PRODUCT DATASHEET
AAT1276
SwitchRegTM
Boost Converter with USB Power Switch
5V Output Capacitor
ΔVOUT = 0.05V
IOUT · DMAX
0.3A · 0.46
COUT(MIN)
=
=
= 3.0µF; use 4.7µF 10V MLC
FS · ΔVOUT
800kHz · 0.05V
AAT1276 Losses
2
(IPK2 + IPK · IV + IV ) · DMAX
(0.9A2 + 0.9A · 0.2A + 0.2A2) · 0.46
3
IRMS(ON)
=
=
= 0.4A
3
2
(IPK2 + IPK · IV + IV ) · (1 - DMAX
)
(0.9A2 + 0.9A · 0.2A + 0.2A2) · (1 - 0.46)
3
IRMS(OFF)
=
=
= 0.43A
3
PTOTAL = IRMS(ON)2 · (RDS(ON)IN + RDS(ON)N) + IRMS(OFF)2 · (RDS(ON)IN + RDS(ON)P + RDS(ON)
)
= 0.4A2 · (0.25Ω + 0.3Ω) + 0.422 · (0.25Ω + 0.3Ω + 0.2Ω) = 0.22W
110°C
TJ(MAX) = PTOTAL · θJA + TAMB = 0.22W ·
+ 85°C = 109°C
W
w w w . a n a l o g i c t e c h . c o m
16
1276.2007.11.1.1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
