Rainbow-electronics MAX152 Manual de usuario descargar pdf (Pagina 7)

MAX152

+3V, 8-Bit ADC with 1µA Power-Down

_______________________________________________________________________________________ 7

Once the MAX152 is in power-down mode, lowest sup-

ply current is drawn with MODE low (RD mode) due to

an internal pull-down resistor at this pin. In addition, for

minimum current consumption, other digital inputs

should remain high in power-down. Refer to the

Reference

section for information on reducing refer-

ence current during power-down.

___________________Digital Interface

The MAX152 has two basic interface modes set by the

status of the MODE input pin. When MODE is low, the

converter is in the RD mode; when MODE is high, the

converter is set up for the WR-RD mode.

Read Mode (MODE = 0)

In RD mode, conversion control and data access are

controlled by the RD input (Figure 3). The comparator

inputs track the analog input voltage for the duration of

. A conversion is initiated by driving RD low. With µPs

that can be forced into a wait state, hold RD low until

output data appears. The µP starts the conversion,

waits, and then reads data with a single read instruction.

WR/RDY is configured as a status output (RDY) in RD

mode, where it can drive the ready or wait input of a

µP. RDY is an open-collector output (with no internal

pull-up) that goes low after the falling edge of CS and

goes high at the end of the conversion. If not used, the

WR/RDY pin can be left unconnected. The INT output

goes low at the end of the conversion and returns high

on the rising edge of CS or RD.

Write-Read Mode (MODE = 1)

Figures 4 and 5 show the operating sequence for the

write-read (WR-RD) mode. The comparator inputs

track the analog input voltage for the duration of t

The conversion is initiated by a falling edge of WR.

When WR returns high, the 4 MSBs' flash result is

latched into the output buffers and the 4 LSBs' conver-

sion begins. INT goes low, indicating conversion end,

and the lower 4 data bits are latched into the output

buffers. The data is then accessible after RD goes low

(see

Timing Characteristics

CSS

CSH

D0-D7

PWRDN

INT

VALID DATA

INTL

ACC2

Figure 4. WR-RD Mode Timing (t

> t

INTL

) (MODE = 1)

CSS

CSH

PWRDN

INT

VALID DATA

INTH

ACC1

CWR

Figure 5. WR-RD Mode Timing (t

< t

INTL

Fastest Operating

Mode (MODE = 1)

CSS

RDY

WITH EXTERNAL

PULL-UP

CSH

INTH

CRD

ACCO

D0-D7

RDY

PWRDN

INT

VALID DATA

Figure 3. RD Mode Timing (MODE = 0)

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

Comentarios a estos manuales

Sin comentarios

Rainbow-electronics MAX152 Manual de usuario Pagina 7

Comentarios a estos manuales

Relacionado con productos y manuales para Sensores Rainbow-electronics MAX152