Datasheet TK11811MTL Datasheet (TOKO)

TK11811

20P

DC-DC CONVERTER

FEATURES

■ Miniature Package (SOT-23L)

■ Low Start-up Voltage [0.6 V (typ.)]

■ Few External Components

■ Selectable Output Voltage (1.9 V or 2.8 V)

■ High and Low Current Optimized Designs

DESCRIPTION

The TK11811 is a low power, low input voltage DC-DC converter.

This device can be optimized for use in high or low current applications through component selection. The output voltage is selectable for 1.9 or 2.8 V operation and can be trimmed to any voltage in between.

The frequency of the built-in relaxation oscillator is set by external components. The internal voltage regulator provides a stable output voltage. Optimized Toko inductor components are available.

APPLICATIONS

■ Pagers

■ Cassette Recorders

■ Cordless Telephones

■ Portable Instrumentation

■ Radio Control Systems

■ Mobile Radios

■ Battery Operated Equipment

■ Local Area Network (LAN) Receivers

TK11811

V

IN

F

B

OSC

T

GND

V

OUT

The TK11811 is available in a miniature SOT-23L surface mount package.

BLOCK DIAGRAM

V

IN

F

B

OSC V

OUT

ORDERING INFORMATION

TK11811M

V

Tape/Reel Code

TAPE/REEL CODE

TL: Tape Left

OSCILLATOR

ref

-

+

GND

January 1999 TOKO, Inc. Page 1

T

TK11811

ABSOLUTE MAXIMUM RATINGS

Input Voltage ............................................................ 16 V

Power Dissipation (Note 1) ................................ 200 mW

Junction Temperature ........................................... 150 °C

TK11811 ELECTRICAL CHARACTERISTICS

Test Conditions: TA = 25 °C, V

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

= 2.9 V (V

OUT

to T open), unless otherwise specified.

OUT

Storage Temperature Range ................... -55 to +150 °C

Operating Temperature Range ...................-10 to +65 °C

Lead Soldering Temperature (10 s) ...................... 235 °C

V

NI

V

TRATS

I

NI

V

TUO

V

I

)WOL(TUO

TUO

tnerruCtupnI

egatloVtuptuO

tnerruCtuptuO

geReniLnoitalugeReniLI

geRdaoLnoitalugeRdaoLV

FFEycneiciffEV

F

CSO

∆V

/∆T

TUO

Note 1: Power dissipation is 400 mW when mounted as recommended. Derate at 3.2 mW/°C for operation above 25 °C. Power dissipation is Note 2: This IC is a frequency-controlled DC-DC converter; thus the value is varied by condition.

200 mW when in Free Air. Derate at 1.6 mW/°C for operation above 25 °C.

egnaRegatloVylppuS 6.041V

egatloVpu-tratSI

)WOL(egatloVtuptuO

ycneuqerFrotallicsOV

tneiciffeoCerutarepmeTV

TUO

V

NI

V

NI

V

NI

V

NI

V

NI

V

NI

V

NI

TUO

NI

Am0=6.057.0V

I,V1.1=

TUO

I,V4.1=

TUO

I,V1.1=

TUO

I,V4.1=

TUO

I,V1.1=

VotT

TUO

Am3=0.11Am Am3=3.8Am Am3=58.2V Am3=07.258.20.3V

,Am3=

detcennoc

57.109.150.2V

V1.1=0.45.4Am V4.1=0.68.6Am

V1.1,Am3= ≤ VNI≤ V0.201Vm

Am5.0,V1.1= ≤ I

I,V4.1=

TUO

I,V4.1=

TUO

I,V4.1=

TUO

≤ Am354Vm

TUO

Am3=3627%

)2etoN(,Am3=003zHk

Am3=7.0C°/Vm

Page 2 January 1999 TOKO, Inc.

TEST CIRCUIT

R

1

V

IN

C

10 µF

10 KΩ

C2 3300 pF

+

1

L

13

R

2

46

22 KΩ

V

IN

F

B

Di

OSC

T

GND

V

OUT

Note: Di: IS2837,38 (NEC) L: Toko 395KN-0369AQ Toko PS5CDL-1639X

TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25°C, unless otherwise specified.

TK11811

(See “Voltage

Adjustment Circuit”)

V

OUT

+

C

3

10 µF

OUTPUT VOLTAGE VS. OUTPUT

CURRENT (V

OUT

= 1.9 V)

2.5

2.0

(V)

1.5

OUT

V

1.0

1.0 V

.5

0

0 2 4 6 8 10

0.8 V

V

= 0.6 V

IN

I

OUT

EFFICIENCY

CURRENT (V

(mA)

VS.

