Datasheet LTC3214 Datasheet (LINEAR TECHNOLOGY)

FEATURES

■

Low Noise Constant Frequency Operation*

■

High Efficiency: Up to 94%

■

Multi-Mode Operation: 1x, 1.5x or 2x Boost Modes

■

Automatic Mode Switching

■

High Output Current: Up to 500mA

■

Tiny Application Circuit (3mm × 3mm DFN Package,
All Components <1mm High)

■

Automatic Soft-Start

■

Output Disconnect

■

Open, Shorted LED Protection

■

No Inductors

■

Internal 110mΩ LED Current Sense Resistor

■

3mm × 3mm 10-Lead DFN Package

U

APPLICATIO S

■

LED Torch/Camera Light Supply for Cell Phones,
PDAs and Digital Cameras

■

General Lighting and/or Flash/Strobe Applications

LTC3214

500mA Camera

LED Charge Pump

U

DESCRIPTIO

The LTC®3214 is a low noise, high current charge pump
DC/DC converter capable of driving high current LEDs at
up to 500mA from a 2.9V to 4.5V input. Low external
parts count (two flying capacitors, one programming
resistor and two bypass capacitors at V
the LTC3214 ideally suited for small, battery-powered
applications.

Built-in soft-start circuitry prevents excessive inrush cur­rent during start-up. High switching frequency enables the
use of small external capacitors.

Output current level is programmed by an external resis­tor. LED current is regulated using an internal 110mΩ
sense resistor. Automatic mode switching optimizes effi­ciency by monitoring the voltage across the charge pump
and switching modes only when dropout is detected. The
part is available in a low profile 3mm x 3mm 10-lead DFN
package.

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

and CPO) make

IN

TYPICAL APPLICATIO

2.9V TO 4.5V

2.2µF

C1

2.2µF

+C1–C2+C2–

C1

V

C

IN

IN

ENDISABLE ENABLE

I

SET

LED: AOT2015

LTC3214

0.11Ω

R

SET

C2

2.2µF

CPO

I

LED

3214 TA01a

U

LED

I

LED

UP TO 500mA

C

CPO

4.7µF

100

100mA

90

80

70

) (%)

IN

/P

60

LED

50

40

30

EFFICIENCY (P

20

LED = AOT2015

10

= 2.9V TYP AT 100mA

V

F

0

2.9

3.1 3.5

Efficiency vs V

200mA

300mA

3.3

3.7

VIN (V)

3.9

IN

50mA

4.1

4.3

3214 TA01b

4.5

3214fa

1

LTC3214

WW

W

U

ABSOLUTE AXI U RATI GS

(Note 1)

VIN to GND ............................................... –0.3V to 5.5V

CPO to GND ............................................. –0.3V to 5.5V

EN ................................................... – 0.3V to V

I

, I

CPO

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

ILED

CPO Short-Circuit Duration ............................ Indefinite

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

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

+ 0.3V

IN

UUW

PACKAGE/ORDER I FOR ATIO

TOP VIEW

+

C2

1

+

C1

2

11

3

CPO

4

I

LED

5

I

SET

10-LEAD (3mm × 3mm) PLASTIC DFN

EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB GND

DD PACKAGE

T

= 125°C, θJA = 43°C/W

JMAX

ORDER PART NUMBER

LTC3214EDD LBVQ

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 specified with wider operating temperature ranges.

–

10

C1

GND

9

–

C2

8

7

V

IN

6

EN

DD PART MARKING

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. V

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Power Supply

VIN Operating Voltage

I

Operating Current I

VIN

I

Shutdown Current EN = LOW 2.5 7.5 µA

VIN

LED Current

LED Current Ratio (I

I

Dropout Voltage (V

LED

Mode Switching Delay (LED Warmup Time) 2.5 ms

LED Current On Time EN to LED Current On 100 µs

Charge Pump (CPO)

Charge Pump Output Clamp Voltage 5V

1x Mode Output Impedance 0.70 Ω

1.5x Mode Output Impedance 3.2 Ω

2x Mode Output Impedance 3.5 Ω

CLK Frequency V

EN

High Level Input Voltage (VIH)

Low Level Input Voltage (VIL)

Input Current (IIH)V

Input Current (IIL)

)I

LED/ISET

) Mode Switch Threshold, I

ILED

The ● denotes the specifications which apply over the full operating

= 3.6V, CIN = C1 = C2 = 2.2µF, C

IN

= 0mA, 1x Mode 980 µA

CPO

= 0mA, 1.5x 4.8 mA

I

CPO

= 0mA, 2x Mode 6.7 mA

I

CPO

= 150mA to 500mA 2715 2950 3190 mA/mA

LED

= 200mA 40 mV

LED

= 3V

IN

= 3.6V

EN

= 4.7µF.

