모두보기

영어판을 공식 버전으로 해주세요돌아가기

유럽
France(Français) Germany(Deutsch) Italy(Italia) Russian(русский) Poland(polski) Czech(Čeština) Luxembourg(Lëtzebuergesch) Netherlands(Nederland) Iceland(íslenska) Hungarian(Magyarország) Spain(español) Portugal(Português) Turkey(Türk dili) Bulgaria(Български език) Ukraine(Україна) Greece(Ελλάδα) Israel(עִבְרִית) Sweden(Svenska) Finland(Svenska) Finland(Suomi) Romania(românesc) Moldova(românesc) Slovakia(Slovenská) Denmark(Dansk) Slovenia(Slovenija) Slovenia(Hrvatska) Croatia(Hrvatska) Serbia(Hrvatska) Montenegro(Hrvatska) Bosnia and Herzegovina(Hrvatska) Lithuania(lietuvių) Spain(Português) Switzerland(Deutsch) United Kingdom(English)
아시아 태평양
Japan(日本語) Korea(한국의) Thailand(ภาษาไทย) Malaysia(Melayu) Singapore(Melayu) Vietnam(Tiếng Việt) Philippines(Pilipino)
아프리카, 인도 및 중동
United Arab Emirates(العربية) Iran(فارسی) Tajikistan(فارسی) India(हिंदी) Madagascar(malaɡasʲ)
남아메리카 / 오세아니아
New Zealand(Maori) Brazil(Português) Angola(Português) Mozambique(Português)
북아메리카
United States(English) Canada(English) Haiti(Ayiti) Mexico(español)
제품 센터전원 공급 장치-보드 장착dc dc 컨버터

dc dc 컨버터

11,620 제품이 발견되었습니다

제품 목록

1...168169170171172173174...233
비교 그림 부분 # 제조사 기술 재고 ECAD 모델 RoHS 능률 출력 수 제어 기능 전류 - 출력 (최대) 전압 - 입력 (최소) 전압 - 출력 1 전압 - 출력 2 전압 - 출력 3 전압 - 출력 (4) 전압 - 분리 승인 기관 표준 번호 기본 제품 번호 패키지 실장 형 연속 작동 온도 크기 / 치수 전압 - 입력 (최대) 유형 풍모 응용 프로그램 패키지 / 케이스 제조업체 장치 패키지 전력 (W) 수량
VE-JW4-MW Vicor Corporation DC DC CONVERTER 48V 100W 유품4510 pcs 90% 1 - 2.08A 18V 48V - - - 3 kV - - VE-JW4 Bulk Through Hole VE-J00™ (100W) -55°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 36V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 100 W
VE-26L-MU Vicor Corporation DC DC CONVERTER 28V 200W 유품4930 pcs 90% 1 - 7.14A 200V 28V - - - 3 kV - - VE-26L Bulk Through Hole VE-200™ (200W) -55°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 400V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 200 W
VE-J53-MY Vicor Corporation DC DC CONVERTER 24V 50W 유품5330 pcs 90% 1 - 2.08A 100V 24V - - - 3 kV - - VE-J53 Bulk Through Hole VE-J00™ (50W) -55°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 200V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 50 W
SXE15-48S1V8 Artesyn Embedded Power DC DC CONVERTER 1.8V 11W 유품4640 pcs 83% 1 - 6A 33V 1.8V - - - 1.5 kV - - - - Surface Mount SXE15 (15W) -40°C ~ 65°C 1.91" L x 1.15" W x 0.34" H (48.5mm x 29.2mm x 8.6mm) 75V Isolated Module Remote On/Off, OCP, OVP, SCP, UVLO ITE (Commercial) 12-SMD Module - 11 W
TPSM84209RKHR Texas Instruments DC DC CONVERTER 1.2-6V 유품22334 pcs 91.7% 1 Enable, Active High 2.5A 4.5V 1.2 ~ 6V - - - - - - TPSM84209 Tape & Reel (TR) Surface Mount TPSM -40°C ~ 85°C (With Derating) 0.18" L x 0.16" W x 0.08" H (4.5mm x 4.0mm x 2.1mm) 28V Non-Isolated PoL Module Adjustable Output, Remote On/Off ITE (Commercial) 9-PowerQFN 9-QFN-FCMOD (4.5x4) -
IB054E120T32N1-00 Vicor Corporation DC DC CONVERTER 유품5370 pcs - - - - - - - - - - - - - Tray - * - - - - - - - - -
