4

NXP Semiconductors

34845

3

Pin connections

3.1

Pinout diagram

Figure 3. 34845 pin connections

3.2

Pin definitions

Table 2. 34845 Pin definitions

Pin number

Pin name

Definition

1

VIN

Main voltage supply Input. IC Power input supply voltage, is used internally to produce internal voltage regulation for logic

functioning, and also as an input voltage for the boost regulator.

2

PGNDB

Power ground. This is the ground pin for the internal Boost FET.

3

SWB

Boost switch node connection B. Switching node of boost converter.

4

SWA

Boost switch node connection A. Switching node of boost converter.

5

PGNDA

Power ground. This is the ground pin for the internal Boost FET.

6

EN

Enable pin (active high, internal pull-down).

7 - 12

CH1 - CH6

LED string connections 1 to 6. LED current drivers. Each line has the capability of driving up to 30 mA.

13, 19, 21

GND

Ground Reference for all internal circuits other than the Boost FET. The Exposed Pad (EP) should be used for thermal

heat dissipation.

14

FAIL

Fault detected pin (open drain):

• No Failure = Low-impedance pull-down

• Failure = High-impedance

When a fault situation is detected, this pin goes into high-impedance.

15

ISET

LED current setting. The maximum current is set using a resistor from this pin to GND.

16

PWM

External PWM control signal.

17

COMP

Boost compensation component connection. This passive pin is used to compensate the boost converter. Add a

capacitor and a resistor in series to GND to stabilize the system as well as a shunt capacitor.

18

WAKE

Low power consumption mode for single wire control. This is achieved by connecting the WAKE and PWM pins together

and grounding the ENABLE (EN) pin.

20

VDC1

2.5 V internal voltage decoupling. This pin is for internal use only, and not to be used for other purposes. A capacitor of

2.2

μF should be connected between this pin and ground.

22

OVP

External boost overvoltage setting. Requires a resistor divider from VOUT to GND. If no external OVP setting is desired,

this pin should be grounded.

VIN

PGNDB

SWB

SWA

PGNDA

GND

EN

WAKE

ISET

FAIL

COMP

PWM

24

17

18

19

20

21

22

23

1

8

7

6

5

4

3

2

16

910

11

12

13

14

15

EP GND

TRANSPARENT

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