YM7405B

The YM7405B is a kind of ISDN basic access interface with D channel packet (IDNDCH).It is an upgraded version of YM7405 chip with the ISDN user-network interface function (digital four-wire time-division full-duplex operation).In only one chip,the YM7405B is compatible with ITU-T Recommondation I.430, Q.920 and Q.921 [1992 edition], supports Layer 1 (physical layer) and Layer 2 (LAP-D protocol) and is making it suitable for D channel packet mode terminals.The YM7405B supports ETSI ETS 300012 [1992] and ETS 300125 [1991] also by setting it ETSI operation mode.The YM7405B also includes the Layer 3 processor interface function and analog driver and receiver in an 80-pin QFP or 100-pin TQFP package and has great potential for mounting and functional designing of terminal equipments (TE) and PBX (NT2) trunk circuits.

There are some features of YM7405B as follows.First is Layer 1.The second is Layer 2.Then is Layer 3 interface function.Next is power-down mode (low-power operation).The fifth is CMOS technology with single +5 V supply.The sixth is 80-pin QFP or 100-pin TQFP.The last one is YM7405 pin and software compatible.

What comes next is about the absolute maximum ratings of YM7405B based on DVSS, AVSS=0.0 V.The VDD (power supply voltage) is from -0.3 V to +7.0 V.The VIN (input voltage) is from -0.3 V to VDD+0.3 V.The TOP (ambient operating temperature) is from 0 to +70.The TST (storage temperature) is from -50 to +125.Then is about the recommended operating conditions.The supply voltage is 5 V ±5% (based on DVSS, AVSS=0.0 V).The ambient operating temperature is from 0 to +70.