

100°C

0

3000

4000

5000

80

4085 G17

2000

1000

2500

3500

4500

1500

500

0

20

40

60

100

V

FWD

(mV)

I

OUT

(mA)

V

BAT

= 3.7V

V

IN

= 0V

Si2333 PFET

–50°C

0°C

50°C

100°C

I

OUT

(A)

0

EFFICIENCY (%)

80

90

100

0.8

40895 G08

70

60

75

85

95

65

55

50

0.2

0.4

0.6

1.0

FIGURE 10 SCHEMATIC

V

BAT

= 4.21V (I

BAT

= 0)

HVIN = 8V

HVIN = 12V

HVIN = 36V

HVIN = 24V

I

OUT

(A)

0

EFFICIENCY (%)

80

90

100

0.8

40895 G09

70

60

75

85

95

65

55

50

0.2

0.4

0.6

1.0

FIGURE 10 SCHEMATIC

V

BAT

= 4.21V (I

BAT

= 0)

HVIN = 8V

HVIN = 12V

HVIN = 36V

HVIN = 24V

TYPICAL PERFORMANCE CHARACTERISTICS

V

FLOAT

Load Regulation

Battery Regulation (Float)
Voltage vs Temperature

Battery Current and Voltage vs
Time (LTC4089)

Charging from USB, I

BAT

vs V

BAT

Charge Current vs Temperature
(Thermal Regulation)

Ideal Diode Current vs Forward
Voltage and Temperature (No
External Device)

Ideal Diode Current vs Forward
Voltage and Temperature with
External Device

LTC4089 High Voltage Regulator
Effi ciency vs Output Load

LTC4089-5 High Voltage
Regulator Effi ciency vs Output
Load

T

A

= 25°C, unless otherwise specifi ed.

LTC4089/LTC4089-5

6

40895fb

VIN (V)

5

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.9
20 30

40895 G10

10 15

25 35

I

OUT

(A)

MINIMUM

TYPICAL

VIN (V)

5

1.8

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.9
20 30

40895 G11

10 15

25 35

I

OUT

(A)

MINIMUM

TYPICAL

SWITCH CURRENT (A)

0

V

CE(SW)

(mV)

150

450

500

550

0.4

0.8

1.0

40895 G12

50

350

250

100

400

0

300

200

0.2

0.6

1.4

1.2

1.6

1.8

TA = 25°C

TA = 85°C

TA = –40°C

TEMPERATURE (°C)

FREQUENCY (kHz)

720

760

800

125

40895 G13

680

640

700

740

780

660

620

600

–25–50

250

75 100 150

50

FEEDBACK VOLTAGE (mV)

0

SWITCHING FREQUENCY (kHz)

400

600

800

40895 G14

200

0

200

400

600

100

300

500

700

800

300

500

100

700

SHDN PIN VOLTAGE (V)

0

0

SWITCH CURRENT LIMIT (A)

0.2

0.6

0.8

1.0

2.0

1.4

0.50 1 1.25

40895 G15

0.4

1.6

1.8

1.2

0.25 0.75 1.50 1.75 2

DUTY CYCLE (%)

0

CURRENT LIMIT (A)

1.6

1.8

2.0

80

40895 G16

1.4

1.2

1.5

1.7

1.9

1.3

1.1

1.0
2010

4030

60 70 90

50

100

TA = –40°C
T

A

= –5°C

T

A

= 25°C

T

A

= 90°C

LOAD CURRENT (mA)

1

5.8

INPUT VOLTAGE (V)

6.0

6.2

6.4

6.6

10 100 1000

40895 G17

5.6

5.4

5.2

5.0

6.8

7.0

TO START

TO RUN

TYPICAL PERFORMANCE CHARACTERISTICS

High Voltage Regulator
Maximum Load Current, L = 10µH

High Voltage Regulator
Maximum Load Current, L = 33µH

High Voltage Regulator
Switch Voltage Drop

High Voltage Regulator
Switch Frequency

High Voltage Regulator
Frequency Foldback

High Voltage Regulator
Soft-Start

High Voltage Switch Current Limit

High Voltage Regulator
Typical Minimum Input Voltage

T

A

= 25°C, unless otherwise specifi ed.