VE-233-CU Vicor Corporation DC DC CONVERTER 24V 200W 유품61 pcs 90% 1 - 8.33A 42V 24V - - - 3 kV - - VE-233 Bulk Through Hole VE-200™ (200W) -25°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 60V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 200 W
LW015C ABB Power Electronics Inc. DC DC CONVERTER 15V 15W 유품5010 pcs 78% 1 - 1A 36V 15V - - - 1.5 kV - - - Bulk Through Hole LW015 (15W) -40°C ~ 105°C 2.00' L x 1.00' W x 0.40' H (50.8mm x 25.4mm x 10.2mm) 75V Isolated Module OCP, OVP, UVLO ITE (Commercial) 6-DIP Module - 15 W
VI-B6L-CV Vicor Corporation DC DC CONVERTER 28V 150W 유품4290 pcs 90% 1 - 5.36A 200V 28V - - - 3 kV - - VI-B6L Bulk Through Hole VI-200™ (150W) -25°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 400V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 150 W
VE-JNY-IZ Vicor Corporation DC DC CONVERTER 3.3V 17W 유품4630 pcs 90% 1 - 5A 36V 3.3V - - - 3 kV - - VE-JNY Bulk Through Hole VE-J00™ (25W) -40°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 76V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 17 W
VI-710483B Vicor Corporation DC DC CONVERTER 유품5270 pcs - - - - - - - - - - - - - Bulk - * - - - - - - - - -
VE-242-MV Vicor Corporation DC DC CONVERTER 15V 150W 유품4440 pcs 90% 1 - 10A 55V 15V - - - 3 kV - - VE-242 Bulk Through Hole VE-200™ (150W) -55°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 100V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 150 W
VE-J34-CZ Vicor Corporation DC DC CONVERTER 48V 25W 유품5100 pcs 90% 1 - 521mA 42V 48V - - - 3 kV - - VE-J34 Bulk Through Hole VE-J00™ (25W) -25°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 60V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 25 W
AM1S-0505SZ aimtec DC DC CONVERTER 5V 1W 유품19133 pcs 81% 1 - 200mA 4.5V 5V - - - 1 kV CE - AM1S Tube Through Hole AM1S-Z (1W) -40°C ~ 85°C 0.46" L x 0.24" W x 0.38" H (11.7mm x 6.0mm x 9.7mm) 5.5V Isolated Module - ITE (Commercial) 4-SIP Module 4-SIP 1 W
PMN8118UWSR Flex Power Modules DC DC CONVERTER 0.7-3.6V 108W 유품2208 pcs 92.6% 1 Enable, Active Low 30A 5.5V 0.7 ~ 3.6V - - - - CB, CSA, IEC, TUV, UL 62368-1 PMN811 Tray Surface Mount PMN 8000 (108W) -40°C ~ 85°C (With Derating) 1.37" L x 0.62" W x 0.33" H (34.8mm x 15.8mm x 8.5mm) 14V Non-Isolated PoL Module Adjustable Output, Remote On/Off, Remote Sense ITE (Commercial) 14-SMD Module - 108 W
NSR003A0X4-49Z ABB Power Electronics Inc. DC DC CONVERTER 0.59-6V 유품4290 pcs 95.8% 1 - 3A 4.5V 0.59 ~ 6V - - - - - - - Bulk Through Hole Naos Raptor -40°C ~ 85°C 0.41" L x 0.31" W x 0.65" H (10.4mm x 7.8mm x 16.5mm) 14V Non-Isolated PoL Module Remote On/Off, OCP, OTP, UVLO ITE (Commercial) 5-SIP Module - -
VE-2W4-CX Vicor Corporation DC DC CONVERTER 48V 75W 유품5490 pcs 90% 1 - 1.56A 18V 48V - - - 3 kV - - VE-2W4 Bulk Through Hole VE-200™ (75W) -25°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 36V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 75 W
