UBA3070_2

© NXP B.V. 2008. All rights reserved.

Product data sheet

Rev. 02 — 2 December 2008

6 of 13

NXP Semiconductors

UBA3070

LED backlight driver IC

below approximately 0.5 V. If the voltage on pin SENSE exceeds 0.5 V, the soft start

switched off, see Figure 4.

7.8 Overtemperature protection

An accurate temperature protection is provided in the UBA3070. When the junction

temperature exceeds the thermal shutdown temperature of typically 140

°C the converter

will stop switching.

7.9 Driver

The driver circuit to the gate of the power FET has a current sourcing capability of 135 mA

typical and a current sinking capability of 560 mA typical. This permits fast turn-on and

turn-off of the FET for efficient operation. A low driver source current has been chosen to

limit the

driver circuit to the gate of the power MOSFET has a current sourcing capability of

135 mA typical and a current sink capability of 560 mA typical. This permits fast turn-on

and turn-off of the power MOSFET for efficient operation.

8.

Limiting values

Fig 4.

Soft start-up

014aaa254

Css

Rss

SENSE

Rsense

Istartup(soft)

Vocp

start-up

6

0.5 V

Table 3.

Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).[1]

Symbol

Parameter

Conditions

Min

Max

Unit[1]

Voltages

supply voltage

current limited

−0.4

+20

V

voltage on pin PWM

−0.4

+5

V

voltage on pin MASK

current limited

−0.4

-

V

voltage on pin SENSE

current limited

−0.4

-

V

voltage on pin DRAIN

−0.4

+650

V

Currents

current on pin PWM

-

5

mA