AAT1138 Datasheet, PDF (17/21 Pages) Skyworks Solutions Inc. – 2A Step-Down Converter with Adjustable Input Current Limit

DATA SHEET
AAT1138
2A Step-Down Converter with Adjustable Input Current Limit
Manufacturer
Murata
AVX
KEMET
Part Number
GRM21BR60J226ME39
TAJD337M006R
TPSD337M006R0150
TAJD477M006R
TPSD477M006R0150
TAJD687M006R
TPSD687M006R0100
T491D337M006AT
T495D337M006ATE100
T491D477M006AT
T495D477M006ATE150
T491D687M006ZT
T495D687M006ZTE150
Value
22μF
330μF
330μF
470μF
470μF
680μF
680μF
330μF
330μF
470μF
470μF
680μF
680μF
Voltage
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.3
Tolerance
20%
20%
20%
20%
20%
20%
20%
20%
20%
20%
20%
20%
20%
Temp. Co.
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
ESR (mΩ)
26
400
150
400
150
500
100
400
100
400
150
500
150
Table 2: Surface Mount Capacitors.
Case
0805
7343
7343
7343
7343
7343
7343
7343
7343
7343
7343
7343
7343
Manufacturer
Sumida
Coiltronics
Part Number
CDRH5D16
CDRH5D16
CDRH8D28
SD53
SD53
SD53
Inductance
(μH)
2.2
3.3
4.7
2.0
3.3
4.7
Saturation
Current (A)
3.0
2.6
3.4
3.3
2.6
2.1
DCR Typ.
(mΩ)
28.7
35.6
19
23
29
39
Table 3: Surface Mount Inductors.
Size (mm)
LxWxH
5.8x5.8x1.8
5.8x5.8x1.8
8.3x8.3x3.0
5.2x5.2x3.0
5.2x5.2x3.0
5.2x5.2x3.0
Type
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Adjustable Output Resistor Selection
For applications requiring an adjustable output voltage,
the 0.6V version can be externally programmed. Resistors
R1 and R2 of Figure 3 program the output to regulate at
a voltage higher than 0.6V. To limit the bias current
required for the external feedback resistor string while
maintaining good noise immunity, the minimum sug-
gested value for R2 is 59kΩ and the R1+R2 should be
less than 1.5MΩ. The external resistor sets the output
voltage according to the following equation:
R1
V_OUT = 0.6 · 1 + _R2
R1 =
V_OUT
0.6
-1
· R2
Table 4 summarizes the standard 1% metal film resistor
values for various output voltages with R2 set to 59kΩ.
V_OUT (V)
1.0
1.2
1.5
1.8
2.0
2.5
3.3
3.6
3.8
4.2
R2 = 59kΩ
R1 (kΩ)
39.2
59.0
88.7
118
137
187
267
294
316
357
Table 4: Resistor Selections for
Different Output Voltage Settings.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201978B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 15, 2013
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