LP8553

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SNVS701B – SEPTEMBER 2011 – REVISED JANUARY 2014

LED Driver Electrical Characteristics (continued)

Symbol

Parameter

Condition

Min

Typ

Max

Units

fLED = 5 kHz, fPLL = 5 MHz

10

fLED = 10 kHz, fPLL = 5 MHz

9

fLED = 20 kHz, fPLL = 5 MHz

8

PWM Output Resolution

PWMRES

bits

(2)

fLED = 5 kHz, fPLL = 40 MHz

13

fLED = 10 kHz, fPLL = 40 MHz

12

fLED = 20 kHz, fPLL = 40 MHz

11

PWM_FREQ[4:0] = 00000b

600

PLL clock 5 MHz

LED Switching Frequency

fLED

Hz

(2)

PWM_FREQ[4:0] = 11111b

19.2k

PLL clock 5 MHz

Output current set to 20 mA

105

220

VSAT

Saturation Voltage (3)

mV

Output current set to 30 mA

160

290

(2)

PWM output resolution and frequency depend on the PLL settings. Please see PWM Frequency Setting for full description

(3)

Saturation voltage is defined as the voltage when the LED current has dropped 10% from the value measured at 1V.

PWM Interface Characteristics

Symbol

Parameter

Condition

Min

Typ

Max

Units

fPWM

PWM Frequency Range

0.1

25

kHz

tMIN_ON

Minimum Pulse ON time

1

μs

tMIN_OFF

Minimum Pulse OFF time

1

Turn on delay from standby to

PWM input active, EN pin rise from low to

tSTARTUP

6

ms

backlight on

high

PWM input low time for turn off, slope

TSTBY

Turn Off Delay

50

ms

disabled

fIN < 9.0 kHz

10

fIN < 4.5 kHz

11

PWMRES

PWM Input Resolution

bits

fIN < 2.2 kHz

12

fIN < 1.1 kHz

13

Under-Voltage Protection

Symbol

Parameter

Condition

Min

Typ

Max

Units

UVLO[1:0] = 00

Disabled

UVLO[1:0] = 01, falling

2.55

2.70

2.94

UVLO[1:0] = 01, rising

2.62

2.76

3.00

VUVLO

VIN UVLO Threshold Voltage

UVLO[1:0] = 10, falling

5.11

5.40

5.68

V

UVLO[1:0] = 10, rising

5.38

5.70

5.98

UVLO[1:0] = 11, falling

7.75

8.10

8.45

UVLO[1:0] = 11, rising

8.36

8.73

9.20

Logic Interface Characteristics

Symbol

Parameter

Condition

Min

Typ

Max

Units

Logic Input EN

VIL

Input Low Level

0.4

V

VIH

Input High Level

1.2

V

II

Input Current

−1.0

1.0

μA

Logic Input VSYNC

VIL

Input Low Level

0.4

V

VIH

Input High Level

2.2

V

II

Input Current

−1.0

1.0

μA

fVSYNC

Frequency Range

58

60

55000

Hz

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