Pre-configured DSP System for Hearing Aids RHYTHM SB3231 Description ON Semiconductors RHYTHM SB3231 hybrid is a trimmer configurable DSP system based on a four channel www.onsemi.com compression circuit featuring Adaptive Feedback Cancellation, Adaptive Noise Reduction, and directional processing. Based on a phase cancellation method, Rhythm SB3231s Adaptive 25 PAD Feedback Reduction algorithm provides added stable gain to enable HYBRID CASE 127DN extra gain and user comfort. It features rapid adjustment for dynamic feedback situations and resistance to tonal inputs. Rhythm SB3231s Adaptive Noise Reduction monitors noise levels independently in 64 individual bands and employs advanced PAD CONNECTION psychoacoustic models to provide user comfort. The directional processing system utilizes a pair of microphones to 18 VIN2 17 1 VREG create a fully customizable static polar pattern, such as bidirectional, VIN1 cardiod, hypercardiod and supercardiod. 19 16 2 MGND TIN In addition to these adaptive algorithms, Rhythm SB3231 also TR4 supports the following features: up to four channel WDRC, 20 GND lowdistortion compression limiting, cross fading between audio DAI 15 3 TR3 paths for clickfree memory changes, eightband graphic equalizer, 21 eight configurable generic biquad filters, programming speed PGND VC 14 4 TR2 enhancements, inchannel squelch to attenuate microphone and 22 circuit noise in quiet environments, optional peak clipping, flexible OUT+ D VC 13 5 TR1 compression adjustments, volume control, rocker switch, noise 23 generation for Tinnitus treatment, and industryleading security SDA OUT 12 6 N/C features to avoid cloning and software piracy. A trimmer interface supports manual circuit configuration. It VBP CLK 11 25 24 7 continuously monitors trimmer positions and translates them into the 2 hearingaid parameters of choice. A Serial Data or I C Interface VB provides full programmability at the factory and in the field. 10 9 8 MS1 The Rhythm SB3231 hybrid contains a 256 kbit EEPROM intended for programmable and trimmer based devices. MS2 (Bottom View) Features Directional Processing MARKING DIAGRAM Adaptive Noise Reduction SB3231E1 Adaptive Feedback Cancellation XXXXXX WDRC Compression with Choice of 1, 2 or 4 Channels of Compression SB3231 = Specific Device Code Auto Telecoil with Programmable Delay E1 = RoHS Compliant Hybrid XXXXXX = Work Order Number EVOKE Acoustic Indicators Noise Generator for Tinnitus Treatment or Insitu Audiometry ORDERING INFORMATION Frequency Response Shaping with Graphic EQ See detailed ordering and shipping information on page 14 of Trimmer Compatibility Four ThreeTerminal this data sheet. Trimmers with Configurable Assignments of Control Parameters Semiconductor Components Industries, LLC, 2014 1 Publication Order Number: March, 2021 Rev. 6 SB3231/D N/C N/CRHYTHM SB3231 2 I C and SDA Programming 96 dB Input Dynamic Range with Headroom Extension Rocker Switch Support for Memory Change and/or 128bit Fingerprint Security System and Other Security Volume Control Adjustment Features to Protect against Device Cloning and Software Piracy Support for Active Hi or Active Lo Switching High Fidelity Audio CODEC Analog or Digital Volume Control with Programmable Range Soft Acoustic Fade between Memory Changes High Quality 20bit Audio Processing Drives ZeroBias TwoTerminal Receivers High Power/High Gain Capability E1 RoHScompliant Hybrid SOUNDFIT Fitting Software Hybrid Typical Dimensions: 0.220 x 0.125 x 0.060 in Configurable Low Battery Indicator (5.59 x 3.18 x 1.52 mm) Eight Biquadratic Filters These Devices are PbFree and are RoHS Compliant 16 kHz or 8 kHz Bandwidth Four Fully Configurable Memories with Audible Memory Change Indicator BLOCK DIAGRAM VB MS2 MS1 SDA CLK 9 12 10 11 8 PROGRAMMING INTERFACE VREG REGULATOR 1 FEEDBACK CANCELLER TONE 7 VBP GENERATOR MIC1 18 A/D PRE BIQUAD FILTERS POST BIQUAD FILTERS 3 & 4 5 OUT+ 14 + D/A PEAK CROSS HBRIDGE CLIPPING FADER MIC2 17 6 OUT MIC / TELECOIL 1, 2 or 4 CHANNEL A/D AGCO COMPENSATION WDRC, EQ, ANR TIN 16 PGND 4 EVOKE DAI 15 POST BIQUAD FILTERS VC GAIN WIDEBAND GAIN 1 & 2 MGND 2 NOISE GENERATOR BIQUAD 14 TRIMMER/VC INTERFACE SB3231 13 14 22 21 20 19 3 D VC GND VC TR1 TR2 TR3 TR4 Figure 1. Hybrid Block Diagram www.onsemi.com 2