1. www.zetex.com Sub Woofer amplifier solutions An introduction

2. www.zetex.com Confidential Objectives Focussed market Quality solution for quality prospects Specific application: Subwoofers Added value for customers Flexible reference designs Ease of design Maintain value Competitive BOM cost

3. www.zetex.com Confidential Zetex audio product strengths Audio quality Value what it sounds like Value specifications Power & efficiency in a small space ‘Mid up’ power (50W to 500W) Smaller amplifiers & speakers Smaller PSUs Less heat Ease of implementation Integrated features Good support Reference designs

4. www.zetex.com Confidential Zetex audio market focus End product focus AVR (multi-channel) Stereo Subwoofer High end home theatre Powered speakers Distributed audio Pro-audio Non focus markets Very low power: mobile phone, MP3 player Mid power integrated: flat panel TV, theatre in a box, boom box, PC audio

5. www.zetex.com Confidential Zetex subwoofer customer profile End product brand Recognised quality product Sound commercial & technical opportunity Market influencer OEM/ODM Visible good link to end brand Already building subwoofer Electronic design capability Fit Audio: value performance Commercial: channel cost, volume match Technical: specifications, reference designs Support requirements Priority vs. capacity (time & effort) Use of reference designs & demo boards Key point: Try to link these together

6. www.zetex.com Confidential Switching amplifier theory A general recap on Class D Modulate an input signal with a clock to generate a PWM output Amplify the PWM signal with an H bridge and filter to recover the analogue power signal The advantages are: 90% efficiency (Class AB at 50%) Less heat dissipation Smaller PSU Cost effective solution But it still has to sound good: Zetex does!

7. www.zetex.com Confidential Switching amplifier theory Class AB 50% efficiency For 500W out, need 1kW in Class D 90% efficiency For 500W out, need 550W in Power supply Class AB Amplifier Audio input 500W 1000W Power supply Class D Amplifier Audio input 500W 50W 550W Actually in practice PSU can be smaller still. Typical audio content is 1/8 full power (but still must be able to supply short term full power)

8. www.zetex.com Confidential Switching amplifier products All Zetex switching amplifiers are Class D. Two types: Analogue input ZXCD Series based Focus on subwoofer applications Can still support mid power full band applications Digital input DDFA TM is the focus (Class Z) Not ready yet for general release

9. www.zetex.com Confidential Analogue input products Part numbers ZXCD1000/1010 Focus on: ZXCD1210 (New for subwoofers) Reference designs ZXCD50STEVAL: 50W 4Ω stereo ZXCD100MOEVAL: 100W 4Ω mono ZXCDSUBEV series: 150W to 500W 4Ω mono: (New for subwoofers)

10. www.zetex.com Confidential Why Class D for subwoofers? Subs reproduce deep bass in movie soundtracks  Sound you can feel (Explosions, rumbles etc)  Requirement for higher power  The ear is less sensitive to low frequencies  The trend to smaller cabinets and a requirement to reach a high sound pressure level (SPL)  Sealed cabinets offer no resonant assistance at low frequencies  Competition with other speakers (fronts, centre and surrounds) Subwoofer solution  A separate channel for low frequencies: Front end EQ  A higher power amplifier: Needs class D for efficiency  A self contained amplifier & speaker unit: Includes its own PSU

11. www.zetex.com Confidential Subwoofer supply Home theatre in a box  DVD receiver and speakers together  More likely to be passive subs Home theatre speaker sets  Higher quality systems  Powered or passive subs Subwoofer separates (most likely target)  Powered subs  Higher quality systems  Higher power  Custom install

12. www.zetex.com Confidential Subwoofer variants Downward firing drive unit Front firing drive unit Sealed or ported Passive radiator design  Second diaphragm on the back face of the sub Twin drive unit  Two drivers, possibly each with its own amp Twin voice coil unit  Single driver, twin coils, twin amps AMP

13. www.zetex.com Confidential What’s in a powered sub? Amplifier  High power & efficiency, cool running: Class D  Good performance: Damping factor, THD+N, DNR Power supply  Linear vs. switching  Regulated vs. unregulated Front end processing  Analogue audio input  Volume, phase, LP/HP filter Peripherals  Short, thermal, DC protection Power supply Peripherals Amplifier Front end Audio input HP filter (e.g. 10Hz) LP filter (e.g. 250Hz) Phase (e.g. 0 to 180) Mix & volume