LTC4089/LTC4089-5

7

40895fb

1ms/DIV

V

IN

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV
I

BAT

0.5A/DIV

40895 G18

V

BAT

= 3.85V

I

OUT

= 100mA

1ms/DIV

V

IN

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV
I

BAT

0.5A/DIV

40895 G19

V

BAT

= 3.85V

I

OUT

= 100mA

100µs/DIV

HPWR
5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

40895 G20

V

BAT

= 3.85V

I

OUT

= 50mA

1ms/DIV

WALL

5V/DIV

V

OUT

5V/DIV

I

WALL

0.5A/DIV
I

BAT

0.5A/DIV

40895 G21

V

BAT

= 3.85V

I

OUT

= 100mA

R

PROG

= 100k

1ms/DIV

WALL

5V/DIV

V

OUT

5V/DIV

I

WALL

0.5A/DIV
I

BAT

0.5A/DIV

40895 G22

V

BAT

= 3.85V

I

OUT

= 100mA

R

PROG

= 100k

100µs/DIV

SUSP

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

40895 G23

V

BAT

= 3.85V

I

OUT

= 50mA

20µS/DIV

H

VOUT

50mV/DIV

I

OUT

0.5A/DIV

40895 G24

20µS/DIV

H

VOUT

50mV/DIV

I

L

0.5A/DIV

40895 G25

Input Connect Waveforms

TYPICAL PERFORMANCE CHARACTERISTICS

Input Disconnect Waveforms Response to HPWR

Wall Connect Waveforms

Wall Disconnect Waveforms Response to Suspend

High Voltage Regulator Load
Transient

High Voltage Regulator Load
Transient

T

A

= 25°C, unless otherwise specifi ed.

LTC4089/LTC4089-5

8

40895fb

PI FU CTIO S

UUU

GND (Pins 1, 2): Ground. Tie the GND pin to a local ground
plane below the LTC4089 and the circuit components.

HVOUT (Pins 3, 18): Voltage Output of the High Voltage
Regulator. When suffi cient voltage is present at HVOUT,
the low voltage power path from IN to OUT will be discon­nected and the HVPR pin will be pulled low to indicate
that a high voltage wall adapter has been detected. The
LTC4089 high voltage regulator will maintain just enough
differential voltage between HVOUT and BAT to keep the
battery charger MOSFET out of dropout (typically 300mV
from OUT to BAT). The LTC4089-5 high voltage regula­tor will provide a fi xed 5V output to the battery charger
MOSFET. HVOUT should be bypassed with at least 10µF
to GND. Connect pins 3 and 18 with a resistance no

greater than 1

.

V

C

(Pin 4): Leave the VC pin fl oating or bypass to ground

with a 10pF capacitor. This optional 10pF capacitor reduces
HVOUT ripple in discontinuous mode.

NTC (Pin 5): Input to the NTC Thermistor Monitoring
Circuits. Under normal operation, tie a thermistor from
the NTC pin to ground and a resistor of equal value from
NTC to VNTC. When the voltage on this pin is above 0.74

• V

VNTC

(Cold, 0°C) or below 0.29 • V

VNTC

(Hot, 50°C)
the timer is suspended but not cleared, the charging is
disabled and the CHRG pin remains in its former state.
When the voltage on NTC comes back between 0.74 •
V

VNTC

and 0.29 • V

VNTC

, the timer continues where it
left off and charging is re-enabled if the battery voltage
is below the recharge threshold. There is approximately
3°C of temperature hysteresis associated with each of the
input comparators.

Connect the NTC pin to ground to disable this feature. This
will disable all of the LTC4089 NTC functions.

VNTC (Pin 6): Output Bias Voltage for NTC. A resistor from
this pin to the NTC pin will bias the NTC thermistor.

HVPR (Pin 7): High Voltage Present Output. Active low
open drain output pin. A low on this pin indicates that the
high voltage regulator has suffi cient voltage to charge the

battery. This feature is disabled if no power is present on
HVIN, IN or BAT (i.e., below UVLO thresholds).

CHRG (Pin 8): Open-Drain Charge Status Output. When the
battery is being charged, the CHRG pin is pulled low by an
internal N-channel MOSFET. When the timer runs out or
the charge current drops below 10% of the programmed
charge current or the input supply is removed, the CHRG
pin is forced to a high impedance state.

PROG (Pin 9): Charge Current Program. Connecting a
resistor, R

PROG

, to ground programs the battery charge
current. The battery charge current is programmed
as follows:

IA

V

R

CHG

PROG

(),=

50 000

GATE (Pin 10): External ideal diode gate pin. This pin can
be used to drive the gate of an optional external PFET con­nected between BAT (drain) and OUT (source). By doing
so, the impedance of the ideal diode between BAT and
OUT can be reduced. When not in use, this pin should be
left fl oating. It is important to maintain a high impedance
on this pin and minimize all leakage paths.

BAT (Pin 11): Connect to a single cell Li-Ion battery. This
pin is used as an output when charging the battery and as
an input when supplying power to OUT. When the OUT pin
potential drops below the BAT pin potential, an ideal diode
function connects BAT to OUT and prevents V

OUT

from

dropping more than 100mV below V

BAT

. A precision internal
resistor divider sets the fi nal fl oat (charging) potential on
this pin. The internal resistor divider is disconnected when
IN and HVIN are in undervoltage lockout.

IN (Pin 12): Input Supply. Connect to USB supply, V

BUS

.
Input current to this pin is limited to either 20% or 100%
of the current programmed by the CLPROG pin as de­termined by the state of the HPWR pin. Charge current
(to the BAT pin) supplied through the input is set to the
current programmed by the PROG pin but will be limited
by the input current limit if charge current is set greater
than the input current limit.