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LINEAR TECHNOLOGY LT3465 LT3465A User Guide Manual

Summary

These high-efficiency LT3465/LT3465A drivers are specialized DC/DC converters designed to power multiple white LEDs safely from low voltages. Featuring a built-in Schottky diode and adjustable switching frequencies (1.2MHz or 2.4MHz), they optimize performance and simplify design by eliminating the need for external components like ballast resistors. This manual provides comprehensive electrical specifications, operational parameters, and application data needed by electronics engineers designing advanced, reliable lighting solutions for consumer products like mobile phones and digital cameras.

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LT3465/LT3465A 1.2MHz/2.4MHz White LED Drivers with Built-in Schottky in Thin SOT

FEATURES DESCRIPTIO

Inherently Matched LED Current The LT®3465/LT3465A are step-up DC/DC converters Drives Up to Six LEDs from a 3.6V Supply designed to drive up to six LEDs in series from a Li-Ion cell. No External Schottky Diode Required Series connection of the LEDs provides identical LED 1.2MHz Switching Frequency (LT3465) currents and eliminates the need for ballast resistors. 2.4MHz Switching Frequency Above AM Broadcast These devices integrate the Schottky diode required exter- Band (LT3465A) nally on competing devices. Additional features include VIN Range: 2.7V to 16V output voltage limiting when LEDs are disconnected, one- VOUT(MAX) = 30V pin shutdown and dimming control. The LT3465 has Automatic Soft-Start (LT3465) internal soft-start. Open LED Protection

The LT3465 switches at 1.2MHz, allowing the use of tiny

High Efficiency: 81% (LT3465) 79% (LT3465A)

external components. The faster LT3465A switches at

Typical EF FI CI EN CY

2.4MHz. Constant frequency switching results in low input

Requires Only 0.22µF Output Capacitor

noise and a small output capacitor. Just 0.22µF is required

Low Profile (1mm) SOT-23

for 3-, 4- or 5-LED applications. APPLICATIO The LT3465 and LT3465A are available in the low profile (1mm) 6-lead SOT-23 (Thin SOTTM) package.

Cellular Phones

, LTC and LT are registered trademarks of Linear Technology Corporation. Thin SOT is a PDAs, Handheld Computers trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.

Digital Cameras MP3 Players GPS Receivers

TYPICAL APPLICATIO

Conversion Efficiency

L1 22µH VIN = 3.6V

3V TO 5V 4 LEDs

SW VOUT VIN

C1 LT3465/ C2 1µF LT3465A 0.22µF

SHUTDOWN

AND DIMMING CTRL FB

CONTROL GND

C1, C2: X5R OR X7R DIELECTRIC

LT3465

L1: MURATA LQH32CN220

LT3465A

Figure 1. Li-Ion Powered Driver for Four White LEDs

LED CURRENT (m A)

