SLASE12A July   2014  – October 2014 PCM5242

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified System Diagram
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
    1. 6.1 Control Mode Effect On Pin Assignments
    2. 6.2 Pin Assignments
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Timing Requirements: SCK Input
    8. 7.8 Timing Requirements: PCM Audio Data
    9. 7.9 Timing Requirements: XSMT
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Terminology
    4. 8.4 Audio Data Interface
      1. 8.4.1 Audio Serial Interface
      2. 8.4.2 PCM Audio Data Formats
      3. 8.4.3 Zero Data Detect
    5. 8.5 XSMT Pin (Soft Mute / Soft Un-Mute)
    6. 8.6 Audio Processing
      1. 8.6.1 PCM5242 Audio Processing Options
        1. 8.6.1.1 Overview
        2. 8.6.1.2 miniDSP Instruction Register
        3. 8.6.1.3 Digital Output
        4. 8.6.1.4 Software
      2. 8.6.2 Interpolation Filter
      3. 8.6.3 Fixed Audio Processing Flow (Program 5)
        1. 8.6.3.1 Processing Blocks - Detailed Descriptions
        2. 8.6.3.2 Biquad Section
        3. 8.6.3.3 Dynamic Range Compression
        4. 8.6.3.4 Stereo Mixer
        5. 8.6.3.5 Stereo Multiplexer
        6. 8.6.3.6 Mono Mixer
        7. 8.6.3.7 Master Volume Control
        8. 8.6.3.8 Miscellaneous Coefficients
    7. 8.7 DAC and Differential Analog Outputs
      1. 8.7.1 Analog Outputs
      2. 8.7.2 Choosing Between VREF and VCOM Modes
        1. 8.7.2.1 Voltage Reference and Output Levels
        2. 8.7.2.2 Mode Switching Sequence, From VREF Mode to VCOM Mode
      3. 8.7.3 Digital Volume Control
        1. 8.7.3.1 Emergency Ramp Down
      4. 8.7.4 Analog Gain Control
    8. 8.8 Reset and System Clock Functions
      1. 8.8.1 Clocking Overview
      2. 8.8.2 Clock Slave Mode With Master Clock (SCK) Input (4 Wire I2S)
      3. 8.8.3 Clock Slave Mode with BCK PLL to Generate Internal Clocks (3-Wire PCM)
      4. 8.8.4 Clock Generation Using The PLL
      5. 8.8.5 PLL Calculation
        1. 8.8.5.1 Examples:
          1. 8.8.5.1.1 Recommended PLL settings
      6. 8.8.6 Clock Master Mode from Audio Rate Master Clock
      7. 8.8.7 Clock Master from a Non-Audio Rate Master Clock
    9. 8.9 Device Functional Modes
      1. 8.9.1 Choosing A Control Mode
        1. 8.9.1.1 Software Control
          1. 8.9.1.1.1 SPI Interface
            1. 8.9.1.1.1.1 Register Read/Write Operation
          2. 8.9.1.1.2 I2C Interface
            1. 8.9.1.1.2.1 Slave Address
            2. 8.9.1.1.2.2 Register Address Auto-Increment Mode
            3. 8.9.1.1.2.3 Packet Protocol
            4. 8.9.1.1.2.4 Write Register
            5. 8.9.1.1.2.5 Read Register
            6. 8.9.1.1.2.6 Timing Characteristics
      2. 8.9.2 Choosing Between VREF and VCOM Modes
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 High Fidelity Smartphone Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Initialization Script
        3. 9.2.1.3 Application Performance Plot
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Distribution and Requirements
    2. 10.2 Recommended Powerdown Sequence
      1. 10.2.1 Planned Shutdown
      2. 10.2.2 Unplanned Shutdown
    3. 10.3 External Power Sense Undervoltage Protection mode (supported only when DVDD = 3.3V)
    4. 10.4 PCM5242 Power Modes
      1. 10.4.1 Setting Digital Power Supplies and I/O Voltage Rails
      2. 10.4.2 Power Save Modes
      3. 10.4.3 Power Save Parameter Programming
  11. 11Layout
    1. 11.1 Layout Guidelines
  12. 12Programming and Registers Reference
    1. 12.1 Coefficient Data Formats
    2. 12.2 PCM5242 Register Map
      1. 12.2.1 Detailed Register Descriptions
        1. 12.2.1.1 Register Map Summary
          1. 12.2.1.1.1 Register Map Summary
        2. 12.2.1.2 Page 0 Registers
          1. 12.2.1.2.1  Page 0 / Register 1
          2. 12.2.1.2.2  Page 0 / Register 2
