Datasheet

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LT3464

3464f

TYPICAL APPLICATIO

APPLICATIO S

DESCRIPTIO

FEATURES

■

Tiny Solution Size

■

Low Quiescent Current

• 25µA in Active Mode

• 0.5µA in Shutdown Mode

■

Internal 115mA, 36V Switch

■

Integrated Schottky Diode

■

Integrated PNP Output Disconnect with

Short-Circuit Protection

■

Internal Reference Override Pin

■

16V at 8mA from 3.6V Input

■

12V at 20mA from 5V Input

■

Input Range: 2.3V to 10V

■

High Output Voltage: Up to 34V

■

Low Profile (1mm) SOT-23 Package

Micropower Boost

Converter with Schottky and

Output Disconnect in ThinSOT™

The LT

3464 is a micropower step-up DC/DC converter

with integrated Schottky diode and output disconnect

packaged in an 8-lead low profile (1mm) SOT-23. The

small package size, high level of integration, and the use

of tiny SMT components yield a solution size of less than

40mm

. The LT3464 has a typical current limit of 115mA

as well as fast switching speed to allow the use of a chip

inductor and small ceramic capacitors. The internal PNP

disconnects the output load from the input during shut-

down, and also provides output short-circuit protection.

An auxiliary reference input allows the user to override the

internal 1.25V feedback reference with any lower value,

allowing full control of the output voltage during opera-

tion. This device features a low 25 µA quiescent current,

which is further reduced to less than 0.5µA in shutdown.

A current limited fixed off-time control scheme conserves

operating current, resulting in high efficiency over a broad

range of operating current. The rugged 36V switch and

output disconnect circuitry allow outputs up to 34V to be

easily generated in a simple boost topology.

, LTC and LT are registered trademarks of Linear Technology Corporation.

■

OEL Panel Bias

■

LCD Bias

■

Handheld Computers

■

Battery Backup

■

Digital Cameras

■

Cellular Phones

CTRL

SHDN

2.3V TO 10V

OUT

16V

GND

OUT

CAP

LT3464

22µH

1µF

0.22µF

0.33µF

3.48M

294k

3464 TA01a

ThinSOT is a trademark of Linear Technolgy Corporation

Efficiency

LOAD CURRENT (mA)

EFFICIENCY (%)

0.01 1 10 100

3464 TA01b

0.1

= 8.4V

= 4.2V

Summary of content (16 pages)

