RHYTHM SB3230 Preconfigured DSP System for Hearing Aids

RHYTHM SB3230
Preconfigured DSP System
for Hearing Aids
Description
• 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
I2C and SDA Programming
Rocker Switch Support for Memory Change and/or Volume Control
Adjustment
Analog or Digital Volume Control with Programmable Range
25 PAD
HYBRID
CASE 127DN
PAD CONNECTION
VIN2
17
18
VIN1
1
VREG
TIN
16
19
TR4
2
MGND
DAI
15
20
TR3
3
GND
VC
14
21
TR2
4
PGND
D_VC
13
22
TR1
5
OUT+
SDA
12
23
N/C
6
OUT−
CLK
11
7
VBP
MS1
10
25
24
N/C
Features
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N/C
The RHYTHMt SB3230 hybrid from ON Semiconductor is
a trimmer−configurable DSP system based on a four−channel
compression circuit featuring adaptive feedback cancellation and
adaptive noise reduction.
Based on a phase cancellation method, SB3230’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.
The SB3230’s Adaptive Noise Reduction monitors noise levels
independently in 64 individual bands and employs advanced
psychoacoustic models to provide user comfort.
In addition to these adaptive algorithms, SB3230 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 I2C Interface
provides full programmability at the factory and in the field.
SB3230 hybrid contains a 256 kbit EEPROM intended for
programmable and trimmer based devices.
9
8
VB
MS2
(Bottom View)
MARKING DIAGRAM
SB3230−E1
XXXXXX
SB3230 = Specific Device Code
E1
= RoHS Compliant Hybrid
XXXXXX = Work Order Number
ORDERING INFORMATION
See detailed ordering and shipping information on page 13 of
this data sheet.
© Semiconductor Components Industries, LLC, 2014
November, 2014 − Rev. 3
1
Publication Order Number:
SB3230/D
RHYTHM SB3230
•
•
•
•
•
•
•
•
• 128−bit Fingerprint Security System and Other Security
High Quality 20−bit Audio Processing
High Power/High Gain Capability
SOUNDFIT® Fitting Software
Configurable Low Battery Indicator
Eight Biquadratic Filters
16 kHz or 8 kHz Bandwidth
Four Fully Configurable Memories with Audible
Memory Change Indicator
96 dB Input Dynamic Range with HRXt Headroom
Extension
•
•
•
•
•
Features to Protect against Device Cloning and
Software Piracy
High Fidelity Audio CODEC
Soft Acoustic Fade between Memory Changes
Drives Zero−Bias Two−Terminal Receivers
E1 RoHS−compliant Hybrid
Hybrid Typical Dimensions:
0.220 x 0.125 x 0.060 in
(5.59 x 3.18 x 1.52 mm)
BLOCK DIAGRAM
MS2
MS1
9
SDA
10
VB
CLK
12
11
8
PROGRAMMING
INTERFACE
VREG
1
MIC1
18
REGULATOR
FEEDBACK
CANCELLER
TONE
GENERATOR
MIC2
17
TIN
16
DAI
15
MGND
2
A/D
A/D
+
PRE BIQUAD FILTERS
1−4
POST BIQUAD FILTERS
3&4
1, 2 or 4 CHANNEL
WDRC, EQ, ANR
AGC−O
MIC / TELECOIL
COMPENSATION
CROSS
FADER
D/A
HBRIDGE
PEAK
CLIPPING
EVOKE
POST BIQUAD FILTERS
1&2
VC GAIN
WIDEBAND GAIN
NOISE GENERATOR
TRIMMER/VC INTERFACE
BIQUAD 1−4
SB3230
13
14
22
21
20
19
3
D_VC
VC
TR1
TR2
TR3
TR4
GND
Figure 1. Hybrid Block Diagram
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2
7
VBP
5
OUT+
6
OUT −
4
PGND
RHYTHM SB3230
SPECIFICATIONS
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Value
Units
0 to +40
°C
−20 to +70
°C
25
mW
Maximum Operating Supply Voltage
1.65
VDC
Absolute Maximum Supply Voltage
1.8
VDC
Operating Temperature Range
Storage Temperature Range
Absolute Maximum Power Dissipation
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
WARNING: Electrostatic Sensitive Device − Do not open packages or handle except at a static−free workstation.
WARNING:
Moisture Sensitive Device − RoHS Compliant; Level 4 MSL. Do not open packages except under controlled conditions.
