Question about Boost Voltage figures in LT3689 datasheet

The three example circuits given in the LT3689 datasheet for generating Boost voltage are not making sense to me. In each case Vout is shown as being connected to ground. Also, the circuit drawings do not seem to match the words - specifically the datasheet says "For lower output voltages, the boost diode can be tied to the input (Figure 6c)," but Figure 6c shows the diode in the same place as in the other figures, but the "OUT" pin tied to the "Vin" pin. 

Are the figures wrong or am I really missing something here? Are there updated figures available?

  • +1
    •  Analog Employees 
    on Sep 7, 2018 3:52 PM


    Thank you for pointing out the issue. The output capacitor is missing in action in all three figures. An ECN is warranted.

    The OUT pin connecting to VIN in Figure 6c is correct however. The OUT pin is tied to the anode of the internal boost diode. The external boost diode, for example, is D2 in Figure 6b. Both Figure 6a and 6c use the internal boost diode.