LTC3589-2_15 Datasheet, PDF (27/50 Pages) Linear Technology – 8-Output Regulator with Sequencing and I2C

LTC3589/LTC3589-1/
LTC3589-2
OPERATION
Inductor Selection
Inductor selection criteria for the buck-boost are similar to
those given for the step-down switching regulators. The
buck-boost converter is designed to work with inductors
in the range of 1µH to 3.3µH. For most applications use a
1.5µH inductor. Choose an inductor with a DC current rating
at least two times larger than the maximum load current to
ensure that the inductor does not saturate during normal
operation. If output short-circuit is a possible condition,
the inductor should be rated to handle the maximum peak
current specified for the buck-boost converter. Table 11
shows several inductors that work well with the LTC3589
buck-boost regulator.
Table 10. Buck-Boost Command Register Settings
COMMAND
VALUE SETTING
REGISTER[BIT]
SCR1[6]
0* Continuous Mode
1 Burst Mode Operation
OVEN[3]
0* Disable
1 Enable
SCR2[3]
LTC3589/
LTC3589-1
0* Wait for Output Below 300mV Before Enable
1 Enable Immediately
SCR2[3]
LTC3589-2
0* Enable Immediately
1 Wait for Output Below 300mV Before Enable
* Denotes Default Power-On Value
Table 11. Inductors for Buck-Boost Switching Regulator
MANUFACTURERS
PART
NUMBER
VALUE
(µH) DCR (Ω)
Coilcraft
XFL4020-152ME
XFL4020-222ME
XFL4020-332ME
LPS6225-332ML
LPS6225-472ML
1.5
0.014
2.2
0.021
3.3
0.035
3.3
0.055
4.7
0.065
Cooper
SD14-1R5-R
SD14-2R0-R
SD14-2R5-R
SD14-3R2-R
SD25-3R3-R
1.5
0.039
2.0
0.045
2.5
0.060
3.2
0.066
3.3
0.038
Sumida
CDRH5D16NP-3R3N
3.3
0.045
CDRH5D16NP-4R7N
4.7
0.064
TDK
VLF5014ST-2R2N2R3
2.2
0.073
VLCF5020T-2R7N2R2-1 2.7
0.083
VLCF5020T-3R3N2R0-1 3.3
0.096
TOKO
1124BS-1R8N
1124BS-3R3N
1.8
0.056
3.3
0.074
Tokin
H-DI-0520-3R3
H-DI-0630-3R8
3.3
0.062
3.8
0.040
Wurth
744052002
7440420027
744053003
7440530047
2.5
0.030
2.7
0.047
3.0
0.024
4.7
0.030
MAX DC
CURRENT (A)
4.10
3.10
2.70
3.50
3.00
2.91
2.56
2.29
2.00
2.21
2.60
2.05
2.3
2.2
2
2.70
2.10
2.00
2.00
2.4
2.2
2.8
2.4
SIZE (mm) W × L × H
4.0 × 4.0 × 2.1
4.0 × 4.0 × 2.1
4.0 × 4.0 × 2.1
6.0 × 6.0 × 2.0
6.0 × 6.0 × 2.0
5.2 × 5.2 × 1.45
5.2 × 5.2 × 1.45
5.2 × 5.2 × 1.45
5.2 × 5.2 × 1.45
4.8 × 4.8 × 2.5
5.6 × 5.6 × 1.8
5.6 × 5.6 × 1.8
4.8 × 4.6 × 1.4
5.0 × 5.0 × 2.0
5.0 × 5.0 × 2.0
4.5 × 4.7 × 1.8
4.5 × 4.7 × 1.8
5.3 × 5.3 × 2.0
6.3 × 6.3 × 3.0
5.8 × 5.8 × 1.8
4.8 × 4.8 × 1.8
5.8 × 5.8 × 2.8
5.8 × 5.8 × 2.8
For more information www.linear.com/LTC3589
3589fg
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