Table 2. ELECTRICAL CHARACTERISTICS (Supply Voltage VB = 1.25 V; Temperature = 25°C)
Parameter
Hybrid Current
Symbol
Conditions
Min
Typ
Max
Units
IAMP
All Functions, 32 kHz Sampling Rate
−
660
−
mA
All Functions, 16 kHz Sampling Rate
−
490
−
Ramp Down, Audio Path
0.93
0.95
0.97
Ramp Down, Control Logic
0.77
0.80
0.83
VBON
Ramp Up
1.06
1.10
1.16
V
EEPROM Burn Cycles
−
−
100 k
−
−
cycles
Low Frequency System Limit
−
−
−
125
−
Hz
Minimum Operating Supply Voltage
Supply Voltage Turn On Threshold
High Frequency System Limit
VBOFF
V
−
−
−
16
−
kHz
THD
VIN = −40 dBV
−
−
1
%
THDM
VIN = −15 dBV, HRX − ON
−
−
3
%
fCLK
−
3.973
4.096
4.218
MHz
−
8 kHz Bandwidth
−
4.2
−
ms
−
16 kHz Bandwidth
−
4.0
−
−
SB3230
−
1600
−
ms
VREG
−
0.87
0.90
0.93
V
PSRRSYS
1 kHz, Input Referred, HRX Enabled
−
70
−
dB
Input Referred Noise
IRN
Bandwidth 100 Hz − 8 kHz, HRX on
−
−108
−106
dBV
Input Impedance
Total Harmonic Distortion
THD at Maximum Input
Clock Frequency
Audio Path Latency
System Power On Time (Note 1)
REGULATOR
Regulator Voltage
System PSRR
INPUT
ZIN
1 kHz
−
3
−
MW
Anti−aliasing Filter Rejection
−
f = fCLK/2 − 8 kHz, VIN = −40 dBV
−
80
−
dB
Crosstalk
−
Between both A/D and Mux
−
60
−
dB
Maximum Input Level
−
−
−15
−13
−
dBV
VAN_IN
VIN1, VIN2, Al
0
−
800
mV
VAN_TIN
TIN
−100
−
800
−
HRX − ON Bandwidth
100 Hz − 8 kHz
−
95
96
Analogue Input Voltage Range
Input Dynamic Range
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3
dB
RHYTHM SB3230
Table 2. ELECTRICAL CHARACTERISTICS (Supply Voltage VB = 1.25 V; Temperature = 25°C) (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
−
100 Hz − 8 kHz
−
88
−
dB
ZOUT
−
−
10
13
W
Resolution (Monotonic)
−
−
7
−
−
bits
Zero Scale Level
−
−
−
0
−
V
Full Scale Level
−
−
−
VREG
−
V
RVC
Three−terminal Connection
100
−
360
kW
−
−
−
−
42
dB
Logic 0 Voltage
−
−
0
−
0.3
V
Logic 1 Voltage
−
−
1
−
1.25
V
Stand−by Pull Up Current
−
Creftrim = 6
3
5
6.5
mA
Sync Pull Up Current
−
Creftrim = 6
748
880
1020
mA
Max Sync Pull Up Current
−
Creftrim = 15
−
1380
−
mA
Min Sync Pull Up Current
−
Creftrim = 0
−
550
−
mA
Logic 0 Current (Pull Down)
−
Creftrim = 6
374
440
506
mA
Logic 1 Current (Pull Up)
−
Creftrim = 6
374
440
506
mA
TSYNC
Baud = 0
237
250
263
ms
Baud = 1
118
125
132
OUTPUT
D/A Dynamic Range
Output Impedance
CONTROL A/D
VOLUME CONTROL
Volume Control Resistance
Volume Control Range
PC_SDA INPUT
PC_SDA OUTPUT
Synchronization Time
(Synchronization Pulse Width)
Baud = 2
59
62.5
66
Baud = 3
29.76
31.25
32.81
Baud = 4
14.88
15.63
16.41
Baud = 5
7.44
7.81
8.20
Baud = 6
3.72
3.91
4.10
Baud = 7
1.86
1.95
2.05
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
1. Times do not include additional programmable startup delay.
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4
RHYTHM SB3230
Table 3. I2C TIMING
Standard Mode
Fast Mode
Symbol
Min
Max
Min
Max
Units
Clock Frequency
fPC_CLK
0
100
0
400
kHz
Hold Time (Repeated) START Condition. After this
Period, the First Clock Pulse is Generated.
tHD;STA
4.0
−
0.6
−
msec
LOW Period of the PC_CLK Clock
tLOW
4.7
−
−
−
msec
HIGH Period of the PC_CLK Clock
tHIGH
4.0
−
−
−
msec
Set−up Time for a Repeated START Condition
tSU;STA
4.7
−
−
−
msec
Data Hold Time:
for CBUS Compatible Masters
for I2C−bus Devices
tHD;DAT
5.0
0
(Note 1)
−
3.45
(Note 2)
−
0
(Note 1)
−
0.9
(Note 2)
Data Set−up Time
tSU;DAT
250
−
100
−
nsec
Rise Time of Both PC_SDA and PC_CLK Signals
tr
−
1000
20 + 0.1 Cb
(Note 4)
300
nsec
Fall Time of Both PC_SDA and PC_CLK Signals
tf
−
300
20 + 0.1 Cb
(Note 4)
300
nsec
tSU;STO
4.0
−
0.6
−
nsec
tBUF
4.7
−
1.3
−
msec
Output Fall Time from VIHmin to VILmax with a Bus
Capacitance from 10 pF to 400 pF
tof
−
250
20 + 0.1 Cb
(Note 4)
250
nsec
Pulse Width of Spikes which Must Be Suppressed by
the Input Filter
tSP
n/a
n/a
0
50
nsec
Capacitive Load for Each Bus Line
Cb
−
400
−
400
pF
Parameter
Set−up Time for STOP Condition
Bus Free Time between a STOP and START Condition
msec
1. A device must internally provide a hold time of at least 300 ns for the PC_SDA signal to bridge the undefined region of the falling edge of PC_CLK.
2. The maximum tHD;DAT has only to be met if the device does not stretch the LOW period (tLOW) of the PC_CLK signal.
3. A Fast−mode I2C−bus device can be used in a Standard−mode I2C−bus system, but the requirement tSU;DAT P250ns must then be met.
This will automatically be the case if the device does not stretch the LOW period of the PC_CLK signal. If such a device does stretch the
LOW period of the PC_CLK signal, it must output the next data bit to the PC_SDA line tr max + tSU;DAT = 1000 + 250 = 1250 ns (according
to the Standard−mode I2C−bus specification) before the PC_CLK line is released.
