LINEAR TECHNOLOGY LTC4090, LTC4090-5 Technical data

LTC4090/LTC4090-5

USB Power Manager with

2A High Voltage Bat-Track

Buck Regulator

FEATURES

■

Seamless Transition Between Power Sources: Li-

Ion Battery, USB, and 6V to 36V Supply (60V Max)

■

2A Output High Voltage Buck Regulator with Bat-

TM

Track

■

Internal 215mΩ Ideal Diode Plus Optional External

Adaptive Output Control (LTC4090)

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

■

Load Dependent Charging from USB Input Guaran-

tees Current Compliance

■

Full Featured Li-Ion Battery Charger

■

1.5A Maximum Charge Current with Thermal Limiting

■

NTC Thermistor Input for Temperature Qualifi ed

Charging

■

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

APPLICATIONS

■

HDD-Based Media Players

■

Personal Navigation Devices

■

Other USB-Based Handheld Products

■

Automotive Accessories

DESCRIPTION

The LTC®4090/LTC4090-5 are USB power managers plus
high voltage Li-Ion/Polymer battery chargers. The 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 LTC4090/LTC4090-5 also accom­modate high voltage power supplies, such as 12V AC/DC
wall adapters, FireWire, or automotive power.

The LTC4090 provides a Bat-Track adaptive output that
tracks the battery voltage for high effi ciency charging from
the high voltage input. The LTC4090-5 provides a fi xed 5V
output from the high voltage input to charge single cell
Li-Ion bateries. The charge current is programmable and an

⎯C⎯H⎯R⎯

end-of-charge status output (
Also featured are programmable total charge time, an NTC
thermistor input used to monitor battery temperature while
charging and automatic recharging of the battery.

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Bat-Track is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.

G) indicates full charge.

TYPICAL APPLICATION

CLPROG

40.2k

(TYP)

+ 0.3V
5V
5V

BAT

BOOST

LTC4090

GND PROG

AVAILABLE INPUT

HV INPUT (LTC4090)

HV INPUT (LTC4090-5)

USB ONLY
BAT ONLY

HIGH (6V-36V)

VOLTAGE INPUT

5V WALL

ADAPTER

USB

59k

270pF

1μF

4.7μF

0.1μF

HVIN

IN

V

C

TIMER

R

T

V

OUT

V

BAT

V

0.47μF

SW

HVOUT

HVPR

OUT

BAT

6.8μH

22μF

1k

LOAD

4.7μF

+

100k2k

Li-Ion BATTERY

4090 TAO1

LTC4090/LTC4090-5 High Voltage

Battery Charger Effi ciency

90

FIGURE 12 SCHEMATIC
WITH R

80

NO OUTPUT LOAD

70

60

50

EFFICIENCY (%)

40

30

20

2.0

PROG

2.5

= 52k

3.0
V

BAT

LTC4090

3.5

(V)

LTC4090-5

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

4.0

4090 TA01b

4.5

4090fa

1

LTC4090/LTC4090-5

(Notes 1, 2, 3, 4)

HVIN, HVEN (Note 9) ................................................60V

BOOST ......................................................................56V

BOOST above SW .....................................................30V

PG, SYNC ..................................................................30V

IN, OUT, HVOUT

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

Steady State ............................................. –0.3V to 6V

BAT, HPWR, SUSP, V

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

, I

, I

I

IN

OUT

(Note 5) ..............................................2.5A

BAT

Operating Temperature Range .....................–40 to 85°C

Junction Temperature ........................................... 110°C

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

, ⎯C⎯H⎯R⎯G, ⎯H⎯V⎯P⎯R ........... –0.3V to 6V

C

+ 0.3V

CC

PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS

TOP VIEW

SYNC

1

PG

2

R

3

T

V

4

C

NTC

5

VNTC

6

HVPR

7

CHRG

8

PROG

9

GATE

10

BAT

11

22-LEAD (6mm × 3mm) PLASTIC DFN

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

DJC PACKAGE

T

= 110°C, θJA = 47°C/W

JMAX

22

HVEN

21

HVIN

20

SW

19

BOOST

18

HVOUT

23

17

TIMER

16

SUSP

15

HPWR

14

CLPROG

13

OUT

12

IN

ORDER INFORMATION

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

LTC4090EDJC#PBF LTC4090EDJC#TRPBF 4090 22-Lead (6mm × 3mm) Plastic DFN –40°C to 85°C

