LTC3444_15 Datasheet, PDF (13/20 Pages) Linear Technology – Micropower Synchronous Buck-Boost DC/DC Converter for WCDMA Applications

U
OPERATIO
Table 1. Shows some typical resistor value combinations
for several V_CONTROL vs V_OUT voltage ranges. One percent
(1%) resistor tolerances were assumed.
Table 1. Typical Resistor Values for V_OUT vs V_CONTROL
V_CONTROL(V)
V_OUT (V)
RESISTANCE (kΩ)
MIN
MAX
MIN MAX R1
R2
R3
0.35
2.4
0.8
4.2 340
271
205
0.35
2.5
0.5
5.0 340
210
162
0.8
2.35
0.8
4.2 340
200
154
0.5
2.5
0.5
4.2 340
249
182
LTC3444
COMPONENT SELECTION
Recommended Component Placement
Figure 6. Shows a recommended component placement.
Traces carrying high current should be made short and
wide. Trace area at FB and V_C pins should be minimized.
Lead lengths to the battery should be kept short. V_OUT and
V_IN ceramic capacitors should be placed close to the IC
pins. Multiple vias should be used between layers.
V_CONTROL
LTC3444
V_IN
1 SHDN
FB 8
2 SW1
V_C 7
3 GND
V_IN 6
4 SW2
V_OUT 5
V_IN
V_OUT
MULTIPLE VIAS
3444 F06
Figure 6. Recommended Component Placement
3444fb
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