SN74ALVC164245: SN74ALVC164245

For high-impedance CMOS inputs, this is specified as the input leakage current (I_I). It is so small that it can be ignored in most cases.

(For the TXB, the outputs on both sides are always active, so the mentioned drive current is required to override the output.)

Thanks for clarifying regarding SN74ALVC164245. 

For Part# TXB inputs are connected to microprocessor MPC555 (to translate 5V to 3.3V) having drive capability of 2 mA.

Since TXB expects minimum 2mA input drive current so do i need to add any additional buffer at input side  or if you can suggest alternate of TXB with lesser drive current requirement that will really help (4channel, 2 Channels and 8 channels Bidirectional level translator with less than 2 mA input drive current)

Are the signals actually bidirectional? Which protocol is this?

A drive strength of 2 mA is enough for the TXB.

Yes signals are bidirectional. 

Regarding 2nd Point i will re-phrase my query: As per section 8.3.2 (page 14) of datasheet TXB0108

"Typical IIN vs VIN characteristics of the TXB0108 are shown in Figure 8-2. For proper operation, the device
driving the data I/Os of the TXB0108 must have drive strength of at least ±2 mA" 

So was asking if TI has similar IC like TXB0108 which has Input drive strength less than 2 mA because

my microprocessor which will drive Input pin of  TXB0108 has 2mA Capability i.e., 

Ioh (Microprocessor) - Iih (TXB) = 2mA - 2mA =0, so i do not have any safe margin

Which protocol is this?

You do not need a safety margin; the microprocessor can provide more than 2 mA by exceeding the specified V_OH, but this does not matter for the TXB.

There is no translator that works like the TXB with a lower input current.