PC1R5-24-5 TDK-Lambda Americas Inc DC DC CONVERTER 5V 1.5W 유품4350 pcs - 1 - 300mA 18V 5V - - - - - - - - Through Hole PC -20°C ~ 70°C (With Derating) 1.08" L x 0.61" W x 0.31" H (27.5mm x 15.5mm x 7.8mm) 36V Isolated Module OCP ITE (Commercial) 6-DIP Module - 1.5 W
VI-B5H-MU Vicor Corporation DC DC CONVERTER 52V 200W 유품34 pcs 90% 1 - 3.85A 100V 52V - - - 3 kV - - VI-B5H Bulk Through Hole VI-200™ (200W) -55°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 200V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 200 W
VE-J22-CY Vicor Corporation DC DC CONVERTER 15V 50W 유품91 pcs 90% 1 - 3.33A 21V 15V - - - 3 kV - - VE-J22 Bulk Through Hole VE-J00™ (50W) -25°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 56V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 50 W
PKB4318NPINB Flex Power Modules DC DC CONVERTER 1V 30W 유품1043 pcs 85.3% 1 Enable, Active Low 30A 36V 1V - - - 2.25 kV CB, CSA, IEC, TUV, UL 62368-1 PKB431 Tray Through Hole PKB4000 (90W) -40°C ~ 120°C (With Derating) 2.30" L x 0.89" W x 0.32" H (58.4mm x 22.7mm x 8.1mm) 75V Isolated Module Adjustable Output, Remote On/Off, Remote Sense ITE (Commercial) Eighth Brick Eighth Brick 30 W
VE-J63-MZ Vicor Corporation DC DC CONVERTER 24V 25W 유품5130 pcs 90% 1 - 1.04A 200V 24V - - - 3 kV - - VE-J63 Bulk Through Hole VE-J00™ (25W) -55°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 400V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 25 W
BXA3-48S05-F Artesyn Embedded Power DC DC CONVERTER 5V 3W 유품5080 pcs 76% 1 - 500mA 36V 5V - - - 500 V - - - Bulk Through Hole BXA3 (3W) -25°C ~ 105°C 1.25" L x 0.80" W x 0.50" H (31.8mm x 20.3mm x 12.7mm) 75V Isolated Module OVP, SCP ITE (Commercial) 24-DIP Module (600 mil, 10 Leads) - 3 W
VE-JT0-MZ Vicor Corporation DC DC CONVERTER 5V 25W 유품3810 pcs 90% 1 - 5A 66V 5V - - - 3 kV - - VE-JT0 Bulk Through Hole VE-J00™ (25W) -55°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 160V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 25 W
VE-252-MU Vicor Corporation DC DC CONVERTER 15V 200W 유품4200 pcs 90% 1 - 13.33A 100V 15V - - - 3 kV - - VE-252 Bulk Through Hole VE-200™ (200W) -55°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 200V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 200 W
VI-B6L-01 Vicor Corporation VI-B6L-01 300V/28V 200W SMD 유품73 pcs - - - - - - - - - - - - VI-B6L Bulk - * - - - - - - - - -
VE-26L-EV Vicor Corporation DC DC CONVERTER 28V 150W 유품95 pcs 88% 1 - 5.36A 200V 28V - - - 3 kV - - VE-26L Bulk Through Hole VE-200™ (150W) -10°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 400V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 150 W
VE-J72-CZ Vicor Corporation DC DC CONVERTER 15V 25W 유품154 pcs 90% 1 - 1.67A 100V 15V - - - 3 kV - - VE-J72 Bulk Through Hole VE-J00™ (25W) -25°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 375V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 25 W
VI-JN1-IY-03 Vicor Corporation VI-JN1-IY-03 48V/12V 50W 유품87 pcs - - - - - - - - - - - - VI-JN1 Bulk - * - - - - - - - - -
