Hi,
The spec sheet for the TPS81256 states that in most applications an external input capacitor is not needed (since there is already a built-in one). However, the TINATI transient model for this chip includes a 150uF input capacitor. This would imply a large component (1210 or something similar), really too big for my available area. Any recommendations? My specs are these: I'm making two voltage rails, a +5V with a current draw between 18 and 30mA, and a -5V rail with a current draw between 1 and 11 mA (depending on what sensor I will be using). For the -5V rail I will be using the LTC1751-5 from Linear, but will be cascaded after the TPS81256, so the current draw for the -5V rail will go through this IC). The source is a 3 V (nominal) Lithium battery.
Thanks!