MAX19700EVKIT 查看數據表（PDF） - Maxim Integrated

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MAX19700EVKIT

MAX19700 Evaluation Kit/Evaluation System

Maxim Integrated 

MAX19700 Evaluation Kit/Evaluation System

MAX19700 Power-Down

The MAX19700 features a global device power-down

pin. Jumper JU2 controls this feature. See Table 1 for

jumper configuration.

Table 1. Power-Down Shunt Settings (JU2)

SHUNT

POSITION

PD PIN

DESCRIPTION

1-2*

OVDD Normal operation

2-3

DGND MAX19700 powered down

*Default configuration: JU2 (1-2).

Measuring the OVDD Supply Current

The level-translating buffer (U2) requires a voltage sup-

ply on each side of the device. By default, the

MAX19700 side of the device is connected to OVDD. If

the OVDD current is measured at the OVDD and GND

pads of the EV kit, a measurement error will occur due

to the extra current flowing into U2. To accurately mea-

sure OVDD current, connect the MAX19700 side of U2

to BVCC by configuring jumper JU5. See Table 2 for

jumper configuration. Ensure that BVCC is equal to

OVDD, when operating in this mode.

Table 2. OVDD Supply Connections (JU5)

SHUNT POSITION

DESCRIPTION

1-2*

Normal operation

2-3

OVDD measurement mode;

note BVCC must equal OVDD

*Default configuration: JU5 (1-2).

Clock

An on-board clock-shaping circuit generates a clock

signal from an AC sine-wave signal applied to the

CLOCK SMA connector. The input signal should not

exceed a magnitude of 2.6VP-P. The frequency of the

signal should not exceed 7.5MHz for the MAX19700.

The frequency of the sinusoidal input signal determines

the sampling frequency (fCLK) of the MAX19700. A dif-

ferential line receiver (U3) processes the input signal to

generate the CMOS clock signal. The signal’s duty

cycle can be adjusted with potentiometer R63. A clock

signal with a 50% duty cycle (recommended) can be

achieved by adjusting R63 until 1.32V is produced

across test points TP3 and TP4 when the clock voltage

supply (CVDD) is set to 3.0V. The clock signal is avail-

able at J11-1 (CLK), which can be used to synchronize

the output signal to the logic analyzer. Measure the

clock signal with an oscilloscope at TP5.

Rx ADC Inputs

Although the MAX19700 accepts differential analog

input signals, the EV kit only requires a single-ended

analog input signal, with an amplitude of less than

4.5dBm provided by the user. Connect the single-ended

sources to J3 (I channel) and J6 (Q channel). Insertion

losses due to a series-connected filter and the intercon-

necting cables will decrease the amount of power seen

at the EV kit input. Account for these losses when setting

the signal generator amplitude. On-board transformers

(T1-T2) convert the single-ended analog input signals

and generate differential analog signals at the ADCs’

differential input pins. The MAX19700 also accepts sin-

gle-ended input signals. See the Configuring for Single-

Ended ADC Operation section in this document for

details on how to modify the MAX19700 EV kit to sup-

port this mode of operation.

Configuring for Single-Ended ADC Operation

The MAX19700 can be configured to accept AC-cou-

pled single-ended signals presented at the input.

Configure the EV kit to support this mode of operation

by completing the steps below:

1) Cut the trace at locations R11, R12, R13, and R14.

2) Install 0Ω resistors at locations R7, R8, R9, R10,

R15, and R16.

3) Install 2kΩ ±1% resistors at locations R21, R22,

R23, and R24.

4) Connect the single-ended sources to J2 (I channel)

and J5 (Q channel).

Configure the EV kit for DC-coupled single-ended sig-

nals by removing capacitors C1 and C2, removing

resistors R9 and R10, and installing 0Ω resistors at

locations R5 and R6.

Tx DAC Outputs

By default, on-board ultra-low-distortion op amps (U4

and U5) buffer the DAC outputs on the MAX19700 EV

kit. The op amps convert the differential signal from the

MAX19700 to a single-ended 50Ω signal. Measure the

buffered output signals at J8 (Q channel) and J9

(I channel).

Measure the differential output of the MAX19700 at the

IDN/IDP and QDN/QDP pads. Full-scale output, offset

voltage, and common-mode voltage functions are con-

trolled through the MAX19700 EV kit software.

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