Maxim USBTO232 Uživatelská příručka stáhnout pdf (Strana 7)

Evaluate: MAX1304–MAX1315

MAX1308 Evaluation Kit/Evaluation System

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The input buffers require a +5.5V positive supply

(HVAVCC) and a -5.5V negative supply (HVAVEE). The

positive supply for the input buffers must be applied on

the HVAVCC pad or connected to AVDD using JU16.

The negative supply must be applied on the HVAVEE

pad. Connect the ground for these supplies to the

AGND pad.

Jumpers on the EV kit allow evaluation of all the parts in

the MAX1304–MAX1315 family. When changing between

parts in the family, JU1 and JU13 must be set according

to whether the IC accepts bipolar or unipolar inputs.

If the IC has less than eight input channels (i.e., four

channels or two channels), the unused input pins can

be connected to AGND or left floating. Note that if the

inputs are buffered and exceed ±5V (i.e., when using

the MAX1312–MAX1315 that support inputs up to

±10V), replace the MAX4351 buffers (U2–U5) with

buffers capable of ±10V voltage range.

The MAX1308 on the EV kit uses the on-board

MAX6126 2.5V reference instead of its internal refer-

ence when shipped. To use the MAX1308’s internal

2.5V reference, remove the shunt from JU2. The user

can also use an external reference by first removing the

shunt from JU2 and applying the reference voltage to

the REF pad. When using a non-default reference

value, the user must update the value in the EV kit soft-

ware’s References box.

A logic analyzer can be used instead of the

68HC16MOD-16WIDE to evaluate the MAX1308 EV kit.

For this configuration, disconnect the EV kit from the

68HC16MOD-16WIDE and connect the logic analyzer

to J1 and J2. These headers allow access to the

MAX1308 control (J1) and data (J2) pins.

When shipped, the MAX1308 EV kit is set to use the

MAX1308 internal clock, but an external clock can be

supported. To use an external clock, connect the clock

signal to the ECLK SMA connector, remove the shunt

from JU4, and set the shunt on JU14 to the 2-3 position.

In this configuration, the 68HC16MOD-16WIDE can no

longer be used and the user must supply a parallel

interface (i.e., a logic analyzer).

When not using the 68HC16MOD-16WIDE as the paral-

lel interface, the MAX1308 EV kit can be put into

autoread mode by placing a jumper on pins 1-2 of JU3.

In this mode, the MAX1308 EOC pin is connected to

the RD strobe and available samples are immediately

outputted on the parallel bus. When performing

autoread, the CS pin can be connected low by placing

a jumper between J1-9 and J1-10.

Note that when the 68HC16MOD-16WIDE is not being

used as the parallel interface, JU15 must be set to the

1-2 position and DVDD must be supplied between the

DVDD and DGND pads on the EV kit.

Jumper Selection Tables

The following tables (Tables 1–9) explain the functional-

ity of each jumper on the MAX1308 EV kit.

JUMPER

SHUNT

POSITION

DESCRIPTION

Short*

Select internal clock as ADC

system clock.

JU4

Open

Select external ECLK SMA as

ADC system clock.

Table 4. ADC Clock-Source Select

*Default configuration.

JUMPER

SHUNT

POSITION

DESCRIPTION

Short*

Midscale voltage is set for bipolar

inputs.

JU1

Open

Midscale voltage is set for unipolar

inputs.

Table 1. Midscale Voltage Select

*Default configuration.

JUMPER

SHUNT

POSITION

DESCRIPTION

Short*

Select on-board 2.5V reference

(MAX6126) as voltage reference.

JU2

Open

Select i nter nal 2.5V r efer ence or

exter nal RE F p ad as vol tag e

r efer ence. N ote that exter nal

r efer ence m ust b e b etw een 2V

and 3V .

Table 2. Reference Select

*Default configuration.

JUMPER

SHUNT

POSITION

DESCRIPTION

Short

Connects RD and EOC lines for

autoread mode.

JU3

Open* Disables autoread mode.

Table 3. Autoread Mode

*Default configuration.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Evaluate: MAX1304–MAX1315 1

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