CPO

●

2.9 4.5 V

●

0.6 0.9 1.2 MHz

●

1.4 V

●

●

●

–1 1 µA

14.4 20 µA

0.4 V

2

3214fa

LTC3214

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. V

A

= 3.6V, CIN = C1 = C2 = 2.2µF, C

IN

= 4.7µF.

CPO

PARAMETER CONDITIONS MIN TYP MAX UNITS

I

SET

V

ISET

I

ISET

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

I

SET

= 50µA

●

1.18 1.21 1.24 V

●

184 µA

durations less than 10 seconds. Max current for continuous operation is
300mA.

Note 3: The LTC3214E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C ambient
operating temperature range are assured by design, characterization and
correlation with statistical process controls.

UW

(T

TYPICAL PERFOR A CE CHARACTERISTICS

I

Dropout Voltage

LED

vs LED Current

0.12

0.10

0.08

600

500

400

= 25°C unless otherwise specified)

A

I

vs R

LED

SET

0.06

0.04

DROPOUT VOLTAGE (V)

0.02

0

0 100

LED CURRENT (mA)

300200 400 500

1x Mode Charge Pump Open-Loop
Output Resistance vs Temperature

1.0
I

= 100mA

CPO

0.9

VIN = 2.9V

0.8

0.7

0.6

OUTPUT RESISTANCE (Ω)

0.5

0.4

–40 –15

VIN = 3.6V

VIN = 4.5V

3510 60 85

TEMPERATURE (°C)

3216 G01

3216 G03

(mA)

300

LED

I

200

100

0

0

50 150

100

200

250

R

(kΩ)

SET

2x Mode Charge Pump
Open-Loop Output Resistance

– V

)/I

(2V

5

4

3

2

OUTPUT RESISTANCE (Ω)

1

0

–40

IN

CPO

VIN = 3.6V

= C1 = C2 = 2.2µF

C

IN

= 4.7µF

C

CPO

–15 35

vs Temperature

CPO

10

TEMPERATURE (°C)

300

350

400

1573 G02

85

60

3216 G05

3214fa

3

LTC3214

UW

TYPICAL PERFOR A CE CHARACTERISTICS

(TA = 25°C unless otherwise specified)

Efficiency vs V

100

100mA

90

80

70

) (%)

IN

/P

60

LED

50

40

30

EFFICIENCY (P

20

LED = AOT2015

10

= 2.9V TYP AT 100mA

V

F

0

2.9

3.1 3.5

Input Shutdown Current
vs Input Voltage

4.5

4.0

3.5

TA = 25°C

3.0

2.5

2.0

1.5

1.0

INPUT SHUTDOWN CURRENT (µA)

0.5

0

2.9 4.5

3.3

IN

200mA

300mA

50mA

3.3

3.7

VIN (V)

3.9

TA = –40°C

3.7

INPUT VOLTAGE (V)

4.3

4.1

4.5

3215 G08

TA = 85°C

4.13.1 3.5 3.9

4.3

3214 G06

I

SET/ILED

vs I

3300

3200

3100

3000

2900

CURRENT RATIO

2800

2700

0

Current Ratio

Current

LED

25°C

85°C

–40°C

I

LED

FREQUENCY (kHz)

200100 300

CURRENT (mA)

Oscillator Frequency
vs Supply Voltage

910

900

890

880

870

860

850

840

830

TA = 25°C

3.1 3.5 3.9

2.9 4.5

400

3.3

500

3214 G09

TA = –40°C

TA = 85°C

3.7

SUPPLY VOLTAGE (V)

600

500

400

300

(mA)

