4305-DEMO THAT Corporation, 4305-DEMO Datasheet
4305-DEMO
Specifications of 4305-DEMO
Related parts for 4305-DEMO
4305-DEMO Summary of contents
Page 1
... What really sets the 4305 apart from other manufacturers’ offerings is the transparent sound of its Blackmer VCA, coupled with its accurate true- RMS level detector. This makes the IC useful in a wide range of analog audio products. ...
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... Reference is to output offset with -60 dB VCA gain. THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com THAT4305 Pre-trimmed Analog Engine® SPECIFICATIONS -40 to +85 ºC Supply Voltages (V -40 to +125 ºC VCA Control Voltage ...
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... THAT Corporation's application note AN101A, The Mathe- matics of Log-Based Dynamic Processors. The VCA - in Brief The VCA in the 4305 is based on THAT Corpo- ration's highly successful complementary log-antilog gain cell topology (the Blackmer® VCA) as used in THAT 2180-Series IC VCAs. VCA symmetry is trimmed distortion ...
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... Finally, as gain approaches 30 dB, output noise begins to increase directly with gain. While the 4305's VCA circuitry is very similar to that of the THAT 2180 Series VCAs, there are several important differences, as follows. 1. Supply current for the 4305 VCA depends on the supply voltage. At ± ...
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... Feedforward Topologies To make a compressor or limiter with a 4305, typically, the input signal is applied to both the VCA and the RMS detector. The RMS output signal is fed forward to the VCA's negative control port (E dc-coupled op-amp based stage ...
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... Practical gates usually require very fast attack times, and carefully programmable release times 4305, this is best accomplished by using the RMS detector as a log rectifier with very short time constants, and following the detector output with a time-constant stage that applies the desired attack and release behavior. This alters the 4305 detector’ ...
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... It is possible to compress (encode) signals using the low-voltage, low-power 4315 or 4320 in a handheld, battery-operated device such as a wireless microphone or instrument belt pack, and expand (decode) that signal using the 4305 in a rack- mount, line-operated receiver. The Mathematics of Log-Based Dynamics Processors At first, the logarithmic output of the RMS detec- ...
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... Substituting the second equation into the first, Out dB Out dB OutdB = In Out dB dB Figure 6. Feedback compressor with level match. THAT4305 Pre-trimmed Analog Engine® (0 dBu). Additionally, it RMS - selecting asymmetrical voltage-to vary the "level where G is the ...
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... LM= -40 0 Out -20 dB -40 -60 -80 -100 -120 -120 Figure 8. Compressor input-output transfer k=1 0 -20 -40 − -60 -80 -120 Figure 9. Compressor input-output transfer ). For the 4305, 140 100 60 20 -20 -60 -100 -140 -60 Figure 10. Expander input-output transfer but fixed -20 -40 -60 -80 -100 -120 -60 Figure 11. Expander input-output transfer ...
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... The output level increases over change in input level -10 -20 . -30 V -40 -50 -60 -70 -80 -90 -100 -100 Figure 13. Transfer function of feedforward compressor THAT4305 Pre-trimmed Analog Engine® G Out dB dB Ideal Diode - This is especially convenient =20 dB, and k=0.75, this dB dB Out In -80 -60 -40 ...
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... Ideal Diode - Figure 14. Feedback compressor with threshold (T), gain (A), and ratio (k) adjustments THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com Substituting yields Out dB which can be reduced to Out dB For output signals below the level set by the ...
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... As mentioned above, many other configurations of the 4305 are possible. THAT intends to publish additional circuits in forthcoming applications notes. Please check with THAT's applications engineering department to see if your application has been covered yet, and for personalized assistance with specific designs ...
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... RMS level of the input voltage. The output of the detector will be approximately zero volts at the "zero dB reference level" -- the point at which the RMS value of the input current equals the timing current (set at 7.5 μA for the 4305). We have chosen a value of -10 dBu, (245 mV ) for the zero dB reference RMS level ...
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... R3 5k1 C4 220p Figure 17. 4305 simple compander circuit - 2:1 encoder (compressor) THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com THAT4305 Pre-trimmed Analog Engine® etc.). The static gain of this circuit zero dB, and a 5.1 kΩ ...
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... The required encoder VCA gain range is - +36 dB, and the required decoder VCA gain range is - +14 dB. These gains are easily within the capabilities of the 4305’s VCA. The range of RMS input currents is easily accommodated at the high end, though accuracy may be slightly compromised at the lowest input levels ...
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... This floor occurs when the RMS current through R1 equals that of R6, and when the current through R10 equals that of R12. This Since the input of the RMS detector is at virtual ground, the current through R6 and R12 will be For a THAT4305 Pre-trimmed Analog Engine® ), the dB ...
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... RMS In 5 RMS Out 2 8k87 CT U3A 4 THAT4305 C13 10u 11 EC+ 15 VCA In VCA Out EC- R13 5k1 12 C21 220p Figure 21. 4305 hi-fi 2:1 decoder circuit Page −50dBV ( ) = 3.16mV . Therefore, 20 RMS (−23.6−(−50))$0.0062 = , And 459k l 464k 0.00316V 8.87k C5 22p R2 84k5 U3 Encode Out ...
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... RMS detector input current. Other Dynamics Processor Configurations We have said before that the building blocks contained within the 4305 are applicable to a very THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com wide range of dynamics processor configurations ...
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... Document 600067 Rev 01 Package and Soldering Information The THAT 4305 is available in a 16-pin QSOP package. The package dimensions are shown in Figure 23 below, while the pinout is given in Table 1 on page 1. The 4305 is available in a lead-free, "green" package. The lead frame is copper, plated with successive layers of nickel palladium, and gold ...
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... Page THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com THAT4305 Pre-trimmed Analog Engine® Notes: ...