Need some help in reading a datasheet - Rohm BD6210

Discussion in 'General Electronics Chat' started by hspalm, Feb 16, 2012.

  1. hspalm

    Thread Starter Active Member

    Feb 17, 2010
    I have a working application with a bluetooth module (3.3v) attiny2313 (5v) and L293D H-bridge driver (5v logic) all working in harmony. Today this circuit is fed with a walwart and two voltage regualtors provide the two supply voltages.

    But now someone wanted me to make 10~100 of these, and he wanted it battery powered. So I want to remove the two "high dropout" linear regulators which are mounted today, and use only one single 3.3v LDO from 6v battery source consisting of 4 AA cells.

    The motor is a 6v geared brushed DC motor, at no load it draws ~100mA. In my customers application it will ideally never exceed 200mA, but I will implement over-current sensing and protection.

    The simplest, cheapest 3.3v 1-channel H-bridge controller I found was the Rohm BD6210 (datasheet PDF). The datasheet states "Rating voltage = 7v", "Vcc supply voltage maximum rating = 7v" and "Vcc supply voltage operating conditions = 3.0 - 5.5v".

    If you look at the datasheet and digikey/farnell etc. it is clearly "promoted" as a 7v capable device, but then again it's its maximum rating? There is only one Vcc input (two Vcc pins, but datasheet says their pins must have the same voltage) so there is no separate supply for the motor, hence I should stay within the "operating conditions" specs.

    My two main questions are these:
    *Can I trust the BD6210 to run directly off of 4 AA cells?
    *Will 4 fully charged/fresh AA cells regardless of chemistry ever exceed 7v?

    As always, I appreciate your help very much.

    PS: There will most certainly be follow-up questions.