Texas Instruments TLC320AC02IFNR, TLC320AC02IPM, TLC320AC02IFN, TLC320AC02CPM, TLC320AC02CFN Datasheet

TLC320AC02C, TLC320AC02I

Data Manual

Single-Supply Analog Interface Circuit

SLAS084C

October 1997

Printed on Recycled Paper

IMPORTANT NOTICE

Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any
semiconductor product or service without notice, and advises its customers to obtain the latest
version of relevant information to verify , before placing orders, that the information being relied
on is current.

TI warrants performance of its semiconductor products and related software to the specifications
applicable at the time of sale in accordance with TI’s standard warranty . T esting and other quality
control techniques are utilized to the extent TI deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed, except those
mandated by government requirements.

Certain applications using semiconductor products may involve potential risks of death,
personal injury, or severe property or environmental damage (“Critical Applications”).

TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT APPLICATIONS, DEVICES
OR SYSTEMS OR OTHER CRITICAL APPLICATIONS.

Inclusion of TI products in such applications is understood to be fully at the risk of the customer.
Use of TI products in such applications requires the written approval of an appropriate TI officer .
Questions concerning potential risk applications should be directed to TI through a local SC
sales office.

In order to minimize risks associated with the customer’s applications, adequate design and
operating safeguards should be provided by the customer to minimize inherent or procedural
hazards.

TI assumes no liability for applications assistance, customer product design, software
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machine, or process in which such semiconductor products or services might be or are used.

Copyright  1997, Texas Instruments Incorporated

iii

Contents

Section Title Page

1 Introduction 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 Features 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Functional Block Diagram 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.3 Terminal Assignments 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.4 Terminal Functions 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.5 Register Functional Summary 1–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 Detailed Description 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 Definitions and Terminology 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 Reset and Power-Down Functions 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.1 Reset 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.2 Conditions of Reset 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.3 Software and Hardware Power-Down 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.4 Register Default Values After POR, Software Reset,

or RESET Is Applied 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Master-Slave Terminal Function 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.4 ADC Signal Channel 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.5 DAC Signal Channel 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.6 Serial Interface 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.7 Number of Slaves 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.8 Required Minimum Number of MCLK Periods 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.8.1 TLC320AC02 AIC Master-Slave Summary 2–6. . . . . . . . . . . . . . . . . . . . . . . . . .

2.8.2 Notes on TLC320AC01/02 AIC Master-Slave Operation 2–7. . . . . . . . . . . . . . .

2.9 Operating Frequencies 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.9.1 Master and Stand-Alone Operating Frequencies 2–9. . . . . . . . . . . . . . . . . . . . .

2.9.2 Slave and Codec Operating Frequencies 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . .

2.10 Switched-Capacitor Filter Frequency (FCLK) 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.11 Filter Bandwidths 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.12 Master and Stand-Alone Modes 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.12.1 Register Programming 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.12.2 Master and Stand-Alone Functional Sequence 2–10. . . . . . . . . . . . . . . . . . . . . .

2.13 Slave and Codec Modes 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.13.1 Slave and Codec Functional Sequence 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.13.2 Slave Register Programming 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.14 Terminal Functions 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.14.1 Frame-Sync Function 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.14.2 Data Out (DOUT) 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.14.3 Data In (DIN) 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.14.4 Hardware Program Terminals (FC1 and FC0) 2–12. . . . . . . . . . . . . . . . . . . . . . .

2.14.5 Midpoint Voltages (ADC V

MID

and DAC V

MID

) 2–13. . . . . . . . . . . . . . . . . . . . . .

iv

2.15 Device Functions 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.1 Phase Adjustment 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.2 Analog Loopback 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.3 16-Bit Mode 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.4 Free-Run Mode 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.5 Force Secondary Communication 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.6 Enable Analog Input Summing 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.15.7 DAC Channel (sin x)/x Error Correction 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.16 Serial Communications 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.16.1 Stand-Alone and Master-Mode Word Sequence and Information Content

During Primary and Secondary Communications 2–15. . . . . . . . . . . . . . . . . . . .

2.16.2 Slave and Codec-Mode Word Sequence and Information Content During

Primary and Secondary Communications 2–16. . . . . . . . . . . . . . . . . . . . . . . . . .

2.17 Request for Secondary Serial Communication and Phase Shift 2–17. . . . . . . . . . . . .

2.17.1 Initiating a Request 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.17.2 Normal Combinations of Control 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.17.3 Additional Control Options 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.18 Primary Serial Communications 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.18.1 Primary Serial Communications Data Format 2–19. . . . . . . . . . . . . . . . . . . . . . .

2.18.2 Data Format From DOUT During Primary Serial Communications 2–19. . . . .

2.19 Secondary Serial Communications 2–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.19.1 Data Format to DIN During Secondary Serial Communications 2–19. . . . . . . .

2.19.2 Control Data-Bit Function in Secondary Serial Communication 2–19. . . . . . . .

2.20 Internal Register Format 2–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.1 Pseudo-Register 0 (No-Op Address) 2–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.2 Register 1 (A Register) 2–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.3 Register 2 (B Register) 2–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.4 Register 3 (A′ Register) 2–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.5 Register 4 (Amplifier Gain-Select Register) 2–22. . . . . . . . . . . . . . . . . . . . . . . . .

2.20.6 Register 5 (Analog Configuration Register) 2–22. . . . . . . . . . . . . . . . . . . . . . . . .

2.20.7 Register 6 (Digital Configuration Register) 2–23. . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.8 Register 7 (Frame-Sync Delay Register) 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . .

2.20.9 Register 8 (Frame-Sync Number Register) 2–24. . . . . . . . . . . . . . . . . . . . . . . . .

3 Specifications 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.1 Absolute Maximum Ratings Over Operating Free-Air Temperature Range 3–1. . . . .

