Datasheet

LM26480
0.47 µF
10 µF
LDO
LDO_FB
Buck
Buck_FB
C1
C2
R1
R2
R1
R2
LM26480
SNVS543I JANUARY 2008REVISED MAY 2013
www.ti.com
Model Type Vendor Voltage Rating Case Size
C2012X5R0J106K Ceramic, X5R TDK 6.3V 0805, (2012)
C1608X5R0J106K Ceramic, X5R TDK 6.3V 0603, (1608)
Feedback Resistors for LDOs
Target V
OUT
(V) Ideal Resistor Values Common R Values Actual V
OUT
W/Com/R (V)
R1 (K) R2 (K) R1 (K) R2 (K)
1 200 200 200 200 1
1.1 240 200 240 200 1.1
1.2 280 200 280 200 1.2
1.3 320 200 324 200 1.31
1.4 360 200 357 200 1.393
1.5 400 200 402 200 1.505
1.6 440 200 442 200 1.605
1.7 480 200 562 232 1.711
1.8 520 200 604 232 1.802
1.9 560 200 562 200 1.905
2 600 200 604 200 2.01
2.1 640 200 715 221 2.118
2.2 680 200 681 200 2.203
2.3 720 200 806 226 2.283
2.4 760 200 845 221 2.412
2.5 800 200 750 187 2.505
2.6 840 200 909 215 2.614
2.7 880 200 1100 249 2.709
2.8 920 200 1150 249 2.809
2.9 960 200 1210 255 2.873
3 1000 200 1000 200 3
3.1 1040 200 1000 191 3.118
3.2 1080 200 1000 187 3.174
3.3 1120 200 1210 215 3.314
3.4 1160 200 1210 210 3.381
3.5 1200 200 1210 200 3.525
The output voltages of the LDOs of the LM26480 are established by the feedback resistor dividers R1 and R2
shown on the application circuit above. The equation for determining V
OUT
is: V
OUT
= V
FB
(R1+R2)/R2, where VFB
is the voltage on the LDOX_FB pin.
The LDO control loop will force the voltage on VFB to be 0.50 V ±3%. The above table shows ideal resistor
values to establish LDO voltages from 1.0V to 3.5V along with common resistor values to establish these
voltages. Common resistors do not always produce the target value, error is given in the final column.
To keep the power consumed by the feedback network low it is recommended that R2 be established as about
200 K. Lesser values of R2 are OK at the users discretion..
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