DC1513B-AD - ANALOG DEVICES

DC1513

DESCRIPTION

Demonstration circuit DC1513 is an evaluation board

featuring Linear Technology Corporation’s LTM9004 14-

Bit Direct Conversion Receiver Subsystem. DC1513

demonstrates good circuit layout techniques and rec-

ommended external circuitry for optimal system per-

formance.

DC1513 comes with Linear Technology’s 14-bit

LTM9004 receiver subsystem installed. The board in-

cludes output CMOS buffers.

DC1513 plugs into the

DC890 Data Acquisition demo board and the output can

be easily analyzed with Linear Technology’s PScope data

processing software, which is available for no charge on

our website at http://www.linear.com.

Design files for this circuit board are available. Call

the LTC factory.

, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered

trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy

Drive, FilterCAD, Hot Swap, LinearView, µModule, Micropower SwitcherCAD, Multimode

Dimming, No Latency ∆Σ, No Latency Delta-Sigma, No R

SENSE

, Operational Filter, PanelProtect,

PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT,

UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names

may be trademarks of the companies that manufacture the products.

QUICK START PROCEDURE

Validating the performance of the LTM9004 is simple

with DC1513, and requires only two input sources, a

clock source, a computer, and a lab power supply. Refer

to Figure 1 for proper board evaluation equipment setup

and follow the procedure below:

Connect the power supply as shown in Figure 1.

There are on-board low-noise voltage regulators

that provide the two supply voltages for the

DC1513. The entire board and all components

share a common ground. The power supply should

still be a low-noise lab power supply capable of

supplying at least 0.5 Amp @ 5.0VDC, and 1 Amp

@ 3.0VDC.

Provide an encode clock to the ADC via SMA con-

nector J7. Use a low-phase-noise clock source

such as a filtered RF signal generator or a high-

quality clock oscillator.

NOTE.

Similar to having a noisy input, a high-jitter (phase noise) encode

clock will degrade the signal-to-noise ratio (SNR) of the system.

Table 1: DC1513 Connectors and Jumpers

REFERENCE FUNCTION

J3 (SHDN) Enables/disables the ADC. Default is ON.

J4 (MODE) Output Format and Clock Duty Stabilizer pin.

Default is VDD.

J5 (SHDN_AMP) Enables/disables the Amplifers. Default is ON.

J6 (LO) Board LO Signal Input. Impedance-matched to

Ω

for use with lab signal generators.

J7 (CLK) Board Clock Input. Impedance-matched to

Ω.

Drive with a low-phase-noise clock oscil-

lator or filtered sine wave signal source.

J8 (MIXER

ENABLE)

Enables/disables the RF mixer. Default is ON.

J11 (RF) Board RF Signal Input. Impedance-matched to

Ω

for use with lab signal generators.

TP1 (SENSE_I) Reference input to adjust the full-scale range of

the DC1513, I Channel. Default is VDD.

TP2 (GND) DC ground.

TP4 (GND) DC ground.

TP5 (+3V) DC Supply input (3VDC).

TP7 (+5V) DC Supply input (5VDC).

TP8 (GND) DC ground.

TP12 (SENSE_Q) Reference input to adjust the full-scale range of

the DC1513, Q Channel. Default is VDD.

Apply an RF input signal to the board. For best

results, use a low distortion, low noise signal

DEMO

CIRCUIT

1513

QUICK START GUIDE

LTM9004 14 Bit D

irect

Conversion Receiver Subsys

tem

DC1513

generator with sufficient filtering to avoid degrading

the performance of the receiver.

Apply an LO input signal to the board. Note that

the difference in frequency between this signal and

the RF signal will be the IF frequency resulting at

the IF filter and ADC input.

Observe the ADC output with demo circuit

DC890B, a USB cable, a Windows computer, and

Linear Technology’s PScope data processing soft-

ware.

Figure 1.

Proper Measurement Equipment Setup

OTHER BOARD CIRCUITRY

Device U1 is an EEPROM device that is used by the PScope software to identify the board and apply the correct set-

tings for the data collection.

Signal

Generator

HP 8644B or equiv.

RF Signal Ge

erator

(HP 8644B) or other

low phase noise

clock source (e.g. DC1216)

Power Supply

(5.0V @ 0.5A, 3.0V @ 1.0A)

To DC

890B

BPF

NOTE.

Even a high

quali

ty signal

synthesizer will still have noise and

harmonics that should be attenuated

with a low-pass or band-pass filter. For

good-quality high order filters, see TTE,

Lark Engineering, or equivalent.

BPF

Signal

Generator

HP 8644B or equiv.

DC1513

USING PSCOPE SOFTWARE

PScope, downloadable from Linear Technology’s website http://www.linear.com/, processes data from the DC890B

FastDAACS board and displays FFT and signal analysis information on the computer screen.

The on-board EEPROM U1 should enable automatic board detection and auto-configuration of the software, but if the

user wishes to change the settings, they can easily do so.

From the Configure menu in the toolbar, uncheck “Autodetect Device”. The default settings for DC1513 are shown in

Figure 2.

Entering the correct device information for your ADC. Select the correct parameters for the DC1513. Under normal conditions,

PScope should automatically recognize the board and adjust the software settings accordingly.

DC1513

Figure 3.

Schematic.