MAX1021 datasheet(32/40 Pages) MAXIM

32 / 40 page

10-Bit, Multichannel ADCs/DACs with FIFO,

Temperature Sensing, and GPIO Ports

______________________________________________________________________________________

Set

CNVST high to begin a conversion. Sampling is

completed approximately 500ns after

CNVST goes

high. After the conversion is complete, the ADC shuts

down and pulls

EOC low. EOC stays low until CS or

CNVST is pulled low again. Wait until EOC goes low

before pulling

CS or CNVST low. The number of CNVST

signals must equal the number of conversions request-

ed by the scan and averaging registers to correctly

update the FIFO. Wait until all conversions are com-

plete before reading the FIFO. SPI communications to

the DAC and GPIO registers are permitted during con-

version. However, coupled noise may result in degrad-

ed ADC SNR.

If averaging is turned on, multiple

CNVST pulses need to

be performed before a result is written to the FIFO. Once

the proper number of conversions has been performed

to generate an averaged FIFO result (as specified to the

averaging register), the scan logic automatically switch-

es the analog input multiplexer to the next requested

channel. If a temperature measurement is programmed,

it is performed after the first rising edge of

CNVST follow-

ing the command byte written to the conversion register.

The temperature-conversion result is available on DOUT

once

EOC has been pulled low. Temperature results are

available in 12-bit format.

Internally Timed Acquisitions and

Conversions Using the Serial Interface

ADC Conversions in Clock Mode 10

In clock mode 10, the wake-up, acquisition, conversion,

and shutdown sequence is initiated by writing a com-

mand byte to the conversion register, and is performed

automatically using the internal oscillator. This is the

default clock mode upon power-up. See Figure 8 for

clock mode 10 timing.

FULL-SCALE

TRANSITION

111....111

INPUT VOLTAGE (LSB)

FS = VREF

111....110

111....101

000....011

000....010

000....001

000....000

1 LSB = VREF / 1024

FS - 3/2 LSB

Figure 3. Unipolar Transfer Function—Full Scale (FS) = VREF

OUTPUT CODE

011....111

TEMPERATURE (

°C)

011....110

000....001

111....101

100....001

100....000

111....111

111....110

000....000

000....010

-256

+255.5

Figure 5. Temperature Transfer Function

011....111

-FS

INPUT VOLTAGE (LSB)

FS = VREF / 2 + VCOM

VREF = VREF+ - VREF-

-FS = -VREF / 2

011....110

011....101

000....001

000....000

111....111

100....011

100....010

100....001

100....000

(COM)

-1

+FS - 1 LSB

1 LSB = VREF / 1024

ZS = COM

VREF

(COM)

VREF

Figure 4. Bipolar Transfer Function—Full Scale (±FS) = ±VREF / 2

MAX1021 Datasheet(PDF) 32 Page - Maxim Integrated Products

MAX1021 Datasheet(HTML) 32 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Datasheet Download

Link URL