RT4539A

Copyright © 2022 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation

www.richtek.com

DS4539A-01

December 2022

8

Parameter

Symbol

Test Conditions

Min

Typ

Max Unit

LED Current Accuracy

IFB_ACC_100 PWM Duty = 100%, IFBx = 20mA,

PWM frequency = 1kHz

−

3

--

3

%

IFB_ACC_5

PWM Duty = 5%, IFBx = 20mA,

PWM frequency = 1kHz

−

5

--

5

IFB_ACC_1

PWM Duty = 1%, IFBx = 20mA,

PWM frequency = 1kHz

−

15

--

15

LED Current Matching

IFB_MAT_100 PWM Duty = 100%, IFBx = 20mA,

PWM frequency = 1kHz

−

2

--

2

%

IFB_MAT_5

PWM Duty = 5%, IFBx = 20mA,

PWM frequency = 1kHz

−5

--

5

IFB_MAT_1

PWM Duty = 1%, IFBx = 20mA,

PWM frequency = 1kHz

−

10

--

10

DC Dimming Resolution

Sres_2k

PWM Freq < 2kHz, 0x07h[1:

0]=B00, 0x00h[2: 0]=B100.

--

4095

--

Steps

Sres_4k

PWM Freq = 2k to 4kHz, 0x07h[1:

0]=B00, 0x00h[2: 0]=B100.

--

2048

--

Steps

Sres_8k

PWM Freq = 4k to 8kHz, 0x07h[1:

0] = B00, 0x00h[2: 0] = B100.

--

1024

--

Steps

Sres_20k

PWM Freq = 8k to 20kHz, 0x07h[1:

0]=B00, 0x00h[2: 0] = B100

--

512

--

Steps

Light Bar Open Threshold

VFB_OPEN

0.01

0.1

0.34

V

Light Bar Short Threshold

VLED_SHORT

3.9

5.6

7.3

V

PWM Minimum On Time

DPWM_MIN

PWM dimming frequency = 20kHz

--

400

--

ns

Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These

are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in

the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect

device reliability.

Note 2. θJA is measured under natural convection (still air) at TA = 25°C with the component mounted on a high

effective-thermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard. θJC is measured

at the exposed pad of the package.

Note 3. Devices are ESD sensitive. Handling precautions are recommended.

Note 4. The device is not guaranteed to function outside its operating conditions.

Note 5. VIN voltage has to rise 2.8V level, I2C can write to MTP.

Note 6. Operating conditions are recommended to be less than the maximum duty cycle

If dimming control selected PWM mode or PWM-26KHz mode, the conversion ratio is recommended to be less than

0.75, as following equation: (1-(Vin/Vout)) < 0.75.

Note 7. Operating conditions is recommended to be less than OCP level * 90%.