LT3498 Просмотр технического описания (PDF) - Linear Technology

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производитель

LT3498

20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN

Linear Technology 

LT3498

PIN FUNCTIONS

VOUT2 (Pin 7): Drain of Output Disconnect PMOS.

Place a bypass capacitor from this pin to GND. See the

Applications Information section.

CAP2 (Pin 8): Output of the OLED Driver. This pin is

connected to the cathode of the internal Schottky diode.

Place a bypass capacitor from this pin to GND.

SW2 (Pin 9): Switch Pin. This is the collector of the in-

ternal NPN power switch. Minimize the metal trace area

connected to this pin to minimize EMI.

VIN (Pin 10): Input Supply Pin. Must be locally by-

passed.

SW1 (Pin 11): Switch Pin. Connect the inductor of the

white LED driver at this pin. Minimize metal trace area at

this pin to minimize EMI.

CAP1 (Pin 12): Output of the White LED Driver. This pin is

connected to the cathode of the internal Schottky. Connect

the output capacitor to this pin and the sense resistor from

this pin to the LED1 pin.

Exposed Pad (Pin 13): Ground. The Exposed Pad must

be soldered to the PCB.

BLOCK DIAGRAM

CAP2

8

C2

0.47μF

C3

10μF

VOUT2

7

DISCONNECT

CONTROL

RFB2

2.21MΩ

SHUNT

CONTROL

L2

10μF

9

SW2

CIN

4.7μF

10

VIN

START-UP

CONTROL

DRIVER

Q2

SWITCH

CONTROL

VREF

A5

GND2

4

182kΩ

FB2

CTRL2

65

L1

15μF

COMPARATOR

–

11

SW1

CAP1

12

A2

+

R

Q

S

DRIVER

Q1

OVERVOLTAGE

PROTECTION

∑

RAMP

GENERATOR

A3

R

RSENSE1

10Ω

C1

1μF

2.3MHz

OSCILLATOR

A1

RC

CC

A4

LED1

1

CTRL1 GND1

2

3

3498 BD

3498fa

7

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