AATIAN19 Datasheet, PDF (6/6 Pages) SiGe Semiconductor, Inc. – AAT1145 EVAL:1.5 MHz, 1.2A Step-Down

EV136
AAT1145 EVAL:1.5 MHz, 1.2A Step-Down
DC/DC Converter with Low Quiescent Current
Component
U1
L1
C1
C2
C3
R1
R2
Part Number
AAT1145
CDRH2D14NP-2R2NC
GRM21BR61C106K
GRM21BR60J226M
C1005COG1H220JT000P
Chip Resistor
Chip Resistor
Description
1.5 MHz,1.2A Synchronous Step-Down Converter
Inductor 2.2uH 1.5A SMD
Cap Ceramic 10uF 0805 X5R 16V10%
Cap Ceramic 10uF 0805 X5R 6.3V 20%
Cap Ceramic 22pF 0402 C0G 50V 5%
Res 316KΩ 1/16W 1% 0402 SMD
Res 634kΩ 1/16W 1% 0402 SMD
Manufacturer
Analogic Tech
Sumida
Murata
Murata
TDK
Any
Any
Table 2: AAT1145 EVAL Bill of Materials.
Output Voltage
There are two versions of the AAT1145, a fixed 1.8V output (AAT1145IDE-1.8) without feedback resistors R1 and
R2, and an adjustable version that is set to 0.6V. To adjust the output from the 0.6V default, set R1 to 316kΩ a nd
select R2 according to Table 3. A smaller value resistor divider can be used for better noise immunity, values are
shown in columns 2 and 5. A larger value resistor divider is used as default for lower current consumption in
columns 3 and 6. Standard 1% resistor values are substituted for calculated values.
V_OUT (V)
0.6
0.8
0.9
1.0
1.1
1.2
1.3
R1=59kΩ
R2 (kΩ)
19.6
29.4
39.2
49.9
59.0
68.1
78.7
R1=316kΩ
R2 (kΩ)
0(short)
105
158
210
261
316
365
V_OUT (V)
1.4
1.5
1.8
1.85
2.5
3.0
3.3
R1=59kΩ
R2 (kΩ)
88.7
118
124
137
187
294
267
Table 3: Resistor Selection for Adjustable Output Voltage.
R1=316kΩ
R2 (kΩ)
422
475
634
655
1000
1270
1430
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EV-136.2007.08.1.1