Package Information SAW Type 20-pin (4mm×4mm) QFN Outline Dimensions Symbol Dimensions in inch Min. Nom. Max. A 0.031 0.033 0.035 A1 0.000 0.001 0.002 A3 — 0.008 BSC — b 0.007 0.010 0.012 D — 0.157 BSC — E — 0.157 BSC — e — 0.020 BSC — D2 0.075 0.079 0.081 E2 0.075 0.079 0.081 L 0.012 0.016 0.020 K 0.008 — — Symbol Dimensions in mm Min. Nom. Max. A 0.800 0.850 0.900 A1 0.000 0.020 0.050 A3 — 0.203 BSC — b 0.180 0.250 0.300 D — 4.000 BSC — E — 4.000 BSC — e — 0.50 BSC — D2 1.90 2.00 2.05 E2 1.90 2.00 2.05 L 0.30 0.40 0.50 K 0.20 — — http://www.holtek.com.tw/pdf/guide.pdf June 03, 2014