LED

I

200

100

0

2.9 4.53.3 3.7 4.13.1 3.5 3.9 4.3

4.1

Current vs Input Voltage

I

LED

4.3

3214 G07

7.15k

11.8k

17.4k

36.6k

72.2k

VIN (V)

3214 G10

4

V

CPO

50mV/DIV

1.5x Mode CPO Output Ripple 2x Mode CPO Output Ripple

V

CPO

50mV/DIV

A/C COUPLED

IN

I

CPO

= 3.6V

= 200mA

500ns/DIVV

3214 G11

I

IN

CPO

= 3.6V

= 400mA

500ns/DIVV

3214 G12

3214fa

LTC3214

U

UU

PI FU CTIO S

C2+, C1+, C2–, C1– (Pins 1, 2, 8, 10): Charge Pump Flying
Capacitor Pins. A 2.2µF X5R or X7R ceramic capacitor
should be connected from C1

–

.

C2

+

to C1– and from C2+ to

CPO (Pin 3): Output. CPO is the output of the charge
pump. This pin may be enabled or disabled using the EN
input. A 4.7µF X5R or X7R ceramic capacitor is required
from CPO to GND.

I

(Pin 4): Input. I

LED

LED is connected between CPO (anode) and I
ode). The current into the I
connected to the I

I

(Pin 5): LED Current Programming Resistor Pin. A

SET

is the LED current sense pin. The

LED

pin is set by a resistor

LED

pin and regulated internally.

SET

LED

(cath-

resistor connected between this pin and GND is used to set
the LED current level.

W

BLOCK DIAGRA

EN (Pin 6): Input. The EN pin is used to enable the part and
bring it into shutdown mode. An internal 250kΩ resistor
pulls this pin to GND when left floating.

(Pin 7): Power. Supply voltage for the LTC3214. V

V

IN

IN

should be bypassed with a 2.2µF to 4.7µF low impedance
ceramic capacitor to GND.

GND (Pin 9): Charge Pump Ground. This pin should be
connected directly to a low impedance ground plane.

Exposed Pad (Pin 11): Control Signal Ground. This pad
must be soldered to a low impedance ground plane for
optimum thermal and electrical performance.

2 10 1 8

OSCILLATOR

+

C1

–

C1

+

C2

–

C2

CPO

3

–

VOLTAGE

CLAMP

+

V

MODE

CONTROL

V

IN

7

EN

6

250k

CONTROL

LOGIC

GND

REF

CURRENT

SOURCE

CONTROL

V

IN

58Ω

I

SET

1159

0.11Ω

GND

I

LED

4

3214 BD

3214fa

5

LTC3214

OPERATIO

U

The LTC3214 uses a fractional switched capacitor charge
pump to power a high current LED with a programmed
regulated current. The part starts up into the 1x mode. In
this mode, VIN is directly connected to CPO. This mode
provides maximum efficiency and minimum noise. The
LTC3214 will remain in this mode until the forward voltage
(VF) approaches the maximum CPO voltage possible in
this mode. When this dropout condition occurs, the
LTC3214 will switch to 1.5x mode after a soft-start period.
Any subsequent dropout detected will cause the part to
enter 2x mode.

A two phase nonoverlapping clock activates the charge
pump switches. In the 2x mode, the flying capacitors are
charged on alternate clock phases from V
capacitor is being charged from V
on top of V

and connected to the output. Alternatively, in

IN

, the other is stacked

IN

. While one

IN

the 1.5x mode the flying capacitors are charged in series
during the first clock phase, and stacked in parallel on top
of VIN on the second clock phase. This sequence of
charging and discharging the flying capacitors continues
at a free running frequency of 900kHz (typ).

The current delivered to the LED load is controlled by the
internal programmable current source. The current is
programmed by a resistor connected between the I

SET

pin
and GND. The resistor value needed to attain the desired
current level can be determined by Equation 1.

R

= 3570/I

SET

LED

(1)

Overcurrent shutdown mode will prevent damage to the
part by shutting down the high power sections of the chip.
Choosing an R

value of 5k or greater will ensure that the

SET

part stays out of this mode.

Regulation is achieved by sensing the voltage at the I

LED

pin and modulating the charge pump strength based on
the error signal.

