Datasheet LT1946A (Linear Technology) - 9
| Fabricante | Linear Technology |
| Descripción | 2.7MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start |
| Páginas / Página | 12 / 9 — APPLICATIO S I FOR ATIO. Setting Output Voltage. Layout Hints. Figure 5. … |
| Revisión | S |
| Formato / tamaño de archivo | PDF / 326 Kb |
| Idioma del documento | Inglés |
APPLICATIO S I FOR ATIO. Setting Output Voltage. Layout Hints. Figure 5. Gain and Phase Plots of Figure 1 Circuit
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LT1946A
U U W U APPLICATIO S I FOR ATIO
100
Setting Output Voltage
To set the output voltage, select the values of R1 and R2 (see Figure 1) according to the following equation: 50 V GAIN (f) R = R OUT 1 2 – 1 0 1 2 V 5 . A good range for R2 is from 5k to 30k. –50
Layout Hints
100 1k 10k 100k 1M FREQUENCY (Hz) 1946A FO5a The high speed operation of the LT1946A demands careful attention to board layout. You will not get advertised 0 performance with careless layouts. Figure 6 shows the recommended component placement for a boost con- verter. –100 GROUND PLANE PHASE (f) CSS C1 58° + CC VIN –180 RC –200 1 8 100 1k 10k 100k 1M R1 2 7 FREQUENCY (Hz) L1 LT1946A 1946A FO5b R2 3 6 SHUTDOWN 4 5
Figure 5. Gain and Phase Plots of Figure 1 Circuit
MULTIPLE VIAs
Diode Selection
C2 GND A Schottky diode is recommended for use with the LT1946A. VOUT The Microsemi UPS120 is a very good choice. Where the input to output voltage differential exceeds 20V, use the UPS140 (a 40V diode). These diodes are rated to handle an 19949 F04 NOTE: DIRECT HIGH CURRENT PATHS USING WIDE PC TRACES. MINIMIZE TRACE AREA AT average forward current of 1A. For applications where the PIN 1(VC) AND PIN 2(FB). USE MULTIPLE VIAS TO TIE PIN 4 COPPER TO GROUND PLANE. USE average forward current of the diode is less than 0.5A, an VIAS AT ONE LOCATION ONLY TO AVOID INTRODUCING SWITCHING CURRENTS INTO THE GROUND PLANE. ON Semiconductor MBR0520 diode can be used.
Figure 6. Recommended Component Placement for Boost Converter
sn1946a 1946afs 9
U U W U APPLICATIO S I FOR ATIO
100
Setting Output Voltage
To set the output voltage, select the values of R1 and R2 (see Figure 1) according to the following equation: 50 V GAIN (f) R = R OUT 1 2 – 1 0 1 2 V 5 . A good range for R2 is from 5k to 30k. –50
Layout Hints
100 1k 10k 100k 1M FREQUENCY (Hz) 1946A FO5a The high speed operation of the LT1946A demands careful attention to board layout. You will not get advertised 0 performance with careless layouts. Figure 6 shows the recommended component placement for a boost con- verter. –100 GROUND PLANE PHASE (f) CSS C1 58° + CC VIN –180 RC –200 1 8 100 1k 10k 100k 1M R1 2 7 FREQUENCY (Hz) L1 LT1946A 1946A FO5b R2 3 6 SHUTDOWN 4 5
Figure 5. Gain and Phase Plots of Figure 1 Circuit
MULTIPLE VIAs
Diode Selection
C2 GND A Schottky diode is recommended for use with the LT1946A. VOUT The Microsemi UPS120 is a very good choice. Where the input to output voltage differential exceeds 20V, use the UPS140 (a 40V diode). These diodes are rated to handle an 19949 F04 NOTE: DIRECT HIGH CURRENT PATHS USING WIDE PC TRACES. MINIMIZE TRACE AREA AT average forward current of 1A. For applications where the PIN 1(VC) AND PIN 2(FB). USE MULTIPLE VIAS TO TIE PIN 4 COPPER TO GROUND PLANE. USE average forward current of the diode is less than 0.5A, an VIAS AT ONE LOCATION ONLY TO AVOID INTRODUCING SWITCHING CURRENTS INTO THE GROUND PLANE. ON Semiconductor MBR0520 diode can be used.
Figure 6. Recommended Component Placement for Boost Converter
sn1946a 1946afs 9