LT3570 PACKAGE DESCRIPTIONUF Package24-Lead Plastic QFN (4mm × 4mm) (Reference LTC DWG # 05-08-1697) BOTTOM VIEW—EXPOSED PAD PIN 1 NOTCH R = 0.20 TYP OR 4.00 ± 0.10 0.75 ± 0.05 R = 0.115 0.35 × 45° CHAMFER (4 SIDES) TYP 23 24 0.70 ±0.05 PIN 1 0.40 ± 0.10 TOP MARK (NOTE 6) 1 2 4.50 ± 0.05 2.45 ± 0.05 2.45 ± 0.10 3.10 ± 0.05 (4 SIDES) (4-SIDES) PACKAGE OUTLINE (UF24) QFN 0105 0.200 REF 0.25 ± 0.05 0.25 ±0.05 0.50 BSC 0.00 – 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGD-X)—TO BE APPROVED 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE FE Package20-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1663) Exposed Pad Variation CB 6.40 – 6.60* 3.86 (.252 – .260) (.152) 3.86 (.152) 20 1918 17 16 15 14 1312 11 6.60 ±0.10 2.74 (.108) 4.50 ±0.10 6.40 2.74 SEE NOTE 4 (.252) (.108) 0.45 ±0.05 BSC 1.05 ±0.10 0.65 BSC RECOMMENDED SOLDER PAD LAYOUT 1 2 3 4 5 6 7 8 9 10 1.20 4.30 – 4.50* (.047) 0.25 (.169 – .177) MAX REF 0° – 8° 0.65 0.09 – 0.20 0.50 – 0.75 (.0256) 0.05 – 0.15 (.0035 – .0079) (.020 – .030) BSC (.002 – .006) 0.195 – 0.30 FE20 (CB) TSSOP 0204 (.0077 – .0118) TYP NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 4. RECOMMENDED MINIMUM PCB METAL SIZE MILLIMETERS FOR EXPOSED PAD ATTACHMENT 2. DIMENSIONS ARE IN (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE 3. DRAWING NOT TO SCALE 3570fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. 19