© Semiconductor Components Industries, LLC, 2014
November, 2014 − Rev. 4
1 Publication Order Number:
SB3231/D
RHYTHM SB3231
Pre-configured DSP System
for Hearing Aids
Description
ON Semiconductor’s RHYTHM t SB3231 hybrid is
a trimmer−configurable DSP system based on a four−channel
compression circuit featuring Adaptive Feedback Cancellation,
Adaptive Noise Reduction, and FrontWave static directionality.
Based on a phase cancellation method, Rhythm SB3231’s Adaptive
Feedback Reduction algorithm provides added stable gain to enable
extra gain and user comfort. It features rapid adjustment for dynamic
feedback situations and resistance to tonal inputs.
Rhythm SB3231’s Adaptive Noise Reduction monitors noise levels
independently in 64 individual bands and employs advanced
psychoacoustic models to provide user comfort.
The FrontWave directional system utilizes a pair of microphones to
create a fully customizable static polar pattern, such as bidirectional,
cardiod, hyper−cardiod and super−cardiod.
In addition to these adaptive algorithms, Rhythm SB3231 also
supports the following features: up to four channel WDRC,
low−distortion compression limiting, cross fading between audio
paths for click−free memory changes, eight−band graphic equalizer,
eight configurable generic biquad filters, programming speed
enhancements, in−channel squelch to attenuate microphone and
circuit noise in quiet environments, optional peak clipping, flexible
compression adjustments, volume control, rocker switch, noise
generation for Tinnitus treatment, and industry−leading security
features to avoid cloning and software piracy.
A trimmer interface supports manual circuit configuration. It
continuously monitors trimmer positions and translates them into the
hearing−aid parameters of choice. A Serial Data or I
2
C Interface
provides full programmability at the factory and in the field.
The Rhythm SB3231 hybrid contains a 256 kbit EEPROM intended
for programmable and trimmer based devices.
Features
• FrontWave Static Directional
• Adaptive Noise Reduction
• Adaptive Feedback Cancellation
• WDRC Compression with Choice of 1, 2 or 4 Channels of
Compression
• Auto Telecoil with Programmable Delay
• EVOKE LITEt Acoustic Indicators
• Noise Generator for Tinnitus Treatment or In−situ Audiometry
• Frequency Response Shaping with Graphic EQ
• Trimmer Compatibility – Four Three−Terminal
Trimmers with Configurable Assignments of Control
Parameters
www.onsemi.com
25 PAD
HYBRID
CASE 127DN
PAD CONNECTION
MARKING DIAGRAM
SB3231−E1
XXXXXX
SB3231 = Specific Device Code
E1 = RoHS Compliant Hybrid
XXXXXX = Work Order Number
(Bottom View)
1
2
3
4
5
6
7
8910
11
12
13
14
15
16
17
18
VIN1
19
TR4
20
TR3
21
TR2
22
TR1
23
N/C
25 24
VIN2
TIN
DAI
VC
D_VC
SDA
CLK
MS1
VREG
MGND
GND
PGND
OUT+
OUT−
VBP
VB
MS2
N/C
N/C
See detailed ordering and shipping information on page 14 o
this data sheet.
ORDERING INFORMATION
