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ssm2164_getting_started [2018/04/23 13:53] phatline [Resistor Solution low voltage - seppomans prefered] |
ssm2164_getting_started [2018/04/26 17:08] phatline [Class AB] |
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- | ======= ssm2164_seppoman pcb - getting started - how to setup ======= | + | ======= ssm2164_seppoman pcb introduction ======= |
+ | seppomans building information;[[ssm2164_pcb]]\\ | ||
the following informations are take from the midibox forum, its a collection of infos, without the claim to be 100% true, i will try to test the given information. | the following informations are take from the midibox forum, its a collection of infos, without the claim to be 100% true, i will try to test the given information. | ||
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**Pro:** easy job, still have a decent precision when calibrating.\\ | **Pro:** easy job, still have a decent precision when calibrating.\\ | ||
**Con:** “just change the jumpers if you need some channel in bipolar mode” thought will not work. (FIXME really?) | **Con:** “just change the jumpers if you need some channel in bipolar mode” thought will not work. (FIXME really?) | ||
- | ==== Resistor Solution Stock - NorthernLightX prefered ==== | + | ==== Resistor Solution Stock - -5V Level shifter - NorthernLightX prefered ==== |
we came to the conclusion that it's probably much easier to have the AOUT only output **unipolar 0 to 10 volt**, and design **a simple -5v level shifter board** that can be used as an add-on (or separate module with hands-on access to the level shifting) to **shift the output to -5 to +5 volt** where needed.\\ | we came to the conclusion that it's probably much easier to have the AOUT only output **unipolar 0 to 10 volt**, and design **a simple -5v level shifter board** that can be used as an add-on (or separate module with hands-on access to the level shifting) to **shift the output to -5 to +5 volt** where needed.\\ | ||
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**Pro:** preserve the "just change the jumpers if you need some channel in bipolar mode" thought behind this option.\\ | **Pro:** preserve the "just change the jumpers if you need some channel in bipolar mode" thought behind this option.\\ | ||
**Con:**dramatically increase the calibration range, i.e. exactly calibrating the outputs will get harder because the same angle of turning the pot will have much more impact.\\ | **Con:**dramatically increase the calibration range, i.e. exactly calibrating the outputs will get harder because the same angle of turning the pot will have much more impact.\\ | ||
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+ | ====== MODs ====== | ||
+ | ===== MODE Resistor - Noise vs Distortion ===== | ||
+ | SSM2164 Pin 1 (the first pin) sets the "Mode" | ||
+ | ==== Class AB ==== | ||
+ | Pin 1 is Open, no Resistor to +12V (PCB Default)\\ | ||
+ | Lower current results in higher distortion/lower noise.\\ | ||
+ | ---i do want distortion and dont care about noise--- so i do not change anything, the pcb is fine. | ||
+ | ==== Class A ==== | ||
+ | Pin 1 is Connected to +12V via a Resistor\\ | ||
+ | Higher current results in lower distortion/higher noise\\ | ||
+ | lets look in the datasheet:\\ | ||
+ | {{:phatline:ssm2164-ab-a.png?600|}}\\ | ||
+ | Figures 11 and 12 show the THD and noise performance of the | ||
+ | SSM2164 as the bias current is adjusted\\ | ||
+ | |||
+ | I_MODE = ( (V+)−0.6V )/ RB\\ | ||
+ | 1,52mA = (12V-0.6V) / 7,5K\\ | ||
+ | Leaving the MODE pin open sets the SSM2164 in Class AB with 30 μA in the Gain-Core\\ |