3.2 Recommended Operating Conditions 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3 Electrical Characteristics Over Recommended Range of Operating Free-Air
Temperature, MCLK = 5.184 MHz, V

DD

= 5 V, Outputs Unloaded,

Total Device 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4 Electrical Characteristics Over Recommended Range of Operating Free-Air
Temperature, V

DD

= 5 V, Digital I/O Terminals (DIN, DOUT, EOC,

FC0, FC1, FS, FSD, MCLK, M/S, SCLK) 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5 Electrical Characteristics Over Recommended Range of Operating Free-Air
Temperature, V

DD

= 5 V, ADC and DAC Channels 3–2. . . . . . . . . . . . . . . . . . . . . . . . .

3.5.1 ADC Channel Filter Transfer Function, FCLK = 144 kHz, f

s

= 8 kHz 3–2. . . .

3.5.2 ADC Channel Input, V

DD

= 5 V, Input Amplifier Gain = 0 dB 3–3. . . . . . . . . . .

3.5.3 ADC Channel Signal-to-Distortion Ratio, V

DD

= 5 V, fs = 8 kHz 3–3. . . . . . . .

v

3.5.4 DAC Channel Filter Transfer Function, FCLK = 144 kHz, fs = 9.6 kHz,

V

DD

= 5 V 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5.5 DAC Channel Signal-to-Distortion Ratio, V

DD

= 5 V, fs = 8 kHz 3–4. . . . . . . .

3.5.6 System Distortion, V

DD

= 5 V, fs = 8 kHz, FCLK = 144 kHz 3–4. . . . . . . . . . . .

3.5.7 Noise, Low-Pass and Band-Pass Switched-Capacitor Filters Included,

V

DD

= 5 V 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5.8 Absolute Gain Error, V

DD

= 5 V, fs = 8 kHz 3–5. . . . . . . . . . . . . . . . . . . . . . . . . .

3.5.9 Relative Gain and Dynamic Range, V

DD

= 5 V, fs = 8 kHz 3–5. . . . . . . . . . . . .

3.5.10 Power-Supply Rejection, V

DD

= 5 V 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5.11 Crosstalk Attenuation, V

DD

= 5 V 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5.12 Monitor Output Characteristics, V

DD

= 5 V 3–7. . . . . . . . . . . . . . . . . . . . . . . . . .

3.6 Timing Requirements and Specifications in Master Mode 3–8. . . . . . . . . . . . . . . . . . .

3.6.1 Recommended Input Timing Requirements for Master Mode,

V

DD

= 5 V 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.6.2 Operating Characteristics Over Recommended Range of Operating Free-Air

Temperature, V

DD

= 5 V 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.7 Timing Requirements and Specifications in Slave Mode and Codec

Emulation Mode 3–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.7.1 Recommended Input Timing Requirements for Slave Mode,

V

DD

= 5 V 3–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.7.2 Operating Characteristics Over Recommended Range of Operating Free-Air

Temperature, V

DD

= 5 V 3–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 Parameter Measurement Information 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Typical Characteristics 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 Application Information 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vi

List of Illustrations

Figure Title Page

1–1 Control Flow Diagram 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1 Functional Sequence for Primary and Secondary Communication 2–5. . . . . . . . . . . . .

2–2 Timing Sequence 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–3 Master and Stand-Alone Functional Sequence 2–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–4 Slave and Codec Functional Sequence 2–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1 IN+ and IN– Gain-Control Circuitry 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–2 AIC Stand-Alone and Master-Mode Timing 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–3 AIC Slave and Codec Emulation Mode 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–4 Master or Stand-Alone FS and FSD Timing 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–5 Slave FS to FSD Timing 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–6 Slave SCLK to FSD Timing 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–7 DOUT Enable Timing From Hi-Z 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–8 DOUT Delay Timing to Hi-Z 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–9 EOC Frame Timing 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–10 Master-Slave Frame-Sync Timing After a Delay Has Been Programmed

Into the FSD Registers 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1 1Master and Slave Frame-Sync Sequence with One Slave 4–5. . . . . . . . . . . . . . . . . . . .

5–1 ADC Low-Pass Response 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–2 ADC Low-Pass Response 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–3 ADC Group Delay 5–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–4 ADC Band-Pass Response 5–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–5 ADC Band-Pass Response 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–6 ADC High-Pass Response 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–7 ADC Band-Pass Group Delay 5–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–8 DAC Low-Pass Response 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–9 DAC Low-Pass Response 5–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–10 DAC Low-P ASS Group Delay 5–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–1 1DAC (sin x)/x Correction Filter Response 5–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–12 DAC (sin x)/x Correction Filter Response 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–13 DAC (sin x)/x Correction Error 5–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii

List of Tables

Table Title Page

1–1 Operating Frequencies 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1 Master-Slave Selection 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–2 Sampling Variation With A′ 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–3 Software and Hardware Requests for Secondary Serial-Communication and

Phase-Shift Truth Table 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1 Gain Control 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1–1

1 Introduction

The TLC320AC02† analog interface circuit (AIC) is an audio-band processor that provides an
analog-to-digital and digital-to-analog input/output interface system on a single monolithic CMOS chip. This
device integrates a band-pass switched-capacitor antialiasing input filter, a 14-bit-resolution
analog-to-digital converter (ADC), a 14-bit-resolution digital-to-analog converter (DAC), a low-pass
switched-capacitor output-reconstruction filter, (sin x)/x compensation, and a serial port for data and control
transfers.

The internal circuit configuration and performance parameters are determined by reading control
information into the eight available data registers. The register data sets up the device for a given mode of
operation and application.

