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TWR-ADCDAC-LTC
User guide
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Freescale Semiconductor TWR-ADCDAC-LTC User guide

TWR-ADCDAC-LTC Tower Module

User's Manual

Rev. 0
Freescale Semiconductor Inc TWRADCDACLTCUM
Table of Contents
1 TWR-ADCDAC-LTC Overview .............................................................................................................. 4
2 Hardware Description ........................................................................................................................... 6
2.1.1 LTC2600 ................................................................................................................................................................................................. 6
2.1.2 LTC2704 ................................................................................................................................................................................................. 6
2.1.3 LTC2498 ................................................................................................................................................................................................. 7
2.1.4 LTC1859 ................................................................................................................................................................................................. 7
2.1.5 LTC3471 ................................................................................................................................................................................................. 7
2.1.6 LTC6655 ................................................................................................................................................................................................. 8
2.4.1 QuikEval Connectors ..................................................................................................................................................................... 12
2.4.2 ADC and DAC Connections .......................................................................................................................................................... 12
2.4.3 Digital Debug Connector .............................................................................................................................................................. 13
TWRADCDACLTCUM TWR-ADCDAC-LTC Tower Module User's Manual Page 2 of 17
Revision
Date
Changes
1.0
Jan 17, 2010
Initial Release
List of Figures
Figure 1. Freescale Tower System Overview .............................................................................................. 4
The features of the TWR-ADCDAC-LTC peripheral module are listed here and pointed out in Figure 2:.. 4
Figure 2. Callouts on top side of the TWR-ADCDAC-LTC ............................................................................ 5
Figure 3. SPI Configuration Options ............................................................................................................ 9
Figure 4. Power Inputs .............................................................................................................................. 10
Figure 5. LTC3471 Switching Regulator .................................................................................................... 11
Figure 6. LTC6655-5 Voltage Reference .................................................................................................... 11
Figure 7. QuikEval Connectors .................................................................................................................. 12
Figure 8. TWR-ADCDAC-LTC Default Jumper Settings .............................................................................. 15
List of Tables
Table 1. SPI Chip-Select Decoder Truth Table............................................................................................. 9
Table 2. Decoded SPI Chip-Select Device Connections ............................................................................. 10
Table 3. Terminal Block Connections ........................................................................................................ 13
Table 4. Digital Debug Connector ............................................................................................................. 14
Table 5. TWR-ADCDAC-LTC Jumper Table ................................................................................................ 14
Table 6. TWR-ADCDAC-LTC Primary Connector Pinout ............................................................................ 15
TWRADCDACLTCUM TWR-ADCDAC-LTC Tower Module User's Manual Page 3 of 17
Revision History

1 TWR-ADCDAC-LTC Overview

The TWR-ADCDAC-LTC is a Tower Peripheral Module compatible with the Freescale Tower System (Figure 1). It features two analog-to-digital converters (ADC), two digital-to-analog converters (DAC), a voltage regulator and high-precision voltage reference from Linear Technology. SPI and I2C interface signal connections on the Primary Elevator Connector allow any Tower Controller Module with a SPI and I2C interface to configure and control all the features of the TWR-ADCDAC-LTC.
Figure 1. Freescale Tower System Overview
The features of the TWR-ADCDAC-LTC peripheral module are listed here and pointed out in Figure 2:
Two Linear Technology digital-to-analog converters (DACs) with SPI interfaces
o LTC2704-16: Quad 16-bit voltage output SoftSpan™ DAC with readback o LTC2600: Octal 16-bit rail-to-rail DACs
Two Linear Technology analog-to-digital converters (ADCs) with SPI interfaces
o LTC1859: 8-channel, 16-bit, 100 ksps SoftSpan ADC with shutdown o LTC2498: 24-bit 8-/16-channel delta sigma ADC with Easy Drive™ input current
cancellation
Linear Technology voltage regulator
o LTC3471: Dual 1.3A, 1.2 MHz boost/inverter
TWRADCDACLTCUM TWR-ADCDAC-LTC Tower Module User's Manual Page 4 of 17
Linear Technology voltage reference
o LTC6655-5: 0.25 ppm noise, low drift precision buffered 5V reference
Four 14-pin headers for connecting to any Linear Technology QuikEval™ demonstration board
via I2C or SPI
Figure 2. Callouts on top side of the TWR-ADCDAC-LTC

