Texas Instruments DAC7741EVM manuale d’uso

DAC7741EVM October 2002 DAP EVMs User ’ s G uide SLAU093[...]

IMPORT ANT NOTICE T exas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orde[...]

EVM IMPORT ANT NOTICE T exas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EV ALUA TION PURPOSES ONL Y and is not considered by TI to be fit for commercial use. As such, the goods being provided may not be complete in terms of[...]

EVM W ARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of ± 15 V and the output voltage range of ± 10 V . Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative p[...]

Information About Cautions and Warnings iii Preface Read This First About This Manual This user ’ s guide describes the characteristics, operation, and the use of the DA7741 evaluation module. It covers all pertinent areas involved to properly use this EVM board along with the devices that it supports. The physical PCB layout, schematic diagram a[...]

T rademarks iv Related Documentation From T exas Instruments T o obtain a copy of any of the following TI documents, call the T exas Instru- ments Literature Response Center at (800) 477 – 8924 or the Product Informa- tion Center (PIC) at (972) 644 – 5580. When ordering, identify this manual by its title and literature number . Updated document[...]

Contents v Contents 1 EVM Overview 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Features 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Power Requirements 1-2 .[...]

Contents vi T ables 2-1 Parts List 2-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Factory Default Jumper Setting 3-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Unity Gain Output Jumper Settings [...]

1-1 EVM Overview EVM Overview This chapter gives a general overview of the DAC7741 evaluation module (EVM), and describes some of the factors that must be considered in using this module. T opic Page 1.1 Features 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Power Requirements 1-2 [...]

Features 1-2 1.1 Features This EVM features the DAC7741 digital-to-analog converter . The DAC7741 EVM is a simple evaluation module designed for a quick and easy way to evaluate the functionality of the high resolution, single-channel, and parallel input DAC. This EVM features a parallel interface to communicate to any host processor base system. 1[...]

EVM Basic Functions 1-3 EVM Overview The REF102 precision reference derives its power of ± 15-V supply through J10 or J7 terminal. The (plus) 15 V connects through J10-1 or J7-2 terminals, while the (minus) -15 V connects through J10-3 or J7-4 terminals. They are both referenced to analog ground through J10-2 and J7-1. The DAC7741 has a REFEN pin [...]

EVM Basic Functions 1-4 A block diagram of the EVM is shown below in the Figure 1-1. Figure 1-1. EVM Block Diagram DAC Out (J4) (J5) W13 Output Buffer Module W14 W4 W3 External Reference Module (J2) (J3) (J6) (J7) +15 V -15 V TP1 +REF IN Ext Ref Input REF IN REF out DAC Module TP2 (J1) VCC VDD VSS +15 V GND -15 V GND VCC VDD VSS REFEN LDAC RST RSTS[...]

2-1 Physical Description Physical Description This chapter describes the physical characteristics and PCB layout of the EVM and lists the components used on the module. T opic Page 2.1 PCB Layout 2-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Bill of Materials 2-7 . . . . . . . . . . . . [...]

PCB Layout 2-2 2.1 PCB Layout The EVM is constructed on a four-layer printed-circuit board using a copper-clad FR-4 laminate material. The printed-circuit board has a dimension of 99,06 mm (3.90 inch) × 104,14 mm (4.10 inch), and the board thickness is 1,57 mm (0.062 inch). Figures 2-1 through 2-6 show the individual artwork layers. Figure 2-1. La[...]

PCB Layout 2-3 Physical Description Figure 2-2. Layer T wo (Ground Plane)[...]

PCB Layout 2-4 Figure 2-3. Layer 3 (Power Plane)[...]

PCB Layout 2-5 Physical Description Figure 2-4. Layer 4 (Bottom Plane)[...]

PCB Layout 2-6 Figure 2-5. Drill Drawing[...]

Bill of Materials 2-7 Physical Description 2.2 Bill of Materials T able 2-1. Parts List Item # Qty Designator Manufacturer Part Number Description 1 1 C8 Panasonic ECJ3VB1C105K 1 µ F , 1206 multilayer ceramic capacitor 2 2 C9 C10 Panasonic ECUV1H103KBM 0.01 µ F , 1206 multilayer ceramic capacitor 3 5 C1 C2 C3 C7 C13 Panasonic ECJ3VB1C104K 0.1 µ [...]

Bill of Materials 2-8 (This page has been left blank intentionally .)[...]

3-1 EVM Operation EVM Operation This chapter covers in detail the operation of the EVM to provide guidance to the user in evaluating the onboard DAC and how to interface the EVM to a specific host processor . Refer to the DAC7741 data sheet, SBAS248, for information about its parallel interface and other related topics. Th e EVM board is factory te[...]

Factory Default Setting 3-2 3.1 Factory Default Setting The EVM board is set to its default configuration from factory as described on th e table below to operate in bipolar ± 10V mode of operation using the internal reference. T able 3-1. Factory Default Jumper Setting Reference Jumper Position Function W1 OPEN V REF output pin is floated and not[...]

Host Processor Operation 3-3 EVM Operation 3.2 Host Processor Operation The host processor basically drives the DAC, so the DACs proper operation depends on the successful configuration between the host processor and the EVM board. In addition, a properly written code is also required to operate the DAC. A custom cable can be made specific to the h[...]

Host Processor Operation 3-4 3.2.2 Output Gain of T wo This configuration allows the DAC output with a gain of two, but is limited to the effective rails of the operational amplifier . When the DAC7741 is configured to operate in bipolar mode, the DAC output must be within the range o f 1 2 V P- P or less. Anywhere above the range of 12 V P- P woul[...]

Jumper Setting 3-5 EVM Operation 3.3 Jumper Setting The figures in T able 3-5 will show the function of each jumper on the EVM. T able 3-5. Jumper Setting Function Reference Jumper Setting Function 13 R OFFSET is strapped to V REF to set V SJ (summing junction) to V REF /2. Refer to the data sheet for offset adjustment. W1 13 R OFFSET is not connec[...]

Jumper Setting 3-6 T able 3-5. Jumper Setting Function (Continued) Reference Jumper Setting Function Disconnects AGND from DGND. W1 1 Connects AGND and DGND together . 13 Positive supply rail of op-amp is powered by +15V . W12 13 Positive supply rail of op-amp is powered by V CC . 26 4 15 3 Routes the raw output of the DAC7741 to J4-2 and J5 output[...]

Schematic 3-7 EVM Operation 3.4 Schematic A schematic of the DAC7741 is found on the following page.[...]

1 2 3 4 56 A B C D 6 5 4 3 2 1 D C B A ti 12500 TI Boulevard. Dallas, Texas 75243 Title: SHEET: OF: FILE: SIZE: DATE: REV: 27-Sep-2002 Draw n By: En gineer : Revis ion History RE V EC N Nu mber A pprov ed DA C7741.Sc h DOCUMENTCONTRO L # C1 0.1µF C7 0.1µF C2 0.1µF D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 VCC DAC_VOUT CS R/W LDAC RST[...]