pin  4
                                  OUT  |    
    - - - - - - - - - - - - - - - - - -+ - - -
    |                                  |     |   R = 10 K Ohm
        +--2R--+--R--+--R--+--R--+--R--+        2R = 20 K Ohm
    |   |      |     |     |     |     |     |   resistors  1/8 W
        |     2R    2R    2R    2R    2R         with accuracy 2 %
    |   |      |     |     |     |     |     |
    - - + - - -+- - -+- - -+- - -+- - -+- - -- 
        |      |     |     |     |     |
   pin  7     12    13     1     2     3
      GND   BIT5   BIT4  BIT3  BIT2   BIT1
   
  (In alternative use all 22 KOhm 5% resistors;
   2R = one 22 KOhm, R = two 22K resistor in parallel)