OUT

OUTPUT

= 2.8 V)

100

1.2 V

50

EFF (%)

1.0 V

1.2 V

1.4 V

1.6 V

1.4 V

1.6 V

EFFICIENCY VS. OUTPUT CURRENT

(V

= 1.9 V)

OUT

100

50

EFF (%)

1.0 V

0.8 V

VIN = 0.6 V

0

0 5 10

I

(mA)

OUT

INPUT CURRENT

VOLTAGE (I

200

OUT

V

OUT

(µA)

IN

I

1.2 V

VS.

INPUT

= 0 mA)

= 2.8 V

1.6 V

1.4 V

OUTPUT VOLTAGE

CURRENT (V

OUT

VS.

= 2.8 V, I

5

4

(V)

3

OUT

V

2

1

VIN = 0.6 V

0

.5 5 10

1.0 V

0.8 V

1.2 V

I

(mA)

OUT

OUTPUT VOLTAGE DRIFT

VS. TEMPERATURE

+50

(mV)

0

OUT

∆V

OUTPUT

= 0 mA)

LOAD

1.6 V

1.4 V

0.8 V

V

= 0.6 V

IN

0

0 5 10

I

(mA)

OUT

100

V

OUT

= 1.9 V

0 10 20

VIN (V)

-50

-50 0 50 100 TA (°C)

January 1999 TOKO, Inc. Page 3

TK11811

INPUT CURRENT VS. INPUT

VOLTAGE (I

OUT

= 0 mA)

0 10 20

VIN (V)

0

I

IN

(µA)

100

200

V

OUT

= 1.9 V

V

OUT

= 2.8 V

V

(V)

TEST CIRCUIT

R

1

V

IN

C

10 µF

10 KΩ

C2 3300 pF

+

1

L

13

R

2

46

22 KΩ

V

IN

F

B

Di

OSC

T

GND

V

OUT

+

Note: L: Toko 395KN-0370UG

Note: This test circuit is effective at low load current.

TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25°C, unless otherwise specified.

C

10 µF

(See “Voltage

Adjustment Circuit”)

V

OUT

3

OUTPUT VOLTAGE

OUTPUT CURRENT

3

2

OUT

1.0 V

0.8 V

V

= 0.6 V

IN

1

0 1 2 3 4 5

I

(mA)

OUT

1.4 V

1.2 V

VS.

1.6 V

EFFICIENCY

VS.

OUTPUT

CURRENT

100

50

EFF (%)

1.0 V

VIN = 0.8 V

0

0 1 2 3 4 5

I

(mA)

OUT

1.6 V

1.4 V

1.2 V

Page 4 January 1999 TOKO, Inc.

TK11811

TEST CIRCUIT

R

1

V

IN

C

10 µF

+

1

10 KΩ

C2 0.1 µF

13

L

46

R

22 KΩ

2

L: Toko 395KN-0369AQ

Note: This test circuit is effective at high load currents. By changing C2 from 3300pF to 0.1 µF, the converter operates in the burst mode. The apparent frequency of operation drops (70 to 100 kHz) and a larger output ripple occurs during burst mode operation. A ripple filter consisting of Cf and Rf can be added to the output to reduce noise. The values of C voltage will drop slightly due to Rf.

TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25°C, unless otherwise specified.

V

IN

F

B

Di

OSC

and Rf should be determined experimentally based on the design parameters. The output

f

T

GND

OUT

RIPPLE FILTER

R

V

OUTV

+

C

3

10 µF

f

+

C

f

OUTPUT VOLTAGE

OUTPUT CURRENT

5

4

(V)

3

OUT

V

2

0.8 V

VIN = 0.6 V

1

0

0 2 4 6 8 10

I

OUT

1.0 V

(mA)

VS

.

1.4 V

1.2 V

EFFICIENCY

VS.

OUTPUT

CURRENT

100

50

EFF (%)

1.0 V

I

OUT

0.8 V

(mA)

VIN = 0.6 V

0

0 5 10

1.4 V

1.2 V

January 1999 TOKO, Inc. Page 5

TK11811

VOL TAGE ADJUSTMENT CIRCUIT

T

R

V

OUT

V

Note: The output voltage can be set between 1.9 V and 2.8 V with an external resistor connected between pins 4 and 6.

1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

OUT

R 0 12 k 22 k 33 k 56 k 82 k 150 k 330 k 560 k *

ADDITIONAL INFORMATION

APPLICATION INFORMATION

Maximize copper foil area connecting to all IC pins for optimum performance. Place input and output bypass capacitors close to the GND pin. For best transient behavior and lowest output impedance use as large a capacitor value as possible. The temperature coefficient of the capacitance and Equivalent Series Resistant (ESR) should be taken into account. These parameters can influence power supply noise and ripple rejection. In extreme cases, oscillation may occur. In order to maintain stability, the output bypass capacitor value should be minimum 10 µF in case of tantalum electrolytic or 15 µF in case of aluminum electrolytic.

