Rainbow-electronics ADC10464 Manual do Utilizador descarregar pdf (Página 9)

Connection Diagrams

Dual-In-Line Package

TL/H/11108– 10

Top View

Dual-In-Line Package

TL/H/11108– 11

Top View

Dual-In-Line Package

TL/H/11108– 12

Top View

Pin Descriptions

DV

CC

,AV

CC

These are the digital and analog positive sup-

ply voltage inputs. They should always be

connected to the same voltage source, but

are brought out separately to allow for sepa-

rate bypass capacitors. Each supply pin

should be bypassed with a 0.1 mF ceramic

capacitor in parallel with a 10 mF tantalum

capacitor to ground.

INT

This is the active low interrupt output. INT

goes low at the end of each conversion, and

returns to a high state following the rising

edge of RD

.

S/H This is the Sample/Hold control input. When

this pin is forced low (and CS

is low), it caus-

es the analog input signal to be sampled and

initiates a new conversion.

RD

This is the active low Read control input.

When this RD

and CS are low, any data pres-

ent in the output registers will be placed on

the data bus.

CS

This is the active low Chip Select control in-

put. When low, this pin enables the RD

and

S

/H pins.

S0, S1 On the multiple-input devices (ADC10462

and ADC10464), these pins select the analog

input that will be connected to the A/D during

the conversion. The input is selected based

on the state of S0 and S1 when S

/H makes

its High-to-Low transition (See the Timing Di-

agrams). The ADC10464 includes both S0

and S1. The ADC10462 includes just S0, and

the ADC10461 includes neither.

V

REF

b

,

These are the reference voltage inputs. They

V

REF

a

may be placed at any voltage between GND

and V

CC

, but V

REF

a

must be greater than

V

REF

b

. An input voltage equal to V

REF

b

produces an output code of 0, and an input

voltage equal to (V

REF

a

b

1 LSB) produces

an output code of 1023.

V

IN

,V

IN0

, These are the analog input pins. The

V

IN1

,V

IN2

, ADC10461 has one input (V

IN

), the

V

IN3

ADC10462 has two inputs (V

IN0

and V

IN1

),

and the ADC10464 has four inputs (V

IN0

,

V

IN1

,V

IN2

and V

IN3

). The impedance of the

source should be less than 500X for best ac-

curacy and conversion speed. For accurate

conversions, no input pin (even one that is

not selected) should be driven more than

50 mV above V

CC

or 50 mV below ground.

GND, AGND, These are the power supply ground pins. The

DGND ADC10461 has a single ground pin (GND),

and the ADC10462 and ADC10464 have sep-

arate analog and digital ground pins (AGND

and DGND) for separate bypassing of the an-

alog and digital supplies. The ground pins

should be connected to a stable, noise-free

system ground. For the devices with two

ground pins, both pins should be returned to

the same potential.

DB0–DB9 These are the TRI-STATE output pins.

SPEED ADJ (ADC10462 and ADC10464 only). This pin is

normally left unconnected, but by connecting

a resistor between this pin and ground, the

conversion time can be reduced. See the

Typical Performance Curves and the table of

Electrical Characteristics.

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