          3. 12.2.1.2.3  Page 0 / Register 3
          4. 12.2.1.2.4  Page 0 / Register 4
          5. 12.2.1.2.5  Page 0 / Register 6
          6. 12.2.1.2.6  Page 0 / Register 7
          7. 12.2.1.2.7  Page 0 / Register 8
          8. 12.2.1.2.8  Page 0 / Register 9
          9. 12.2.1.2.9  Page 0 / Register 10
          10. 12.2.1.2.10 Page 0 / Register 12
          11. 12.2.1.2.11 Page 0 / Register 13
          12. 12.2.1.2.12 Page 0 / Register 14
          13. 12.2.1.2.13 Page 0 / Register 18
          14. 12.2.1.2.14 Page 0 / Register 19
          15. 12.2.1.2.15 Page 0 / Register 20
          16. 12.2.1.2.16 Page 0 / Register 21
          17. 12.2.1.2.17 Page 0 / Register 22
          18. 12.2.1.2.18 Page 0 / Register 23
          19. 12.2.1.2.19 Page 0 / Register 24
          20. 12.2.1.2.20 Page 0 / Register 27
          21. 12.2.1.2.21 Page 0 / Register 28
          22. 12.2.1.2.22 Page 0 / Register 29
          23. 12.2.1.2.23 Page 0 / Register 30
          24. 12.2.1.2.24 Page 0 / Register 32
          25. 12.2.1.2.25 Page 0 / Register 33
          26. 12.2.1.2.26 Page 0 / Register 34
          27. 12.2.1.2.27 Page 0 / Register 35
          28. 12.2.1.2.28 Page 0 / Register 36
          29. 12.2.1.2.29 Page 0 / Register 37
          30. 12.2.1.2.30 Page 0 / Register 40
          31. 12.2.1.2.31 Page 0 / Register 41
          32. 12.2.1.2.32 Page 0 / Register 42
          33. 12.2.1.2.33 Page 0 / Register 43
          34. 12.2.1.2.34 Page 0 / Register 44
          35. 12.2.1.2.35 Page 0 / Register 59
          36. 12.2.1.2.36 Page 0 / Register 60
          37. 12.2.1.2.37 Page 0 / Register 61
          38. 12.2.1.2.38 Page 0 / Register 62
          39. 12.2.1.2.39 Page 0 / Register 63
          40. 12.2.1.2.40 Page 0 / Register 64
          41. 12.2.1.2.41 Page 0 / Register 65
          42. 12.2.1.2.42 Page 0 / Register 80
          43. 12.2.1.2.43 Page 0 / Register 81
          44. 12.2.1.2.44 Page 0 / Register 82
          45. 12.2.1.2.45 Page 0 / Register 83
          46. 12.2.1.2.46 Page 0 / Register 84
          47. 12.2.1.2.47 Page 0 / Register 85
          48. 12.2.1.2.48 Page 0 / Register 86
          49. 12.2.1.2.49 Page 0 / Register 87
          50. 12.2.1.2.50 Page 0 / Register 90
          51. 12.2.1.2.51 Page 0 / Register 91
          52. 12.2.1.2.52 Page 0 / Register 92
          53. 12.2.1.2.53 Page 0 / Register 93
          54. 12.2.1.2.54 Page 0 / Register 94
          55. 12.2.1.2.55 Page 0 / Register 95
          56. 12.2.1.2.56 Page 0 / Register 108
          57. 12.2.1.2.57 Page 0 / Register 109
          58. 12.2.1.2.58 Page 0 / Register 114
          59. 12.2.1.2.59 Page 0 / Register 115
          60. 12.2.1.2.60 Page 0 / Register 118
          61. 12.2.1.2.61 Page 0 / Register 119
          62. 12.2.1.2.62 Page 0 / Register 120
          63. 12.2.1.2.63 Page 0 / Register 121
          64. 12.2.1.2.64 Page 0 / Register 122
          65. 12.2.1.2.65 Page 0 / Register 123
          66. 12.2.1.2.66 Page 0 / Register 124
          67. 12.2.1.2.67 Page 0 / Register 125
        3. 12.2.1.3 Page 1 Registers
          1. 12.2.1.3.1 Page 1 / Register 1
          2. 12.2.1.3.2 Page 1 / Register 2
          3. 12.2.1.3.3 Page 1 / Register 5
          4. 12.2.1.3.4 Page 1 / Register 6
          5. 12.2.1.3.5 Page 1 / Register 7
          6. 12.2.1.3.6 Page 1 / Register 8
          7. 12.2.1.3.7 Page 1 / Register 9
        4. 12.2.1.4 Page 44 Registers
          1. 12.2.1.4.1 Page 44 / Register 1
        5. 12.2.1.5 Page 253 Registers
          1. 12.2.1.5.1 Page 253 / Register 63
          2. 12.2.1.5.2 Page 253 / Register 64
      2. 12.2.2 PLL Tables for Software Controlled Devices
  13. 13Device and Documentation Support
    1. 13.1 Community Resources
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10 Power Supply Recommendations