The major functions of the TLC320AC02 are:

1. T o convert audio-signal data to digital format by the ADC channel

2. To provide the interface and control logic to transfer data between its serial input and output
terminals and a digital signal processor (DSP) or microprocessor

3. T o convert received digital data back to an audio signal through the DAC channel

The antialiasing input low-pass filter is a switched-capacitor filter with a sixth-order elliptic characteristic. The
high-pass filter is a single-pole filter to preserve low-frequency response as the low-pass filter cutoff is
adjusted. There is a three-pole continuous-time filter that precedes this filter to eliminate any aliasing caused
by the filter clock signal.

The output-reconstruction switched-capacitor filter is a sixth-order elliptic transitional low-pass filter followed
by a second-order (sin x)/x correction filter. This filter is followed by a three-pole continuous-time filter to
eliminate images of the filter clock signal.

The TLC320AC02 consists of two signal-processing channels, an ADC channel and a DAC channel, and
the associated digital control. The two channels operate synchronously; data reception at the DAC channel
and data transmission from the ADC channel occur during the same time interval. The data transfer is in
2s-complement format.

There are three basic modes of operation available: the stand-alone analog-interface mode, the
master-slave mode, and the linear-codec mode. In the stand-alone mode, the TLC320AC02 generates the
shift clock and frame synchronization for the data transfers and is the only AIC used. The master-slave mode
has one TLC320AC02 as the master that generates the master-shift clock and frame synchronization; the
remaining AICs are slaves to these signals. In the linear-codec mode, the shift clock and the frame­synchronization signals are externally generated and the timing can be any of the standard codec-timing
patterns.

Typical applications for this device include modems, speech processing, analog interface for DSPs,
industrial-process control, acoustical-signal processing, spectral analysis, data acquisition, and
instrumentation recorders.

The TLC320AC02C is characterized for operation from 0°C to 70°C and the TLC320AC02I is characterized
for operation from –40°C to 85°C.

†

The TLC320AC02 is functionally equivalent to the TLC320AC01 and differs in the electrical specifications as shown
in Appendix C.

1–2

1.1 Features

• General-Purpose Signal-Processing Analog Front End (AFE)

• Single 5-V Power Supply

• Power Dissipation . . . 100 mW Typ

• Signal-to-Distortion Ratio . . . 70 dB Typ

• Programmable Filter Bandwidths (Up to 10.8 kHz) and Synchronous ADC and DAC Sampling

• Serial-Port Interface

• Monitor Output With Programmable Gains of 0 dB, –8 dB, –18 dB, and Squelch

• Two Sets of Differential Inputs With Programmable Gains of 0 dB, 6 dB, 12 dB, and Squelch

• Differential or Single-Ended Analog Output With Programmable Gains of 0 dB, –6 dB, –12 dB,

and Squelch

• Differential Outputs Drive 3-V Peak Into a 600-

Ω Differential Load

• Differential Architecture Throughout

• 1-

µm Advanced LinEPIC Process

• 14-Bit Dynamic-Range ADC and DAC

• 2s-Complement Data Format

LinEPIC is a trademark of Texas Instruments Incorporated.

1–3

1.2 Functional Block Diagram

DAC Channel

OUT–

OUT+

AUX IN–

AUX IN+

IN–

IN+

DAC

EOC

FSD

DIN

SCLK

MCL

K

DOUT

FS

RESETADC

V

MID

DGTL

GND

DAC
V

DD

PWR
DWN

Correction

(sin x)/x

Port

Serial

Reference

Voltage

Internal

ADC

ADC Channel

M
U
X

X

U

M

Filter

26
25
28
27

3
4

11
12

14
13

10
17
19

25 923 8

Filter

M/S

15
16

18

FC0
FC1

DAC
GND

720

DGTL

V

DD

ADC
V

DD

24

ADC
GND

22

SUBS21DAC

V

MID

6

1

MON OUT

Terminal numbers shown are for the FN package.

1.3 Terminal Assignments

321

13 14

5
6
7
8
9
10
11

IN–
ADC V

DD

ADC V

MID

ADC GND
SUBS
DGTL GND
EOC

DAC V

DD

DAC V

MID

DAC GND

RESET

DGTL V

DD

DIN

DOUT

4

15 16 17 18

SCLK

MCLK

FC0

FC1

FSD

M/S

OUT –

OUT +

PWR DWN

MON OUT

FN PACKAGE

(TOP VIEW)

28 27 26

25
24
23
22
21
20
19

12

FS

AUX IN +

AUX IN –

IN +

1–4

1.3 Terminal Assignments (Continued)

18 19

NC
NC
OUT–
NC
NC
OUT+
PWR

DWN
NC
MON OUT
NC
AUXIN+
AUXIN–
IN+
IN–
NC
NC

48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33

20

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

DIN

NC

DOUT

FS
NC
NC
NC

SCLK

NC

MCLK

FC0
FC1

NC

FSD

NC

M/S

21 22 23 24

PM PACKAGE

(TOP VIEW)

NC

DAC GND

63 62 61 60 5964 58

NCNCNC

DGTL VNCRESET

NC

NC

ADC GND

NC

NC

NC

NC

NC

DGTL GND

NC

SUBS

NC

56 55 5457

25 26 27 28 29

53 52

17

EOC

NC

NC

51 50 49

30 31 32

MID

NC

DAC VNCDAC V

NC – No internal connection

NC

NC

NC

DD

MID

DD

ADC V

DD

ADC V

1–5

1.4 Terminal Functions

TERMINAL

NAME NO.†NO.

‡

I/O

DESCRIPTION

ADC V

DD

24 32 I Analog supply voltage for the ADC channel

ADC V

MID

23 30 O Midsupply for the ADC channel (requires a bypass capacitor). ADC V

MID

must be

buffered when used as an external reference.
ADC GND 22 27 I Analog ground for the ADC channel
AUX IN+ 28 38 I Noninverting input to auxiliary analog input amplifier
AUX IN– 27 37 I Inverting input to auxiliary analog input amplifier
DAC V

DD

5 49 I Digital supply voltage for the DAC channel

DAC V

MID

6 51 O Midsupply for the DAC channel (requires a bypass capacitor). DAC V

MID

must be

buffered when used as an external reference.
DAC GND 7 54 I Analog ground for the DAC channel
DIN 10 1 I Data input. DIN receives the DAC input data and command information and is

synchronized with SCLK.
DOUT 11 3 O Data output. DOUT outputs the ADC data results and register read contents.

