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QuantAsylum QA450 User’s Manual

 

 

 

 

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QuantAsylum QA450 User’s Manual

 

Programmable 4/8 Ohm Load

 

 

 

 

 

 

SW Release 1.11 

January 2019 

 

 

Summary of Contents for QA450

Page 1: ...QuantAsylum QA450 User s Manual Page 1 QuantAsylum QA450 User s Manual Programmable 4 8 Ohm Load SW Release 1 11 January 2019 ...

Page 2: ...ting conditions will be replaced or repaired for free not including shipping Generally you will be responsible for shipping to us and we will be responsible for shipping it back to you Devices that have suffered a failure due to operation in excess of specified parameters can usually be repaired for a nominal fee The contents of this document are provided as is and may be changed or updated withou...

Page 3: ...res 6 QA450 Front Panel 6 Front Panel Summary 6 LEDs 6 Current Sense Inputs 7 DUT Power Soft Start 7 Load Inputs 8 BNC Outputs 8 QA450 Software 8 Application Temperature Sensing 9 Application Current Sensing 9 DUT Power 9 Fault Conditions 10 QA450 Load Resistors 10 Audio Bursts 11 Low Temperature Operation 11 Soft Start 12 Thermal Considerations 12 Impact of Switchover 13 Appendix I Typical Connec...

Page 4: ...QuantAsylum QA450 User s Manual Page 4 ...

Page 5: ... This isolation is limited to 50V Do not connect the QA450 to a product that has its ground reference more than 50V from the PC ground Current Sense Inputs The QA450 has a 3 wire current sense connector S from power supply S to DUT and DUT GND for monitoring the high side DC supply of an amplifier The voltages on the S pin of this connector must not exceed 50V DC and must be greater than 5V to ens...

Page 6: ...iting of supply for accidental shorts trips when 15A for more than 2mS Soft start allowing gentle turn on of the amplifier DUT First order filter to limit the slew rate of filterless class D amplifiers We hope you enjoy your purchase Check back from time to time for new software updates QA450 Front Panel This section covers the various connectors on the analyzer and reviews the input and or output...

Page 7: ...ent sensing is not required to be used For example if you are testing Class D amplifier boards it might make sense to use the current sense and power the boards from a fixed external supply But if you are testing finished amplifiers that run from AC then the DC measurement provided by the QA450 isn t useful and can be skipped ATTENTION DO NOT CONNECT THE CURRENT SENSE CONNECTOR WHEN THE DUT LED IS...

Page 8: ...e across L and L and the QA450 load is set for 8 ohms then the QA450 will be dissipating 3 16 2 8 1 24W The BNC outputs will measure 6 dB lower which would be 4 dBV 1 58Vrms The first order low pass filter in the QA450 has its corner at 34 KHz QA450 Software The QA450 will appear on your PC as a HID device with a USB VID PID of 0x16C0 0x4E2C It doesn t need drivers It will show up in the Device Ma...

Page 9: ...emperatures must remain under 60C Above 60C or below 5C the QA450 will disconnect the loads and require time to cool down or warm up The sensors are very accurate and respond very quickly Generally as long as you do not impart more than 300W of power per channel you do not need to worry about harming the QA450 It will self protect The temperature readings are provided for information only Applicat...

Page 10: ...or used for the QA450 is the Bourns PWR163 series The QA450 has 16 of these resistors 8 per channel When presenting an 8 ohm load four 2 ohm resistors per channel are used 4S1P When presenting a 4 ohm load eight 2 ohm resistors per channel are used 4S2P There are half as many resistors used when presenting an 8 ohm load versus a 4 ohm load This has implications for maximum power handling The PWR16...

Page 11: ...stors are hit with 800W for 100 mS then the temperature of the resistor active area will climb very quickly while the temp sensor located 2 3 mm away from the resistor body will remain unchanged Because of this lag the 200W figure must not be exceeded as the QA450 won t be able to protect itself quickly enough But at power levels below 200W the QA450 can fully protect itself and you don t need to ...

Page 12: ...0 mF or so then the 1 second soft start time may not be enough Assume for a moment you are running an amp with 50 mF of bulk capacitance When the power switch is turned on an RC circuit comprised of the 10 ohm soft start resistor and the 50 mF bulk capacitance begins to charge One time constant will be 10 50 m 500 mS and thus after one time constant the voltage will have risen to 31 6V At that poi...

Page 13: ... tested per day per test bay Impact of Switchover The impact of switchover time is significant in the average power calculation If the switchover time is 2 minutes due in part to an operator managing several bays and a fully manual switchover then the average power drops to 1 5W In summary you need to plan your thermal budget ahead of time to ensure the QA450 can meet your needs Hitting the therma...

Page 14: ...QuantAsylum QA450 User s Manual Page 14 Appendix I Typical Connection Diagram ...

Page 15: ...nuous 15A peak Trip Current 15A for 2 mS Soft Start 10 ohm for 1 second Load Inputs Load Options 4 and 8 ohms Max Voltage on any pin 50Vrms AC relative to DUT GND Max Current on any pin 10Arms Max Power into Load Inputs 200W per channel for 220mS Load Tolerance 5 USB Isolation 10 GΩ 1KV Output Attenuation 6 dB Frequency Response F3db 34 KHz Output Impedance 100 ohms General Interface USB 12Mbps Po...

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