HANDLING MOLDED RESIN PACKAGES

All plastic molded packages absorb some moisture from the air. If moisture absorption occurs prior to soldering the device into the printed circuit board, increased separation of the lead from the plastic molding may occur, degrading the moisture barrier characteristics of the device. This property of plastic molding compounds should not be overlooked, particularly in the case of very small packages where the plastic is very thin. In order to preserve the original moisture barrier properties of the package, devices are stored and shipped in moisture proof bags filled with dry air. The bags should not be opened or damaged prior

to actual use of the devices. If this is unavoidable, the devices should be stored in a low relative humidity environment (40 to 65 %) or in an enclosed environment with desiccant.

INDUCTOR NOTES

The output current and efficiency are largely dependant upon the coil used. A coil with lower DC resistance is generally better in efficiency than one with a higher DCR (DC Resistance). The recommended TOKO 395KN-0369 AQ is 1:1 turns ratio transformer with an inductance of 110 µH and Toko 395KN-0370UG is 1:3 turns ratio transformer with inductance of 60 µH:600 µH. These coils, or equivalent, should be used. Smaller coils with higher DCR will not perform as well as the above coil, and the oscillator will not be stable.

FEEDBACK RC TIME CONSTANT

If a different coil is used other than the one mentioned, the RC time constant of the feedback loop will need to be adjusted for optimum performance. Generally, a lower resistance will give more output current. In fact, R can be zero; however, lower resistance will sacrifice efficiency at low output currents as the quiescent current increases. If the capacitance is increased beyond or below a certain value, the oscillator will become unstable. The optimum

Page 6 January 1999 TOKO, Inc.

ADDITIONAL INFORMATION (CONT.)

RC values depend upon the operating current, and should be chosen experimentally using the given values of 3300 pF and 22 kΩ as a starting point.

INPUT/OUTPUT DECOUPLING CAPACITORS

DC-DC converters generate a large ripple current on both the input and the output of the circuit. The capacitors used should be as large as possible and have low impedance in the 300 kHz range. Since low temperatures cause capacitors to decrease capacitance and increase Equivalent Series Resistance (ESR), care should be taken to choose capacitors that have acceptable characteristics over the temperature range you intend to use. This should be done experimentally to verify results, as capacitor performance varies widely from manufacturer to manufacturer. Tantalum capacitors are generally the best choice and 10 µF should be adequate for most applications.

LOAD CHARACTERISTICS

TK11811

The TK11811 should not be allowed to start-up under full load conditions. If this occurs, the output may not stabilize to the correct output voltage. This can be compensated for, somewhat, by adjusting the RC of the feedback loop or by decreasing the output decoupling capacitor. Maximum current can be drawn after the oscillator has started and the output has reached nominal output voltage. This is more critical with input voltages under 1.3 V as the converter needs to generate sufficient output to ensure correct internal bandgap and bias voltages.

January 1999 TOKO, Inc. Page 7

TK11811

PACKAGE OUTLINE

SOT-23L (SOT-23L-6)

456

123

e e

0.95 0.95

+0.3

- 0.1

3.5

(3.4)

0.1

Dimensions are shown in millimeters Tolerance: x.x = ± 0.2 mm (unless otherwise specified)

0.32

+0.15

- 0.05

Marking

Marking Information

Marking TK11811 D1

0.6

1.0

3.0 e1

0.1

M

Recommended Mount Pad

0.3

1.2

1.4 max

+0.15

- 0.05

0 - 0.1

0.15

ee

0.95 0.95

2.2

+ 0.3

3.3

15 max

0.4

Toko America, Inc. Headquarters 1250 Feehanville Drive, Mount Prospect, Illinois 60056 Tel: (847) 297-0070 Fax: (847) 699-7864

TOKO AMERICA REGIONAL OFFICES

Midwest Regional Office Toko America, Inc. 1250 Feehanville Drive Mount Prospect, IL 60056 Tel: (847) 297-0070 Fax: (847) 699-7864

Western Regional Office Toko America, Inc. 2480 North First Street , Suite 260 San Jose, CA 95131 Tel: (408) 432-8281 Fax: (408) 943-9790

Eastern Regional Office Toko America, Inc. 107 Mill Plain Road Danbury, CT 06811 Tel: (203) 748-6871 Fax: (203) 797-1223

Semiconductor Technical Support Toko Design Center 4755 Forge Road Colorado Springs, CO 80907 Tel: (719) 528-2200 Fax: (719) 528-2375

Visit our Internet site at http://www.tokoam.com

The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc.

Page 8 January 1999 TOKO, Inc.

IC-134-TK11811

0798O0.0K