SLAS986D November   2014  – February 2018 AMC7836

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: DAC
    6. 6.6  Electrical Characteristics: ADC and Temperature Sensor
    7. 6.7  Electrical Characteristics: General
    8. 6.8  Timing Requirements
    9. 6.9  Typical Characteristics: DAC
    10. 6.10 Typical Characteristics: ADC
    11. 6.11 Typical Characteristics: Reference
    12. 6.12 Typical Characteristics: Temperature Sensor
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Digital-to-Analog Converters (DACs)
        1. 7.3.1.1 DAC Output Range and Clamp Configuration
          1. 7.3.1.1.1 Auto-Range Detection
        2. 7.3.1.2 DAC Register Structure
        3. 7.3.1.3 DAC Clear Operation
      2. 7.3.2 Analog-to-Digital Converter (ADC)
        1. 7.3.2.1 Analog Inputs
          1. 7.3.2.1.1 Bipolar Analog Inputs
          2. 7.3.2.1.2 Unipolar Analog Inputs
        2. 7.3.2.2 ADC Sequencing
        3. 7.3.2.3 ADC Synchronization
        4. 7.3.2.4 Programmable Out-of-Range Alarms
          1. 7.3.2.4.1 Unipolar Inputs Out-of-Range Alarms
          2. 7.3.2.4.2 Unipolar Inputs Out-of-Range Alarms
          3. 7.3.2.4.3 ALARMIN Alarm
          4. 7.3.2.4.4 Hysteresis
          5. 7.3.2.4.5 False-Alarm Protection
      3. 7.3.3 Internal Temperature Sensor
      4. 7.3.4 Internal Reference
      5. 7.3.5 General Purpose I/Os
    4. 7.4 Device Functional Modes
      1. 7.4.1 All-Positive DAC Range Mode
      2. 7.4.2 All-Negative DAC Range Mode
      3. 7.4.3 Mixed DAC Range Mode
    5. 7.5 Programming
    6. 7.6 Register Maps
      1. 7.6.1  Interface Configuration: Address 0x00 – 0x02
        1. 7.6.1.1 Interface Configuration 0 Register (address = 0x00) [reset = 0x30]
          1. Table 9. Interface Config 0 Register Field Descriptions (R/W)
        2. 7.6.1.2 Interface Configuration 1 Register (address = 0x01) [reset = 0x00]
          1. Table 10. Interface Config 1 Register Field Descriptions
        3. 7.6.1.3 Device Configuration Register (address = 0x02) [reset = 0x03]
          1. Table 11. Device Config Register Field Descriptions
      2. 7.6.2  Device Identification: Address 0x03 – 0x0D
        1. 7.6.2.1 Chip Type Register (address = 0x03) [reset = 0x08]
          1. Table 12. Chip Type Register Field Descriptions
        2. 7.6.2.2 Chip ID Low Byte Register (address = 0x04) [reset = 0x36]
          1. Table 13. Chip ID Low Byte Register Field Descriptions
        3. 7.6.2.3 Chip ID High Byte Register (address = 0x05) [reset = 0x0C]
          1. Table 14. Chip ID High Byte Register Field Descriptions
        4. 7.6.2.4 Version ID Register (address = 0x06) [reset = 0x00]
          1. Table 15. Version ID Register Field Descriptions
        5. 7.6.2.5 Manufacturer ID Low Byte Register (address = 0x0C) [reset = 0x51]
          1. Table 16. Manufacturer ID Low Byte Register Field Descriptions
        6. 7.6.2.6 Manufacturer ID High Byte Register (address = 0x0D) [reset = 0x04]
          1. Table 17. Manufacturer ID High Byte Register Field Descriptions
      3. 7.6.3  Register Update (Buffered Registers): Address 0x0F
        1. 7.6.3.1 Register Update Register (address = 0x0F) [reset = 0x00]
          1. Table 18. Register Update Register Field Descriptions
      4. 7.6.4  General Device Configuration: Address 0x10 through 0x17
        1. 7.6.4.1 ADC Configuration Register (address = 0x10) [reset = 0x00]
          1. Table 19. ADC Configuration Register Field Descriptions
        2. 7.6.4.2 False Alarm Configuration Register (address = 0x11) [reset = 0x70]