3465afa

Page Summary Contents For LINEAR TECHNOLOGY LT3465 LT3465A User Guide Manual

Page 1 LT3465/LT3465A 1.2MHz/2.4MHz White LED Drivers with Built-in Schottky in Thin SOT FEATURES DESCRIPTIO Inherently Matched LED Current The LT®3465/LT3465A are step-up DC/DC converters Drives Up to Six L...
Page 2 LT3465/LT3465A ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW Input Voltage (VIN) 16V VOUT 1 6 SW SW Voltage 36V GND 2 5 VIN FB Voltage 2V FB 3 4 CTRL CTRL Voltage 10V S6 PACKAGE Op...
Page 3 FE ED BA CK OL TA GE (m V) SW IT CH AT UR AT IO VO LT AG (m V) LT3465/LT3465A TYPICAL PERFOR A CE CHARACTERISTICS Shutdown Quiescent Current Switch Saturation Voltage (VCESAT) Schottky Forward Voltage...
Page 4 FE ED BA CK OL TA GE (m V) LT3465/LT3465A TYPICAL PERFOR A CE CHARACTERISTICS EF FI CI EN CY Feedback Voltage Quiescent Current (CTRL = 3V) Switching Current Limit 3.0 TEMPERATURE (°C) VIN (V) DUTY CY...
Page 5 LT3465/LT3465A PI FU CTIO S VOUT (Pin 1): Output Pin. Connect to output capacitor and CTRL (Pin 4): Dimming Control and Shutdown Pin. Ground LEDs. Minimize trace between this pin and output capaci- th...
Page 6 LT3465/LT3465A BLOCK DIAGRA VIN FB COMPARATOR A1VREF 1.25V DRIVER OVERVOLTAGE CC PROTECT RAMP GENERATOR GND 3465A F02 1.2MHz* OSCILLATOR *2.4MHz FOR LT3465A Figure 2. LT3465 Block Diagram 3465afa
Page 7 LT3465/LT3465A APPLICATIO S I FOR ATIO Operation Minimum Output Current The LT3465 uses a constant frequency, current mode The LT3465 can drive a 3-LED string at 1.5m A LED control scheme to provide e...
Page 8 LT3465/LT3465A APPLICATIO S I FOR ATIO skipping using a 1k resistor from FB to GND. The photo VIN = 3.6V 4 LEDs in Figure 3b details circuit operation driving three white LEDs at a 0.2m A load. Peak i...
Page 9 LT3465/LT3465A APPLICATIO S I FOR ATIO Soft-Start (LT3465) inductors, which is usually the case for this application, the peak inrush current can be simplified as follows: The LT3465 has an internal s...
Page 10 LT3465/LT3465A APPLICATIO S I FOR ATIO lower than the frequency of the PWM signal. R1 needs to percent duty cycle sets the LED current to zero, while be much smaller than the internal impedance in the...
Page 11 LT3465/LT3465A APPLICATIO S I FOR ATIO AV ER AG FE ED BA CK OL TA GE (m V) AV ER AG FE ED BA CK OL TA GE (m V) case. The Average FB Voltage vs PWM Duty Cycle curves the nonlinearity in the high PWM fr...
Page 12 LT3465/LT3465A APPLICATIO S I FOR ATIO Open-Circuit Protection resistor R1 should be tied directly to the GND pin and not shared with any other component, ensuring a clean, noise- The LT3465 and LT346...
Page 13 LT3465/LT3465A TYPICAL APPLICATIO S Li-Ion to Two White LEDs VIN = 3.6V 2 LEDs 3V TO 5V SW VOUT VIN CIN COUT LT3465/ LT3465A CTRL FB GND R1 3465A TA01a CIN: TAIYO YUDEN JMK107BJ105 LT3465 COUT: AVX 06...
Page 14 LT3465/LT3465A TYPICAL APPLICATIO Li-Ion to Five White LEDs VIN = 3.6V 5 LEDs 3V TO 5V SW VOUT VIN CIN COUT LT3465/ LT3465A CTRL FB GND R1 LT3465 3465A TA03a LT3465A CIN: TAIYO YUDEN JMK107BJ105 COUT:...
Page 15 LT3465/LT3465A PACKAGE DESCRIPTIO S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 2.90 BSC (NOTE 4) MAX REF 1.22 REF 2.80 BSC 3.85 MAX 1.4 MIN2.62 REF (NOTE 4) PIN ONE ID RECOMMENDE...
Page 16 LT3465/LT3465A TYPICAL APPLICATIO Li-Ion to Six White LEDs VIN = 3.6V 6 LEDs 3V TO 5V SW VOUT VIN CIN COUT LT3465/ LT3465A CTRL FB GND R1 3465A TA04a LT3465 CIN: TAIYO YUDEN JMK107BJ105 LT3465A COUT: ...

Manual Details

Brand Linear
Pages 16
File Size 330.32 KB
Published May 29, 2026
54 views

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Frequently Asked Questions

What is the maximum number of LEDs this device can drive in series?

The LT3465/LT3465A are designed to drive up to six LEDs in series.

Does this converter require an external Schottky diode?

No, it eliminates the need for a ballast resistor and doesn't require an external Schottky diode.

What is the recommended operating temperature range?

The LT3465E/LT3465AE are guaranteed to meet performance in -40°C to 85°C.

How can low input noise be maintained?

Constant frequency switching results in low input current noise and requires only a small output capacitor (0.22µF).

What is the expected efficiency during normal operation?

Typical conversion efficiencies are listed as 81% for LT3465 and 79% for LT3465A.