DOUT is synchronized with SCLK.
DGTL V

DD

9 59 I Digital supply voltage for control logic
DGTL GND 20 22 I Digital ground for control logic
EOC 19 17 O End-of-conversion output. EOC goes high at the start of the ADC conversion

period and low when conversion is complete. EOC remains low until the next ADC
conversion period begins and indicates the internal device conversion period.

FC0 15 11 I Hardware control input. FC0 is used in conjunction with FC1 to request secondary

communication and phase adjustments. FC0 should be tied low if it is not used.

FC1 16 12 I Hardware control input. FC1 is used in conjunction with FC0 to request secondary

communication and phase adjustments. FC1 should be tied low if it is not used.

FS 12 4 I/O Frame synchronization. When FS goes low, DIN begins receiving data bits and

DOUT begins transmitting data bits. In master mode, FS

is low during the

simultaneous 16-bit transmission to DIN and from DOUT. In slave mode, FS

is
externally generated and must be low for one shift-clock period minimum to initiate
the data transfer.

FSD 17 14 O Frame-synchronization delayed output. This active-low output synchronizes a

slave device to the frame synchronization timing of the master device. FSD

is
applied to the slave FS

input and is the same duration as the master FS signal but

delayed in time by the number of shift clocks programmed in the FSD

register.
IN+ 26 36 I Noninverting input to analog input amplifier
IN– 25 35 I Inverting input to analog input amplifier
MCLK 14 10 I The master-clock input drives all the key logic signals of the AIC.
MON OUT 1 40 O The monitor output allows monitoring of analog input and is a high-impedance

output.

M/S 18 16 I Master/slave select input. When M/S is high, the device is the master and when

low, it is a slave.

†

Terminal numbers shown are for the FN package.

‡

Terminal numbers shown are for the PM package.

1–6

1.4 Terminal Functions (Continued)

TERMINAL

NAME NO.†NO.

‡

I/O

DESCRIPTION

OUT+ 3 43 O Noninverting output of analog output power amplifier . OUT+ can drive transformer

hybrids or high-impedance loads directly in a differential connection or a
single-ended configuration with a buffered V

MID

.

OUT– 4 46 O Inverting output of analog output power amplifier. OUT– is functionally identical

with and complementary to OUT+.

PWR DWN 2 42 I Power-down input. When PWR DWN is taken low, the device is powered down

such that the existing internally programmed state is maintained. When PWR
DWN is brought high, full operation resumes.

RESET 8 57 I Reset input that initializes the internal counters and control registers. RESET

initiates the serial data communications, initializes all of the registers to their
default values, and puts the device in a preprogrammed state. After a low-going
pulse on RESET

, the device registers are initialized to provide a 16-kHz
data-conversion rate and 7.2-kHz filter bandwidth for a 10.368-MHz master clock
input signal.

SCLK 13 8 I/O Shift clock. SCLK clocks the digital data into DIN and out of DOUT during the

frame-synchronization interval. When configured as an output (M/S

high), SCLK
is generated internally by dividing the master clock signal frequency by four. When
configured as an input (M/S

low), SCLK is generated externally and
synchronously to the master clock. This signal clocks the serial data into and out
of the device.

SUBS 21 24 I Substrate connection. SUBS should be tied to ADC GND.

†

Terminal numbers shown are for the FN package.

‡

Terminal numbers shown are for the PM package.

1–7

A Register

(8 bits)

Divide by 2

576 kHz

B Register

(8 bits)

Divide by 4

1.296 MHz

2.592 MHz

5.184 MHz

10.368 MHz

MCLK

Processor

SCLK

A Register + A′ Register

(8 bits)

2s Complement

Program Divide

A Counter

(8 bits)

B Counter

288 kHz

FCLK [low-pass filter and

(sin x)/x filter clock]

Conversion

Rate

Single, A-Counter

Period

One-Shot

Phase ShiftNormal

Control

Figure 1–1. Control Flow Diagram

Table 1–1. Operating Frequencies

FCLK

(kHz)

LOW-PASS FILTER

BANDWIDTH

(kHz)

B REGISTER CONTENTS

(Program No. of Filter Clocks)

(Decimal)

CONVERSION

RATE

(kHz)

HIGH-PASS

POLE FREQUENCY

(Hz)

144 3.6 20 (see Note 1)

18
15
10 (see Note 2)

7.2
8

9.6

14.4

36
40
48
72

288 7.2 20 (see Note 1)

18
15
10 (see Notes 2 and 3)

14.4
16

19.2

28.8

72
80
96

144

432 10.8 20 (see Note 1)

18
15 (see Note 3)
10 (see Notes 2 and 3)

21.6
24

28.8

43.2

108
120
144
216

NOTES: 1. The B register can be programmed for values greater than 20; however, since the sample rate is lower than

7.2 kHz and the internal filter remains at 3.6 kHz, an external antialiasing filter is required.

2. When the B register is programmed for a value less than 10, the ADC and the DAC conversions are not
completed before the next frame-sync signal and the results are in error.

