EVM Overview
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14
DAC Output Update Options
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15
Data Format Options
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List of Tables
1
Parts List
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2
Factory Default Jumper Settings
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3
Digital Control Interface Signal Mapping for J2/P2 Header/Socket Connectors
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4
Bipolar Output Operation Jumper Settings
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5
Gain of Two Output Jumper Settings
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6
Capacitive Load Drive Output Jumper Settings
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7
Jumper Setting Functions
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8
DXP GPIO Controlled DAC Functions
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9
Output Update Features
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1
EVM Overview
This chapter provides a general overview of the DAC8881 evaluation module (EVM) and describes some
of the factors that must be considered in using this module.
1.1
Features
This EVM features the DAC8881 digital-to-analog converter. The DAC8881 EVM is a simple evaluation
module designed for a quick and easy way to evaluate the functionality and performance of the 16-bit high
resolution, voltage output, single channel, and serial input DAC. This EVM features a high-speed serial
interface of up to 50MHz to communicate with any host microprocessor or DSP-based system.
The DAC8881 is designed for unipolar output operation (default mode), but it can also be configured for
bipolar output operation with the addition of an external amplifier and some resistors. The option for
bipolar mode of operation is included in the EVM with just some minor jumper configuration.
A +5V precision voltage reference is provided on-board via U3 (REF02) to supply the necessary external
reference voltage to set the DAC8881 output range. The footprint of U3 is compatible with many SO-8
package type reference devices, so the user has the flexibility to select the reference supply to set the
output range of the DAC8881 other than what is provided on-board. The family of REF50xx precision
reference sources works well with this EVM. In addition, the provision of test points, TP1 and TP8, allows
the user to use their own external reference supply. Typically, TP1 (V
REF
L) should be connected to ground,
but it can accept up to ±0.2V if necessary. The test point, TP8 (V
REF
H), is typically set to +5V, but can
accept a minimum of +1.25V and up to a maximum of +5.5V.
The voltage reference configuration implemented on this EVM utilizes the Kelvin connection feature of the
DAC8881 device. This connection helps minimize the internal errors caused by the changing reference
current and its associated circuit impedances.
1.2
Power Requirements
The following sections describe the power requirements of this EVM.
1.2.1
Supply Voltage
The dc power supply requirement for this DAC8881 EVM (AV
DD
and DV
DD
) is selectable b3.3VA
and +5VA via the W1 jumper. The +3.3VA comes from the J6-8 terminal and the +5VA comes from the
J6-3 terminal. These power supply voltages are referenced to analog ground through the J6-5 and J6-6
terminals.
The logic voltage, IOV
DD
, is selectable b1.8VD, +3.3VD, and +5VD via the J3 jumper.
V
CC
and V
SS
range from +15V to –15V maximum and connect through the J6-1 and J6-2 terminals
respectively. All analog power supplies are referenced to analog ground through the J6-5 and J6-6
terminals.
2
DAC8881 Evaluation Module
SLAU257A – September 2008 – Revised November 2009
Copyright © 2008–2009, Texas Instruments Incorporated