Bias Card RevD to RevF changes
From MCEWiki
- Low-noise Bias lines
- Low noise bias lines are meant to be used as TES bias lines. Bias Card Rev. F provides 12 independent bipolar low-noise bias lines (LN_BIAS) in addition to the 32 regular biases. The 12th low-noise bias is what was called det_bias in Rev. D cards. Rev. D cards shared a DAC between two outputs called Heater and det_bias.
- 10V supply
- Vah or 10V supply is not used by Rev. F cards anymore. The reference voltage for the DACs is generated from pVa or 6.2V supply instead.
- Vah is used in Rev. D cards to provide the reference voltage for the DACs.
- Faster Bias lines
- In order to allow fast switching of the 32 regular biases (<1MHz), the output opamp (U10) is replaced with a faster opamp and the 10kHz output filter is removed (compared to Rev. D). This allows Rev. F cards to be used for switching SQ2FB lines at row-visit rate.
- hard-wired pcb revision
- In Rev. F, 4 pins are introduced to provide the ability of reading back the pcb revision by software. These 4 bits are reported in the upper 16 bits of card_type. e.g., in a *.run file:
- RB bc2 card_type 00001537
- translates to 0x601 or bc2 card_type 1 pcb_rev 6
- card_type reads 00000001 for cards prior to Rev. F.