3. The maximum sampling rate for the ADC channel is 43.2 kHz. The maximum rate for the DAC channel is
25 kHz.

1–8

1.5 Register Functional Summary

There are nine data registers that are used as follows:
Register 0 The No-op register. The 0 address allows phase adjustments to be made without

reprogramming a data register .
Register 1 The A register controls the count of the A counter.
Register 2 The B register controls the count of the B counter.
Register 3 The A

′ register controls the phase adjustment of the sampling period. The adjustment is

equal to the register value multiplied by the input master period.
Register 4 The amplifier gain register controls the gains of the input, output, and monitor amplifiers.
Register 5 The analog configuration register controls:

• The addition/deletion of the high-pass filter to the ADC signal path

• The enable/disable of the analog loopback

• The selection of the regular inputs or auxiliary inputs

• The function that allows processing of signals that are the sum of the regular inputs and

the auxiliary inputs (V

IN

+ V

AUX IN

)

Register 6 The digital configuration register controls:

• Selection of the free-run function

• FSD

[frame-synchronization (sync) delay] output enable/disable

• Selection of 16-bit function

• Forcing secondary communications

• Software reset

• Software power down

Register 7 The frame-sync delay register controls the time delay between the master-device frame

sync and slave-device frame sync. Register 7 must be the last register programmed when

using slave devices since all register data is latched and valid on the sixteenth falling edge

of SCLK. On the sixteenth falling edge of SCLK, all delayed frame-sync intervals are shifted

by this programmed amount.
Register 8 The frame-sync number register informs the master device of the number of slaves that are

connected in the chain. The frame-sync number is equal to the number of slaves plus one.

2–1

2 Detailed Description

2.1 Definitions and Terminology

ADC Channel All signal processing circuits between the analog input and the digital conversion

results at DOUT

Codec Mode The operating mode under which the device receives shift clock and frame-sync

signals from a host processor. The device has no slaves.

d The d represents valid programmed or default data in the control register format

(see Section 2.19) when discussing other data-bit portions of the register.
Dxx Bit position in the primary data word (xx is the bit number)
DAC Channel All signal processing circuits between the digital data word applied to DIN and the

differential output analog signal available at OUT+ and OUT–
Data T ransfer Interval The time during which data is transferred from DOUT and to DIN. This interval is 16

shift clocks regardless of whether the shift clock is internally or externally generated.

The data transfer is initiated by the falling edge of the frame-sync signal.
DSxx Bit position in the secondary data word (xx is the bit number)
FCLK An internal clock frequency that is a division of MCLK that controls the low-pass filter

and (sinx)/x filter clock (see Figure 1–1 and Table 1-1).
f

i

The analog input frequency of interest
Frame Sync The falling edge of the signal that initiates the data-transfer interval. The primary

frame sync starts the primary communications, and the secondary frame sync starts

the secondary communications.
Frame Sync and The time between falling edges of successive primary frame-sync signals

Sampling Period
Frame-Sync Interval The time period occupied by 16 shift clocks. Regardless of the mode of operation,

there is always an internal frame-sync interval signal that goes low on the rising

edge of SCLK and remains low for 16 shift clocks. It is used for synchronization of

the serial-port internal signals. It goes high on the seventeenth rising edge of SCLK.
f

s

The sampling frequency that is the reciprocal of the sampling period.
Host Any processing system that interfaces to DIN, DOUT, SCLK, or FS

.

Master Mode The operating mode under which the device generates and uses its own shift clock

and frame-sync signal and generates all delayed frame-sync signals necessary to

support slave devices.
Phase Adjustment The programmed time variation from the falling edge of one frame-sync signal to the

falling edge of the next frame sync signal. The time variation is determined by the

contents of the A

′ register. Since the time between falling edges of successive

frame-sync signals is the the sampling period, the sampling period is adjusted.
Primary (Serial) The digital data-transfer interval. Since the device is synchronous, the signal data

Communications words from the ADC channel and to the DAC channel occur simultaneously.
Secondary (Serial) The digital control and configuration data-transfer interval into DIN and the register

Communications read-data cycle from DOUT. The data-transfer interval occurs when requested by

hardware or software.
Signal Data The input signal and all of the converted representations through the ADC channel

and return through the DAC channel to the analog output. This is contrasted with

the purely digital software-control data.
Slave Mode The operating mode under which the device receives shift clock and frame-sync

signals from a master device.

2–2

Stand-Alone Mode The operating mode under which the device generates and uses its own shift clock

and frame-sync signal. The device has no slave devices.
X The X represents a don’t-care bit position within the control register format.

2.2 Reset and Power-Down Functions

2.2.1 Reset

The TLC320AC02 resets both the internal counters and registers, including the programmed registers, by
any of the following:

• Applying power to the device, causing a power-on reset (POR)

• Applying a low reset pulse to RESET

• Reading in the programmable software reset bit (DS01 in register 6)

PWR

DWN resets the counters only and preserves the programmed register contents.

2.2.2 Conditions of Reset

The two internal reset signals used for the reset and synchronization functions are as follows:

1. Counter reset: This signal resets all flip-flops and latches that are not externally programmed with
the exception of those generating the reset pulse itself. In addition, this signal resets the software
power-down bit.

Counter reset = power-on reset + RESET

+ RESET bit + PWR DWN

2. Register reset: This signal resets all flip-flops and latches that are not reset by the counter reset
except those generating the reset pulse itself.

Register reset = power-on reset + RESET

+ RESET bit

Both reset signals are at least one master-clock period long and release on the falling edge of the master
clock.

2.2.3 Software and Hardware Power-Down

Given the definitions and conditions of RESET , the software-programmed power-down condition is cleared
by resetting the software bit (DS00 in register 6) to zero. It is also cleared by either cycling the power to the
device, bringing PWR

DWN low, or bringing RESET low.

PWR

DWN powers down the entire chip ( < 1 mA ). The software-programmable power-down bit only
powers down the analog section of the chip ( < 3 mA ), which allows a software power-up function. Cycling
PWR

DWN high to low and back to high resets all flip-flops and latches that are not externally programmed,
thereby preserving the register contents.

When PWR

DWN is not used, it should be tied high.

