LTC3775 View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC3775 Datasheet PDF : 34 Pages
| |||
LTC3775
APPLICATIONS INFORMATION
The worst-case peak inductor current based on a sense
resistor tolerance of ±1% is
IL(SAT)
110μA • 732
2.97m
=
27.1A
The input RMS current is highest at VIN(MIN) = 5V and
IOUT(MAX) = 15A:
IRMS ≈ 15A
1.2V(5V – 1.2V)
= 6.4A
5V
CIN is chosen for an RMS current rating of >6.4A at 85°C.
For the output capacitor, two low ESR OS-CON capacitors
(470μF/5mΩ each) are used to minimize output voltage
changes due to inductor current ripple and load steps.
The ripple voltage will be:
VOUT(RIPPLE)
=
6.4A
•
0.005
2
+
8
•
1
500kHz •
470μF
•
2
= 17.7mV
However, a 0A to 15A load step will cause an output volt-
age change of at least:
ΔVOUT(STEP) = (15A)(0.0025Ω) = 37.5mV
3775fa
27
Share Link: 