VE-J6Y-EY Vicor Corporation DC DC CONVERTER 3.3V 33W 유품4730 pcs 88% 1 - 10A 200V 3.3V - - - 3 kV - - VE-J6Y Bulk Through Hole VE-J00™ (50W) -10°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 400V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 33 W
VE-JW4-CY Vicor Corporation DC DC CONVERTER 48V 50W 유품111 pcs 90% 1 - 1.04A 18V 48V - - - 3 kV - - VE-JW4 Bulk Through Hole VE-J00™ (50W) -25°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 36V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 50 W
VE-214-CX Vicor Corporation DC DC CONVERTER 48V 75W 유품4670 pcs 90% 1 - 1.56A 21V 48V - - - 3 kV - - VE-214 Bulk Through Hole VE-200™ (75W) -25°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 32V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 75 W
VE-JWL-IW Vicor Corporation DC DC CONVERTER 28V 100W 유품4640 pcs 90% 1 - 3.57A 18V 28V - - - 3 kV - - VE-JWL Bulk Through Hole VE-J00™ (100W) -40°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 36V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 100 W
VE-JW0-MY Vicor Corporation DC DC CONVERTER 5V 50W 유품39 pcs 90% 1 - 10A 18V 5V - - - 3 kV - - VE-JW0 Bulk Through Hole VE-J00™ (50W) -55°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 36V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 50 W
VE-2T3-EV Vicor Corporation DC DC CONVERTER 24V 150W 유품4620 pcs 88% 1 - 6.25A 66V 24V - - - 3 kV - - VE-2T3 Bulk Through Hole VE-200™ (150W) -10°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 160V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 150 W
VE-JW4-EX Vicor Corporation DC DC CONVERTER 48V 75W 유품128 pcs 88% 1 - 1.56A 18V 48V - - - 3 kV - - VE-JW4 Bulk Through Hole VE-J00™ (75W) -10°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 36V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 75 W
VE-J10-MW Vicor Corporation DC DC CONVERTER 5V 100W 유품4500 pcs 90% 1 - 20A 21V 5V - - - 3 kV - - VE-J10 Bulk Through Hole VE-J00™ (100W) -55°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 32V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 100 W
BM80A-300L-022F75 Artesyn Embedded Power DC DC CONVERTER 2.2V 300W 유품3820 pcs - 1 - 75A 180V 2.2V - - - - - - - - Through Hole BM80A (300W) -20°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 400V Non-Isolated PoL Module Remote On/Off, OTP, OVP ITE (Commercial) Module - 300 W
VE-232-EY Vicor Corporation DC DC CONVERTER 15V 50W 유품5100 pcs 88% 1 - 3.33A 42V 15V - - - 3 kV - - VE-232 Bulk Through Hole VE-200™ (50W) -10°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 60V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 50 W
VE-262-EY Vicor Corporation DC DC CONVERTER 15V 50W 유품5120 pcs 88% 1 - 3.33A 200V 15V - - - 3 kV - - VE-262 Bulk Through Hole VE-200™ (50W) -10°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 400V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 50 W
XCL206F083CR-G Torex Semiconductor Ltd 600MA INDUCTOR BUILT-IN PWM STEP 유품21884 pcs - - - - - - - - - - - - XCL206 Tape & Reel (TR) - * - - - - - - - - -
