• Pre-trimmed Blackmer® Voltage Controlled Amplifier (VCA)
• RMS-Level Detector
• Single supply operation
• Wide voltage range: 4.5V ~ 16V
• Low supply current:1.6 mA typ. (5V)
• Wide dynamic range: 118 dB as compressor

Datasheet Download

Datasheet Download
4315 Datasheet (208 kB)
Low-voltage Low-power Low Cost Dynamics Processor


• Companding noise reduction systems

— Wireless microphones
— Wireless instrument packs
— Wireless in-ear monitors

• Battery-operated dynamics processors

— Compressors
— Limiters
— AGCs
— De-essers


The THAT4315 is a single-chip Analog Engine optimized for low-voltage, low-power operation. Incorporating a high-performance Blackmer® voltage-controlled amplifier (VCA), RMS-level sensor, the surface mount part is aimed at battery-operated audio applications such as wireless microphones, wireless instruments and in-ear monitors. The 4315 operates from a single supply voltage down to +4.5Vdc, drawing only 1.6mA.

Key Specifications(see1510/1512 datasheetfor complete specifications)




Power supply voltage

4.5 to 16


Supply current





Dynamic Range



Gain Range

-60 to +60


Total Harmonic Distortion



Control Constant
(both positive & negative- sense control available)

± 6.2


Output Noise

0 dB gain



RMS Detector

Averaging Method

Root Mean Squared (RMS)

Output Scaling



Dynamic Range




> 20


Crest Factor

1 dB reading error





Order Number

Pricing (1000)

Min Order Quantity



16 Pin QSOP




Request Samples

16 Pin QSOP Tape & Reel


Contact us


All 4315 parts are RoHS compliant. Minimum Order Quantity (MOQ) is one tube or one reel. Parts must be ordered in multiples of the MOQ. Samples are available for qualified applicants. Pricing is subject to change.
ICs designated -UR are available on tape and reel for a modest increase in price and require an extended lead time. Please contact our sales department for pricing and current lead time.
Design Notes(as PDF files)

Design Note 00ABasic Compressor/Limiter Design (113k) (formerly Application Note 100A)

Design Note 01AThe Mathematics of Log-Based Dynamic Processors (64k) (formerly Application Note 101A)

Design Note 02Digital Gain Control with Analog VCAs (106k) (formerly Application Note 102)

Design Note 03Signal Limiter for Power Amplifiers (95k) (formerly Application Note 103)

Design Note 04Improving Loudspeaker Signal Handling Capability (217k) (formerly Application Note 104)

Design Note 05A Low Parts Count, Two-Slope Compressor (78k) (Application Note 105)

Design Note 100A Fully Adjustable Noise Gate (69k)

Design Note 101Peak Detection with the THAT4301 (37k)

Design Note 102Adjustable Ducker using the THAT 4301 (76k)

Design Note 107/111A Simple Effective Soft-Knee Compressor / Limiter (81k)

Design Note 108Single Chip Automatic Gain Control  (73k)

Design Note 112LED Bar-Graph Compression Indictor (83k)

Design Note 113THAT4301 Gain Reduction Indicator (33k)

Design Note 114Adaptive Attack and Release Rates using THAT RMS Detectors (48k)

Design Note 115Fully Adjustable Compressor/Limiter (46k)

Design Note 116Techniques for Stereo Volume Control (126k)

Design Note 117Input Limited for ADCs (120k)

Design Note 118High Performance Stereo AGC (90k)

Design Note 119Wide Ranging dB Meter (177k)

Design Note 125The “One Knob Squeezer”  (90k)

Design Note 128What’s a PTAT Temp. Coefficient, & Where Does It Come From?  (64k)

Design Note 131Dealing with the PTAT Coefficient (75k)

Design Note 132Alternate Method of Indicating Compression (52k)

Related Products
Other Analog Engines
THAT 4305 Low-cost basic Analog Engine for dual supply voltages. 4305 Datasheet
THAT 4320 Low-voltage, low-power versatile Analog Engine for single supply voltages. 4320 Datasheet
THAT 4316 Very low-voltage, low-power basic Analog Engine for single supply voltages. 4316 Datasheet
Voltage Controlled Amplifiers (VCAs)
THAT 2180 Series Pre-trimmed Blackmer VCAs 2180 Series Datasheet
THAT 2181 Series Trimmable Blackmer VCAs 2181 Series Datasheet
THAT 2162 Dual Blackmer VCAs 2162 Datasheet

Additional Resources

Analog Engine Selector
A side by side comparison of the features and specifications of our Analog Engine dynamic processor ICs.

4315 Surface Mount Adapter Board
– For our integrated circuits which are only available in surface mount packages THAT Corporation offers adapter boards which allow one of these surface-mount ICs to interface to a circuit board via traditional thru-hole mounting. These adapters make it easy for a design engineer to evaluate our surface-mount products on a prototype board without having to employ SMT technology. Adapter boards are available to qualified applicants.

Harsh Environment Packaging
– TT Semiconductor repackages THAT Corporation’s IC products in ruggidized plastic for the medical, aerospace, defense, and heavy industrial marketplaces.

The History of VCAs
– THAT Blackmer® VCAs are the successors to the original dbx® line of VCAs. Their development for professional audio use has a long history, and can provide some insight into the care and feeding of these essential devices.

4305 Material Data Declaration Sheet
Material Data Declaration Sheets (MDDS) disclose the hazardous materials in our integrated circuits as required by the European RoHS directive.