14. www.zetex.com Confidential Where does the signal come from? LFE signal  Low frequency effects channel  Level preset at +10dB Bass management signal  Mix of low frequency information filtered from other channels HPF LPF +10dB Decoded AV source Bass Management Left Right Centre Left sur Right sur LFE Frequency Bass M’gement LFE Main channels Subwoofer bandwidth

15. www.zetex.com Confidential Subwoofer design issues Damping factor  Mass of drive unit and coil back EMF makes it difficult to control  Low amplifier output impedance helps significantly  Closed loop designs reduce output impedance  Ratio of load to amplifier output impedance is the damping factor Power supply  With unregulated supplies, amplifier must accommodate off load voltages and deal with supply dips  Means more headroom in the amp (higher power) and closed loop amp design (PSRR) Thermal  Subwoofer enclosure plus high power amplifier means lots of heat  High efficiency Class D is essential

16. www.zetex.com Confidential ZXCDSUBEV series (New) ZXCD1210 based (New) Opportunity for Zetex FETs  ZXMN10A09L3 in 150W design (New)  Other Zetex FETs in development Closed loop BTL (B) and SE (S) designs All N channel output Split power supply rail Optional additional circuits Zetex sub reference designs Architecture:

17. www.zetex.com Confidential New modulator: ZXCD1210 QFN16 4x4 Bottom view New device specification: ZXCD1210JB16 (New) Developed for ZXCDSUBEV series of reference designs Performance matched for ZXCDSUBEV reference designs QFN SM package  Smaller space (4mm x 4mm)  Thermally efficient (thermal pad)

18. www.zetex.com Confidential New FETs: ZXMN10A09 New device specification: ZXMN10A09L3 (New) Developed for ZXCDSUBEV150S reference design FETs for the rest of the reference designs under consideration TO220 package

19. www.zetex.com Confidential Solution value ZXCDSUBEV BOM cost is approximately $20 in volume This is low compared to many competitive solutions Must maintain the value in Zetex BOM content ZXCD1210$2 ZXMN10A09$0.25 (ea) Note: guide prices only. Always refer back to your local Zetex office

20. www.zetex.com Confidential AC feedback  Reduces THD+N  Increases supply rejection DC servo  Ensures no DC offset Feedback after inductor  Increased damping factor for tighter bass ZXCDSUBEV Series Why closed loop:

21. www.zetex.com Confidential Power options:  ZXCDSUBEV500B: 500W into 4   ZXCDSUBEV250B: 250W into 4   ZXCDSUBEV150S: 150W into 4  THD+N @ 1W to 400W 0.05%, Dynamic range 98dB Noise floor -135dB Damping factor >285 >90% efficiency Frequency response flat 10Hz to 250Hz (-3dB @ 5kHz) ZXCDSUBEV Series Performance:

22. www.zetex.com Confidential ZXCDSUBEV Series Power options: Output power (W) Supply voltage (±V) 75150250500 25 35 40 ZXCDSUBEV150S Single ended (SE) ZXCD1210 ZXMN10A09 ZXCDSUBEV250B Bridge tied load (BTL) ZXCD1210 ZXCDSUBEV500B Bridge tied load (BTL) ZXCD1210

23. www.zetex.com Confidential ZXCDSUBEV Series Architecture:

24. www.zetex.com Confidential THD+N <0.05% @ 1W to 400W ZXCDSUBEV Series Performance:

25. www.zetex.com Confidential Frequency response flat 10Hz to 250Hz ZXCDSUBEV Series Performance:

26. www.zetex.com Confidential ZXCDSUBEV Series Design flexibility: Supports PSU options  Unregulated linear: simplest to  Regulated switcher: most efficient Single platform  One design supports BTL and SE  One design supports power options Other features added easily  Front end: Volume, phase, high/low pass filters  Protection: Short circuit, thermal, DC

27. www.zetex.com Confidential ZXCDSUBEV Series Design flexibility:

28. www.zetex.com Confidential Zetex subwoofer platform advantage High performance solution Sound quality advantage High efficiency, cool running Small size Cost effective Single adaptable platform Flexible power range System power supply options Easy addition of value added features