In shutdown mode all circuitry is turned off and the
LTC3214 draws a very low current from the VIN supply.
The output is disconnected from V

and is pulled down by

IN

a resistance of approximately 43kΩ. The LTC3214 enters
shutdown mode when the EN pin is brought low.

Thermal Protection

The LTC3214 has built-in overtemperature protection.
Thermal shutdown circuitry will shut down the part when
the junction temperature exceeds approximately 165°C. It
will re-enable the part once the junction temperature drops
back to approximately 150°C. The LTC3214 will cycle in
and out of thermal shutdown indefinitely without latch up
or damage until the heat source is removed.

Short-Circuit Protection

When EN is brought high, the part will connect VIN and
CPO through a weak pull-up. If the CPO capacitor fails to
charge up to over 1V (i.e. CPO is shorted), the chip will not
be enabled. Similarly, during operation if CPO is pulled
down below 1V, the part will be disabled.

Soft-Start

To prevent excessive inrush current during start-up and
mode switching, the LTC3214 employs built-in soft-start
circuitry. Soft-start is achieved by increasing the amount
of current available to the output charge storage capacitor
linearly over a period of approximately 150µs.

Charge Pump Strength

When the LTC3214 operates in either the 1.5x mode or 2x
mode, the charge pump can be modeled as a Thevenin
equivalent circuit to determine the amount of current
available from the effective input voltage and effective
open-loop output resistance, R

1.5V

IN

+

OR

–

2V

IN

Figure 1. Charge Pump Open-Loop Thevenin-Equivalent Circuit

OL

R

OL

3214 F01

(Figure 1).

+

CPO

–

6

3214fa

OPERATIO

LTC3214

U

ROL is dependent on a number of factors including the
oscillator frequency, flying capacitor values and switch
resistances. From Figure 1, we can see that the output
current is proportional to:

15 2.– –V CPO

IN

R

OL

OR

V CPO

IN

R

OL

in the 1.5x mode or 2x mode respectively.

LED Current Programming

The LTC3214 includes an accurate, programmable cur­rent source that is capable of driving LED currents up to
300mA continuously and up to 500mA for pulsed opera­tion. Pulsed operation may be achieved by toggling the EN
pin. In either continuous or pulsed operation, proper
board layout is required for effective heat sinking.

The current may be programmed using a single external
resistor. Equation 1, used to calculate the resistor value
from the desired current level is repeated below:

For applications requiring multiple current levels, several
schemes may be used to change the resistance for the
R

resistor. Figure 2 shows one such scheme. The

SET

circuit in Figure 2 uses the I/O output of a microcontroller
to switch a second resistor (R2) in parallel or series with
R1, changing the effective I

current.

SET

Mode Switching

The LTC3214 will automatically switch from 1x mode to

1.5x mode, and subsequently from 1.5x mode to 2x mode
whenever the LED forward voltage approaches the maxi­mum CPO voltage for that mode. The part will wait
approximately 2.5ms before switching to the next mode.
This delay allows the LED to warm up and reduce its
forward voltage which may remove the dropout condition.
The part may be reset to 1X mode by bringing the part into
shutdown by setting the EN pin low. Once the EN pin is
low, it may be immediately brought high to re-enable the
part.

R

SET

= 3570/I

LED

2.2µF 2.2µF

+C1–C2+C2–

C1

2.9V TO 4.5V

µP

ON/OFF

TORCH/FLASH

*I

TORCH

I

FLASH

Figure 2. Recommended Circuit for Attaining Two Current Levels (Torch and Flash Modes)

2.2µF

V

IO

V

IO

= [(1.21V/R1) – ((VIO – 1.21V)/R2)] • 2950

= [(1.21V/(R1 • R2/(R1 + R2))] • 2950

V

IN

LTC3214

EN

I

R2

SET

R1

CPO

I

LED

3214 F02

4.7µF

I

*

LED

3214fa

7

LTC3214

WUUU

APPLICATIO S I FOR ATIO

VIN, CPO Capacitor Selection

The value and type of capacitors used with the LTC3214
determine several important parameters such as regulator
control loop stability, output ripple, charge pump strength
and minimum start-up time.

