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DC1147A-E

器件型号:DC1147A-E
器件类别:开发板_开发套件_开发工具   
厂商名称:Analog Devices Inc.
标准:
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器件描述

Data Conversion IC Development Tools LTC6403-1 demo circuit

参数

产品属性属性值
Product AttributeAttribute Value
制造商:
Manufacturer:
Analog Devices Inc.
产品种类:
Product Category:
Data Conversion IC Development Tools
RoHS:YES
产品:
Product:
Demonstration Boards
类型:
Type:
ADC
工具用于评估:
Tool Is For Evaluation Of:
LTC6403-1
工作电源电压:
Operating Supply Voltage:
2.7 V to 5.25 V
系列:
Series:
LTC6403
商标:
Brand:
Analog Devices
产品类型:
Product Type:
Data Conversion IC Development Tools
工厂包装数量:
Factory Pack Quantity:
1
子类别:
Subcategory:
Development Tools

DC1147A-E器件文档内容

DEMO CIRCUIT DC1147 QUICK STARTDGEUMIDOECIRCUIT 1147

LOW NOISE/DISTORTION 16-BIT DIFFERENTIAL AQDCUIDCRKIVESRTASRT GUIDE

                                                                 LTC6404-x, LTC6406,LTC6405

                                                                                                    and LTC6403-1

                                                                 16-Bit Differential ADC Drivers

DESCRIPTION

Demonstration  circuit  1147  features      the  LTC6404-x,      These     fully-differential  amplifiers     accept  single-ended         or

LTC6406, LTC6403-1, and LTC6405 16-bit ADC Drivers. It           differential inputs with almost no difference in distortion

incorporates a variety of passive components to support          performance. Each part has the ability to independently ad-

configurations for varied applications. Single-ended or dif-     just the output common-mode voltage without any addi-

ferential input and output configurations are possible, and      tional    components,         and  flexible  input   common-mode

there is a calibration circuit to null out the effects of other  ranges which enable level-shifting of input signals for ADC

circuit components.                                              driving applications.

                                                                 Design files for this circuit board are available. Call

The LTC640x are high-speed differential amplifiers with su-      the LTC factory.

perior distortion and noise performance, perfect for de-         , LTC and LT are registered trademarks of Linear Technology Corporation.

manding  communications      transceivers,  cellular  base-

stations, and other high-speed signal chain applications.

QUICK START PROCEDURE

Table 1 shows the function of each SMA connector on the          Table 1: DC1147 Board I/O Descriptions

board. Refer to Figure 1 for the connection diagram and          CONNECTOR   FUNCTION

follow the procedure below:                                      J1 (IN+)    Differential Input. Use this connector to supply an input

1. Connect the power supply as shown. The power labels of                    to the DC1147. Drive from a 50ohm signal source, no

                                                                             external termination necessary.

V+, VOCM, and GND directly correspond to the power               J2 (OUT-)   Differential Output. Not connected by default. Resistor

supply and VOCM pins of the LTC640x ICs (U1). Jumper                         R9 can installed and R10 removed to receive the output

JP1 enables or shuts down the amplifier.                                     signal differentially.

2. The power supplies available for each part are shown in       J3 (OUT+)   Output. Impedance-matched to 50 ohms, can be used

Table 1. Do not exceed the maximum power supply                              to drive a 50ohm network/spectrum analyzer input.

voltage for the parts.                                           J4 (IN-)    Differential Input. Not connected by default. Resistor

                                                                             R24 can be installed and R27 removed for differential

3. Apply an input signal to J1. A low-distortion, low                        input drive. R4 and R7 should be matched or both re-

                                                                             moved to provide a balanced input impedance.

noise signal source with an external high-order filter           JP1 (SHDN)  Shutdown jumper. The left (EN) position enables the

will yield the best performance. DC1147’s input is                           part, while the right (DIS) puts it into shutdown mode.

impedance-matched to 50Ω; no external termination                E3 (VOCM)   Output Common-Mode Adjust. By default, this pin is

is necessary.                                                                self-biasing within U1. Override this voltage with any

                                                                             DC voltage source.

4. Observe the output via J3. The output is impedance-           E5 (VTIP)   Corresponds to the VTIP pin in DC1147-D

matched to 50Ω, suitable for the input of a network or                       (LTC6405/6). Consult the datasheet for pin function.

spectrum analyzer.                                                           Leave floating if unused. This pin is not connected for

                                                                             all the other parts in the family.

