SNAS348G May   2006  – April 2016 DAC124S085

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 DAC Section
      2. 8.3.2 Output Amplifiers
      3. 8.3.3 Reference Voltage
      4. 8.3.4 Power-On Reset
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Down Modes
    5. 8.5 Programming
      1. 8.5.1 Serial Interface
      2. 8.5.2 Input Shift Register
      3. 8.5.3 DSP or Microprocessor Interfacing
        1. 8.5.3.1 ADSP-2101 or ADSP2103 Interfacing
        2. 8.5.3.2 80C51 or 80L51 Interface
        3. 8.5.3.3 68HC11 Interface
      4. 8.5.4 Microwire Interface
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Bipolar Operation
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
  10. 10Power Supply Recommendations
    1. 10.1 Using References as Power Supplies
      1. 10.1.1 LM4132
      2. 10.1.2 LM4050
      3. 10.1.3 LP3985
      4. 10.1.4 LP2980
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Device Nomenclature
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

Figure 35 is an example of the DAC124S085 in a typical application. This circuit is basic and generally requires modification for specific circumstances.

9.2 Typical Application

9.2.1 Bipolar Operation

The DAC124S085 is designed for single-supply operation and thus has a unipolar output. However, a bipolar output may be obtained with the circuit in Figure 35. This circuit provides an output voltage range of ±5 V. A rail-to-rail amplifier must be used if the amplifier supplies are limited to ±5 V.

DAC124S085 20173217.gif Figure 35. Bipolar Operation

9.2.1.1 Design Requirements

  • The DAC124S085 uses a single supply.
  • The output is required to be bipolar with a voltage range of ±5 V.
  • Dual supplies are used for the output amplifier.

9.2.1.2 Detailed Design Procedure

The output voltage of this circuit for any code is found with Equation 2.

Equation 2. VO = (VA × (D / 4096) × ((R1 + R2) / R1) – VA × R2 / R1

where

  • D is the input code in decimal form

Equation 3 is calculated with VA = 5 V and R1 = R2.

Equation 3. VO = (10 × D / 4096) – 5 V

A list of rail-to-rail amplifiers suitable for this application are indicated in Table 2.

Table 2. Some Rail-to-Rail Amplifiers

AMP PKGS  VOS (TYP) ISUPPLY (TYP)
LMC7111 DIP-8
SOT23-5		 0.9 mV 25 µA
LM7301 SO-8
SOT23-5		 0.03 mV 620 µA
LM8261 SOT23-5 0.7 mV 1 mA

9.2.1.3 Application Curve

DAC124S085 Application1.gif Figure 36. Bipolar Input and Output Transfer Characteristic