To reduce noise and ripple, it is recommended that low
equivalent series resistance (ESR) ceramic capacitors be
used for both C

VIN

and C

. Tantalum and aluminum

CPO

capacitors are not recommended because of their high ESR.

The value of C

directly controls the amount of output

CPO

ripple for a given load current. Increasing the size of
C

will reduce the output ripple at the expense of higher

CPO

start-up current. The peak-to-peak output ripple for 1.5x
mode is approximately given by the expression:

V

RIPPLE(P-P)

Where f

OSC

cally 900kHz) and C

= I

OUT

/(3f

OSC

• C

CPO

)

is the LTC3214’s oscillator frequency (typi-

is the output storage capacitor.

CPO

Both the style and value of the output capacitor can
significantly affect the stability of the LTC3214. As shown
in the Block Diagram, the LTC3214 uses a control loop to
adjust the strength of the charge pump to match the
current required at the output. The error signal of this loop
is stored directly on the output charge storage capacitor.
The charge storage capacitor also serves as the dominant
pole for the control loop. To prevent ringing or instability,
it is important for the output capacitor to maintain at least
3µF of actual capacitance over all conditions.

small (~15ns), these missing “notches” will result in only
a small perturbation on the input power supply line. Note
that a higher ESR capacitor such as tantalum will have
higher input noise due to the input current change times
the ESR. Therefore, ceramic capacitors are again recom­mended for their exceptional ESR performance. Input
noise can be further reduced by powering the LTC3214
through a very small series inductor as shown in Figure 3.
A 10nH inductor will reject the fast current notches,
thereby presenting a nearly constant current load to the
input power supply. For economy, the 10nH inductor can
be fabricated on the PC board with about 1cm (0.4") of PC
board trace.

10nH

2.2µF0.1µF

Figure 3. 10nH Inductor Used for Input Noise Reduction
(Approximately 1cm of Wire)

V

IN

GND

LTC3214

3214 F03

Flying Capacitor Selection

Warning: Polarized capacitors such as tantalum or alu­minum should never be used for the flying capacitors
since their voltage can reverse upon start-up of the
LTC3214. Ceramic capacitors should always be used for
the flying capacitors.

Likewise, excessive ESR on the output capacitor will tend
to degrade the loop stability of the LTC3214. To prevent
poor load transient response and instability, the ESR of the
output capacitor should be kept below 50mΩ. Multilayer
ceramic chip capacitors typically have exceptional ESR
performance. MLCCs combined with a tight board layout
will yield very good stability. As the value of C
the amount of output ripple, the value of C
amount of ripple present at the input pin (V

controls

CPO

controls the

VIN

). The input

IN

current to the LTC3214 will be relatively constant while the
charge pump is on either the input charging phase or the
output charging phase but will drop to zero during the
clock nonoverlap times. Since the nonoverlap time is

8

The flying capacitors control the strength of the charge
pump. In order to achieve the rated output current it is
necessary to have at least 1.6µF of actual capacitance for
each of the flying capacitors. Capacitors of different mate­rials lose their capacitance with higher temperature and
voltage at different rates. For example, a ceramic capacitor
made of X7R material will retain most of its capacitance from
–40°C to 85°C whereas a Z5U or Y5V style capacitor
will lose considerable capacitance over that range. Z5U and
Y5V capacitors may also have a very poor voltage coeffi­cient causing them to lose 60% or more of their capacitance
when the rated voltage is applied. Therefore, when compar­ing different capacitors, it is often more appropriate to

3214fa

WUUU

APPLICATIO S I FOR ATIO

LTC3214

compare the amount of achievable capacitance for a given
case size rather than comparing the specified capacitance
value. For example, over rated voltage and temperature
conditions, a 1µF, 10V, Y5V ceramic capacitor in a 0603 case
may not provide any more capacitance than a 0.22µF, 10V,
X7R available in the same case. The capacitor
manufacturer’s data sheet should be consulted to determine
what value of capacitor is needed to ensure minimum
capacitances at all temperatures and voltages.

Table 1 shows a list of ceramic capacitor manufacturers
and how to contact them.