                                                                                                                                           1
DEMO CIRCUIT DC1147 QUICK START GUIDE

LOW NOISE/DISTORTION 16-BIT DIFFERENTIAL ADC DRIVERS

                                 Figure 1: Proper Measurement Equipment Setup

ADDITIONAL INFORMATION

Although the DC1147 demo board is ready to use out of             DC1147A-C  LTC6404-4  2.7-5.25V

the box, it has features that you can access by adding, re-       DC1147A-D  LTC6406    2.7-3.5V

moving or changing components on the board. These are             DC1147A-E  LTC6403-1  2.7-5.25V

described below.                                                  DC1147A-F  LTC6405    2.7-5.25V

DEMO BOARD VERSIONS                                               DIFFERENTIAL INPUTS

DC1147  has  four  versions      to  support  all  of  the  pin-  To drive the inputs differentially, remove resistor R27 and

compatible parts in the LTC640x amplifier family. Table 1         install R24. J1 and J4 can now be driven differentially from

contains a listing of the different amplifiers and their supply   a 50Ω signal source. R4 and R7 should be changed to dif-

voltage ranges. See the schematic (on the last page of this       ferentially match the input to 50Ω if necessary.

guide) for component differences between the versions.            DRIVING THE INPUTS DC-COUPLED

DEMO BOARD SUPPLY VOLTAGES                                        It is possible to drive the DC1147 inputs differentially with

Table 2: DC1147 Supply Voltages                                   DC coupling. Transformer T1 should be replaced with 0Ω

DEMO         U1              SUPPLY VOLTAGE RANGE                 resistors. The inputs are now DC-coupled and can be dri-

BOARD                                                             ven single-ended or differentially (resistor values may be

DC1147A-A    LTC6404-1       2.7-5.25V                            changed to balance the source impedances, et cetera. See

DC1147A-B    LTC6404-2       2.7-5.25V

                                                                                                                    2
DEMO CIRCUIT DC1147 QUICK START GUIDE

LOW NOISE/DISTORTION 16-BIT DIFFERENTIAL ADC DRIVERS

the product datasheets for more information. Input bias        ENABLE (SHUTDOWN)

currents will flow through the amplifier’s input resistors if  Jumper JP1 controls the enable function of DC1147. When

DC1147 is driven DC coupled.                                   set to the EN position, the part will be on and draw quies-

DIFFERENTIAL OUTPUTS                                           cent current. In the DIS position, the part will be in shut-

                                                               down and draw a very small amount of quiescent current.

To use the both outputs of the DC1147, remove resistor

R10 and install R9. The output now appears differentially      GROUND AND VCC CONNECTIONS

across J3 and J2. The output of the DC1147 will still be       DC1147’s GND connector is not only connected to V- of

matched to 50Ω (differentially) when used in this manner.      the LTC640x, it also serves as the board ground. For best

CHANGING THE OUTPUT COMMON-MODE VOLTAGE                        performance, a low-impedance return path to the power

                                                               supply from GND is crucial. Short, low impedance wires to

Turret E3 controls the output common-mode voltage of U1.       the V+ and GND connectors of DC1147 will yield the best

This function can be used to level-shift the DC output volt-   performance from the LTC6400/1.

age for optimum system performance. If used for this pur-

pose, transformer T2 can be replaced by 0Ω resistors to        SCHEMATIC NOTES

allow the DC bias to reach the output. By default, the VOCM

voltage is self-biased through resistors internal to the IC’s  Note that transformer T2 and the series resistors at the

(U1).                                                          amplifier outputs create a 12.6dB attenuation (if the output

                                                               has a 50Ω load) that will affect the measured gain of the

OUTPUT DRIVE                                                   demo board. This is done so that the output of DC1147 can

Since the output of the LTC6400/1 is a low-impedance op-       plug directly into a 50Ω network/spectrum analyzer input,

erational amplifier output, performance will degrade when      but the amplifier sees a higher 400Ω load impedance.

the output is directly driving low impedances such as 50Ω.

On DC1147 there are series 100 ohms resistors at the out-

put as well as a 4:1 transformer to increase the load im-

pedance seen by the amplifier.

                                                                                                                        3
DEMO CIRCUIT DC1147 QUICK START GUIDE

LOW NOISE/DISTORTION 16-BIT DIFFERENTIAL ADC DRIVERS

                                                      4
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