UDC Package 18-Lead Plastic QFN (3mm × 4mm) (Reference LTC DWG # 05-08-1956 Rev B) Exposed Pad Variation AA 0.055 BSC 0.70 ±0.05 3.50 ±0.05 2.10 ±0.05 1.50 REF 0.770 BSC 0.220 ±0.05 0.356 ±0.05 0.400 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.50 REF 3.10 ±0.05 4.50 ±0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 3.00 ±0.10 0.75 ±0.05 1.50 REF PIN 1 ID 0.12 × 45° 0.40 ±0.10 1 PIN 1 TOP MARK (NOTE 5) 4.00 ±0.10 0.220 ±0.05 2.127 ±0.10 2 2.50 REF 0.770 BSC 0.356 ±0.05 0.400 ±0.05 (UDC18) QFN 1213 REV B 0.200 REF 0.00 – 0.05 R = 0.110 TYP 0.25 ±0.05 0.50 BSC BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 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 5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE