Datasheet

ManualsBrandsLinear Technology ManualsDC / DC ControllersDC/DC Converter SOT-23 ... 34V 1.2A

LT1930/LT1930A

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

1A, 1.2MHz/2.2MHz,

Step-Up DC/DC Converters

in ThinSOT

■

1.2MHz Switching Frequency (LT1930)

■

2.2MHz Switching Frequency (LT1930A)

■

Low V

CESAT

Switch: 400mV at 1A

■

High Output Voltage: Up to 34V

■

5V at 480mA from 3.3V Input (LT1930)

■

12V at 250mA from 5V Input (LT1930A)

■

Wide Input Range: 2.6V to 16V

■

Uses Small Surface Mount Components

■

Low Shutdown Current: <1µA

■

Low Profile (1mm) ThinSOT

Package

■

Pin-for-Pin Compatible with the LT1613

Figure 1. 5V to 12V, 300mA Step-Up DC/DC Converter

■

TFT-LCD Bias Supply

■

Digital Cameras

■

Cordless Phones

■

Battery Backup

■

Medical Diagnostic Equipment

■

Local 5V or 12V Supply

■

External Modems

■

PC Cards

■

xDSL Power Supply

Efficiency

The LT

1930 and LT1930A

are the industry’s highest

power SOT-23 switching regulators. Both include an

internal 1A, 36V switch allowing high current outputs to be

generated in a small footprint. The LT1930 switches at

1.2MHz, allowing the use of tiny, low cost and low height

capacitors and inductors. The faster LT1930A switches at

2.2MHz, enabling further reductions in inductor size.

Complete regulator solutions approaching one tenth of a

square inch in area are achievable with these devices.

Multiple output power supplies can now use a separate

regulator for each output voltage, replacing cumbersome

quasi-regulated approaches using a single regulator and

custom transformers.

A constant frequency internally compensated current mode

PWM architecture results in low, predictable output noise

that is easy to filter. Low ESR ceramic capacitors can be

used at the output, further reducing noise to the millivolt

level. The high voltage switch on the LT1930/LT1930A is

rated at 36V, making the device ideal for boost converters

up to 34V as well as for single-ended primary inductance

converter (SEPIC) and flyback designs. The LT1930 can

generate 5V at up to 480mA from a 3.3V supply or 5V at

300mA from four alkaline cells in a SEPIC design.

The LT1930/LT1930A are available in the 5-lead ThinSOT

package.

GND

SHDN FB

10µH

113k

LT1930

1930/A F01

4.7µF

C3*

10pF

2.2µF

13.3k

OUT

12V

300mA

C1: TAIYO-YUDEN X5R LMK212BJ225MG

C2: TAIYO-YUDEN X5R EMK316BJ475ML

D1: ON SEMICONDUCTOR MBR0520

L1: SUMIDA CR43-100

*OPTIONAL

SHDN

LOAD CURRENT (mA)

EFFICIENCY (%)

400

1930 TA01

100

200

300

= 5V

= 3.3V

, LTC and LT are registered trademarks of Linear Technology Corporation

ThinSOT is a trademark of Linear Technology Corporation.

Summary of content (13 pages)

