LINEAR TECHNOLOGY LTC3210-2, LTC3210-3 Technical data

LTC3210-2/LTC3210-3

MAIN/CAM LED Controllers

with 32-Step Brightness Control

in 3mm × 3mm QFN

FEATURES DESCRIPTION

■

Low Noise Charge Pump Provides High Effi ciency

with Automatic Mode Switching

■

Multimode Operation: 1x, 1.5x, 2x

■

Individual Full-Scale Current Set Resistors

■

Up to 500mA Total Output Current

■

Single Wire EN/Brightness Control for MAIN and

CAM LEDs

■

32:1 Linear Brightness Control Range for

MAIN Display

■

Three or Four 25mA Low Dropout MAIN LED Outputs

■

One 400mA Low Dropout CAM LED Output

■

Low Noise Constant Frequency Operation*

■

Low Shutdown Current: 3µA

■

Internal Soft-Start Limits Inrush Current During

Startup and Mode Switching

■

Open/Short LED Protection

■

No Inductors

■

3mm × 3mm 16-Lead Plastic QFN Package

APPLICATIONS

■

Multi-LED Light Supply for Cellphones/DSCs/PDAs

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by US Patents including 6411531.

The LTC®3210-2/LTC3210-3 are low noise charge pump
DC/DC converters designed to drive three or four MAIN
LEDs and one high current CAM LED for camera lighting.
The LTC3210-2/LTC3210-3 require only four small ceramic
capacitors and two current set resistors to form a complete
LED power supply and current controller.

Built-in soft-start circuitry prevents excessive inrush cur­rent during start-up and mode changes. High switching
frequency enables the use of small external capacitors.
Independent MAIN and CAM full-scale current settings
are programmed by two external resistors.

Shutdown mode and current output levels are selected
via two logic inputs. ENM and ENC are toggled to adjust
the LED currents via internal counters and DACs. A 5-bit
linear DAC (32 steps) provides high resolution brightness
control for the MAIN display.

The charge pump optimizes effi ciency based on the volt­age across the LED current sources. The part powers up
in 1x mode and will automatically switch to boost mode
whenever any enabled LED current source begins to enter
dropout. The LTC3210-2/LTC3210-3 are available in a
3mm × 3mm 16-lead QFN package.

TYPICAL APPLICATION

C2

2.2µF

C1P C1M C2P

V

BAT

C1

2.2µF

ENM

ENC

V

BAT

LTC3210-2

ENM

ENC

RM RC GND

30.1k1%24.3k
1%

C3

2.2µF

C2M

CPO

MLED1

MLED2

MLED3

MLED4

CLED

C4

2.2µF

MAIN CAM

321023 TA01

Effi ciency vs V

100

90

80

) (%)

70

IN

/P

60

LED

50

40

30

EFFICIENCY (P

20

4 LEDs AT 9mA/LED
(TYP V

10

= 25°C

T

A

0

3.0

4-LED MAIN Display

Voltage

BAT

AT 9mA = 3V, NICHIA NSCW100)

F

3.2

3.6

3.4

3.8

BAT

4.0

(V)

V

4.44.2

321023 TA01b

321023f

1

LTC3210-2/LTC3210-3

ABSOLUTE MAXIMUM RATINGS

V

, CPO to GND ........................................–0.3V to 6V

BAT

ENM, ENC ................................... – 0.3V to (V

(Note 2) ........................................................600mA

I

CPO

I

MLED1-4

.................................................................35mA

BAT

(Note 1)

+ 0.3V)

PACKAGE/ORDER INFORMATION

TOP VIEW

BAT

C2P

V

C1M

C2M

16 15 14 13

RM

MLED4

12

GND

CLED

11

ENC

10

RC

9

1C1P

CPO

2

ENM

MLED1

16-LEAD (3mm × 3mm) PLASTIC QFN

T

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

JMAX

17

3

4

5 6 7 8

MLED2

MLED3

UD PACKAGE

= 125°C, θJA = 68°C/W

(Note 2) ......................................................500mA

I

CLED

CPO Short-Circuit Duration .............................. Indefi nite

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

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

TOP VIEW

BAT

C2P

V

C1M

C2M

16 15 14 13

NC

RM

12

GND

CLED

11

ENC

10

RC

9

1C1P

CPO

2

ENM

MLED1

16-LEAD (3mm × 3mm) PLASTIC QFN

T

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

JMAX

17

3

4

5 6 7 8

MLED2

MLED3

UD PACKAGE

= 125°C, θJA = 68°C/W

ORDER PART NUMBER UD PART MARKING ORDER PART NUMBER UD PART MARKING

LTC3210EUD-2 LCHX LTC3210EUD-3 LCHY

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.