LTC4090EDJC-5#PBF LTC4090EDJC-5#TRPBF 40905 22-Lead (6mm × 3mm) Plastic DFN –40°C to 85°C

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/

ELECTRICAL CHARACTERISTICS

The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at TA = 25°C. HVIN = HVEN = 12V, BOOST = 17V, VIN = HPWR = 5V, V
R

= 100k, R

PROG

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

USB Input Current Limit

V

IN

I

IN

I

LIM

I

IN(MAX)

R

ON

V

CLPROG

I

SS

USB Input Supply Voltage

Input Bias Current I

Current Limit HPWR = 5V

Maximum Input Current Limit (Note 7) 2.4 A

On-Resistance VIN to V

CLPROG Servo Voltage in Current Limit R

Soft-Start Inrush Current 10 mA/μs

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

CLPROG

= 0 (Note 6)

BAT

Suspend Mode; SUSP = 5V

HPWR = 0V

I

OUT

= 80mA 0.215

OUT

CLPROG

R

CLPROG

= 2k
= 1k

●

4.35 5.5 V

●

●

●

475

●

90

●

0.98

●

0.98

0.5
50

500
100

1.00

1.00

BAT

= 3.7V,

1

100

525
110

1.02

1.02

mA

μA

mA
mA

Ω

V
V

2

4090fa

LTC4090/LTC4090-5

ELECTRICAL CHARACTERISTICS

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

PROG

= 100k, R

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

CLPROG

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

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

V

ΔV

CLEN

UVLO

UVLO

Input Current Limit Enable Threshold
Voltage (V

- V

OUT

)

IN

Input Undervoltage Lockout VIN Rising

Input Undervoltage Lockout Hysteresis VIN Rising – VIN Falling 130 mV

(V
(V

- V

) Rising

IN

OUT

- V

) Falling

IN

OUT

20

–80

●

3.6 3.8 4 V

50

–50

High Voltage Regulator

V

V

I

HVIN

V

V

HVIN

OVLO

OUT

OUT

HVIN Supply Voltage

HVIN Overvoltage Lockout Threshold

HVIN Bias Current Shutdown; HVEN = 0.2V

Not Switching, HVOUT = 3.6V

Output Voltage with HVIN Present Assumes HVOUT to OUT Connection,

0 ≤ V

≤ 4.2V (LTC4090)

BAT

Output Voltage with HVIN Present Assumes HVOUT to OUT Connection

●

660V

●

36 41.5 45 V

0.01

●

3.45 V

130

+ 0.3 4.6 V

BAT

4.85 5 5.15 V

(LTC4090-5)

f

SW

t

OFF

I

SW(MAX)

V

SAT

I

R

V

B(MIN)

I

BST

Switching Frequency RT = 8.66k

R

= 29.4k

T

R

= 187k

T

Minimum Switch Off-Time

2.1

0.9

160

●

2.4

1.0

200

60 150 ns

Switch Current Limit Duty Cycle = 5% 3.0 3.5 4.0 A

Switch V

CESAT

ISW = 2A 500 mV

Boost Schottky Reverse Leakage SW = 10V, HVOUT = 0V 0.02 2 μA

Minimum Boost Voltage (Note 8)

●

1.5 2.1 V

BOOST Pin Current ISW = 1A 22 35 mA

Battery Management

I

BAT

V

FLOAT

I

CHG

I

CHG(MAX)

V

PROG

k

EOC

Battery Drain Current V

= 4.3V, Charging Stopped

BAT

Suspend Mode, SUSP = 5V
V

= 0V, BAT Powers OUT, No Load

IN

V

Regulated Output Voltage I

BAT

Constant-Current Mode Charge Current,
No Load

= 2mA

BAT

I

= 2mA; 0 ≤ TA ≤ 85°C

BAT

R

= 100k

PROG

R

= 50k, 0 ≤ TA ≤ 85°C

PROG

Maximum Charge Current 1.5 A

PROG Pin Servo Voltage R

Ratio of End-of-Charge Indication

R

V

PROG
PROG

BAT

= 100k
= 50k

= V

FLOAT

(4.2V)