PAGE 1
LT1930/LT1930A 1A, 1.2MHz/2.2MHz, Step-Up DC/DC Converters in ThinSOT DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT®1930 and LT1930A are the industry’s highest power SOT-23 switching regulators. Both include an internal 1A, 36V switch allowing high current outputs to be generated in a small footprint. The LT1930 switches at 1.2MHz, allowing the use of tiny, low cost and low height capacitors and inductors. The faster LT1930A switches at 2.2MHz, enabling further reductions in inductor size.
PAGE 2
LT1930/LT1930A W W W AXI U U U W PACKAGE/ORDER I FOR ATIO U ABSOLUTE RATI GS (Note 1) VIN Voltage .............................................................. 16V SW Voltage ................................................– 0.4V to 36V FB Voltage .............................................................. 2.5V Current Into FB Pin .............................................. ±1mA SHDN Voltage ......................................................... 10V Maximum Junction Temperature ..........
PAGE 3
LT1930/LT1930A U W TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current FB Pin Voltage 7.0 SHDN Pin Current 1.28 90 NOT SWITCHING 80 SHDN PIN CURRENT (µA) 1.27 6.0 FB VOLTAGE (V) QUIESCENT CURRENT (mA) 6.5 LT1930A 5.5 5.0 4.5 LT1930 1.26 1.25 1.24 4.0 50 40 30 LT1930 20 0 3.0 –50 0 25 50 TEMPERATURE (°C) –25 1.22 –50 100 75 –25 0 25 50 TEMPERATURE (°C) 75 –10 100 Current Limit 1.4 0.40 2.3 0.35 2.1 1.2 FREQUENCY (MHz) 2.5 0.30 VCESAT (V) 0.6 0.25 0.20 0.15 0.
PAGE 4
LT1930/LT1930A W BLOCK DIAGRA 1.255V REFERENCE VIN 5 1 SW + – A1 – DRIVER RC VOUT COMPARATOR + A2 R CC R1 (EXTERNAL) S Q1 Q + Σ FB 0.01Ω – R2 (EXTERNAL) RAMP GENERATOR SHUTDOWN 4 SHDN 3 FB 2 GND 1930/A BD 1.2MHz OSCILLATOR* *2.2MHz FOR LT1930A Figure 2. Block Diagram U OPERATIO The LT1930 uses a constant frequency, current-mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the block diagram in Figure 2.
PAGE 5
LT1930/LT1930A U W U U APPLICATIONS INFORMATION LT1930 AND LT1930A DIFFERENCES Switching Frequency The key difference between the LT1930 and LT1930A is the faster switching frequency of the LT1930A. At 2.2MHz, the LT1930A switches at nearly twice the rate of the LT1930. Care must be taken in deciding which part to use.
PAGE 6
LT1930/LT1930A U W U U APPLICATIONS INFORMATION CAPACITOR SELECTION Low ESR (equivalent series resistance) capacitors should be used at the output to minimize the output ripple voltage. Multi-layer ceramic capacitors are an excellent choice, as they have extremely low ESR and are available in very small packages. X5R dielectrics are preferred, followed by X7R, as these materials retain the capacitance over wide voltage and temperature ranges. A 4.
PAGE 7
LT1930/LT1930A U W U U APPLICATIONS INFORMATION LAYOUT HINTS VOUT 0.2V/DIV AC COUPLED The high speed operation of the LT1930/LT1930A demands careful attention to board layout. You will not get advertised performance with careless layout. Figure 6 shows the recommended component placement. ILI 0.5A/DIV AC COUPLED LOAD 250mA CURRENT 150mA 200µs/DIV 1930 F04 Figure 5.
PAGE 8
LT1930/LT1930A U TYPICAL APPLICATIO S Efficiency 4-Cell to 5V SEPIC Converter SHDN 5 1 VIN SW D1 VIN = 4V VOUT 5V 300mA 70 243k LT1930 4 SHDN FB 3 L2 10µH GND VIN = 6.5V 75 EFFICIENCY (%) C1 2.2µF 4-CELL BATTERY C3 1µF L1 10µH 4V TO 6.5V 80 C2 10µF 65 60 55 50 82.
PAGE 9
LT1930/LT1930A U TYPICAL APPLICATIO S Boost Converter with Reverse Battery Protection L1 4.7µH M1 VIN 3V to 6V C1 2.2µF D1 5 1 VIN SW R1 60.4k LT1930 SHDN 4 SHDN FB VOUT 8V 520mA AT VIN = 6V 240mA AT VIN = 3V C3 47pF 3 GND 2 C2 22µF R2 11.3k C1: TAIYO-YUDEN X5R LMK432BJ226MM C2: TAIYO-YUDEN X5R LMK212BJ225MG D1: ON SEMICONDUCTOR MBR0520 L1: SUMIDA CR43-4R7 M1: SILICONIX Si6433DQ 1930/A TA06 Efficiency 3.3V to 5V Boost Converter VIN 3.3V C1 4.
PAGE 10
LT1930/LT1930A U TYPICAL APPLICATIO S 9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start D1 D2 18V 10mA C4 1µF C3 0.1µF L1 4.7µH VIN 3.3V C1 2.2µF 5 + RSS 30k VSS LT1930 4 SHDN FB C5 10µF 3 GND 0V 2 CSS 68nF 9V OUTPUT 5V/DIV R1 124k SW DSS 1N4148 3.3V 9V 200mA 1 VIN Start-Up Waveforms D5 C2 0.1µF C1: X5R OR X7R, 6.
PAGE 11
LT1930/LT1930A U PACKAGE DESCRIPTIO S5 Package 5-Lead Plastic SOT-23 (Reference LTC DWG # 05-08-1633) (Reference LTC DWG # 05-08-1635) 2.80 – 3.10 (.110 – .118) (NOTE 3) A SOT-23 (Original) .90 – 1.45 (.035 – .057) SOT-23 (ThinSOT) 1.00 MAX (.039 MAX) A1 .00 – .15 (.00 – .006) .01 – .10 (.0004 – .004) A2 .90 – 1.30 (.035 – .051) .80 – .90 (.031 – .035) L .35 – .55 (.014 – .021) .30 – .50 REF (.012 – .019 REF) 2.60 – 3.00 (.102 – .118) 1.50 – 1.75 (.059 – .069) (NOTE 3) PIN ONE .95 (.
PAGE 12
LT1930/LT1930A U TYPICAL APPLICATIO 3.3V to 5V, 450mA Step-Up Converter L1 2.2µH VIN 3.3V C1 2.2µF SHDN D1 5 1 VIN SW R1 30.1k LT1930A 4 SHDN FB VOUT 5V 450mA C2 10µF 3 GND 2 R2 10k C1: TAIYO-YUDEN X5R LMK212BJ225MG C2: TAIYO-YUDEN X5R JMK316B106ML D1: ON SEMICONDUCTOR MBR0520 L1: MURATA LQH3C2R2M24 1930/A TA09a Efficiency 90 3.3V to 5V Transient Response VIN = 3.3V VOUT = 5V 85 80 EFFICIENCY (%) VOUT 50mV/DIV AC COUPLED ILI 0.
PAGE 13
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