2.2.4 Register Default Values After POR, Software Reset, or RESET Is Applied

Register 1 – The A Register
The default value of the A-register data is decimal 18 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 1 0 0 1 0

2–3

Register 2 – The B Register
The default value of the B-register data is decimal 18 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 1 0 0 1 0

Register 3 – The A′ Register
The default value of the A

′-register data is decimal 0 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 0 0 0 0 0

Register 4 – The Amplifier Gain-Select Register
The default value of the amplifier gain-select register data is shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 0 0 1 0 1

Register 5 – The Analog Control-Configuration Register
The power-up and reset conditions are as shown below. In the read mode, 8 bits are read but the 4 LSBs

are repeated as the 4 MSBs.

DS03 DS02 DS01 DS00

0 0 0 1

Register 6 – The Digital Configuration Register
The default value of DS07 – DS00 is 0 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 0 0 0 0 0

Register 7 – The Frame-Sync Delay Register
The default value of DS07 – DS00 is 0 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 0 0 0 0 0

Register 8 – The Frame-Sync Number Register
The default value of DS07 – DS00 is 1 as shown below.

DS07 DS06 DS05 DS04 DS03 DS02 DS01 DS00

0 0 0 0 0 0 0 1

2–4

2.3 Master-Slave Terminal Function

Table 2–1 describes the function of the master/slave (M/S) input. The only difference between master and
slave operations in the TLC320AC02 is that SCLK and FS

are outputs when M/S is high and inputs when

M/S

is low.

Table 2–1. Master-Slave Selection

MODE M/S

†

FS SCLK

Master and Stand Alone H Output Output
Slave and Codec Emulation L Input Input

†

When the stand-alone mode is desired or when the device is
permanently in the master mode, M/S

must be high.

2.4 ADC Signal Channel

To produce excellent common-mode rejection of unwanted signals, the analog signal is processed
differentially until it is converted to digital data. The signal is amplified by the input amplifier at one of three
software-selectable gains (typically 0 dB, 6 dB, or 12 dB). A squelch mode can also be programmed for the
input amplifier.

The amplifier output is filtered and applied to the ADC input. The ADC converts the signal into discrete digital
words in 2s-complement format corresponding to the analog-signal value at the sampling time. These 16-bit
digital words, representing sampled values of the analog input signal, are clocked out of the serial port
(DOUT), one word for each primary communication interval. During secondary communications, the data
previously programmed into the registers can be read out with the appropriate register address and with the
read bit set to 1. When a register read is not requested, all 16 bits are 0.

2.5 DAC Signal Channel

DIN receives the 16-bit serial data word (2s complement) from the host during the primary communications
interval and latches the data on the seventeenth rising edge of SCLK. The data are converted to an analog
voltage by the DAC with a sample and hold and then through a (sin x)/x correction circuit and a smoothing
filter. An output buffer with three software-programmable gains (0 dB, –6 dB, and –12 dB), as shown in
register 4, drives the differential outputs OUT+ and OUT–. A squelch mode can also be programmed for
the output buffer. During secondary communications, the configuration program data are read into the
device control registers.

2.6 Serial Interface

The digital serial interface consists of the shift clock, the frame-synchronization signal, the ADC-channel
data output, and the DAC-channel data input. During the primary 16-bit frame-synchronization interval, the
SCLK transfers the ADC channel results from DOUT and transfers 16-bit DAC data into DIN.

During the secondary frame-synchronization interval, the SCLK transfers the register read data from DOUT
when the read bit is set to a 1. In addition, the SCLK transfers control and device parameter information into
DIN. The functional sequence is shown in Figure 2–1.

2–5

Register Read Data or All 0s

ADC Conversion Result

DAC Input Data

Control and Device Parameter

Data

16 SCLKs

16 SCLKs

Frame-Sync Interval

(primary communication)

Frame-Sync Interval

(secondary

communication)

SCLK

FS

DOUT

DIN

[ (B register)/2] FCLK Periods

†

†

The time between the primary and secondary frame sync is the time equal to filter clock (FCLK) period multiplied by the
B-register contents divided by two. The time interval is rounded to the nearest shift clock. The secondary frame-sync
signal goes from high to low on the next shift clock low-to-high transition after (B register/2) filter clock periods.

Figure 2–1. Functional Sequence for Primary and Secondary Communication

2.7 Number of Slaves

The maximum number of slaves is determined by the sum of the individual device delays from the
frame-sync (FS

) input low to the frame-sync delayed (FSD) low for all slaves according to equation 1:

(n) / tp(FS–FSD) < 1/2 shift-clock period

(1)

Where:

n is the number of slave devices.
Example:
From equation 1 above, the number of slaves is given by equation 2:

(n)

v

1
2

x (SCLK period) x

1

tp(FS*FSD

)

(2)

assuming the master clock is 10.368 MHz and the shift clock is 2.5965 MHz and tp(FS – FSD) is 40 ns, then
according to equation 3, the number of slaves is:

n

v

1

2.5965 MHz

x

1
2

x

1

40 ns

+

1000

192

+

4.8

(3)

The maximum number of slaves under these conditions is four.

2–6

2.8 Required Minimum Number of MCLK Periods

Master with slave operation is summarized in the following sections.

2.8.1 TLC320AC02 AIC Master-Slave Summary

After initial setup and the master and slave frame syncs are separated, when secondary communication is
needed for a slave device, a 11 must be placed in the 2 LSBs of each primary data word for all devices in
the system, master and slave, by the host processor. In other words, all AICs must receive secondary frame
requests.

The host processor must issue the command by setting D01 and D00 to a 1 in the primary frame sync data
word of all devices. Then the master generates the master primary frame sync and, after the number of shift
clocks set by the FSD register value, the slave primary frame sync intervals. Then, after (B register value/2)
FCLK periods, the master secondary frame sync occurs first, and then the slave secondary frame sync
occurs. These are also rippled through the slave devices.

In other words, when a secondary communications interval is requested by the host processor as described
above:

1. The master outputs the master primary frame sync interval, and then the slave primary frame
sync intervals after the FSD register value number of shift clocks.