ELECTRICAL CHARACTERISTICS

The
temperature range, otherwise specifi cations are at T

= 25°C.V

A

ENM = high, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Operating Voltage

V

BAT

Operating Current I

I

VBAT

Shutdown Current ENM = ENC = Low

V

BAT

MLED1, MLED2, MLED3 and MLED4 (LTC3210-2 Only) Current

LED Current Ratio (I

MLED/IRM

)I

LED Dropout Voltage

LED Current Matching

MLED Current, 5-Bit Linear DAC 1 ENM Strobe (FS)

= 0, 1x Mode, LSB Setting

CPO

I

= 0, 1.5x Mode

CPO

I

= 0, 2x Mode

CPO

MLED

Mode Switch Threshold, I

Any Two Outputs 0.5 %

31 ENM Strobes (FS/31)

●

denotes the specifi cations which apply over the full operating

BAT

= Full Scale

= 3.6V, C1 = C2 = C3 = C4 = 2.2µF, RM = 30.1k, RC = 24.3k,

●

2.9 4.5 V

0.4

2.5

4.5

= Full Scale

MLED

●

●

481 525 589 A/A

36 µA

75 mV

20

0.640

mA
mA
mA

mA
mA

2

321023f

LTC3210-2/LTC3210-3

The

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifi cations are at T

= 25°C.V

A

●

denotes the specifi cations which apply over the full operating

= 3.6V, C1 = C2 = C3 = C4 = 2.2µF, RM = 30.1k, RC = 24.3k,

BAT

ENM = high, unless otherwise noted.

PARAMETER CONDITIONS MIN TYP MAX UNITS

CLED Current

LED Current Ratio (I

)I

CLED/IRC

LED Dropout Voltage Mode Switch Threshold, I

= Full Scale

CLED

= Full Scale 500 mV

CLED

CLED Current, 3-Bit Linear DAC 1 ENC Strobe (FS)

7 ENC Strobes (FS/7)

Charge Pump (CPO)

1x Mode Output Voltage I

1.5x Mode Output Voltage I

2x Mode Output Voltage I

= 0mA V

CPO

= 0mA 4.55 V

CPO

= 0mA 5.05 V

CPO

1x Mode Output Impedance 0.55

1.5x Mode Output Impedance V

2x Mode Output Impedance V

= 3.4V, V

BAT

= 3.2V, V

BAT

= 4.6V (Note 4) 3.15

CPO

= 5.1V (Note 4) 3.95

CPO

CLOCK Frequency

Mode Switching Delay 0.4 ms

ENC, ENM

V

IL

V

IH

I

IH

I

IL

ENM = ENC = 3.6V

ENM = ENC = 0V

ENC, ENM Timing

t

PW

t

SD

t

EN

Minimum Pulse Width

Low Time to Shutdown (ENC, ENM = Low)

Current Source Enable Time
(ENC, ENM = High) (Note 5)

RM, RC

V

, V

RM

RC

, I

I

RM

RC

●

6930 7700 8470 A/A

380

54

BAT

0.8 MHz

●

●

1.4 V

●

10 15 20 µA

●

–1 1 µA

●

200 ns

●

50 150 250 µs

50 150 250 µs

●

●

1.16 1.20 1.24 V

●

0.4 V

80 µA

mA
mA

V

Ω

Ω

Ω

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: Based on long-term current density limitations. Assumes an
operating duty cycle of ≤10% under absolute maximum conditions
for durations less than 10 seconds. Maximum current for continuous
operation is 300mA.

Note 3: The LTC3210-2/LTC3210-3 are guaranteed to meet performance
specifi cations from 0°C to 70°C. Specifi cations over the – 40°C to
85°C ambient operating temperature range are assured by design,
characterization and correlation with statistical process controls.

Note 4: 1.5x mode output impedance is defi ned as (1.5V
2x mode output impedance is defi ned as (2V

BAT

– V

CPO

)/I

BAT

OUT

– V

.

CPO

)/I

OUT

.

Note 5: If the part has been shut down then the initial enable time is about
100µs longer due to the bandgap enable time.

321023f

3

LTC3210-2/LTC3210-3

= 25°C unless otherwise stated.

1.5X

T

A

V

BAT

I

2X

50mV/DIV

COUPLED

CPO

C

CPO

V

CPO

AC

TYPICAL PERFORMANCE CHARACTERISTICS

Dropout Time from Shutdown Dropout Time When Enabled 1.5x CPO Ripple

MODE

RESET

5.1V

1X

CPO

1V/DIV

2V/DIV

5.1V

1X

EN

MODE

RESET

1.5X

2X

CPO

1V/DIV

ENC

2V/DIV

= 3.6V

= 200mA

= 2.2µF

2x CPO Ripple

V

= 3.6V

BAT

= 200mA

I

CPO

= 2.2µF

C

CPO

V

CPO

20mV/DIV

AC

COUPLED

1.5x Mode CPO Voltage
vs Load Current

4.8
C2 = C3 = C4 = 2.2µF

4.6

4.4

4.2

4.0

CPO VOLTAGE (V)