10.1 Power Supply Distribution and Requirements

The PCM5242 is powered through the following pins:

pcm5xxx_pwrtree.gifFigure 82. Power Distribution Tree within PCM5242

Table 45. Power Supply Pin Descriptions

NAME USAGE / DESCRIPTION
AVDD Analog Voltage Supply - should be 3.3V. Powers the ADC, PGA, Reference, and Secondary ADC
DVDD Digital Voltage Supply - This is used as the I/O voltage control and the input to the onchip LDO.
CPVDD Charge Pump Voltage Supply - should be 3.3V
LDOO Output from the Onchip LDO. Should be used with a 0.1uF decoupling cap. Can be driven (used as power input) with a 1.8V supply to bypass the onchip LDO for lower power consumption.
AGND Analog Ground
DGND Digital Ground

10.2 Recommended Powerdown Sequence

Under certain conditions, the PCM5242 can exhibit some pop on power down. Pops are caused by the device not having enough time to detect power loss and start the muting process.

The PCM5242 has two auto-mute functions to mute the device upon power loss (intentional or unintentional).

XSMT = 0

When the XSMT pin is pulled low, the incoming PCM data is attenuated to 0, closely followed by a hard analog mute. This process takes 150 sample times (ts) + 0.2mS.

Because this mute time is mainly dominated by the sampling frequency, systems sampling at 192kHz will mute much faster than a 48kHz system.

Clock Error Detect

When clock error is detected on the incoming data clock, the PCM5242 switches to an internal oscillator, and continues to the drive the output, while attenuating the data from the last known value. Once this process is complete, the PCM5242 outputs are hard muted to ground.

10.2.1 Planned Shutdown

These auto-muting processes can be manipulated by system designs to mute before power loss in the following ways:

  1. Assert XSMT low 150tS + 0.2mS before power is removed.
    2. f_pcm51xx_anti-pop_pwrdwn_seq.gif
  2. Stop I2S clocks (SCK, BCK, LRCK) 3ms before powerdown as shown below:
    3. f_pcm51xx_anti-pop_pwrdwn_seq2.gif

10.2.2 Unplanned Shutdown

Many systems use a low-noise regulator to provide an AVDD 3.3V supply for the DAC. The XSMT Pin can take advantage of such a feature to measure the pre-regulated output from the system SMPS to mute the output before the entire SMPS discharges. Figure 83 shows how to configure such a system to use the XSMT pin. The XSMT pin can also be used in parallel with a GPIO pin from the system microcontroller/DSP or Power Supply.

f_pcm51xx_xsmt_anti_pwrdwnpop.gifFigure 83. Using the XSMT Pin

10.3 External Power Sense Undervoltage Protection mode (supported only when DVDD = 3.3V)

The XSMT pin can also be used to monitor a system voltage, such as the 24VDC LCD TV backlight, or 12VDC system supply using a voltage divider created with two resistors. (See Figure 84 )

  • If the XSMT pin makes a transition from “1” to “0” over 6ms or more, the device switches into external under-voltage protection mode. This mode uses two trigger levels.
  • When the XSMT pin level reaches 2V, soft mute process begins.
  • When the XSMT pin level reaches 1.2V, analog mute engages, regardless of digital audio level, and analog shutdown begins. (DAC and related circuitry powers down).