4. Cb = total capacitance of one bus line in pF.
TYPICAL APPLICATIONS
VB
9
10
12
11
8
PROGRAMMING
INTERFACE
1
REGULATOR
FEEDBACK
CANCELLER
TONE
GENERATOR
3k9
A/D
18
PRE BIQUAD FILTERS
1−4
+
3k9
CROSS
FADER
17
A/D
16
1, 2 or 4 CHANNEL
WDRC, EQ, ANR
AGC−O
POST BIQUAD FILTERS
1&2
VC GAIN
WIDEBAND GAIN
MIC / TELECOIL
COMPENSATION
7
OUT
POST BIQUAD FILTERS
3&4
D/A
HBRIDGE
PEAK
CLIPPING
15
2
NOISE GENERATOR
TRIMMER/VC INTERFACE
BIQUAD 1−4
SB3230
13
14
22
21
20
19
3
Note: All resistors in ohms and all capacitors in farads, unless otherwise stated.
Figure 2. Test Circuit
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5
LP FILTER
6
4
EVOKE
1k
5
RHYTHM SB3230
TYPICAL APPLICATIONS (continued)
VB
MS2
MS1
To Programming box
9
12
10
11
8
PROGRAMMING
INTERFACE
REGULATOR
1
FEEDBACK
CANCELLER
TONE
GENERATOR
A/D
18
PRE BIQUAD FILTERS
1−4
+
CROSS
FADER
17
A/D
16
1, 2 or 4 CHANNEL
WDRC, EQ, ANR
MIC / TELECOIL
COMPENSATION
7
POST BIQUAD FILTERS
3&4
5
D/A
HBRIDGE
PEAK
CLIPPING
6
AGC−O
4
EVOKE
15
POST BIQUAD FILTERS
1&2
VC GAIN
WIDEBAND GAIN
2
NOISE GENERATOR
TRIMMER/VC INTERFACE
BIQUAD 1−4
SB3230
14
13
22
20
21
3
19
VC
200 k
Note: All resistors in ohms and all capacitors in farads, unless otherwise stated.
Figure 3. Typical Programmable Application Circuit
VB
Reed Switch
For Autotcoil
22
MS1
47μ
9
12
10
11
8
PROGRAMMING
INTERFACE
1
REGULATOR
FEEDBACK
CANCELLER
TONE
GENERATOR
A/D
18
PRE BIQUAD FILTERS
1−4
+
POST BIQUAD FILTERS
3&4
CROSS
FADER
17
A/D
16
1, 2 or 4 CHANNEL
WDRC, EQ, ANR
MIC / TELECOIL
COMPENSATION
7
D/A
HBRIDGE
PEAK
CLIPPING
POST BIQUAD FILTERS
1&2
4
VC GAIN
WIDEBAND GAIN
2
NOISE GENERATOR
TRIMMER/VC INTERFACE
BIQUAD 1−4
SB3230
13
14
22
VC
21
TR1
20
TR2 TR3
3
19
TR4
Note: All resistors in ohms and all capacitors in farads, unless otherwise stated.
Figure 4. Typical Trimmer Application Circuit
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6
6
AGC−O
EVOKE
15
5
RHYTHM SB3230
SB3230 OVERVIEW
The DSP core implements Adaptive Feedback
Cancellation, Adaptive Noise Reduction, compression,
wideband gain, and volume control. The Adaptive Feedback
Canceller reduces acoustic feedback while offering robust
performance against pure tones.
During trimmer mode operation, a low−speed A/D circuit
monitors the positions of up to four manual trimmers and
a VC potentiometer. Trimmer position changes are
immediately interpreted and translated into new circuit
parameter values, which are then used to update the signal
path.
SB3230 is a DSP system implemented on
ON Semiconductor’s Wolverinet hardware platform.
Wolverine is the hearing industry’s first 90 nm
Silicon−on−Chip
platform
enabling
design
of
highly−efficient and flexible hearing aid solutions. The
device is packaged for easy integration into a wide range of
applications from CIC to BTE. SB3230 can be used as a
programmable or trimmer adjustable device. It may be
configured as one, two or four channels with linear or
WDRC processing. Configuration data stored in
non−volatile memory defines hearing−aid parameters.
SB3230 can be programmed via the SDA or I2C
programming interfaces.
FUNCTIONAL BLOCK DESCRIPTION
• Low input level linear region
• Compression region
• High input level linear region (return to linear)
A/D and D/A Converter
The system’s A/D converter is a 2nd−order sigma−delta
modulator operating at a 2.048 MHz sample rate.
The system’s input is pre−conditioned with anti−alias
filtering and a programmable gain pre−amplifier. The
analog output is oversampled and modulated to produce
a 1−bit pulse density modulated (PDM) data stream. The
digital PDM data is then decimated down to pulse−code
modulated (PCM) digital words at the system’s sampling
rate of 32 kHz.
The D/A is comprised of a digital 3rd−order sigma−delta
modulator and an H−bridge. The modulator accepts PCM
audio data from the DSP path and converts it into a 64−times
oversampled, 1−bit PDM data stream, which is then
supplied to the H−bridge. The H−bridge is a specialized
CMOS output driver used to convert the 1−bit data stream
into a low−impedance, differential output voltage waveform
suitable for driving zero−biased hearing aid receivers.