2. After (B register value/2) FCLK periods, the master then outputs the master secondary frame
sync interval, and after the FSD register value number of shift clocks, the slave secondary frame
sync intervals.

This sequence is shown in Figure 2–2.
The host must keep track of whether the master or a slave is then being addressed and also the number

of slave devices. The master always outputs a 00 in the last 2 bits of the DOUT word, and a slave always
outputs a 1 in the LSB of the DOUT word. This information allows the system to recognize a starting point
by interrogating the least significant bit of the DOUT word. If the LSB is 0, then that device is the master,
and the system is at the starting point.

Note: This identification always happens except in 16-bit mode when the 2 LSBs are not available

for identification purposes.

Sampling Period

(B Register Value/2) FCLK Periods

FSD Value

in SCLKs

Frame Sync

Sequence

MP SP1 SP2 SPn MS SS1 SS2 SSn MP

Period Symbol

Periods shown: Each period must be a minimum of 16 SCLKs plus 2 additional SCLKs

MP = Master Primary Period
SP1 = 1st Slave Primary Period
SP2 = 2nd Slave Primary Period
SPn = nth Slave Primary Period

MS = Master Secondary Period
SS1 = 1st Slave Secondary Period
SS2 = 2nd Slave Secondary Period
SSn = nth Slave Secondary Period

Figure 2–2. Timing Sequence

2–7

2.8.2 Notes on TLC320AC01/02 AIC Master-Slave Operation

Master/slave operational detail is summarized in the following notes:

1. The slave devices can be programmed independently of the master as long as the clock divide
register numbers are not changed. The gain settings, for example, can be changed
independently.

2. The method that is used to program a slave independently is to request a secondary
communication of the master and all slaves and ripple the delayed frame sync to the desired slave
device to be programmed.

3. Secondary frame syncs must be requested for all devices in the system or none. This is required
so that the master generates secondary frames for the slaves and allows the slaves to know that
the second frame syncs they receive are secondary frame syncs. Each device in the system must
receive a secondary frame request in its corresponding primary frame sync period (1 1 in the last
2 LSBs).

4. Calculation of the sampling frequency in terms of the master clock and the shift clock and the
respective register ratios is (see equations 4–6):

Sampling frequency+f

s

+

FCLK

B register value

+

f(MCLK

)

2 (A register value)

(B register value

)

(4)

Therefore,

f(MCLK

)

f

s

+2 (A register value) (B register value

)

(5)

and in terms of the shift clock frequency, since

(6)

f(SCLK)

f

s

+

(A register value)

(B register value

)

2

+

Number of SCLK periods

Sampling period

f(MCLK)+4 f(SCLK)

then

5. The minimum number of shift clocks between falling edges of any two frame syncs is 18 because
the frame sync delay register minimum number is 18.

When a secondary communication is requested by the host, the master secondary frame sync
begins at the middle of the sampling period (followed by the slave secondary frame syncs), so all
primary frame sync intervals (master and slave) must occur within one-half the sampling time.

2–8

The first secondary frame-sync falling edge, therefore, occurs at the following time (see
equation 7):

Time to first secondary frame sync

+

B register value

2

(

FCLK periods)+

(7)

A register value B register value (number of MCLK periods)

+

A register value B register value

4

(number of SCLK periods)

6. Number of frame sync intervals using equation 8.
All master and slave primary frame sync intervals must occur within the time of equation 7.
Since 18 shift clocks are required for each frame sync interval, then the number of frame sync

intervals from equation 8 is:

Number of frame sync intervals

+

A register value B register value

4 18 (SCLKsńframe sync interval)

(8)

+

A register value B register value

72

7. Number of devices, master and slave, in terms of f(MCLK) and fs.
Substituting the value from equation 5 for the A ×B register value product gives the total number

of devices, including the master and all slaves that can be used, for a given master clock and
sampling frequency. Therefore, using equation 9:

Number of devices

+

f(MCLK)

144 f

s

(9)

8. Number of devices, master and slave, if slave devices are reprogrammed.
Equation 9 does not include reprogramming the slave devices after the frame sync delay occurs.

So if programming is required after shifting the slave frame syncs by the FSD register, then the
total number of devices is given by equation 10 is:

Number of devices

+

f(MCLK)

288 f

s

(10)

9. Example of the maximum number of devices if the slave devices are reprogrammed assuming
the following values:

f(MCLK)+10.368 MHz, f

s

+

8kHz

then from equation 10,

Maximum number of devices

+

10.368 MHz
288 (8 kHz)

+

4.5

therefore, one master and three slaves can be used.

2–9

2.9 Operating Frequencies

2.9.1 Master and Stand-Alone Operating Frequencies

The sampling (conversion) frequency is derived from the master-clock (MCLK) input by equation 11:

fs+

Sampling (conversion) frequency

+

MCLK

(A register value) (B register value) 2

(11)

The inverse is the time between the falling edges of two successive primary frame-synchronization signals.
The input and output data clock (SCLK) frequency is given in equation 12:

SCLK frequency

+

MCLK frequency

4

(12)

2.9.2 Slave and Codec Operating Frequencies

The slave operating frequencies are either the default values or programmed by the control data word from
the master and codec conversion and the data frequencies are determined by the externally applied SCLK
and FS

signals.

