SNAS348G May   2006  – April 2016

PRODUCTION DATA.

1. Features
2. Applications
3. Description
4. Revision History
5. Description (continued)
6. Pin Configuration and Functions
7. Specifications
8. Detailed Description
1. 8.1 Overview
2. 8.2 Functional Block Diagram
3. 8.3 Feature Description
4. 8.4 Device Functional Modes
5. 8.5 Programming
9. Application and Implementation
1. 9.1 Application Information
2. 9.2 Typical Application
1. 9.2.1 Bipolar Operation
10. 10Power Supply Recommendations
1. 10.1 Using References as Power Supplies
11. 11Layout
12. 12Device and Documentation Support
13. 13Mechanical, Packaging, and Orderable Information

• DGS|10
• DSC|10
• DSC|10

## 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.

#### 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

Figure 36. Bipolar Input and Output Transfer Characteristic