V

= 3.2V

BAT

3.8

V

= 3.1V

BAT

3.6

0

V

100 200 300 400

500µs/DIV

500ns/DIV

V

= 3.3V

BAT

V

BAT

= 3V

BAT

LOAD CURRENT (mA)

= 3.4V

V

BAT

V

BAT

321023 G01

321023 G04

= 3.5V

= 3.6V

321023 G07

500

ENM = HIGH

250µs/DIV

1x Mode Switch Resistance
vs Temperature

0.70
I

= 200mA

CPO

0.65

0.60

V

= 3.3V

0.55

0.50

SWITCH RESISTANCE (Ω)

0.45

0.40

BAT

V

= 3.9V

BAT

–40

–15 10 35 60

TEMPERATURE (°C)

V

BAT

2x Mode Charge Pump Open-Loop
Output Resistance vs Temperature

– V

(2V

4.6
V

BAT

V

CPO

4.4
C2 = C3 = C4 = 2.2µF

4.2

4.0

3.8

3.6

3.4

OPEN-LOOP OUTPUT RESISTANCE (Ω)

3.2

–40

BAT

= 3V

= 4.8V

–15 10 35 85

)/I

CPO

CPO

TEMPERATURE (°C)

= 3.6V

60

321023 G02

321023 G05

321023 G08

85

500ns/DIV

1.5x Mode Charge Pump Open-Loop
Output Resistance vs Temperature

– V

(1.5V

3.8
V

BAT

V

CPO

3.6
C2 = C3 = C4 = 2.2µF

3.4

3.2

3.0

2.8

2.6

OPEN-LOOP OUTPUT RESISTANCE (Ω)

2.4

–40

BAT

= 3V
= 4.2V

–15 10 35 85

)/I

CPO

CPO

TEMPERATURE (°C)

2x Mode CPO Voltage
vs Load Current

5.2
C2 = C3 = C4 = 2.2µF

5.1

5.0

4.9

4.8

4.7

4.6

CPO VOLTAGE (V)

4.5

4.4

4.3

4.2

0

V

BAT

V

BAT

V

100

200

LOAD CURRENT (mA)

= 3.5V

= 3.4V

BAT

V

BAT

V

BAT

= 3.3V

= 3.2V

= 3.1V

V

300

BAT

V

BAT

= 3V

400

321023 G03

60

321023 G06

= 3.6V

500

321023 G09

4

321023f

TYPICAL PERFORMANCE CHARACTERISTICS

LTC3210-2/LTC3210-3

= 25°C unless otherwise stated.

T

A

CLED Pin Dropout Voltage
vs CLED Pin Current

500

V

= 3.6V

BAT

400

300

200

100

CLED PIN DROPOUT VOLTAGE (mV)

SHUTDOWN CURRENT (µA)

V

BAT

0

50 100

V

Shutdown Current

BAT

vs V

BAT

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

2.7

3.0 3.3

150

CLED PIN CURRENT (mA)

Voltage

TA = 85°C

200

TA = 25°C

TA = –40°C

3.6 4.2

V

VOLTAGE (V)

BAT

250

350

321023 G10

321023 G13

400

300

3.9 4.5

MLED Pin Dropout Voltage
vs MLED Pin Current

120

V

= 3.6V

BAT

100

80

60

40

20

MLED PIN DROPOUT VOLTAGE (mV)

CURRENT (µA)

V

BAT

0

800

780

760

740

720

700

680

660

640

620

600

42

0

86

10

MLED PIN CURRENT (mA)

1x Mode No Load V

Voltage

vs V

BAT

RM = 33.2k
RC = 24.3k

2.7

3.0

3.3

V

VOLTAGE (V)

BAT

3.6 3.9

12 14 18

BAT

16

Current

4.2

321023 G11

321023 G14

20

4.5

Oscillator Frequency

Voltage

vs V

BAT

850

840

830

820

TA = 85°C

810

800

790

FREQUENCY (kHz)

780

770

760

2.7

3.0

TA = 25°C

TA = –40°C

3.6 4.5

3.3
V

VOLTAGE (V)

BAT

1.5x Mode Supply Current
vs I

(IV

CPO

20

V

= 3.6V

BAT

15

10

SUPPLY CURRENT (mA)

5

0

100

0

– 1.5I

BAT

200

LOAD CURRENT (mA)

CPO

300

3.9

4.2

321023 G12

)

400

500

321023 G15

2x Mode Supply Current

(IV

vs I

CPO

20

V

= 3.6V

BAT

15

10

SUPPLY CURRENT (mA)

5

0

0

– 2I

BAT

100

200

LOAD CURRENT (mA)

CPO

300

CLED Pin Current

)

400

500

321023 G16

vs CLED Pin Voltage

400

V

= 3.6V

BAT

360

320

280

240

200

160

120

CLED PIN CURRENT (mA)

80

40

0

0.2

0

CLED PIN VOLTAGE (V)

0.4

0.6

0.8

1

321023 G17

321023f

5