AAT1147 AAT, AAT1147 Datasheet - Page 16

• Manufacturer Part Number: AAT1147
• Description: Step-Down Converter
• Manufacturer: AAT

Input Capacitor
Input Ripple V
AAT1147 Losses
C
I
P = esr · I
P
T
16
RMS
J(MAX)
TOTAL
IN
=
=
⎛
⎝
=
+ (t
=
+ (5ns · 1.4MHz · 0.4A + 70μA) · 4.2V = 126mW
= T
I
2
O
V
I
I
0.4
O
PP
O
= 0.2Arms
RMS
sw
AMB
2
· (R
· F
2
- ESR · 4 · F
2
· (0.725 Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
+ Θ
PP
= 5mΩ · (0.2A)
S
DSON(H)
· I
= 25mV
1
JA
O
⎞
⎠
· P
+ I
· V
LOSS
Q
) · V
O
S
V
+ R
= 85°C + (160°C/W) · 126mW = 105.1°C
=
IN
IN
2
4.2V
DSON(L)
⎛
⎝
= 0.2mW
25mV
0.4A
· [V
- 5mΩ · 4 · 1.4MHz
IN
-V
O
1
] )
⎞
⎠
High Efficiency, Low Noise, Fast Transient
= 3.11μF; use 4.7μF
400mA Step-Down Converter
1147.2006.05.1.0