●

●

●

4.165

4.158

●

465
900

●

0.98

●

0.98

●

0.085 0.1 0.11 mA/mA

15
22
60

4.200

4.200

500

1000

1.00

1.00

Current to Charge Current

I

TRKL

V

TRKL

V

CEN

ΔV

RECHRG

Trickle Charge Current BAT = 2V 35 50 60 mA

Trickle Charge Threshold Voltage BAT Rising

Charge Enable Threshold Voltage (V

(V

OUT
OUT

– V
– V

) Falling; V

BAT

) Rising; V

BAT

BAT

BAT

= 4V

= 4V

Recharge Battery Threshold Voltage Threshold Voltage Relative to V

FLOAT

●

2.75 2.9 3.0 V

55
80

●

–65 –100 –135 mV

BAT

= 3.7V,

80

–20

0.5

200

2.7

1.15
240

27
35

100

4.235

4.242

535

1080

1.02

1.02

mV
mV

MHz
MHz

kHz

mA
mA

mV
mV

μA
μA

μA
μA
μA

V
V

V
V

4090fa

3

LTC4090/LTC4090-5

ELECTRICAL CHARACTERISTICS

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

PROG

= 100k, R

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

CLPROG

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

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

TIMER

TIMER Accuracy V

= 4.3V –10 10 %

BAT

Recharge Time Percent of Total Charge Time 50 %

Low Battery Trickle Charge Time Percent of Total Charge Time,

<2.9V

V

BAT

T

LIM

Junction Temperature in Constant

25 %

105 °C

Temperature Mode

Internal Ideal Diode

R

FWD

R

DIO, ON

V

FWD

V

OFF

I

FWD

I

D(MAX)

Incremental Resistance, VON Regulation I

On-Resistance V

Voltage Forward Drop (V

BAT

to V

OUT

BAT

– V

OUT

)I

Diode Disable Battery Voltage 2.7 V

Load Current Limit for VON Regulation 550 mA

Diode Current Limit 2.2 A

= 100mA 125 mΩ

OUT

I

= 600mA 215 mΩ

OUT

●

10 30

55

160

I
I

OUT
OUT
OUT

= 5mA
= 100mA
= 600mA

External Ideal Diode

V

FWD, EXT

Logic (

V

CHG, SD

External Diode Forward Voltage 20 mV

⎯C⎯H⎯R⎯

G, ⎯H⎯V⎯P⎯R, TIMER, SUSP, HPWR, HVEN, PG, SYNC)

Charger Shutdown Threshold Voltage

●

0.14 0.4 V

on TIMER

I

CHG, SD

Charger Shutdown Pull-Up Current on

V

TIMER

= 0V

●

514 μA

TIMER

V

OL

V

IH

V

IL

V

HVEN, H

V

HVEN, L

I

PULLDN

I

HVEN

V

PG

ΔV

PG

I

PGLK

I

PG

V

SYNC, L

V

SYNC, H

I

SYNC

Output Low Voltage (⎯C⎯H⎯R⎯G, ⎯H⎯V⎯P⎯R); I

SINK

= 5mA

Input High Voltage SUSP, HPWR 1.2 V

Input Low Voltage SUSP, HPWR 0.4 V

HVEN High Threshold 2.3 V

HVEN Low Threshold 0.3 V

Logic Input Pull-Down Current SUSP, HPWR 2 μA

HVEN Pin Bias Current HVEN = 2.5V 5 10 μA

PG Threshold HVOUT Rising 2.8 V

PG Hysteresis 35 mV

PG Leakage PG = 5V 0.1 1 μA

PG Sink Current PG = 0.4V

SYNC Low Threshold 0.5 V

SYNC High Threshold 0.8 V

SYNC Pin Bias Current V

= 0V 0.1 μA

SYNC

●

●

100 900 μA

0.1 0.4 V

= 3.7V,

BAT

50 mV

mV
mV

4

4090fa

LTC4090/LTC4090-5

ELECTRICAL CHARACTERISTICS

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

PROG

= 100k, R

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

CLPROG

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

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

NTC

I

VNTC

V

VNTC

I

NTC

V

COLD

V

HOT

V

DIS

VNTC Pin Current VNTC = 2.5V

VNTC Bias Voltage I

VNTC

= 500μA

NTC Input Leakage Current NTC = 1V 0 ±1 μA

Cold Temperature Fault Threshold
Voltage

Hot Temperature Fault Threshold
Voltage

Rising NTC Voltage
Hysteresis

Falling NTC Voltage
Hysteresis

NTC Disable Threshold Voltage Falling NTC Voltage

Hysteresis

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: The LTC4090/LTC4090-5 are guaranteed to meet performance
specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.