          1. Table 21. False Alarm Configuration Register Field Descriptions
        3. 7.6.4.3 GPIO Configuration Register (address = 0x12) [reset = 0x00]
          1. Table 24. GPIO Configuration Register Field Descriptions
        4. 7.6.4.4 ADC MUX Configuration 0 Register (address = 0x13) [reset = 0x00]
          1. Table 25. ADC MUX Configuration 0 Register Field Descriptions
        5. 7.6.4.5 ADC MUX Configuration 1 Register (address = 0x14) [reset = 0x00]
          1. Table 26. ADC MUX Configuration 1 Register Field Descriptions
        6. 7.6.4.6 ADC MUX Configuration 2 Register (address = 0x15) [reset = 0x00]
          1. Table 27. ADC MUX Configuration 2 Register Field Descriptions
        7. 7.6.4.7 DAC Clear Enable 0 Register (address = 0x18) [reset = 0x00]
          1. Table 28. DAC Clear Enable 0 Register Field Descriptions
        8. 7.6.4.8 DAC Clear Enable 1 Register (address = 0x19) [reset = 0x00]
          1. Table 29. DAC Clear Enable 1 Register Field Descriptions
      5. 7.6.5  DAC Clear and ALARMOUT Source Select: Address 0x1A through 0x1D
        1. 7.6.5.1 DAC Clear Source 0 Register (address = 0x1A) [reset = 0x00]
          1. Table 30. DAC Clear Source 0 Register Field Descriptions
        2. 7.6.5.2 DAC Clear Source 1 Register (address = 0x1B) [reset = 0x00]
          1. Table 31. DAC Clear Source 1 Register Field Descriptions
        3. 7.6.5.3 ALARMOUT Source 0 Register (address = 0x1c) [reset = 0x00]
          1. Table 32. ALARMOUT Source 0 Register Field Descriptions
        4. 7.6.5.4 ALARMOUT Source 1 Register (address = 0x1D) [reset = 0x00]
          1. Table 33. ALARMOUT Source 1 Register Field Descriptions
      6. 7.6.6  DAC Range: Address 0x1E
        1. 7.6.6.1 DAC Range Register (address = 0x1E) [reset = 0x00]
          1. Table 34. DAC Range Register Field Descriptions
        2. 7.6.6.2 DAC Range 1 Register (address = 0x1F) [reset = 0x00]
          1. Table 36. DAC Range 1 Register Field Descriptions
      7. 7.6.7  ADC and Temperature Data: Address 0x20 through 0x4B
        1. 7.6.7.1 ADCn-Data (Low Byte) Register (address = 0x20 through 0x49) [reset = 0x00]
          1. Table 37. ADCn-Data (Low Byte) Register Field Descriptions
        2. 7.6.7.2 ADCn-Data (High Byte) Register (address = 0x20 through 0x49) [reset = 0x00]
          1. Table 38. ADCn-Data (High Byte) Register Field Descriptions
        3. 7.6.7.3 Temperature Data (Low Byte) Register (address = 0x4A) [reset = 0x00]
          1. Table 39. Temperature Data (Low Byte) Register Field Descriptions
        4. 7.6.7.4 Temperature Data (High Byte) Register (address = 0x4B) [reset = 0x00]
          1. Table 40. Temperature Data (High Byte) Register Field Descriptions
      8. 7.6.8  DAC Data: Address 0x50 through 0x6F
        1. 7.6.8.1 DACn-Data (Low Byte) Register (address = 0x50 through 0x6F) [reset = 0x00]
          1. Table 41. DACn-Data (Low Byte) Register Field Descriptions
        2. 7.6.8.2 DACn Data (High Byte) Register (address = 0x50 through 0x6F) [reset = 0x00]
          1. Table 42. DACn Data (High Byte) Register Field Descriptions
      9. 7.6.9  Status Registers: Address 0x70 through 0x72
        1. 7.6.9.1 Alarm Status 0 Register (address = 0x70) [reset = 0x00]
          1. Table 43. Alarm Status 0 Register Field Descriptions
        2. 7.6.9.2 Alarm Status 1 Register (address = 0x71) [reset = 0x00]
          1. Table 44. Alarm Status 1 Register Field Descriptions
        3. 7.6.9.3 General Status Register (address = 0x72) [reset = 0x0C]