0
High Level
Gain
OUTPUT LEVEL (dBV)
−10
−20
−30 Low Level
−40 Gain
−50
Compression
Ratio
Lower
Threshold
Upper
Threshold
−60
−70
−80
Squelch
Threshold
−90
−100
−120 −110 −100 −90 −80 −70 −60 −50 −40 −30 −20
INPUT LEVEL (dBV)
Figure 5. Independent Channel I/O Curve Flexibility
Analog Inputs
SB3230 provides for up to four analog inputs,
Microphone 1 (MIC1), Microphone 2 (MIC2), Telecoil
(TCOIL) and Direct Audio Input (DAI) with the following
configurable front end modes:
• 1 Mic Omni
• 1 Mic Omni (Rear channel only)
• DAI
• TCOIL
• 1 Mic Omni + TCOIL
• 1 Mic Omni + DAI
Channel I/O processing is specified by the Squelch
threshold (SQUELCHTH) and any four of the following
five parameters (only four of the five properties are
independent):
• Low level gain (LLGAIN)
• Lower threshold (LTH)
• High level gain (HLGAIN)
• Upper threshold (UTH)
• Compression ratio (CR)
During the Parameter Map creation, constraints are
applied to the compression parameters to ensure that the
I/O characteristics are continuous. Parameter adjustments
support two popular styles of compression ratio adjustment:
• The compression region of the I/O curve pivots about
the upper threshold. As the compression ratio trimmer
is adjusted, high−level gain remains constant while the
low−level gain changes.
Attenuation can be applied to the input when mixing with
either TCOIL or DAI inputs.
Channel Processing
Figure 5 represents the I/O characteristic of independent
AGC channel processing. The I/O curve can be divided into
four main regions:
• Low input level expansion (squelch) region
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RHYTHM SB3230
• The compression region of the I/O curve pivots about
Feedback path
the lower threshold. Low−level gain remains constant
as the compression ratio trimmer is adjusted.
+
The squelch region within each channel implements a low
level noise reduction scheme (1:3 expansion) for listener
comfort. This scheme operates in quiet listening
environments (programmable threshold) to reduce the gain
at very low levels.
−
Σ
H
G
H’
Estimated feedback
Automatic Telecoil
Figure 6. Adaptive Feedback Canceller (AFC)
Block Diagram
The automatic telecoil feature in SB3230 is to be used
with memory D programmed with the telecoil or
MIC + TCOIL front end configuration. The feature enables
the part to transition to memory D upon the closing of
a switch connected to MS2. With the feature enabled and
a reed switch connected to MS2, the static magnetic field of
a telephone handset will close the switch whenever the
handset is brought close to the device, causing the hybrid to
change to memory D. The part will transition back to the
initial memory once the switch is deemed opened after
proper debouncing.
A debounce algorithm with a programmable debounce
period is used to prevent needless switching in and out of
memory D due to physical switch bounces when MS2 is
configured for automatic telecoil. Upon detecting a close to
open switch transition, the debounce algorithm monitors the
switch status. The debounce algorithm switches the device
out of memory D only once the switch signal has been
continuously sampled open over the specified debounce
period.
Feedback Path Measurement Tool
The feedback path measurement tool uses the onboard
feedback cancellation algorithm and noise generator to
measure the acoustic feedback path of the device. The noise
generator is used to create an acoustic output signal from the
hearing aid, some of which leaks back to the microphone via
the feedback path. The feedback canceller algorithm
automatically calculates the feedback path impulse response
by analyzing the input and output signals. Following
a suitable adaptation period, the feedback canceller
coefficients can be read out of the device and used as an
estimate of the feedback−path impulse response.
Adaptive Noise Reduction
The noise reduction algorithm is built upon a high
resolution 64−band filter bank (32 bands at 16 kHz
sampling) enabling precise removal of noise. The algorithm
monitors the signal and noise activities in these bands, and
imposes a carefully calculated attenuation gain
independently in each of the 64 bands.
The noise reduction gain applied to a given band is
determined by a combination of three factors:
• Signal−to−Noise Ratio (SNR)
• Masking threshold
• Dynamics of the SNR per band
Adaptive Feedback Canceller
The Adaptive Feedback Canceller (AFC) reduces
acoustic feedback by forming an estimate of the hearing aid
feedback signal and then subtracting this estimate from the
hearing aid input. The forward path of the hearing aid is not
affected. Unlike adaptive notch filter approaches, SB3230’s
AFC does not reduce the hearing aid’s gain. The AFC is
based on a time−domain model of the feedback path.
The third−generation AFC (see Figure 6) allows for an
increase in the stable gain (Note 1) of the hearing instrument
while minimizing artefacts for music and tonal input signals.
As with previous products, the feedback canceller provides
completely automatic operation.
The SNR in each band determines the maximum amount
of attenuation to be applied to the band − the poorer the SNR,
the greater the amount of attenuation. Simultaneously, in
each band, the masking threshold variations resulting from
the energy in other adjacent bands is taken into account.
Finally, the noise reduction gain is also adjusted to take
advantage of the natural masking of ‘noisy’ bands by speech
bands over time.
1. Added stable gain will vary based on hearing aid style and
acoustic setup. Please refer to the Adaptive Feedback
Cancellation Information note for more details.
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RHYTHM SB3230
Based on this approach, only enough attenuation is
applied to bring the energy in each ‘noisy’ band to just below
the masking threshold. This prevents excessive amounts of
attenuation from being applied and thereby reduces
unwanted artifacts and audio distortion. The Noise
Reduction algorithm efficiently removes a wide variety of
types of noise, while retaining natural speech quality and
level. The level of noise reduction (aggressiveness) is
configurable to 3, 6, 9 and 12 dB of reduction.
GND
VC
D_VC
Volume Control, Trimmers and Switches
Figure 7. Wiring for Digital Volume Control
External Volume Control
The volume of the device can either be set statically via
software or controlled externally via a physical interface.
SB3230 supports both analog and digital volume control
functionality, although only one can be enabled at a time.