PAGE 1
LT3464 Micropower Boost Converter with Schottky and Output Disconnect in ThinSOT™ U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT®3464 is a micropower step-up DC/DC converter with integrated Schottky diode and output disconnect packaged in an 8-lead low profile (1mm) SOT-23. The small package size, high level of integration, and the use of tiny SMT components yield a solution size of less than 40mm2.
PAGE 2
LT3464 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) VIN, SHDN, CTRL Voltage ........................................ 10V OUT, CAP Voltage .................................................... 36V SW Voltage .............................................................. 36V FB Voltage ................................................................. 6V Maximum Junction Temperature .......................... 125°C Operating Temperature Range (Note 2) ..
PAGE 3
LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS Switch Off-Time, VCAP – VIN = 5V Switch Current Limit 220 140 400 200 120 350 180 160 140 120 100 SWITCH OFF-TIME (ns) SWITCH CURRENT (mA) SWITCH VOLTAGE (mV) Switch Saturation Voltage ISW = 80mA 80 60 40 20 100 –50 –25 0 25 50 TEMPERATURE (°C) 75 –25 0 25 50 TEMPERATURE (°C) 75 3464 G01 Minimum Switch On-Time 60 50 40 30 20 75 250 1.1 1.0 0.9 0.8 0.7 IOUT = 10mA 200 150 IOUT = 200µA 100 50 0.
PAGE 4
LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS Schottky Forward Drop at ID = 110mA Schottky Reverse Leakage Schottky Forward Voltage 800 250 20 200 16 SCHOTTKY CURRENT (mA) VOLTAGE DROP (mV) 700 650 600 550 500 450 400 LEAKAGE CURRENT (µA) 750 150 100 50 VCAP – SW = 36V 12 8 4 350 300 –50 –25 0 25 50 TEMPERATURE (°C) 75 0 200 100 300 400 500 600 700 FORWARD VOLTAGE (mV) 0 –50 800 30 12 16 18 16 14 12 10 –50 –25 0 25 50 TEMPERATURE (°C) 75 14 10 QUIESCENT CURRENT (nA)
PAGE 5
LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS FB Pin Voltage vs CTRL Pin Voltage FB and CTRL Pin Bias Currents 1.50 8 7 1.00 0.75 0.50 10 CTRL PIN 6 HYSTERESIS (mV) BIAS CURRENT (nA) 1.25 FB PIN VOLTAGE (V) FB Pin Hysteresis 12 5 4 FEEDBACK PIN 3 8 6 4 2 0.25 0 2 1 0 0.25 0.5 0.75 1.0 1.25 1.5 CONTROL PIN VOLTAGE (V) 1.
PAGE 6
LT3464 W BLOCK DIAGRA VIN SW CAP OUT 7 6 5 3 DELAY CPL FB CTRL 2 1 + – – S Q R Q OUT ANTI SAT + 1.25V OUT 12mV – SHDN 8 0.1Ω VREF 4 GND 3464 BD U OPERATIO The LT3464 uses a constant off-time control scheme in conjunction with Burst Mode ® operation to provide high efficiency over a wide range of output current. Operation can best be understood by studying the Block Diagram. When the FB pin voltage is lower than the 1.
PAGE 7
LT3464 U W W SWITCHI G TI E WAVEFOR S Operating Waveforms Start up Waveforms IL 0.1A/DIV IL 0.
PAGE 8
LT3464 U U W U APPLICATIO S I FOR ATIO in discontinuous mode. If the left hand side of inequality 1 evaluates to less than Ot FF, then use Equation 3 to calculate maximum output current. Otherwise, use Equation 2. Choosing an Inductor The low current limit and fast switching of the LT3464 allow the use of very small surface mount inductors. The minimum inductor size that may be used in a given application depends on required efficiency and output current.
PAGE 9
LT3464 U W U U APPLICATIO S I FOR ATIO user to select between using the built-in reference, and supplying an external reference voltage. The voltage at the The small size and low ESR of ceramic capacitors makes CTRL pin can be adjusted while the chip is operating to them suitable for LT3464 applications. X5R and X7R types alter the output voltage of the LT3464 for purposes such are recommended because they retain their capacitance as display dimming or contrast adjustment.
PAGE 10
LT3464 U W U U APPLICATIO S I FOR ATIO 300 6 7 6 SW VIN SW OUT CTRL LT3464 CAP 8 SHDN FB GND 4 3 5 VOUT R2 1 OUT CTRL LT3464 CAP 8 2 3 VOUT 5 R2 SHDN FB R1 250 GND VCAP-OUT (SAT) 1 7 VIN 200 150 100 2 R1 4 50 0 3464 F01 0 5 10 15 20 25 COLLECTOR CURRENT (mA) 30 3464 F02 Figure 4.
PAGE 11
LT3464 U W U U APPLICATIO S I FOR ATIO pin has sharp rising and falling edges. Minimize the length As with all switching regulators, careful attention must be and area of all traces connected to the SW pin and always paid to the PCB board layout and component placement. use a ground plane under the switching regulator to To maximize efficiency, switch rise and fall times are made minimize interplane coupling. In addition, the ground as short as possible.
PAGE 12
LT3464 U TYPICAL APPLICATIO S 15V Output Converter with Output Disconnect L1 22µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 5 2 VOUT 15V C3 0.22µF C2 0.22µF VIN (V) IOUT (mA) 3.6 7.0 5.0 10.0 8.4 19.0 VIN (V) IOUT (mA) 3.6 3.5 5.0 4.5 8.4 7.5 R2 3.
PAGE 13
LT3464 U TYPICAL APPLICATIO S 20V Output Converter with Output Disconnect L1 47µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 VOUT 20V C3 0.22µF 5 C2 0.33µF 2 R2 4.53M R1 301k GND 4 VIN (V) IOUT (mA) 3.6 6.0 5.0 9.0 8.4 16.5 VIN (V) IOUT (mA) 3.6 5.0 3464 TA05 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG L1: MURATA LQH32CN470K 20V Output Converter with Soft Start L1 22µH VIN 2.
PAGE 14
LT3464 U TYPICAL APPLICATIO S 8V Output Converter with Output Disconnect L1 22µH VIN 2.3V TO 7V 6 7 VIN C4 1µF 8 SW SHDN LT3464 1 3 OUT 5 CAP CTRL C2 2.2µF 2 FB VOUT 8V C3 0.47µF R2 1.62M C4 20pF VIN (V) IOUT (mA) 3.6 13.5 5.0 20 R1 301k GND 4 3464 TA07 C1: TAIYO YUDEN CE LMK107 BJ105MA-T C2: TAIYO YUDEN CE LMK212 BJ225MG-T C3: TAIYO YUDEN CE LMK107 BJ474MA-T L1: MURATA LQH32CN220K ±20V Dual Output Converter with Output Disconnect L1 47µH VIN 2.
PAGE 15
LT3464 U PACKAGE DESCRIPTIO TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.52 MAX 2.90 BSC (NOTE 4) 0.65 REF 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.22 – 0.36 8 PLCS (NOTE 3) 0.65 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.95 BSC NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3.
PAGE 16
LT3464 U TYPICAL APPLICATIO S 20V Output Converter with Variable Output Voltage and Shutdown VIN 2.3V TO 10V L1 22µH C1 1µF 1 DAC 7 6 VIN SW OUT CTRL LT3464 8 µC CAP SHDN FB 3 5 2 VOUT 20V C3 0.22µF C2 0.33µF R2 4.53M R1 301k GND 4 VIN (V) IOUT (mA) 3.6 5.0 5.0 6.5 8.4 11.0 3464 TA09 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN GMK212 BJ224MG-T L1: MURATA LQH32CN220K RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1613 550mA (ISW), 1.