Note 3: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 110°C when overtemperature protection is

Note 4: V

is the greater of VIN, V

CC

Note 5: Guaranteed by long term current density limitations.
Note 6: Total input current is equal to this specifi cation plus 1.002 • I

where I

is the charge current.

BAT

Note 7: Accuracy of programmed current may degrade for currents
greater than 1.5A.

Note 8: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the switch.

Note 9: Absolute Maximum Voltage at HVIN and HVEN pins is for non­repetative 1 second transients; 40V for continuous operation.

●

1.4 2.5 3.5 mA

●

4.4 4.85 V

0.738 • VNTC

0.02 • VNTC

0.29 • VNTC

0.01 • VNTC

●

75 100

35

, and V

OUT

BAT

active. Continuous operation above the specifi ed maximum operating
junction temperature may result in device degradation or failure.

= 3.7V,

BAT

125 mV

BAT

mV

V
V

V
V

TYPICAL PERFORMANCE CHARACTERISTICS

Battery Regulation (Float)

V

4.30

4.25

4.20

(V)

4.15

FLOAT

V

4.10

4.05

4.00

Load Regulation

FLOAT

R

= 34k

PROG

0

200 400 600 800

I

BAT

(mA)

1000

4090 G01

Voltage vs Temperature

4.220

VIN = 5V

= 2mA

I

BAT

4.215

4.210

4.205

(V)

4.200

FLOAT

V

4.195

4.190

4.185

4.180
–25 0 50

–50

25

TEMPERATURE (°C)

Battery Current and Voltage vs
Time (LTC4090)

5

4

(V)

3

CHRGB

, V

OUT

2

, V

BAT

V

1250mAh

1

CELL
HVIN = 12V

= 50k

R

PROG

100

0

0

50

TIME (MIN)

75

4090 G02

100

V

BAT

V

OUT

V

CHRGB

I

BAT

C/10

TERMINATION

150

4090 G03

200

1500

1200

900

600

300

0

4090fa

I

BAT

(mA)

5

LTC4090/LTC4090-5

TYPICAL PERFORMANCE CHARACTERISTICS

Charge Current vs Temperature

Charging from USB, I

600

VIN = 5V

= NO LOAD

V

OUT

= 100k

R

500

PROG

= 2k

R

CLPROG

400

(mA)

300

BAT

I

200

100

0

0.5 1.5

0

1

2

V

BAT

Ideal Diode Current vs Forward
Voltage and Temperature with
External Device

5000

V

= 3.7V

BAT

4500

4000

3500

3000

(mA)

2500

OUT

I

2000

1500

1000

500

0

= 0V

V

IN

Si2333 PFET

0

20

40

V

(mV)

FWD

vs V

BAT

2.5 4.5
(V)

60

HPWR = 5V

HPWR = 0V

3.5

3

–50°C

100°C

80

BAT

4

4090 G04

0°C

50°C

100

4090 G07

(Thermal Regulation)

600

500

400

(mA)

300

BAT

I

200

R

= 2.1k

PROG

= 5V

V

100

IN

= 3.5V

V

BAT

= 40°C/W

θ

JA

0

–50

–25 0

TEMPERATURE (°C)

50 100 125

25 75

LTC4090 High Voltage Regulator
Effi ciency vs Output Load

100

FIGURE 12 SCHEMATIC

= 4.21V (I

V

95

BAT

90

85

80

75

70

EFFICIENCY (%)

65

60

55

50

0

0.2

BAT

0.4

= 0)

I

OUT

0.6

(A)

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

0.8

4090 G05

4090 G08

1.0

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

1000

V

= 3.7V

BAT

900

= 0V

V

IN

800

700

600

(mA)

500

OUT

I

400

300

200

100

0

0

50

100

V

(mV)