Digital control is supported with either a momentary switch
or a rocker switch. In the latter case, the rocker switch can
also be used to control memory selects.
Memory Select Switches
Two Memory Select (MS) interfaces are available to
support one or two 2−pole switches that can be used to
switch between up to four memory profiles. The MS
interface can be configured for the use of either momentary
or static switches. The interface hardware can be configured
to internally activate either a pull−up or pull−down resistor,
depending on the physical wiring of the switch.
The audio path is temporarily faded−out and an acoustic
indicator is optionally played out whenever the device
transitions between memories. Each memory is assigned
a unique acoustic indicator. See the Evoke Lite Acoustic
Indicators section for details on the acoustic indicators and
related configurations.
NOTE: In situations where D−Only mode is activated,
there is an option to disable the MS2 pin for
products that may contain a reed switch, and you
want to have it disabled.
Analog Volume Control
Both the external (analog) volume control and trimmers
work with a three−terminal 100 kW – 360 kW variable
resistor. The volume control can have either a log or linear
taper, which is selectable via software. It is possible to use
a VC with up to 1 MW of resistance, but this could result in
a slight decrease in the resolution of the taper.
Trimmers
The trimmer interface provides the ability to control up to
19 hearing aid parameters through up to four trimmers.
A single trimmer parameter can have up to 16 values and
a single trimmer can control multiple parameters
(e.g., Trimmer 1 can control compression ratio in all four
channels simultaneously). The trimmer must be
three−terminal 100 kW to 360 kW variable resistors and
have a linear taper.
Parameters that can be assigned to trimmers include Noise
Reduction, Low Cut, High Cut, Compression Ratio,
Wideband Gain, Tinnitus Noise Level, Crossover
Frequency, Lower Threshold, Upper Threshold, EQ Gain,
Squelch Threshold, High Level Gain, Low Level Gain,
AGC−O Threshold, Static Volume Control and Peak Clipper
Threshold.
NOTE: There may be limitations to which parameters
can be used together.
Momentary Switch on MS1
This mode uses a single momentary switch on MS1 input
to change memories. Using this mode causes the part to start
in memory A, and whenever the button is pressed, the next
valid memory is loaded. When the user is in the last valid
memory, a button press causes memory A to be loaded.
Thus, the possible selection sequences are:
If 4 valid memories: ABCDABCDA…
If 3 valid memories: ABCABCA…
If 2 valid memories: ABABA…
If 1 valid memory: AAA…
Momentary Switch on MS1, Static Switch on MS2
(D−only, Jump to Last Memory)
This mode uses a static switch on MS2 and a momentary
switch on MS1 to change memories. It can be used to support
the Automatic Telecoil feature, see section Automatic
Telecoil. There are two possible configurations, depending
on the setting of the pull−up/pull−down resistors.
Digital Volume Control
The digital volume control makes use of two pins for
volume control adjustment, VC and D_VC, with
momentary switches connected to each. Closure of the
switch to the VC pin indicates a gain increase while closure
to the D_VC pin indicates a gain decrease. Figure 7 shows
how to wire the digital volume control to SB3230.
www.onsemi.com
9
RHYTHM SB3230
Case 1. Pull−up/Pull−down Resistors set to Pull−down
Table 4. STATIC SWITCH TRUTH TABLE:
D−ONLY ENABLED; INTERNAL RESISTORS SET TO
PULL−DOWN (EXAMPLE WITH THREE−VALID
MEMORIES)
If the static switch on MS2 is LOW, the part starts in
memory A and is controlled by the momentary switch on
MS1 as described in section Momentary Switch on MS1,
with the exception that memory D is not used. If the static
switch on MS2 is set to HIGH, the part automatically jumps
to memory D (occurs on startup or during normal operation).
In this setup, the state of the momentary switch on MS1 is
ignored. When MS2 is set to LOW, the part loads in the
memory that was active prior to jumping to memory D.
The possible memory selection sequences are:
If MS2 = LOW and there are four valid memories, MS1
selects: ABCABCA…
If MS2 = LOW and there are three valid memories, MS1
selects: ABABA…
If MS2 = LOW and there is one valid memory: A
If MS2 = HIGH: D
Binary State (MS1/MS2)
Selected Memory
00
Memory A
10
Memory B
x1
Memory D
Table 5. STATIC SWITCH TRUTH TABLE:
D−ONLY ENABLED; INTERNAL RESISTORS SET TO
PULL−UP (EXAMPLE WITH THREE VALID
MEMORIES)
Binary State (MS1/MS2)
Selected Memory
01
Memory A
11
Memory B
x0
Memory D
Case 2. Pull−up/Pull−down Resistors set to Pull−up
If the static switch on MS2 is HIGH, the part starts in
memory A and is controlled by the momentary switch on
MS1 as described in section Momentary Switch on MS1,
with the exception that memory D is not used. If the static
switch on MS2 is set to LOW, the part automatically jumps
to memory D (occurs on startup or during normal operation).
In this setup, the state of the momentary switch on MS1 is
ignored. When MS2 is set to HIGH, the part loads in the
memory that was active prior to jumping to memory D.
The possible memory selection sequences are:
If MS2 = HIGH and there are four valid memories, MS1
selects: ABCABCA...
If MS2 = HIGH and there are three valid memories, MS1
selects: ABABA...
If MS2 = HIGH and there is one valid memory: A
If MS2 = LOW: D
Static Switch on MS1 and MS2
This mode uses two static switches to change memories.
In this mode, it is possible to jump from any memory to any
other memory by changing the state of both switches. If the
two switches are changed one after the other, the part
transitions to an intermediate memory before reaching the
final memory. The part starts in whatever memory the
switches are selecting. If a memory is invalid, the part
defaults to memory A.