1.1 Getting Started

The TWR-ADCDAC-LTC is a Tower Peripheral Module that operates under the control of a Tower Controller Module. A software Demo Suite is available and is the best way to get started and exercise the features of the TWR-ADCDAC-LTC. A separate lab guide is available to walk the user through the Demo Suite. Refer to the TWR-ADCDAC-LTC Lab Guide (TWRADCDACLTCLAB) for a list of the Tower Controller Modules that can run the Demo Suite.

1.2 Reference Documents

The documents and links listed below should be referenced for more information on the TWR­ADCDAC-LTC and the Tower System.
Freescale Tower System: www.freescale.com/tower TWR-ADCDAC-LTC Tool Support Page TWRADCDACLTCQSG: Quick Start Guide TWRADCDACLTCLAB: Lab Guide and Software TWRADCDACLTCSCH: Schematics TWR-ADCDAC-LTC-PWB: Design Package
Please refer to the following links for information on the Linear Technology devices featured on the TWR-ADCDAC-LTC.
LTC2600 Product Details LTC2704-16 Product Details
TWRADCDACLTCUM TWR-ADCDAC-LTC Tower Module User's Manual Page 5 of 17
LTC2498 Product Details LTC1859 Product Details LTC3471 Product Details LTC6655-5 Product Details

2 Hardware Description

The TWR-ADCDAC-LTC features four Linear Technology converter devices, a voltage regulator and a high precision voltage reference. Each of the ADCs and DACs on the TWR-ADCDAC-LTC provide a SPI digital interface for configuration and control. In addition, the QuikEval headers utilize either a SPI or I2C interface. This section gives an overview of each of the on-board Linear Technology devices and describes the system power and digital interface configuration options.

2.1 Linear Technology Devices

This section provides a short description of each of the Linear Technology devices on the TWR­ADCDAC-LTC. Refer to the datasheets and product page links in the “Reference Documents” section for more product information. Refer to the TWR-ADCDAC-LTC schematics to see how these devices are connected on the TWR-ADCDAC-LTC.

2.1.1 LTC2600

The LTC2600/LTC2610/LTC2620 are octal 16-, 14- and 12-bit, 2.5V-to-5.5V rail-to-rail voltage-output DACs in 16-lead narrow SSOP and 20-lead 4mm × 5mm QFN packages. They have built-in high performance output buffers and are guaranteed monotonic.
These parts establish new board-density benchmarks for 16- and 14-bit DACs and advance performance standards for output drive, crosstalk and load regulation in single-supply, voltage-output multiples.
The parts use a simple SPI/MICROWIRE compatible 3-wire serial interface which can be operated at clock rates up to 50MHz. Daisychain capability and a hardware CLR function are included.
The LTC2600/LTC2610/LTC2620 incorporates a power-on reset circuit. During power-up, the voltage outputs rise less than 10mV above zero-scale; and after power-up, they stay at zero-scale until a valid write and update take place.

2.1.2 LTC2704

The LTC2704-16/LTC2704-14/LTC2704-12 are serial input, 12-, 14- or 16-bit, voltage output SoftSpan™ DACs that operate from 3V to 5V logic and ±5V to ±15V analog supplies. SoftSpan offers six output spans—two unipolar and four bipolar—fully programmable through the 3-wire SPI serial interface. INL is accurate to 1LSB (2LSB for the LTC2704-16). DNL is accurate to 1LSB for all versions.
Readback commands allow verification of any on-chip register in just one 24- or 32- bit instruction
cycle. All other commands produce a “rolling readback” response from the LTC2704, dramatically
reducing the needed number of instruction cycles.
TWRADCDACLTCUM TWR-ADCDAC-LTC Tower Module User's Manual Page 6 of 17
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