          1. Table 45. General Status Register Field Descriptions
      10. 7.6.10 GPIO: Address 0x7A
        1. 7.6.10.1 GPIO Register (address = 0x7A) [reset = 0xFF]
          1. Table 46. GPIO Register Field Descriptions
      11. 7.6.11 Out-Of-Range ADC Thresholds: Address 0x80 through 0x93
        1. 7.6.11.1 ADCn-Upper-Thresh (Low Byte) Register (address = 0x80 through 0x93) [reset = 0xFF]
          1. Table 47. ADCn-Upper-Thresh (Low Byte) Register Field Descriptions
        2. 7.6.11.2 ADCn-Upper-Thresh (High Byte) Register (address = 0x80 through 0x93) [reset = 0x0F]
          1. Table 48. ADCn-Upper-Thresh (High Byte) Register Field Descriptions
        3. 7.6.11.3 ADCn-Lower-Thresh (Low Byte) Register (address = 0x80 through 0x93) [reset = 0x00]
          1. Table 49. ADCn-Lower-Thresh (Low Byte) Register Field Descriptions
        4. 7.6.11.4 ADCn-Lower-Thresh (High Byte) Register (address = 0x80 through 0x93) [reset = 0x00]
          1. Table 50. ADCn-Lower-Thresh (High Byte) Register Field Descriptions Field Descriptions
        5. 7.6.11.5 LT-Upper-Thresh (Low Byte) Register (address = 0x94) [reset = 0xFF]
          1. Table 51. LT-Upper-Thresh (Low Byte) Register Field Descriptions
        6. 7.6.11.6 LT-Upper-Thresh (High Byte) Register (address = 0x95) [reset = 0x07]
          1. Table 52. LT-Upper-Thresh (High Byte) Register Field Descriptions
        7. 7.6.11.7 LT-Lower-Thresh (Low Byte) Register (address = 0x96) [reset = 0x00]
          1. Table 53. LT-Lower-Thresh (Low Byte) Register Field Descriptions
        8. 7.6.11.8 LT-Lower-Thresh (High Byte) Register (address = 0x97) [reset = 0x08]
          1. Table 54. LT-Lower-Thresh (High Byte) Register Field Descriptions
      12. 7.6.12 Alarm Hysteresis Configuration: Address 0xA0 and 0xA5
        1. 7.6.12.1 ADCn-Hysteresis Register (address = 0xA0 through 0xA4) [reset = 0x08]
          1. Table 55. ADCn-Hysteresis Register Field Descriptions
        2. 7.6.12.2 LT-Hysteresis Register (address = 0xA5) [reset = 0x08]
          1. Table 56. LT-Hysteresis Register Field Descriptions
      13. 7.6.13 Clear and Power-Down Registers: Address 0xB0 through 0XB4
        1. 7.6.13.1 DAC Clear 0 Register (address = 0xB0) [reset = 0x00]
          1. Table 57. DAC Clear 0 Register Field Descriptions
        2. 7.6.13.2 DAC Clear 1 Register (address = 0xB1) [reset = 0x00]
          1. Table 58. DAC Clear 1 Register Field Descriptions
        3. 7.6.13.3 Power-Down 0 Register (address = 0xB2) [reset = 0x00]
          1. Table 59. Power-Down 0 Register Field Descriptions
        4. 7.6.13.4 Power-Down 1 Register (address = 0xB3) [reset = 0x00]
          1. Table 60. Power-Down 1 Register Field Descriptions
        5. 7.6.13.5 Power-Down 2 Register (address = 0xB4) [reset = 0x00]
          1. Table 61. Power-Down 2 Register Field Descriptions
      14. 7.6.14 ADC Trigger: Address 0xC0
        1. 7.6.14.1 ADC Trigger Register (address = 0xC0) [reset = 0x00]
          1. Table 62. ADC Trigger Register Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Temperature Sensing Applications
      2. 8.1.2 Current Sensing Applications
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 ADC Input Conditioning
        2. 8.2.2.2 DAC Output Range Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Device Reset Options
      1. 9.1.1 Power-on-Reset (POR)
      2. 9.1.2 Hardware Reset
        1. 9.1.2.1 Software Reset
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.1 ADC Input Conditioning

