SiPM digital control board power supplies

As seen in the SiPM digital control board netlist, the ICs on the control board have many different power requirements. In total there are 6 different voltages required. To minimize the number of actual power supplies needed, however, we plan on supplying only +5V, -5V, and +210V to the board from external power supplies. The other voltages will be created by appropriate voltage regulator ICs on the control board.

+5V supply

The +5V supply is responsible for powering most of the components on the control board. Here is a breakdown of those components by their voltage requirements. Voltages less than +5V will be created using voltage regulators

ICs requiring +5V

IC Name	Pin Name	Tolerance	Current Requirements	Description	Notes
AD5535	V+	±0.25V	0.5mA typ, 1mA max	Positive amplifier
AD5535	AVCC	±0.25V	15mA typ, 18mA max	Analog supply
AD7928	AVDD	±0.25V	2.7mA max operating	Analog supply	AVDD can be as low as 2.7V if voltages measured never exceed 2.5V

ICs requiring +3.3V

IC Name	Pin Name	Tolerance	Current Requirements	Description	Notes
AD5535	ANODE	large	set by external resistor	Temperature sensing diode	Diode drop varies w/ temperature. Requires external current limiting resistor.
AD5535	REF_IN	~±0.4V	1.25uA max	Reference voltage	Should be as high as possible but not exceed AVCC-1.15V
AD7314	VDD	±0.3V	1.2mA typ operating		Indicates ±1°C precision
AD7928	VDRIVE	±0.3V	200uA	Logic output driver
CP2201	AV+	±0.3V	???	Analog supply pin
CP2201	VDD1	±0.3V	75mA typ, 155mA max operating	Digital supply pin
CP2201	VDD2	±0.3V	75mA typ, 155mA max operating	Digital supply pin
XC3S50A	VCCAUX	±0.3V	Varies	Auxiliary power supply	FPGA program greatly affects power requirements
XC3S50A	VCCO	±0.3V	Varies	Auxiliary power supply	FPGA program greatly affects power requirements

ICs requiring 2.5V

IC Name	Pin Name	Tolerance	Current Requirements	Description	Notes
AD7928	REF_IN	±1% (±0.025V)	±1uA max	Reference voltage

| ANODE | large | set by external resistor | Temperature sensing diode | Diode drop varies w/ temperature. Requires external current limiting resistor.

-5V supply

Use for:

• AD5535 DAC
  • V- amplifier supply pins

+210V supply

Use for:

• AD5535 DAC
  • VPP high voltage supply
    • Using this high voltage will allow for large adjustments of the SiPM amplifier bias voltages. Large variations may be necessary because the MATLAB model showed that adjustments between 0 and +50V had no effect on the SiPM.