Table 6. STATIC SWITCH TRUTH TABLE:
D−ONLY DISABLED
Binary State (MS1/MS2)
Selected Memory
00
Memory A
10
Memory B
01
Memory C
11
Memory D
Static Switch on MS1, Static Switch on MS2
(D−Only, Jump to Last Memory)
This mode uses two static switches to change memories.
Similar to the behaviour described in the Static Switch on
MS1 and MS2 section, this mode will switch to memory D
if the static switch on MS2 is HIGH (the state of the switch
on MS1 is ignored). The mode, however, supports
a maximum of three memories (even if four valid memories
are programmed). This mode can be used to support the
Automatic Telecoil feature (see the Automatic Telecoil
section).
In this mode, it is possible to jump from any memory to
any other memory by changing the state of both switches. If
the two switches are changed one after the other, the part
transitions to an intermediate memory before reaching the
final memory.
The part starts in whatever memory the switches are
selecting. If a memory is invalid, the part defaults to
memory A.
Rocker Switch Support
The device supports connection of a rocker switch to the
digital volume control interface that can perform volume
control (VC) adjustments and/or memory selection (MS).
There are three modes of operation:
• Digital Volume Control Mode
• Momentary Memory Select Mode
• Mixed Mode (VC and MS)
In Digital VC mode, the rocker switch provides the digital
volume control functionality described in this section.
In Momentary Memory Select mode, the rocker switch
allows cycling through the memory profiles in both
directions. An “up” switch closure indicates a program
advance to the next higher numbered memory and “down”
www.onsemi.com
10
RHYTHM SB3230
the coefficients into the hybrid. If the Interactive Data Sheet
receives an exception from the underlying stability checking
code, it automatically disables the biquad being modified
and displays a warning message. When the filter is made
stable again, it can be re−enabled.
Also note that in some configurations, some of these
filters may be used by the product component for
microphone/telecoil compensation, low−frequency EQ, etc.
If this is the case, the coefficients entered by the user into
IDS are ignored and the filter designed by the software is
programmed instead. For more information on filter design
refer to the Biquad Filters In PARAGONt Digital Hybrid
information note.
switch closures indicates a program retreat to the next lower
numbered memory. In this mode, volume control is only
available through software control.
In Mixed Mode, operation of the switch as a volume
control or memory select is governed by the time duration
of the switch closure: either short or long. The
discrimination of short and long pulses is set by
a programmable, time−threshold value, from 1 s to 5 s in 1 s
increments. An additional programmable parameter
determines whether the short pulses refer to volume−control
operation or memory−select operation.
If long pulses control memory select operation, the
memory change is initiated once the switch is held for the
long pulse period without requiring the switch to be
released. In Digital VC mode or Momentary Memory Select
mode, the action takes place after the switch is released.
Tinnitus Treatment Noise
The Tinnitus Treatment noise is generated using white
noise generator hardware and shaping the generated noise
using four 2nd order biquadratic filters. The filter parameters
are the same coefficients as those presented in the
Biquadratic Filters section.
The Tinnitus Treatment noise can be added into the signal
path at two possible locations: before the VC (before the
AGC−O, but compensated for the Wideband Gain) or after
the VC (between the last generic biquad and the Cross
Fader).
If the noise is injected before the VC and the audio path
is also enabled, the device can be set up to either have both
the audio path and noise adjust via the VC, or to have only
the noise adjust via the VC (see Table 7). If the noise is
injected after the VC, it is not affected by VC changes.
AGC−O
The AGC−O module is an output limiting circuit with
a fixed compression ratio of ∞ : 1. The limiting level is
programmable as a level measured in dB from full scale. The
maximum output of the device is 0 dBFS.
The AGC−O module has its own level detector, with
programmable attack and release time constants.
Graphic Equalizer
SB3230 has a 8−band graphic equalizer. Each band
provides up to 31 dB of gain adjustment in 1 dB increments.
Biquadratic Filters
Additional frequency shaping can be achieved by
configuring generic biquad filters. The transfer function for
each of the biquad filters is as follows:
H(z) + b0 ) b1
1 ) a1
z −1 ) b2
z −1 ) a2
Table 7. NOISE INSERTION MODES
Noise Insertion Modes
z −2
z −2
Off
NOTE: The a0 coefficient is hard−wired to always be
‘1’. The coefficients are each 16 bits in length
and formatted as one sign bit, one integer bit and
14 fractional bits. This maps onto a decimal
range of −2.0 to 2.0 before quantization (−32767
to 32767 after quantization).
Thus, before quantization, the floating−point coefficients
must be in the range −2.0 ≤ x < 2.0 and quantized with the
function:
round ǒx 2 14Ǔ
VC Controls
Noise Injected
Audio
Off
Pre VC
Audio + Noise
Pre VC
Post VC
Audio
Post VC
Noise only Pre VC
Noise
Pre VC
Noise only Post VC
−
Post VC
Pre VC with Noise
Noise
Pre VC
EVOKE Lite Acoustic Indicators
Ten Acoustic Indicators are available for indicating
events. Each indicator is fixed to a particular event. Any
event can have its assigned indicator enabled or disabled
although not always independently. Individual enable/
disable control is provided for the following event or group
of events:
• Power on reset (POR)
• Four memory selects
• Volume Up and Volume Down
• Volume Max and Volume Min
• Low Battery
After designing a filter, the quantized coefficients can be
entered into the PreBiquads or PostBiquads tab in the
Interactive Data Sheet. The coefficients b0, b1, b2, a1, and
a2 are as defined in the transfer function above. The
parameters meta0 and meta1 do not have any effect on the
signal processing, but can be used to store additional
information related to the associated biquad.