VI-221-18 Vicor Corporation VI-221-18 24V/12V 125W 유품4950 pcs - - - - - - - - - - - - VI-221 Bulk - * - - - - - - - - -
VI-B13-CW Vicor Corporation DC DC CONVERTER 24V 100W 유품4650 pcs 90% 1 - 4.17A 21V 24V - - - 3 kV - - VI-B13 Bulk Through Hole VI-200™ (100W) -25°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 32V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 100 W
VE-J32-MX Vicor Corporation DC DC CONVERTER 15V 75W 유품4910 pcs 90% 1 - 5A 42V 15V - - - 3 kV - - VE-J32 Bulk Through Hole VE-J00™ (75W) -55°C ~ 100°C 2.28" L x 2.40" W x 0.50" H (57.9mm x 70.0mm x 12.7mm) 60V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 75 W
PKM4511EPI Flex Power Modules DC DC CONVERTER 5V 50W 유품4210 pcs 90.5% 1 Enable, Active Low 10A 36V 5V - - - 1.5 kV CB, CSA, IEC, TUV, UL 62368-1 - Tray Through Hole PKM 4000E (50W) -40°C ~ 110°C (With Derating) 2.28" L x 1.45" W x 0.33" H (57.9mm x 36.8mm x 8.5mm) 75V Isolated Module Adjustable Output, Remote On/Off, Remote Sense ITE (Commercial) Quarter Brick Quarter Brick 50 W
BXB75-48D3V3-2V5FH Artesyn Embedded Power DC DC CONVERTER 3.3V 2.5V 60W 유품4000 pcs 74% 2 - 15A, 15A 36V 3.3V 2.5V - - 1.5 kV - - - Bulk Through Hole BXB75 (75W) -40°C ~ 100°C 2.40" L x 2.28" W x 0.50" H (61.0mm x 57.9mm x 12.7mm) 75V Isolated Module Remote On/Off, OTP, OVP, SCP, UVLO ITE (Commercial) 10-DIP Module - 60 W
VI-B73-CW Vicor Corporation DC DC CONVERTER 24V 100W 유품121 pcs 90% 1 - 4.17A 100V 24V - - - 3 kV - - VI-B73 Bulk Through Hole VI-200™ (100W) -25°C ~ 85°C 4.60' L x 2.40' W x 0.50' H (116.8mm x 61.0mm x 12.7mm) 375V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 100 W
VE-230-EW Vicor Corporation DC DC CONVERTER 5V 100W 유품4290 pcs 88% 1 - 20A 42V 5V - - - 3 kV - - VE-230 Bulk Through Hole VE-200™ (100W) -10°C ~ 85°C 4.60" L x 2.40" W x 0.50" H (116.8mm x 61.0mm x 12.7mm) 60V Isolated Module OCP, OTP, OVP, SCP ITE (Commercial) Full Brick - 100 W
PMG8218TP Flex Power Modules DC DC CONVERTER 0.8V 9.6W 유품4460 pcs 89.3% 1 Enable, Active Low 12A 10.8V 0.8V - - - - CB, CSA, IEC, TUV, UL 62368-1 - Tray Through Hole PMG 8000 (66W) -40°C ~ 85°C (With Derating) 1.37" L x 0.62" W x 0.35" H (34.8mm x 15.8mm x 9.0mm) 13.2V Non-Isolated PoL Module Adjustable Output, Remote On/Off, Remote Sense ITE (Commercial) 10-DIP Module - 9.6 W
VE-J04-CX Vicor Corporation DC DC CONVERTER 48V 75W 유품99 pcs 90% 1 - 1.56A 10V 48V - - - 3 kV - - VE-J04 Bulk Through Hole VE-J00™ (75W) -25°C ~ 100°C 2.28' L x 2.40' W x 0.50' H (57.9mm x 70.0mm x 12.7mm) 20V Isolated Module OCP, SCP ITE (Commercial) Half Brick - 75 W
1...168169170171172173174...233
0 RFQ
쇼핑 카트 (0 Items)
비어 있습니다.
목록을 비교하십시오 (0 Items)
비어 있습니다.
피드백

귀하의 의견이 중요합니다!Allelco에서는 사용자 경험을 소중히 여기며 지속적으로 개선하기 위해 노력합니다.
피드백 양식을 통해 귀하의 의견을 공유하십시오. 즉시 응답하겠습니다.
Allelco을 선택해 주셔서 감사합니다.

주제
이메일
메모/주석
인증 코드
파일을 업로드하려면 드래그 또는 클릭하십시오
파일 업로드
유형 : .xls, .xlsx, .doc, .docx, .jpg, .png 및 .pdf.
최대 파일 크기 : 10MB