AAT1236

High Efficiency White LED Drivers

for Backlight and Keypad

2

1236.2007.02.1.1

Pin Descriptions

Pin Configuration

TDFN34-16

(Top View)

EN

B1

B2

VIN

OV

3

RSET

IN

GND

A2

A3

AGND

LIN

A1

SCL

SDA

SW

4

5

1

2

6

7

8

14

13

12

16

15

11

10

9

Pin #

Symbol

Function

1

VIN

Input supply for the converter. Connect a 2.2µF or larger ceramic capacitor from VIN to GND.

2

OV

Boost output over voltage detect pin. Use resistor divider to set the circuit's external over-

voltage protection. See Applications Information for details.

3

EN

Enable pin.

4

B1

Backlight current sink 1. Connect the cathode of the last LED in the string to B1.

5

B2

Backlight current sink 2. Connect the cathode of the last LED in the string to B2.

6

RSET

LED current set resistor. A 22.6k

Ω resistor from RSET to AGND sets the maximum LED cur-

rent in A1-A3 and B1-B2 to 20mA.

7

IN

Input bias supply for the internal circuitry. Connect IN to VIN directly at the AAT1236.

8

GND

Power ground for the boost converter. Connect GND to AGND at a single point as close to

the AAT1236 as practical.

9

SW

Boost converter switching node. A 2.2µH inductor, connected between SW and LIN, sets the

boost converter's switching frequency.

10

SDA

11

SCL

12

AGND

Ground pin. Connect AGND to GND at a single point as close to the AAT1236 as practical.

13

A3

Auxiliary current sink 3. Connect the cathode of the last LED in the string to A3.

14

A2

Auxiliary current sink 2. Connect the cathode of the last LED in the string to A2.

15

A1

Auxiliary current sink 1. Connect the cathode of the last LED in the string to A1.

16

LIN

Switched power input. Connect LIN to the external power inductor.

EP

Exposed paddle (bottom). Connected internally to SW. Connect to SW or leave floating.