AAT1121
1.5MHz, 250mA Step-Down Converter
1
Ω
Ω
Output Voltage
VOUT (V)
R2 = 59k
R2 = 221k
Ω
Ω
R1 (k )
R1 (k )
L1 (μH)
0.62
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
1.85
2.0
2.5
3.3
—
—
75
1.5
1.5
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
113
150
187
221
261
301
332
442
464
523
715
1000
1.5
1.5
1.5
1.5
1.5
2.2
2.7
3.0/3.3
3.0/3.3
3.0/3.3
3.9/4.2
5.6
124
137
187
267
Table 3: Evaluation Board Component Values.
Inductance
Max DC
Current (mA)
DCR
(mΩ)
Size (mm)
LxWxH
Manufacturer
Part Number
(μH)
Type
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
FDK
CDRH2D09-1R5
CDRH2D09-2R2
CDRH2D09-2R5
CDRH2D09-3R0
CDRH2D09-3R9
CDRH2D09-4R7
CDRH2D09-5R6
CDRH2D11-1R5
CDRH2D11-2R2
CDRH2D11-3R3
CDRH2D11-4R7
NR3010
1.5
2.2
2.5
3
730
600
530
470
450
410
370
900
780
600
500
1200
1100
870
750
1200
1100
1000
900
88
115
135
150
180
230
260
54
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.2x3.2x1.2
3.2x3.2x1.2
3.2x3.2x1.2
3.2x3.2x1.2
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.2x2.6x0.8
3.2x2.6x0.8
3.2x2.6x0.8
3.2x2.6x0.8
Shielded
Shielded
Shielded
Shielded
3.9
4.7
5.6
1.5
2.2
3.3
4.7
1.5
2.2
3.3
4.7
1.5
2.2
3
Shielded
Shielded
Shielded
Shielded
78
Shielded
98
Shielded
135
80
Shielded
Shielded
NR3010
95
Shielded
NR3010
140
190
90
Shielded
NR3010
Shielded
MIPWT3226D-1R5
MIPWT3226D-2R2
MIPWT3226D-3R0
MIPWT3226D-4R2
Chip shielded
Chip shielded
Chip shielded
Chip shielded
FDK
100
120
140
FDK
FDK
4.2
Table 4: Suggested Inductors and Suppliers.
1. For reduced quiescent current, R2 = 221kΩ.
2. R2 is opened, R1 is shorted.
1121.2006.04.1.0
17
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