LM3152,LMZ14201,LMZ14202,LMZ14203 Literature Number: JAJA420
POWER designer Expert tips, tricks, and techniques for powerful designs No. 129 national.com/powerdesigner By Rich Rosen, Field Applications Engineer DC/DC Figure 1 DC/DC PWM 2 1 f (BOM) / FET FET WEBENCH V IN I SWITCH 1 V IN I SWITCH 1 I LOAD I LOAD V SW V OUT V OUT I SWITCH 2 I SWITCH 2 Figure 1. DC/DC
SIMPLE SWITCHER SIMPLE SWITCHER EMI V IN LMZ14203 V OUT EN SS GND ADJ V OUT 2010, National Semiconductor Corporation. National Semiconductor,, and SIMPLE SWITCHER are registered trademarks. All rights reserved. EMI LMZ EMI CISPR22 Class B national.com / switcher
POWER designer 2 / RF IC 2: VIN = 24V 2 WEBENCH LM3152 3.3V SIMPLE SWITCHER LMZ14203 SIMPLE SWITCHER WEBENCH national.com/webench BOM PCB BOM Figure 2 LM3152 3.3V WEBENCH 30 CAD Vout = 3.3V = 3.0A = 55 C 24V CIN 1 µf + Cbyp 100n Css 15 nf 3 2 6 4 7 8 1 U1 EN VIN SS FB NC NC VCC 11 HG 12 BST 10 SW 13 LG 15 DAP 5 SGND SGND 9 14 SGND Cbst 470 µf 2 3 1 M1 2 3 1 M2 L1 39 µh COUT 47 µf + 3.3V Cbst Cbyp C IN C OUT C SS C VCC L1 M1 470 nf/16v 100 nf/50v 1 µf/50v 47 µf/16v 15 nf/50v 2.2 µf/10v 10 µh/4a 80V/30 m $ 0.02 $ 0.05 $ 0.41 $ 0.02 $ 0.54 $ 0.39 Cvcc 2.2 µf M2 U1 80V/30 m LM3152MH-3.3 $ 0.39 $ 2.30 0V 0V BOM $ 4.14 Figure 2. LM3152 3.3V national.com/powerdesigner 3
POWER designer 24V C IN + 10 F Rent 68.1k Renb 11.8k Ron 49.9k 1 3 5 2 C SS 10 nf U1 VIN EN SS RON VOUT FB GND EP 7 6 4 8 Rfbt 3.32k Rfbb 1.07k Cf 22 nf C OUT 47 F + 3.3V Cf C IN C OUT C SS Renb Rent Rfbb Rfbt 22 nf/50v 10 µf/50v 47 µf/6.3v 10 nf/50v 11.8 K 68.1 K 1.07 K 3.32 K $ 0.43 $ 0.18 $ 0.02 0V 0V Ron U1 49.9 K LMZ14203 $ 9.50 BOM $ 10.19 Figure 3. LMZ14203 Figure 3 LMZ14203 WEBENCH FET BOM 1,000 500 WEBENCH 1,000 PCB Figure 4 PCB CAD PCB 1 Figure 4. 4
POWER designer WEBENCH 50% 526 mm 2 / 0.815 in 2 1.22 in 2 1.4 in 2 374 mm 2 / 0.58 in 2 0.87 in 2 0.902 in 2 Figure 5. LMZ Figure 4 LMZ14203 WEBENCH ( 24V3.3V3A 55 C1.5 ) WEBENCH PCBmm 2 1mm Figure 5 50% Figure 6 7 1 M1 FET M2 FET 90 C Efficiency (%) 24V V IN 3.3V V OUT 3A88% IC 86 C 810 C 77 C 73 C 68 C 64 C 59 C 55 C Figure 6. WEBENCH national.com/powerdesigner 5
POWER designer Tj max = 87 C 90 C 86 C Efficiency (%) 24V V IN 3.3V V OUT 3A80% 810 C 77 C 73 C 68 C 64 C I OUT (A) Figure 7. WEBENCH 59 C 55 C 1 FET 55 C (Tj) 125 C 38 C 2 1 (ESR) LMZ Figure 8 24V V IN 3.3V V OUT 24V V IN 3.3V V OUT : AC BW=150 MHz Figure 8. 6
7 PCB DC/DC / ESR / 3 3 national.com/powerdesigner POWER designer RF PCB RF SIMPLE SWITCHER EN55022 CAD PCB national.com/power
/ national.com / webench national.com / training national.com / edge national.com / refdesigns Power Designer national.com / powerdesigner Signal Path Designer national.com / spdesigner www.national.com/jpn jpn.feedback@nsc.com National Semiconductor Corporation, June 2010. National Semiconductor,, PowerWise, Signal Path Designer, WEBENCH, and SIMPLE SWITCHER are registered trademarks of National Semiconductor. All other brand or product names are trademarks or registered trademarks of their respective holders. All rights reserved.
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