FWD

LTC4090-5 High Voltage Regulator
Effi ciency vs Output Load

100

FIGURE 12 SCHEMATIC

= 4.21V (I

V

95

BAT

90

85

80

75

70

EFFICIENCY (%)

65

60

55

50

0

0.2

BAT

0.4

= 0)

I

OUT

0.6

(A)

–50°C

50°C

100°C

150

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

0.8

0°C

200

4090 G06

1.0

4090 G29

High Voltage Regulator Maximum
Load Current

3.0

FIGURE 12 SCHEMATIC

(A)

OUT

I

2.8

2.6

2.4

2.2

2.0

1.8

V

5

= 4.21V (I

BAT

10

= 0)

BAT

TYPICAL

MINIMUM

15 20 25

HVIN (V)

6

30 35

4090 G09

High Voltage Regulator Minimum
Switch On-Time vs Temperature

140

120

100

80

60

40

MINIMUM SWITCH ON TIME (ns)

20

0

–50 25–25 0 50 75 100 150125

TEMPERATURE (˚C)

4090 G10

High Voltage Regulator Switch
Voltage Drop

700

600

500

400

300

VOLTAGE DROP (mV)

200

100

0

0

500 1000 2000 2500

SWITCH CURRENT (mA)

1500

4090 G11

4090fa

TYPICAL PERFORMANCE CHARACTERISTICS

LTC4090/LTC4090-5

High Voltage Regulator Switch
Frequency

1100

1000

900

800

700

FREQUENCY (kHz)

600

500

–50

050

–25 25

TEMPERATURE (°C)

High Voltage Regulator Switch
Current Limit

4.0

3.5

3.0

2.5

2.0

SWITCH CURRENT LIMIT(A)

1.5

1.0
20 60

0

40

DUTY CYCLE (%)

75

100

125

80 100

4090 G12

4090 G15

150

High Voltage Regulator
Frequency Foldback High Voltage Regulator Soft-Start

1000

900

800

700

600

500

400

300

200

SWITCHING FREQUENCY (kHz)

100

0

0

1

2

HVOUT (V)

High Voltage Regulator Switch
Current Limit

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

SWITCH CURRENT LIMIT (A)

0.5

0

–50 25–25 0 50 75 100 150125

DUTY CYCLE = 10 %

DUTY CYCLE = 90 %

TEMPERATURE (°C)

4

3

4090 G13

4090 G16

4.0

3.5

3.0

2.5

2.0

1.5

1.0

SWITCH CURRENT LIMIT (A)

0.5

0

0.5 1 2

0

RUN/SS PIN VOLTAGE (V)

1.5

2.5 3 3.5

High Voltage Regulator Minimum
Input Voltage

7.0

6.5

6.0

5.5

5.0

HVIN (V)

4.5

4.0

3.5

3.0

TO START

TO RUN

1

10 100 1000

LOAD CURRENT (mA)

4090 G14

4090 G17

High Voltage Regulator Boost
Diode VF vs I

1.4

1.2

1.0

(V)

f

0.8

0.6

BOOST DIODE V

0.4

0.2

0

0

F

0.5 1.0 1.5

BOOST DIODE CURRENT (A)

4090 G18

2.0

High Voltage Regulator VC
Voltages

2.50

2.00

1.50

VOLTAGE (V)

1.00

C

V

0.50

CURRENT LIMIT CLAMP

SWITCHING THRESHOLD

0

–50 25–25 0 50 75 100 150125

TEMPERATURE (°C)

4090 G19

High Voltage Regulator Power
Good Threshold

2.90

2.85

2.80

2.75

2.70

HVOUT THRESHOLD VOLTAGE (V)

2.65
–50

–25 0

50

25 75 150

TEMPERATURE (°C)

