AAT2153 Datasheet, PDF (16/17 Pages) Advanced Analogic Technologies – 2.5A Low Noise Step-Down Converter

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PRODUCT DATASHEET
AAT2153
2.5A Low Noise Step-Down Converter
AAT2153 Losses
Total losses can be estimated by calculating the dropout (V_IN = V_O) losses where the power MOSFET R_DS(ON) will be at
the maximum value. All values assume an 85°C ambient temperature and a 120°C junction temperature with the QFN
50°C/W package.
P_LOSS = I_O2 · R_DS(ON)H = 2.5A² · 0.12Ω = 750mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (50°C/W) · 750mW = 122.5°C
The total losses are also investigated at the nominal lithium-ion battery voltage (3.6V). The simplified version of the
R_DS(ON) losses assumes that the N-channel and P-channel R_DS(ON) are equal.
P_TOTAL = I_O2 · R_DS(ON) + [(t_sw · F_S · I_O + I_Q) · V_IN]
= 2.5A² · 120mΩ + [(5ns · 1.4MHz · 2.5A + 70µA) · 3.6V] = 813mW
T_J(MAX) = T_AMB + Θ_JA · P_LOSS = 85°C + (50°C/W) · 813mW = 125.6°C
V_OUT (V)
3.3
3.3
2.5
1.8
1.5
1.2
1.0
0.8
0.6
Inductance
(μH)
3.0
3.3
2.5
1.8
1.4
1.2
1.0
0.9
0.6
Part Number
CDRH5D28RHPNP
7447789003
CDRH5D28NP
CDRH4D28
CDRH5D14HPNP
CDRH4D28
CDRH5D14NP
CDRH5D14HPNP
CDRH5D14HPNP
Manufacturer
Sumida
Wurth
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Size (mm)
6x6x3
7x7x3
6x6x3
6x6x2
6x6x1.5
5x5x3
6x6x1.5
6x6x1.5
6x6x1.5
Rated Current
(A)
2.4
3.42
2.6
2.5
2.8
2.56
3.6
3.5
3.9
Table 2: Surface Mount Inductors.
I_SAT
(A)
4.7
4.2
5.0
3.9
3.3
5.0
6.0
DCR
(mΩ)
31.8
30.0
24.0
46.0
40.3
23.6
25.6
27.5
22.5
Manufacturer
Murata
Murata
Murata
Part Number
GRM21BR60J106KE19
GRM21BR60J226ME39
GRM31CR60J226KE19
Value
10μF
22μF
22μF
Voltage
6.3V
6.3V
6.3V
Table 3: Surface Mount Capacitors.
Temp. Co.
X5R
X5R
X5R
Case
0805
0805
1206
16
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2153.2008.09.1.0