AAT1157
1MHz 1.2A Buck DC/DC Converter
AAT1157 Dissipation and Junction Temperature Estimate:
IO2 · (RDSON(HS) · VO + RDSON(LS) · (VIN -VO))
PTOTAL
=
=
+ (tsw · F · IO + IQ) · VIN
VIN
1.2A2 · (0.17Ω · 2.5V + 0.16Ω · (4.2V - 2.5V))
+ (20nsec · 1MHz · 1.2A + 275µA) · 4.2V
4.2V
= 341mW
TJ(MAX) = TAMB + ΘJA · PTOTAL = 85°C + 50°C/W · 0.341W = 102°C
Surface Mount Inductors
Value
(µH)
Max DC
DCR
Size (mm)
L x W x H
Manufacturer Part Number
Current (A) (mΩ)
Type
Sumida
Sumida
Sumida
TaiyoYuden
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
MuRata
MuRata
CDRH5D28-2R6
CDRH5D28-3R0
CDRH5D28-4R2
NPO5DB4R7M
2.6
3.0
4.2
4.7
2.2
2.7
3.3
4.1
2.2
3.3
4.7
4.7
2.6
2.4
18
24
31
38
31
43
49
57
59
85
41
25
5.7x5.7x3.0
5.7x5.7x3.0
5.7x5.7x3.0
5.9x6.1x2.8
5.0x5.0x3.0
5.0x5.0x3.0
5.0x5.0x3.0
5.7x5.7x2.0
4.0x4.0x1.8
4.0x4.0x1.8
5.0x5.0x4.7
6.3x6.3x4.7
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Non-Shielded
Shielded
2.2
1.4
CDRH4D28-2R2
CDRH4D28-2R7
CDRH4D28-3R3
CDRH5D18-4R1
CDRH3D16/HP-2R2
CDRH3D16/HP-3R3
LQH55DN4R7M03
LQH66SN4R7M03
2.04
1.6
1.57
1.95
2.3
1.8
2.7
2.2
Surface Mount Capacitors
Value
(µF)
Voltage
(V)
Manufacturer
Part Number
Temp. Co.
Case
MuRata
MuRata
MuRata
GRM21BR60J106ME01L
GRM21BR60J226ME01L
GRM31CR60J106KA01L
10
22
10
6.3
6.3
6.3
X5R
X5R
X5R
0805
0805
1206
12
1157.2005.11.1.4
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