The AMC7836 device has an ADC with 21 analog inputs for external voltage sensing. Sixteen of these inputs are bipolar and the other five are unipolar. The bipolar inputs (ADC_0 through ADC_15) range is –12.5 to 12.5 V, and the unipolar analog inputs (LV_ADC16 through LV_ADC20) range is 0 to 2 × Vref. The ADC operates from an internal 2.5 V reference (Vref, measured at the REF_CMP pin). For additional noise filtering, a 4.7-µF capacitor should be connected between the REF_CMP and AGND2 pins. A high-quality ceramic type NP0 or X7R is recommended because of the optimal performance of the capacitor across temperature and very-low dissipation factor.

The ADC timing signals are driven from an on-chip temperature compensated 4-MHz oscillator. The on-chip oscillator is primarily responsible for the sampling frequency of the ADC. The sampling frequency of the ADC is dynamic and dependent on the acquisition and conversion time of each channel. Table 64 lists the relationship between the total update time and the internal oscillator frequency.

Table 64. ADC Conversion Rate and Total Update Number of Clocks

ADC CONVERSION RATEADC INPUT CHANNELACQUISITION CLOCKS CONVERSION CLOCKS tS (ACQUISITION + CONVERSION)
NUMBER OF CLOCKS
00 Bipolar 124.5 13.5 138
Unipolar 32.5 13.5 46
Internal Temperature Sensor — — 1025
01 Bipolar 124.5 13.5 138
Unipolar 78.5 13.5 92
Internal Temperature Sensor — — 1025
10 Bipolar 124.5 13.5 138
Unipolar 124.5 13.5 138
Internal Temperature Sensor — — 1025
11 Bipolar 262.5 13.5 276
Unipolar 262.5 13.5 276
Internal Temperature Sensor — — 1025

The minimum and maximum oscillator frequency specifications in conjunction with the number of clocks required for the unipolar, bipolar and temperature sensor inputs should be applied to Equation 5 to calculate the total update time range.

Equation 5. AMC7836 eq_05_slas986.gif

where

  • TS is the total update time
  • BCLK is the total bipolar clocks
  • #BCH is the number of active bipolar inputs
  • UCLK is the total unipolar clocks
  • #UCH is the number of active unipolar inputs
  • TCKL is the total internal temperature-sensor clocks
  • #TCH is the number of active internal temperature sensor channels; either 1 or 0
  • ƒOSC is the internal oscillator frequency

The following is an example of a complete calculation of the total update time range. In this example, the ADC conversion rate is set to 00 and the following ADC input channels are used:

  • Bipolar channels: ADC_1 through ADC_5 (5 active bipolar channels)
  • Unipolar channels: LV_ADC16 through LV_ADC18 (3 active unipolar channels)
  • Internal temperature sensor (1 active temperature channel)

Table 64 gives the total number of clocks required for each ADC input under the example conditions.

For the minimum specified oscillator frequency of 3.7 MHz, and with the ADC conversion rate set to 00, use Equation 6 to calculate the total maximum update time for this example.

Equation 6. AMC7836 eq_06_slas986.gif

For the maximum specified oscillator frequency of 4.3 MHz, use Equation 7 to calculate the total minimum update time for this example.

Equation 7. AMC7836 eq_07_slas986.gif

Therefore, the total update time range is 430.93 µs to 500.811 µs.

During the conversion, the input current per channel varies with the total update time which is determined by the number and type of channels (NCH) and the conversion rate setting of the CONV-RATE bit in the ADC configuration register (address 0x10).

NOTE

The source of the analog input voltage must be able to charge the input capacitance to a 12-bit settling level within the acquisition time.