6.3 Recommended Operating Conditions
|
|
MIN |
NOM |
MAX |
UNIT |
VIN |
Input voltage |
2.9 |
|
18 |
V |
VO |
Output voltage |
VIN |
|
38 |
V |
L |
Inductor(1) |
4.7 |
|
47 |
μH |
CI |
Input capacitor |
4.7 |
|
— |
μF |
CO |
Output capacitor |
4.7 |
|
10 |
μF |
Cdim |
Analog dimming capacitor(2) |
0.1 |
|
— |
μF |
PWM |
PWM dimming frequency(3) |
200 |
|
1000 |
Hz |
Analog dimming frequency(3) |
200 |
|
40 000 |
TA |
Operating ambient temperature |
–40 |
|
85 |
°C |
TJ |
Operating junction temperature |
–40 |
|
125 |
°C |
(1) The inductance value depends on the switching frequency and end applications. While larger values may be used, values between 4.7 μH and 47 μH have been successfully tested in various applications. Refer to
Selecting the Inductor for details.
(2) The Cdim with the internal resistor (25 kΩ typical) forms a RC filter that generates the FB reference voltage according to the duty cycle of PWM signal. To optimize the RC filter and reduce the output ripple, the value larger than 0.1 μF of Cdim is recommended.
(3) When analog dimming, the maximum PWM frequency is set by on the RC filter to optimize the output ripple. When PWM dimming, the PWM frequency is set by the device loop response.