Table 1. Recommended Capacitor Vendors

AVX www.avxcorp.com

Kemet www.kemet.com

Murata www.murata.com

Taiyo Yuden www.t-yuden.com

Vishay www.vishay.com

TDK www.tdk.com

Layout Considerations and Noise

Due to the high switching frequency and the transient
currents produced by the LTC3214, careful board layout is
necessary. A true ground plane and short connections to
all capacitors will improve performance and ensure proper
regulation under all conditions. An example of such a
layout is shown in Figure 4.

The flying capacitor pins C1+, C2+, C1– and C2– will have
very high edge rate waveforms. The large dv/dt on these

pins can couple energy capacitively to adjacent PCB runs.
Magnetic fields can also be generated if the flying capaci­tors are not close to the LTC3214 (i.e., the loop area is
large). To decouple capacitive energy transfer, a Faraday
shield may be used. This is a grounded PCB trace between
the sensitive node and the LTC3214 pins. For a high quality
AC ground, it should be returned to a solid ground plane
that extends all the way to the LTC3214.

The following guidelines should be followed when design­ing a PCB layout for the LTC3214.

• The Exposed Pad should be soldered to a large copper
plane that is connected to a solid, low impedance
ground plane using plated, through-hole vias for proper
heat sinking and noise protection.

• Input and output capacitors (C

and C

IN

) must also

CPO

be placed as close to the part as possible.

• The flying capacitors must also be placed as close to the
part as possible. The traces running from the pins to the
capacitor pads should be as wide as possible.

•VIN, CPO and I

traces must be made as wide as

LED

possible. This is necessary to minimize inductance,
as well as provide sufficient area for high current
applications.

• LED pads must be large and should be connected to as
much solid metal as possible to ensure proper heat
sinking.

C1

C

CPO

PIN 1

RSET

Figure 4. Example Board Layout

C2

C

IN

3214 F04

3214fa

9

LTC3214

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APPLICATIO S I FOR ATIO

Power Efficiency

To calculate the power efficiency (η) of a white LED driver
chip, the LED power should be compared to the input
power. The difference between these two numbers repre­sents lost power whether it is in the charge pump or the
current sources. Stated mathematically, the power effi­ciency is given by:

P

LED

η≡

P

IN

The efficiency of the LTC3214 depends upon the mode in
which it is operating. Recall that the LTC3214 operates as
a pass switch, connecting V
detected at the I

pin. This feature provides the optimum

LED

to CPO, until dropout is

IN

efficiency available for a given input voltage and LED
forward voltage. When it is operating as a switch, the
efficiency is approximated by:

P

LED

η≡ = ≈

P

IN

•

VI

LED LED

•

VIVV

IN IN

LED

IN

since the input current will be very close to the LED
current.

At moderate to high output power, the quiescent current
of the LTC3214 is negligible and the expression above is
valid.

Once dropout is detected at the I

pin, the LTC3214

LED

enables the charge pump in 1.5x mode.

In 1.5x boost mode, the efficiency is similar to that of a
linear regulator with an effective input voltage of 1.5 times
the actual input voltage. This is because the input current
for a 1.5x charge pump is approximately 1.5 times the load
current. In an ideal 1.5x charge pump, the power efficiency
would be given by:

η

IDEAL

P

LED

≡ = ≈

P

IN

VI

•

LED LED

VIVV

•. .15 15

IN LED

LED

IN

Similarly, in 2x boost mode, the efficiency is similar to that
of a linear regulator with an effective input voltage of 2
times the actual input voltage. In an ideal 2x charge pump,
the power efficiency would be given by:

η

IDEAL

P

LED

≡ = ≈

P

VI

LED LED

VIVV

IN

••22

IN LED

•

LED

IN

Thermal Management

For higher input voltages and maximum output current,
there can be substantial power dissipation in the LTC3214.
If the junction temperature increases above approximately
165°C, the thermal shutdown circuitry will automatically
deactivate the output. To reduce maximum junction tem­perature, a good thermal connection to the PC board is
recommended. Connecting the Exposed Pad to a ground
plane and maintaining a solid ground plane under the
device can reduce the thermal resistance of the package
and PC board considerably.