100 125

4090 G20

4090fa

7

LTC4090/LTC4090-5

TYPICAL PERFORMANCE CHARACTERISTICS

LTC4090 Input Connect
Waveforms

V

IN

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

V

= 3.85V

BAT

= 100mA

I

OUT

LTC4090 High Voltage Input
Connect Waveforms

V

HVIN

10V/DIV

V

OUT

5V/DIV

I

HVIN

1A/DIV

I

BAT

1A/DIV

1ms/DIV

4090 G21

LTC4090 Input Disconnect
Waveforms

V

IN

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

V

= 3.85V

BAT

= 100mA

I

OUT

LTC4090 High Voltage Input
Disconnect Waveforms

V

HVIN

5V/DIV

V

OUT

5V/DIV

I

HVIN

1A/DIV

I

BAT

1A/DIV

1ms/DIV

4090 G22

LTC4090 Response to Suspend

SUSP

5V/DIV

V

OUT

5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

V
I

BAT

OUT

= 3.85V

= 50mA

1ms/DIV

LTC4090 Response to HPWR

HPWR

5V/DIV

I

IN

0.5A/DIV

I

BAT

0.5A/DIV

4090 G23

V
I

OUT

BAT

= 3.85V

= 100mA

2ms/DIV

4090 G24

LTC4090 High Voltage Regulator
Load Transient

HVOUT

50mV/DIV

I

OUT

1A/DIV

I

LOAD

= 500mA

25μs/DIV

V
I

OUT

BAT

4090 G27

= 3.85V

= 100mA

2ms/DIV

HVOUT

50mV/DIV

1A/DIV

4090 G25

V
I

BAT

OUT

= 3.85V

= 50mA

LTC4090 High Voltage Regulator
Load Transient

I

L

I

LOAD

= 500mA

25μs/DIV

100μs/DIV

4090 G28

4090 G26

8

4090fa

PIN FUNCTIONS

LTC4090/LTC4090-5

SYNC (Pin 1): External Clock Synchronization Input. See
synchronizing section in the Applications Information
section. Ground pin when not used.

PG (Pin 2): The PG pin is the open collector output of an
internal comparator. PG remains low until the HVOUT pin
is above 2.8V. PG output is valid when HVIN is above 3.6V
and HVEN is high.

(Pin 3): Oscillator Resistor Input. Connecting a resistor

R

T

to ground from this pin sets the switching frequency.

(Pin 4): High Voltage Buck Regulator Control Pin. The

V

C

voltage on this pin controls the peak switch current in the
high voltage regulator. Tie an RC network from this pin to
ground to compensate the control loop.

NTC (Pin 5): Input to the NTC Thermistor Monitoring
Circuits. The NTC pin connects to a negative temperature
coeffi cient thermistor which is typically co-packaged with
the battery pack to determine if the battery is too hot or too
cold to charge. If the battery temperature is out of range,
charging is paused until the battery temperature re-enters
the valid range. A low drift bias resistor is required from
VNTC to NTC and a thermistor is required from NTC to
ground. If the NTC function is not desired, the NTC pin
should be grounded.

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

⎯H⎯V⎯P⎯

R (Pin 7): High Voltage Present Output (Active Low).

A low on this pin indicates that the high voltage regulator
has suffi cient voltage to charge the battery. This feature
is enabled if power is present on HVIN, IN, or BAT (i.e.,
above UVLO thresholds).

⎯C⎯H⎯R⎯

G (Pin 8): Open-Drain Charge Status Output. When the

⎯C⎯H⎯R⎯

battery is being charged, the
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
pin is forced to a high impedance state.

G pin is pulled low by an

⎯C⎯H⎯R⎯

G

PROG (Pin 9): Charge Current Program Pin. Connecting
a resistor from PROG to ground programs the charge
current:

(),=

50 000

IA

CHG

GATE (Pin 10): External Ideal Diode Gate Connection. This
pin controls the gate of an optional external P-channel
MOSFET transistor used to supplement the internal ideal
diode. The source of the P-channel MOSFET should be
connected to OUT and the drain should be connected to
BAT. When not in use, this pin should be left fl oating. It
is important to maintain high impedance on this pin and
minimize all leakage paths.

BAT (Pin 11): 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 OUT from dropping
more than 100mV below 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
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 or if the sum of charge current plus load
current is greater than the input current limit.

OUT (Pin 13): Voltage Output. This pin is used to provide
controlled power to a USB device from either USB V
(IN), an external high voltage supply (HVIN), or the battery
(BAT) when no other supply is present. The high voltage
supply is prioritized over the USB V
be bypassed with at least 4.7μF to GND.

R

PROG

V

.

BUS

BUS

input. OUT should

BUS

4090fa

9