THAT 4305 Low-Cost Analog Engine^®

The THAT4305 is a single-chip Analog Engine optimized for low-cost applications. It incorporates a high-performance Blackmer® voltage-controlled amplifier (VCA) and log-responding RMS-level sensor. The VCA and RMS detector are pre-trimmed at wafer stage to deliver low distortion without further adjustment.

Available only in a small (QSOP) surface- mount package, the 4305 is aimed at line-operated audio applications such as compressor/limiters, gates, and other dynamic processors. The part normally operates from a split supply voltage up to ±16 Vdc, drawing only 3.5 mA at ±15 V. This IC also works at supply voltages as low as ±4.5 V, making it useful in some battery-operated products as well.

The 4305 was developed specifically for use in low-cost dynamics processors, drawing from THAT's long history and experience with such designs. Both VCA control ports and the detector input and output are available for the designer to connect as s/he sees fit. As a result, the part is extremely flexible and can be configured for a wide range of applications including single- and multi-band companders, digital overload protectors, voltage-controlled faders, level indicators, etc.

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.

For a side by side comparison chart of our family of Analog Engines, see our Analog Engine Selector Guide.

Features   · Pre-trimmed Blackmer® VCA and         RMS-level detector   · Wide supply voltage range: ±4.5V ~±16V   · Low supply current: 3.5 mA typ. (±15V)   · Wide dynamic range:        117 dB (VCA)        60 dB (RMS-level detector) Applications   · Compressors & Limiters   · Gates & Expanders   · AGCs   · Line-operated dynamics processors   · De-Essers   · Duckers   · Mixers   · Level indicators   · Companding noise reduction systems		Basic Specifications (typical) VCA Section    Gain Range: -60 to +60 dB     Gain-Control Constant: ± 6.2 mV/dB     Output Noise: -97.5 dBV (typ, 0 dB gain)     Total Harmonic Distortion: 0.07 %     Dynamic Range: 117 dB Detector Section    Averaging Method: Root Mean Square (RMS)     Output Scaling: +6.2 mV/dB     Dynamic Range: 60 dB     Bandwidth: > 20 kHz     Crest Factor: 10 (for 1 dB reading error) Overall    Power supply voltage: ±4.5 to ±16 V     Supply current: typically 3.5 mA (±15V)

For complete specifications, download a copy of the 4305 Datasheet. Datasheets are provided in Adobe's PDF format. You need to have Adobe Acrobat Reader installed on your computer to view the file. To obtain a free copy of Acrobat Reader follow the link at right.

Model	Package	Order Number	Pricing (1000)	Min Order Quantity	Reference
4305	16 Pin QSOP	4305Q16-U	$2.59	98	Datasheet RoHS Info

The 4305 is available on tape and reel for a modest increase in price and requires an extended lead time. Tape and reel parts have a 2000 piece minimum and must be ordered in multiples of 2000. Please contact our sales department for pricing and delivery.

All 4305 parts are RoHS compliant.
Minimum Order Quantity is one tube full. Parts must be ordered in multiples of the MOQ.
Samples are available for qualified applicants.
Pricing is subject to change.

The THAT 4305 Demonstration System (US$100) allows the engineer to test the performance of a THAT4305 quickly and easily. The 4305 Demo Board is self-contained circuit board with XLR connectors for signal input and output and a 3-pin header for connection to an external regulated DC power supply (not included). Contact us for more information.

For samples or further pricing information please contact us or one of our international distributors.