10

3214fa

PACKAGE DESCRIPTIO

LTC3214

U

DD Package

10-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1698)

0.675 ±0.05

3.50 ±0.05

1.65 ±0.05
(2 SIDES)2.15 ± 0.05

PACKAGE
OUTLINE

0.25 ± 0.05

2.38 ±0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

PIN 1

TOP MARK

(SEE NOTE 6)

0.200 REF

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE

0.50
BSC

(2 SIDES)

3.00 ±0.10
(4 SIDES)

0.75 ±0.05

0.00 – 0.05

1.65 ± 0.10
(2 SIDES)

R = 0.115

TYP

2.38 ±0.10
(2 SIDES)

BOTTOM VIEW—EXPOSED PAD

106

15

0.50 BSC

0.38 ± 0.10

0.25 ± 0.05

(DD10) DFN 1103

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen­tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

3214fa

11

LTC3214

TYPICAL APPLICATIO

ON/OFF

U

High Power Camera Light and Flash

2.2µF 2.2µF

+C1–C2+C2–

C1

V

IN

EN

µP

2.9V TO 4.5V

2.2µF

2.8V

LTC3214

CPO

I

LED

I

LED

100mA/300mA

4.7µF

2.8V

TORCH/FLASH

41.2k
1%

I

SET

16.9k
1%

3214 TA02

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1618 Constant Current, 1.4MHz, 1.5A Boost Converter VIN: 1.6V to 18V, V

MS Package

LT1961 1.5A (ISW), 1.25MHz, High Efficiency Step-Up VIN: 3V to 25V, V

OUT(MAX)

DC/DC Converter MS8E Package

LTC3205 250mA, 1MHz, Multi-Display LED Controller VIN: 2.8V to 4.5V, V

DFN Package

LTC3206 400mA, 800kHz, Multi-Display LED Controller VIN: 2.8V to 4.5V, V

DFN Package

LTC3208 High Current Software Configurable Multidisplay 95% Efficiency, VIN: 2.9V to 4.5V, V

LED Controller I

< 1µA, (5mm × 5mm) QFN-32 Package

SD

LTC3215 700mA Low Noise High Current LED Charge Pump VIN: 2.9V to 4.4V, V

(3mm × 3mm) DFN Package

LTC3216 1A Low Noise High Current LED Charge Pump with VIN: 2.9V to 4.4V, V

Independent Flash/Torch Current Control (3mm × 4mm) DFN Package

LTC3440/LTC3441 600mA/1.2A I

, 2MHz/1MHz, Synchronous VIN: 2.4V to 5.5V, V

OUT

Buck-Boost DC/DC Converter MS, DFN Packages

LTC3443 600mA/1.2A I

, 600kHz, Synchronous VIN: 2.4V to 5.5V, V

OUT

Buck-Boost DC/DC Converter DFN Package

LTC3453 1MHz, 800mA Synchronous Buck-Boost VIN: 2.7V to 5.5V, V

High Power LED Driver QFN Package

LT3467/LT3467A 1.1A (ISW), 1.3/2.1MHz, High Efficiency Step-Up VIN: 2.4V to 16V, V

DC/DC Converters with Integrated Soft-Start ThinSOT Package

LT3479 3A, 42V, 3.5MHz Boost Converter VIN: 2.5V to 24V, V

DFN, TSSOP Packages

= 36V, IQ = 1.8mA, ISD < 1µA

OUT(MAX)

= 35V, IQ = 0.9mA, ISD < 6µA

= 5.5V, IQ = 50µA, ISD < 1µA

OUT(MAX)

= 5.5V, IQ = 50µA, ISD < 1µA

OUT(MAX)

= 5.5V, IQ = 300µA, ISD < 2.5µA

OUT(MAX)

= 5.5V, IQ = 300µA, ISD < 2.5µA

OUT(MAX)

= 5.25V, IQ = 25µA/50µA, ISD <1µA

OUT(MAX)

= 5.25V, IQ = 28µA, ISD <1µA

OUT(MAX)

: 2.7V to 4.5V, IQ = 2.5mA, ISD < 6µA

OUT

= 40V, IQ = 1.2mA, ISD < 1µA

OUT(MAX)

= 40V, IQ = 2µA, ISD < 1µA

OUT(MAX)

OUT(MAX)

: 5.5V, IQ = 280µA,

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone] ● www.linear.com

3214fa

LT 0306 REV A • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 2005