The underlying code in the product components
automatically checks all of the filters in the system for
stability (i.e., the poles have to be within the unit circle)
before updating the graphs on the screen or programming
Each Acoustic Indicator is made up of up to four faded
tones. A faded tone exhibits a nominal 32 ms fade−in and
www.onsemi.com
11
RHYTHM SB3230
Advanced Reset Mode
fade−out transition time. The duration of an Acoustic
Indicator is configurable, with a maximum value of 6.35
seconds.
EVOKE Lite Acoustic Indicators can be programmed as
output referred or input referred (prior to the filter bank).
Advanced Reset Mode on SB3230 is a more sophisticated
power management scheme than shallow and deep reset
modes. This mode attempts to maximize the device’s usable
battery life by reducing the gain to stabilize the supply based
on the instantaneous and average supply voltage levels.
Instantaneous supply fluctuations below 0.95 V can trigger
up to two 3 dB, instantaneous gain reductions. Average
supply drops below 0.95 V can trigger up to eighteen, 1 dB
average gain reductions.
While the average supply voltage is above 0.95 V, an
instantaneous supply voltage fluctuation below 0.95 V will
trigger an immediate 3 dB gain reduction. After the 3 dB
gain reduction has been applied, the advanced reset model
holds off checking the instantaneous voltage level for
a monitoring period of 30 second in order to allow the
voltage level to stabilize. If after the stabilization time the
instantaneous voltage drops a second time below 0.95 V
during the next monitoring period, the gain will be reduced
an additional 3 dB for a 6 dB total reduction and a 30 second
stabilization time is activated. The advanced reset mode
continues to monitor the instantaneous voltage levels over
30 second monitoring periods. If the instantaneous voltage
remains above 1.1 V during that monitoring period, the gain
will be restored to the original setting regardless of whether
one or two gain reductions are applied. If two gain
reductions are applied and the instantaneous voltage level
remains above 1.0 V for a monitoring period, the gain will
be restored to a 3 dB reduction.
Should the average supply voltage drop below 0.95 V, the
device will then reduce the gain by 1 dB every 10 seconds
until either the average supply voltage rises above 0.95 V or
a total of 18 average gain reductions have been applied, at
which point the audio path will be muted. If the average
supply voltage returns to a level above 1.1 V, the audio path
will first be un−muted, if required. The gain will then be
increased by 1 dB every 10 seconds until either the average
supply voltage drops below 1.1 V, or all average gain
reductions have been removed. No action is taken while the
average supply voltage resides between 0.95 V and 1.1 V.
NOTE: Instantaneous and average gain reductions are
adjusted independently.
When the instantaneous voltage falls below the hardware
shutdown voltage, the device will undergo a hardware reset.
When it turns back on because the voltage has risen above
the turn−on threshold of 0.6 V, it will behave the same as it
would in shallow reset mode.
Power Management
SB3230 has three user−selectable power management
schemes to ensure the hearing aid turns off gracefully at the
end of battery life. Shallow reset, Deep reset and Advanced
Reset mode. It also contains a programmable power on reset
delay function.
Power On Reset Delay
The programmable POR delay controls the amount of
time between power being connected to the hybrid and the
audio output being enabled. This gives the user time to
properly insert the hearing aid before the audio starts,
avoiding the temporary feedback that can occur while the
device is being inserted. During the delay period,
momentary button presses are ignored.
Power Management Functionality
As the voltage on the hearing aid battery decreases, an
audible warning is given to the user indicating the battery
life is low. In addition to this audible warning, the hearing
aid takes other steps to ensure proper operation given the
weak supply. The exact hearing aid behaviour in low supply
conditions depends on the selected POR mode. The hearing
aid has three POR modes:
• Shallow Reset Mode
• Deep Reset Mode
• Advanced Mode
Shallow Reset Mode
In Shallow Reset mode, the hearing aid will operate
normally when the battery is above 0.95 V. Once the supply
voltage drops below 0.95 V the audio will be muted and
remain in that state until the supply voltage rises above
1.1 V. Once the supply voltage drops below the control logic
ramp down voltage, the device will undergo a hardware
reset. At this point, the device will remain off until the supply
voltage returns to 1.1 V. When the supply voltage is below
the control logic voltage, but above 0.6 V and rises above the
1.1 V turn on threshold, the device will activate its output
and operate from the memory that was active prior to reset.
If the supply voltage drops below 0.6 V, and rises above the
1.1 V turn on threshold, the device will reinitialize, activate
its output and operate from memory A.
Low Battery Notification
Deep Reset Mode
Notification of the low battery condition via an acoustic
indicator is optionally performed when the battery voltage
drops below a configurable low battery notification
threshold. The low battery indicator is repeated every five
minutes until the device shuts down.
In Deep Reset mode, the hearing aid will operate normally
when the battery is above 0.95 V. Once the supply voltage
drops below 0.95 V the audio will be muted. The device
remains in this state until the supply voltage drops below the
hardware reset voltage of 0.6 V. When this occurs, the
device will load memory A and operate normally after the
supply voltage goes above 1.1 V.
www.onsemi.com
12
RHYTHM SB3230
parameters in ARKonline® can be selected to reduce the
number of pages that need to be read out. In SDA mode,
SB3230 is programmed via the SDA pin using industry
standard programming boxes. I2C mode is a two−wire
interface which uses the SDA pin for bidirectional data and
CLK as the interface clock input. I2C programming support
is available on the HiPro (serial or USB versions) and
ON Semiconductor’s DSP Programmer 3.0.