2.10 Switched-Capacitor Filter Frequency (FCLK)

The filter clock (FCLK) is an internal clock signal that determines the filter band-pass frequency and is the
B counter clock. The frequency of the filter clock is derived by equation 13:

FCLK

+

MCLK

(A register value) 2

(13)

2.11 Filter Bandwidths

The low-pass (LP) filter –3 dB corner is derived in equation 14:

f(LP)

+

FCLK

40

+

MCLK

40 (A register value) 2

(14)

The high-pass (HP) filter –3 dB corner is derived in equation 15:

f(HP)

+

Sampling frequency

200

+

MCLK

200 2 (A register value) (B register value)

(15)

2.12 Master and Stand-Alone Modes

The difference between the master and stand-alone modes is that in the stand-alone mode there are no
slave devices. Functionally these two modes are the same. In both, the AIC internally generates the shift
clock and frame-sync signal for the serial communications. These signals and the filter clock (FCLK) are
derived from the input master clock.The master clock applied at the MCLK input determines the internal
device timing. The shift clock frequency is a divide-by-four of the master clock frequency and shifts both the
input and output data at DIN and DOUT, respectively, during the frame-sync interval (16 shift clocks long).
To begin the communication sequence, the device is reset (see Section 2.2.1), and the first frame sync
occurs approximately 648 master clocks after the reset condition disappears.

2.12.1 Register Programming

All register programming occurs during secondary communications, and data is latched and valid on the
sixteenth falling edge of SCLK. After a reset condition, eight primary and secondary communications cycles
are required to set up the eight programmable registers. Registers 1 through 8 are programmed in
secondary communications intervals 1 through 8, respectively. If the default value for a particular register
is desired, that register does not need to be addressed during the secondary communications. The no-op
command addresses the pseudo-register (register 0), and no register programming takes place during this
communications. The no-op command allows phase shifts of the sampling period without reprogramming
any register.

During the eight register programming cycles, DOUT is in the high-impedance state. DOUT is released on
the rising edge of the eighth primary internal frame-sync interval. In addition, each register can be read back

2–10

during DOUT secondary communications by setting the read bit to 1 in the appropriate register. Since the
register is in the read mode, no data can be written to the register during this cycle. To return this register
to the write mode requires a subsequent secondary communication (see Section 2.19 for detailed register
description).

2.12.2 Master and Stand-Alone Functional Sequence

The A counter counts according to the contents of the A register, and the A counter frequency is divided by
two to produce the filter clock (FCLK). The B counter is clocked by FCLK with the following functional
sequence:

1. The B counter starts counting down from the B register value minus one. Each count remains in
the counter for one FCLK period including the zero count. This total counter time is referred to
as the B cycle. The end of the zero count is called the end of B cycle.

2. When the B counter gets to a count of nine, the analog-to-digital (A-to-D) conversion starts.

3. The A-to-D conversion is complete ten FCLK periods later.

4. FS

goes low on a rising edge of SCLK after the A-to-D conversion is complete. That rising edge
of SCLK must be preceded by a falling edge of SCLK, which is the first falling edge to occur after
the end of B cycle.

5. The D-to-A conversion cycle begins on the rising edge of the internal frame-sync interval and is
complete ten FCLK periods later.

2.13 Slave and Codec Modes

The only difference between the slave and codec modes is that the codec mode is controlled directly by the
host and does not use a delayed frame-sync signal. In both modes, the shift clock and the frame sync are
both externally generated and must be synchronous with MCLK. The conversion frequency is set by the time
interval of externally applied frame-sync falling edges except when the free-run function is selected by bit 5
of register 6 (see Section 2.15.4). The slave device or devices share the shift clock generated by the master
device but receive the frame sync from the previous slave in the chain. The Nth slave FS

receives the

(N–1)st slave FSD

output and so on. The first slave device in the chain receives FSD from the master.

2–11

2.13.1 Slave and Codec Functional Sequence

The A counter counts according to the contents of the A register, and the A counter frequency is divided by
two to produce the FCLK. The device function in the slave or codec mode is the same as steps 1 through
3 of the B cycle description in the master mode but differs as follows:

1. Same as master

2. Same as master

3. Same as master

4. All internal clocks stop 1/2 FCLK before the end of count 0 in the B counter cycle.

5. All internal clocks are restarted on the first rising edge of MCLK after the external FS

input goes

low. This operation provides the synchronization necessary when using an external FS

signal.

6. The D-to-A conversion starts on the rising edge of the internally generated frame-sync interval
at the end of the 16-shift clock data transfer.

In the slave mode, the master controls the phase adjustments for itself and all slaves since all devices are
programmed in the same frame-sync interval. In the codec mode, the shift clock and frame sync are
externally generated and provide the timing for the ADC and DAC if the free-run function has not been
selected (see Subsection 2.15.4). In the codec mode, there is usually no need for phase adjustments;
however, any required phase adjustments must be made by adjusting the external frame-sync timing
(sampling time).

2.13.2 Slave Register Programming

When slave devices are used on power-up or reset, all slave frame-sync signals occur at the same time as
the master frame-sync signal and all slave devices are programmed during the master secondary frame­sync interval with the same data as the master. The last register programmed must be the frame-sync delay
(FSD) register because the delay starts immediately on the rising edge of the seventeenth shift clock of that
frame- sync interval. After the FSD register programming is completed for the master and slave, the slave
primary frame interval is shifted in time (time slot allocated) according to the data contained in the slave FSD
registers. The master then generates frame-sync intervals for itself and each slave to synchronize the host
serial port for data transfers for itself and all slave devices.

The number of slaves is specified in the FSN register (register 8); therefore, the number of frame-sync
intervals generated by the master is equal to the number of slaves plus one (see Section 2.7). These master
frame-sync intervals are separated in time by the delay time specified by the FSD register (register 7). These
master-generated intervals are the only frame-sync interval signals applied to the host serial port to provide
the data-transfer time slot for the slave devices.

2.14 Terminal Functions

2.14.1 Frame-Sync Function

The frame-sync signal indicates that the device is ready to send and receive data for both master and slave
modes. The data transfer begins on the falling edge of the frame-sync signal.

2.14.1.1 Frame Sync (FS), Master Mode

The frame sync is generated internally. FS goes low on the rising edge of SCLK and remains low for the
16-bit data transfer. In addition to generating its own frame-sync interval, the master also outputs a frame
sync for each slave that is being used.