A timing diagram to show this is shown in Figure 85.

NOTE

The XSMT input pin voltage range is from -0.3V to DVDD + 0.3V.The ratio of external resistors must produce a voltage within this input range. Any increase in power supply (such as power supply positive noise or ripple) can pull the XSMT pin higher than DVDD+0.3V.

For example, if the PCM5242 is monitoring a 12V input, and dividing the voltage by 4, then the voltage at XSMT during ideal power supply conditions is 3V. A voltage spike higher than 14.4V causes a voltage greater than 3.6V (DVDD+0.3) on the XSMT pin, potentially damaging the device.

Providing the divider is set appropriately, any DC voltage can be monitored.

f_pcm51xx_xsmt_ext_uvp_ckt.gifFigure 84. XSMT in External UVP Mode
f_pcm51xx_td_xsmt_uvp.gifFigure 85. XSMT Timing for Undervoltage Protection

Power-On Reset Function

Power-On Reset, DVDD 3.3V Supply

The PCM5242 includes a power-on reset function shown in Figure 86. With VDD > 2.8V, the power-on reset function is enabled. After the initialization period, the PCM5242 is set to its default reset state.

pcm512x4x_por_3p3.gifFigure 86. Power-On Reset Timing, DVDD = 3.3V

Power-On Reset, DVDD 1.8V Supply

The PCM5242 includes a power-on reset function shown in Figure 87 operating at DVDD=1.8V. With AVDD greater than approximately 2.8V, CPVDD greater than approximately 2.8V, and DVDD greater than approximately 1.5V, the power-on reset function is enabled. After the initialization period, the PCM5242 is set to its default reset state.

pcm512x4x_por_1p8.gifFigure 87. Power-On Reset Timing, DVDD = 1.8V

10.4 PCM5242 Power Modes

10.4.1 Setting Digital Power Supplies and I/O Voltage Rails

The internal digital core of the PCM5242 runs from a 1.8V supply. This can be generated by the internal LDO, or by an external 1.8V supply.

DVDD is used to set the I/O voltage, and to be used as the input to the onchip LDO that creates the 1.8V required by the digital core.

For systems that require 3.3V IO support, but lower power consumption, DVDD should be connected to 3.3V and LDOO can be connected to an external 1.8V source. Doing so will disable the onchip LDO.

When setting IO voltage to be 1.8V, both DVDD and LDOO must be provided with an external 1.8V supply.

10.4.2 Power Save Modes

The PCM5242 offers two power-save modes; standby and power-down.

When a clock error (SCK, BCK, and LRCK) or clock halt is detected, the PCM5242 automatically enters standby mode. The DAC and line driver are also powered down. The device can also be placed in standby mode via software command.

When BCK and LRCK remain at a low level for more than 1 second, the PCM5242 automatically enters power-down mode. Power-down mode disables the negative charge pump and bias/reference circuit, in addition to those disabled in standby mode. The device can also be placed in power-down mode via software command.

The detection time of BCK and LRCK halt can be controlled by Page 0, Register 44, D(2:0).

When expected Audio clocks (SCK, BCK, LRCK) are applied to the PCM5242, the device starts its powerup sequence automatically. The detection time for BCK and LRCK halt is programmable.

10.4.3 Power Save Parameter Programming

Register Description
Page 0, Register 2, D(4) Software standby mode command
Page 0, Register 2, D(0) Software power-down command
Page 0, Register 2, D(4) and D(0) Software power-up sequence command (required after software standby or power-down)
Page 0, Register 44, D(2:0) Detection time of BCK and LRCK halt