SDA and I2C Communication
I2C
SB3230 can be programmed using the SDA or
protocol. During parameter changes, the main audio signal
path of the hybrid is temporarily muted using the memory
switch fader to avoid the generation of disturbing audio
transients. Once the changes are complete, the main audio
path is reactivated. Any changes made during programming
are lost at power−off unless they are explicitly burned to
EEPROM memory.
Improvements have been made to the ARK software,
resulting in improved communication speed. Certain
ORDERING INFORMATION
Device
SA3230−E1−T
Package
Shipping†
25 Pad Hybrid
Case 127DN
250 Units / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
Hybrid Jig Ordering Information
To order a Hybrid Jig Evaluation Board for SB3230 contact your Sales Account Manager or FAE and use part number
SA3405GEVB.
www.onsemi.com
13
RHYTHM SB3230
PAD LOCATIONS
Table 8. PAD POSITION AND DIMENSIONS
Pad Position
Pad Dimensions
Pad No.
X
Y
Xdim (mil)
Ydim (mil)
1
0
0
20
33
2
−27
0
20
33
3
−54
−5
20
23
4
−81
−5
20
23
5
−108
−5
20
23
6
−135
−5
20
23
7
−162
−5
20
23
8
−189
0
20
33
9
−189
42
20
23
10
−189
85
20
23
11
−162
85
20
23
12
−135
85
20
23
13
−108
85
20
23
14
−81
85
20
23
15
−54
85
20
23
16
−27
85
20
23
17
0
85
20
23
18
0
42
20
23
19
−27
42
20
23
20
−54
42
20
23
21
−81
42
20
23
22
−108
42
20
23
23
−135
42
20
23
24
−162
26.5
18
12
25
−162
53.5
18
12
www.onsemi.com
14
RHYTHM SB3230
Table 8. PAD POSITION AND DIMENSIONS
Pad No.
X
Y
Xdim (mm)
Ydim (mm)
1
0
0
0.508
0.838
2
−0.686
0
0.508
0.838
3
−1.372
−0.127
0.508
0.584
4
−2.057
−0.127
0.508
0.584
5
−2.743
−0.127
0.508
0.584
6
−3.429
−0.127
0.508
0.584
7
−4.115
−0.127
0.508
0.584
8
−4.801
0
0.508
0.838
9
−4.801
1.067
0.508
0.584
10
−4.801
2.159
0.508
0.584
11
−4.115
2.159
0.508
0.584
12
−3.429
2.159
0.508
0.584
13
−2.743
2.159
0.508
0.584
14
−2.057
2.159
0.508
0.584
15
−1.372
2.159
0.508
0.584
16
−0.686
2.159
0.508
0.584
17
0
2.159
0.508
0.584
18
0
1.067
0.508
0.584
19
−0.686
1.067
0.508
0.584
20
−1.372
1.067
0.508
0.584
21
−2.057
1.067
0.508
0.584
22
−2.743
1.067
0.508
0.584
23
−3.429
1.067
0.508
0.584
24
−4.115
0.673
0.457
0.305
25
−4.115
1.359
0.457
0.305
www.onsemi.com
15
RHYTHM SB3230
PACKAGE DIMENSIONS
SIP25, 5.59x3.18
CASE 127DN
ISSUE O
E
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. COPLANARITY APPLIES TO THE SPHERICAL
CROWNS OF THE PADS.
A B
D
PIN A1
INDICATOR
0.13 C
2X
0.13 C
2X
e
ÈÈÈ
ÈÈÈ
3X
L2
20X
2X
TOP VIEW
L
L3
A2
2X
b1
0.13 C
DETAIL A
A
0.05 C
A1
NOTE 3
C
SIDE VIEW
DIM
A
A1
A2
b
b1
D
E
e
e1
e2
e3
L
L2
L3
MILLIMETERS
MIN
MAX
−−−
1.83
0.08
0.18
−−−
1.65
0.478
0.538
0.427
0.487
3.18 BSC
5.59 BSC
0.686 BSC
0.051 BSC
1.067 BSC
1.092 BSC
0.554
0.614
0.808
0.868
0.275
0.335
SEATING
PLANE
e
e/2
e2
A
e
e/2
B
e1
C
e3
1
2
3
4
5
6
7
8
23X
b
0.05
0.03
BOTTOM VIEW
C A
C
B
RECOMMENDED
SOLDERING FOOTPRINT*
NOTE 4
23X
0.538
0.686
1.092
20X
1.067
0.614
2X
2X
0.487
0.335
0.051
3X
0.686
0.868
A1
DETAIL B
0.686
PITCH
DETAIL B
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
www.onsemi.com
16
RHYTHM SB3230
RHYTHM, HRX, PARAGON, WOLVERINE and EVOKE Lite are trademarks of Semiconductor Components Industries, LLC.
SOUNDFIT and ARKonline are registered trademarks of Semiconductor Components Industries, LLC.
ON Semiconductor and the
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.
SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed
at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation
or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets
and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each
customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended,
or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which
the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or
unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim
alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable
copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
Literature Distribution Center for ON Semiconductor
P.O. Box 5163, Denver, Colorado 80217 USA
Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada
Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada
Email: [email protected]
N. American Technical Support: 800−282−9855 Toll Free
USA/Canada
Europe, Middle East and Africa Technical Support:
Phone: 421 33 790 2910
Japan Customer Focus Center
Phone: 81−3−5817−1050
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17
ON Semiconductor Website: www.onsemi.com
Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
SB3230/D