InGenius Line Receiver IC Demonstration System THAT 1200-DEMO Description Description The THAT 4305-DEMO Compressor Demonstra- available at a test point to facilitate direct measure- The THAT1200 Demonstration System is a high frequencies resulting from any mismatch tion System is a self-contained circuit board that ments of the detector. Both the power supply and between C1 and C2, (the shunt paths for each self-contained circuit board that simplifies simplifies evaluating the performance of a 4305 external CV inputs are made via standard five-way input share C3, and C3 s impedance dominates evaluation of the THAT1200, THAT1203, and Analog Engine Dynamics Processor IC. It features the binding posts. that of C1 and C2). R2 and R3 further improve THAT1206 InGenius line receiver ICs. 4305 connected in a basic three-control (ratio, Completely assembled and tested, this system RFI rejection. To facilitate prototyping specific applications, threshold and gain) compressor/limiter circuit. An spare circuit board area is perforated with plated- comes with XLR connectors for signal input and external (15V) power supply is required. InGenius circuit operation is enabled by through holes. This makes the board particularly output, and a 3 pin header for connection to an bootstrapping the ICs common mode input Completely assembled and tested, the 4305- useful for experimentation. external regulated DC power supply. impedance via C4. CMout is the output of an DEMO comes with XLR connectors for signal input With a 4305-DEMO and standard audio cables, and output. A ZIF socket is provided for easy inser- on-board amplifier connected to sample the J1 is a Female XLR connector that can an engineer can start testing the performance of tion of a 4305. To simplify testing of the 4305 VCA accept a balanced or unbalanced input signal, common mode voltage at pins 2 and 3. CMin basic 4305 circuitry and begin trying out additional section, the board includes an external control uses the AC coupled version of this voltage to while P1, a male XLR connector, delivers an circuit ideas in minutes. voltage (CV) input. The RMS detector output is bootstrap the internal resistors provided to refer- unbalanced output from the IC line receiver. An ence the inputs to the Ref pin (typically connected external 15V power supply should be connected via header P2 (labeled CN1 on some older to ground) and to provided a return for the input revisions of the PCB fabrication). bias currents when the IC is AC coupled. The net effect is to make the IC nearly immune to imbal- C1-C3 shunt unwanted RFI currents to ances in common mode source impedances over chassis ground. The arrangement of these the audio frequency range. Putting an components minimizes CMRR degradation at +15 TP1 R4 0R D1 + C7 P2 1N4004 22u TP2 3 2 1 J1 (INPUT) + C8 D2 XLR-FEMALE INPUT 22u TP3 1N4004 POWER 2 1 3 -15 P1 (OUTPUT) +15 XLR-M 1 5 4 2 3 R6 1 2 4k75 C4 + 3 C5 R2 220u 100n 100R 2 8 C1 In- 1 3 24 5 7 TP6 470p CMout TP4 Vcc R1 5 6 C3 CMin Out Ref 51R Vee 3 1 100p C2 In+ 4 U1 470p TP5 R3 R5 THAT1206 0R 100R C6 RFI Protection 100n See applications section of the THAT1200 datsheet for alternatives -15 Figure 1. THAT1200 Demonstration System Schematic THAT Corporation 45 Sumner Street Milford, MA 01757-1656 USA Tel: +1 508 478 9200 Fax: +1 508 478 0990 Web: www.thatcorp.com Document 600036 Rev 01+ Doc. 600036 Rev. 01 InGenius Line Receiver IC Demonstration System unbalanced impedance in the location of R2 or consequence, these components cannot load any R3 is a useful way to test this feature. potentially unbalanced common mode source impedance. Without this loading, there cannot be While C4 provides a means to bootstrap the any common mode to differential conversion that ICs internal input impedance, it does nothing for might otherwise be associated with external impedances (like the capacitors in the un-bootstrapped loads. RFI protection). R6 improves this situation under many circumstances. At frequencies where To ease prototyping of specific applications, the impedance of R6 is substantially less than spare circuit board area is perforated with plated that of C3 (and the THAT120x has sufficient through holes. This makes this board particu- GBW product), the common node of C1-3 and R6 larly useful for experimentation. will be driven by a replica of the common mode With a THAT1200 Demonstration System voltage found on pins 2 and 3. Since the and standard audio cables, an engineer can begin common mode voltage cannot develop across C1 evaluating the performance of the THAT1200 and C2, there cannot be any current associated series of InGenius line receivers in seconds, with this common mode voltage, and as a and try out new circuit ideas in minutes. Molex male header 22-23-2031 Mating housing: Molex 22-01-2037 and 4-40 Threaded crimp terminal 2759 or equivalent Standoff (4 pl) V+ V- P2 1 THAT 1200 Series XLR + + D1 D2 Demo Board Connector C7 C8 TP2 Circuit Design 2003 TP3 TP1 THAT Corporation R4 D7 C3 C4 P1 J1 R6 C5 TP4 R3 U1 3.000 2.600 R1 R2 C6 TP5 D8 Input Output 3.800 .200 0.200 4.000 Standoff is TP6 Figure 2. THAT1200 Demonstration System Outline Drawing THAT Corporation 45 Sumner Street Milford, MA 01757-1656 USA Tel: +1 508 478 9200 Fax: +1 508 478 0990 Web: www.thatcorp.com C1 R5 C2 D5 D3 D6 D4