MAX144 Просмотр технического описания (PDF) - Maxim Integrated

Номер в каталоге

Компоненты Описание

производитель

MAX144

+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX

Maxim Integrated 

+2.7V, Low-Power, 2-Channel, 108ksps,

Serial 12-Bit ADCs in 8-Pin µMAX

DOUT valid timing characteristic. Data should be

clocked into the µP on SCLK’s rising edge.

4) Pull CS/SHDN high at or after the 16th falling clock

edge. If CS/SHDN remains low, trailing zeros will be

clocked out after the LSB.

5) With CS/SHDN high, wait at least 60ns (tCS) before

starting a new conversion by pulling CS/SHDN low.

A conversion can be aborted by pulling CS/SHDN

high before the conversion ends; wait at least 60ns

before starting a new conversion.

Data can be output in two 8-bit sequences or continu-

ously. The bytes will contain the result of the conversion

padded with three leading ones and the channel identi-

fication before the MSB. If the serial clock hasn’t been

idled after the last LSB and CS/SHDN is kept low,

DOUT sends trailing zeros.

SPI and MICROWIRE Interface

When using SPI (Figure 8a) or MICROWIRE (Figure 8b)

interfaces, set CPOL = 0 and CPHA = 0. Conversion

begins with a falling edge on CS/SHDN (Figure 8c).

Two consecutive 8-bit readings are necessary to obtain

the entire 12-bit result from the ADC. DOUT data transi-

tions on the serial clock’s falling edge and is clocked

into the µP on SCLK’s rising edge. The first 8-bit data

stream contains three leading ones, the channel identi-

CS/SHDN

SCLK

tSCLKS

•••

tCH

tCL

•••

tDV

DOUT

HIGH-Z

tDO

•••

Figure 7. Detailed Serial-Interface Timing Sequence

tCS

tTR

HIGH-Z

I/O

SCK

MISO

SPI

VDD

SS

CS/SHDN

SCLK

DOUT

MAX144

MAX145

I/O

SK

SI

MICROWIRE

CS/SHDN

SCLK

DOUT

MAX144

MAX145

Figure 8a. SPI Connections

8b. MICROWIRE Connections

SCLK

CS/SHDN

1ST BYTE READ

1 2345678

DOUT*

CHID D11 D10 D9 D8

D7

SAMPLING INSTANT MSB

*WHEN CS/SHDN IS HIGH, DOUT = HIGH-Z

Figure 8c. SPI/MICROWIRE Interface Timing Sequence (CPOL = CPHA = 0)

2ND BYTE READ

9 10 11 12 13 14 15 16

D6 D5 D4 D3 D2 D1 D0

LSB

HIGH-Z

______________________________________________________________________________________ 11

Share Link: