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  1. CommanderLake

    Ribbon cable 120 ohm?

    Look at THIS ribbon cable, it has an impedance of 120 ohm could somebody explain why a cable would have such an impedance?
  2. CommanderLake

    Simple switching +-5v supply

    Actually going back to my BJT question, a lower Pd for a given DC collector current does mean its more efficient because the collector emitter saturation voltage is lower, take this for example: nxp.com/documents/data_sheet/PBSS4041NZ.pdf they have an extremely low Vcesat making them cooler at...
  3. CommanderLake

    Simple switching +-5v supply

    Yea that was a stupid question I figured it out.
  4. CommanderLake

    Simple switching +-5v supply

    Using the falstad circuit simulator I can see an oscilation on the positive outout created by the capacitors and inductors when its powered on then fades away and the negative voltage is reduced by the forward voltage of the diode. This seems to be turning into a wild goose chase. Ah ha! If I...
  5. CommanderLake

    Simple switching +-5v supply

    I asked for help on the TI community forum and Anston Lobo a TI employee came up with THIS I just wanted to see what you think?
  6. CommanderLake

    Simple switching +-5v supply

    Look at this article: electronicdesign.com/boards/turn-positive-buckboost-circuits-negative and click the link for Figure 1, do you think its possible to just swap all the polarities with the TL2575-05? Or just connect it backwards with gnd-gnd, in-out and out-in?
  7. CommanderLake

    Simple switching +-5v supply

    The main supply on the amplifier is symmetrical. Yea I dont want a module I want everything on 1 PCB.
  8. CommanderLake

    Simple switching +-5v supply

    What about the negative side? I found the TL2575-05 for the positive. By SMPS module do you mean a separate board because this is for an all in one 7.1 amplifier board?
  9. CommanderLake

    Simple switching +-5v supply

    I need a symmetric 5v supply for 2x PGA4311's and a 14M2 Picaxe and another for 2x 5v relays, the supply is +-30v so linear regulators would be very hot and inefficient so I need help finding the right IC's for a switching supply and I need them to be easy to solder so if they are surface mount...
  10. CommanderLake

    Power a relay with a zener diode

    Actually, I'm using a Picaxe for the PGA4311 volume control IC's so I think I will use a 5v relay and a darlington transistor to control it with the Picaxe instead, I'm always having great ideas!
  11. CommanderLake

    Power a relay with a zener diode

    No I didnt mean they are connected together I mean does the relay switch to them when its not powered.
  12. CommanderLake

    Power a relay with a zener diode

    Just to be sure, http://www.farnell.com/datasheets/419217.pdf on the 5th page numbered 207 on the datasheet the Terminal Arrangement drawing for G2RL-2 (bottom most) shows pins 2 and 7 are connected I'm assuming this is the normal powered off state yes?
  13. CommanderLake

    Power a relay with a zener diode

    Yes wise to discharge to ground.
  14. CommanderLake

    Power a relay with a zener diode

    Sorry that sounded stupid I am fully aware what a zener does and does not do, I'm improving on an amplifier I have recently built by combining everything into a single board, with my current amplifier I get a pop at power on and when powered off the negative cap discharges slightly quicker...
  15. CommanderLake

    Power a relay with a zener diode

    I've been designing a 7.1 amplifier board (7 amps and sub out) with built in volume control and I want to add some protection with a DPDT relay that switches the + and - of the smoothing caps to a large resistor to discharge them, the supply will be effectively 61v from + to - so if I use a 47v...
  16. CommanderLake

    PGA4311 bypass caps

    Look at C12 on the right why is it there and why is it connected to the digital ground why is it closer to the digital ground why is there no positive capacitor on the right, I would use PP film for the 0.1µF caps is this ideal?
  17. CommanderLake

    PGA4311 bypass caps

    Heres the datasheet: www.ti.com/lit/ds/symlink/pga4311.pdf Look at page 11 figure 5, could somebody please clarify the placement of the bypass capacitors on this IC, theres a 0.1uF on the left side + and - and on the right side theres a 0.1uF on just the negative but connected to the digital...
  18. CommanderLake

    Inverting LM4780 circuit

    What would be more suitable ceramic or mica?
  19. CommanderLake

    Inverting LM4780 circuit

    Looking at figure 39 on page 24 of the datasheet I cant find any mention of the CN capacitors on the datasheet, what do they do?
  20. CommanderLake

    Inverting LM4780 circuit

    Well I know now and thanks for the info.
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